root/drivers/tty/serial/serial_core.c

DEFINITIONS

1. uart_dcd_enabled
2. uart_port_ref
3. uart_port_deref
4. uart_port_check
5. uart_write_wakeup
6. uart_stop
7. __uart_start
8. uart_start
9. uart_update_mctrl
10. uart_port_dtr_rts
11. uart_port_startup
12. uart_startup
13. uart_shutdown
14. uart_update_timeout
15. uart_get_baud_rate
16. uart_get_divisor
17. uart_change_speed
18. uart_put_char
19. uart_flush_chars
20. uart_write
21. uart_write_room
22. uart_chars_in_buffer
23. uart_flush_buffer
24. uart_send_xchar
25. uart_throttle
26. uart_unthrottle
27. uart_get_info
28. uart_get_info_user
29. uart_set_info
30. uart_set_info_user
31. uart_get_lsr_info
32. uart_tiocmget
33. uart_tiocmset
34. uart_break_ctl
35. uart_do_autoconfig
36. uart_enable_ms
37. uart_wait_modem_status
38. uart_get_icount
39. uart_get_rs485_config
40. uart_set_rs485_config
41. uart_get_iso7816_config
42. uart_set_iso7816_config
43. uart_ioctl
44. uart_set_ldisc
45. uart_set_termios
46. uart_close
47. uart_tty_port_shutdown
48. uart_wait_until_sent
49. uart_hangup
50. uart_port_shutdown
51. uart_carrier_raised
52. uart_dtr_rts
53. uart_install
54. uart_open
55. uart_port_activate
56. uart_type
57. uart_line_info
58. uart_proc_show
59. uart_console_write
60. uart_get_console
61. uart_parse_earlycon
62. uart_parse_options
63. uart_set_options
64. uart_change_pm
65. serial_match_port
66. uart_suspend_port
67. uart_resume_port
68. uart_report_port
69. uart_configure_port
70. uart_poll_init
71. uart_poll_get_char
72. uart_poll_put_char
73. uart_register_driver
74. uart_unregister_driver
75. uart_console_device
76. uart_get_attr_uartclk
77. uart_get_attr_type
78. uart_get_attr_line
79. uart_get_attr_port
80. uart_get_attr_irq
81. uart_get_attr_flags
82. uart_get_attr_xmit_fifo_size
83. uart_get_attr_close_delay
84. uart_get_attr_closing_wait
85. uart_get_attr_custom_divisor
86. uart_get_attr_io_type
87. uart_get_attr_iomem_base
88. uart_get_attr_iomem_reg_shift
89. uart_add_one_port
90. uart_remove_one_port
91. uart_match_port
92. uart_handle_dcd_change
93. uart_handle_cts_change
94. uart_insert_char
95. uart_get_rs485_mode

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  Driver core for serial ports
   4  *
   5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   6  *
   7  *  Copyright 1999 ARM Limited
   8  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
   9  */
  10 #include <linux/module.h>
  11 #include <linux/tty.h>
  12 #include <linux/tty_flip.h>
  13 #include <linux/slab.h>
  14 #include <linux/sched/signal.h>
  15 #include <linux/init.h>
  16 #include <linux/console.h>
  17 #include <linux/of.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/device.h>
  21 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
  22 #include <linux/serial_core.h>
  23 #include <linux/delay.h>
  24 #include <linux/mutex.h>
  25 #include <linux/security.h>
  26 
  27 #include <linux/irq.h>
  28 #include <linux/uaccess.h>
  29 
  30 /*
  31  * This is used to lock changes in serial line configuration.
  32  */
  33 static DEFINE_MUTEX(port_mutex);
  34 
  35 /*
  36  * lockdep: port->lock is initialized in two places, but we
  37  *          want only one lock-class:
  38  */
  39 static struct lock_class_key port_lock_key;
  40 
  41 #define HIGH_BITS_OFFSET        ((sizeof(long)-sizeof(int))*8)
  42 
  43 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
  44                                         struct ktermios *old_termios);
  45 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
  46 static void uart_change_pm(struct uart_state *state,
  47                            enum uart_pm_state pm_state);
  48 
  49 static void uart_port_shutdown(struct tty_port *port);
  50 
  51 static int uart_dcd_enabled(struct uart_port *uport)
  52 {
  53         return !!(uport->status & UPSTAT_DCD_ENABLE);
  54 }
  55 
  56 static inline struct uart_port *uart_port_ref(struct uart_state *state)
  57 {
  58         if (atomic_add_unless(&state->refcount, 1, 0))
  59                 return state->uart_port;
  60         return NULL;
  61 }
  62 
  63 static inline void uart_port_deref(struct uart_port *uport)
  64 {
  65         if (atomic_dec_and_test(&uport->state->refcount))
  66                 wake_up(&uport->state->remove_wait);
  67 }
  68 
  69 #define uart_port_lock(state, flags)                                    \
  70         ({                                                              \
  71                 struct uart_port *__uport = uart_port_ref(state);       \
  72                 if (__uport)                                            \
  73                         spin_lock_irqsave(&__uport->lock, flags);       \
  74                 __uport;                                                \
  75         })
  76 
  77 #define uart_port_unlock(uport, flags)                                  \
  78         ({                                                              \
  79                 struct uart_port *__uport = uport;                      \
  80                 if (__uport) {                                          \
  81                         spin_unlock_irqrestore(&__uport->lock, flags);  \
  82                         uart_port_deref(__uport);                       \
  83                 }                                                       \
  84         })
  85 
  86 static inline struct uart_port *uart_port_check(struct uart_state *state)
  87 {
  88         lockdep_assert_held(&state->port.mutex);
  89         return state->uart_port;
  90 }
  91 
  92 /*
  93  * This routine is used by the interrupt handler to schedule processing in
  94  * the software interrupt portion of the driver.
  95  */
  96 void uart_write_wakeup(struct uart_port *port)
  97 {
  98         struct uart_state *state = port->state;
  99         /*
 100          * This means you called this function _after_ the port was
 101          * closed.  No cookie for you.
 102          */
 103         BUG_ON(!state);
 104         tty_port_tty_wakeup(&state->port);
 105 }
 106 
 107 static void uart_stop(struct tty_struct *tty)
 108 {
 109         struct uart_state *state = tty->driver_data;
 110         struct uart_port *port;
 111         unsigned long flags;
 112 
 113         port = uart_port_lock(state, flags);
 114         if (port)
 115                 port->ops->stop_tx(port);
 116         uart_port_unlock(port, flags);
 117 }
 118 
 119 static void __uart_start(struct tty_struct *tty)
 120 {
 121         struct uart_state *state = tty->driver_data;
 122         struct uart_port *port = state->uart_port;
 123 
 124         if (port && !uart_tx_stopped(port))
 125                 port->ops->start_tx(port);
 126 }
 127 
 128 static void uart_start(struct tty_struct *tty)
 129 {
 130         struct uart_state *state = tty->driver_data;
 131         struct uart_port *port;
 132         unsigned long flags;
 133 
 134         port = uart_port_lock(state, flags);
 135         __uart_start(tty);
 136         uart_port_unlock(port, flags);
 137 }
 138 
 139 static void
 140 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
 141 {
 142         unsigned long flags;
 143         unsigned int old;
 144 
 145         spin_lock_irqsave(&port->lock, flags);
 146         old = port->mctrl;
 147         port->mctrl = (old & ~clear) | set;
 148         if (old != port->mctrl)
 149                 port->ops->set_mctrl(port, port->mctrl);
 150         spin_unlock_irqrestore(&port->lock, flags);
 151 }
 152 
 153 #define uart_set_mctrl(port, set)       uart_update_mctrl(port, set, 0)
 154 #define uart_clear_mctrl(port, clear)   uart_update_mctrl(port, 0, clear)
 155 
 156 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
 157 {
 158         int rs485_on = uport->rs485_config &&
 159                 (uport->rs485.flags & SER_RS485_ENABLED);
 160         int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
 161 
 162         if (raise) {
 163                 if (rs485_on && !RTS_after_send) {
 164                         uart_set_mctrl(uport, TIOCM_DTR);
 165                         uart_clear_mctrl(uport, TIOCM_RTS);
 166                 } else {
 167                         uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
 168                 }
 169         } else {
 170                 unsigned int clear = TIOCM_DTR;
 171 
 172                 clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
 173                 uart_clear_mctrl(uport, clear);
 174         }
 175 }
 176 
 177 /*
 178  * Startup the port.  This will be called once per open.  All calls
 179  * will be serialised by the per-port mutex.
 180  */
 181 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 182                 int init_hw)
 183 {
 184         struct uart_port *uport = uart_port_check(state);
 185         unsigned long page;
 186         unsigned long flags = 0;
 187         int retval = 0;
 188 
 189         if (uport->type == PORT_UNKNOWN)
 190                 return 1;
 191 
 192         /*
 193          * Make sure the device is in D0 state.
 194          */
 195         uart_change_pm(state, UART_PM_STATE_ON);
 196 
 197         /*
 198          * Initialise and allocate the transmit and temporary
 199          * buffer.
 200          */
 201         page = get_zeroed_page(GFP_KERNEL);
 202         if (!page)
 203                 return -ENOMEM;
 204 
 205         uart_port_lock(state, flags);
 206         if (!state->xmit.buf) {
 207                 state->xmit.buf = (unsigned char *) page;
 208                 uart_circ_clear(&state->xmit);
 209                 uart_port_unlock(uport, flags);
 210         } else {
 211                 uart_port_unlock(uport, flags);
 212                 /*
 213                  * Do not free() the page under the port lock, see
 214                  * uart_shutdown().
 215                  */
 216                 free_page(page);
 217         }
 218 
 219         retval = uport->ops->startup(uport);
 220         if (retval == 0) {
 221                 if (uart_console(uport) && uport->cons->cflag) {
 222                         tty->termios.c_cflag = uport->cons->cflag;
 223                         uport->cons->cflag = 0;
 224                 }
 225                 /*
 226                  * Initialise the hardware port settings.
 227                  */
 228                 uart_change_speed(tty, state, NULL);
 229 
 230                 /*
 231                  * Setup the RTS and DTR signals once the
 232                  * port is open and ready to respond.
 233                  */
 234                 if (init_hw && C_BAUD(tty))
 235                         uart_port_dtr_rts(uport, 1);
 236         }
 237 
 238         /*
 239          * This is to allow setserial on this port. People may want to set
 240          * port/irq/type and then reconfigure the port properly if it failed
 241          * now.
 242          */
 243         if (retval && capable(CAP_SYS_ADMIN))
 244                 return 1;
 245 
 246         return retval;
 247 }
 248 
 249 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
 250                 int init_hw)
 251 {
 252         struct tty_port *port = &state->port;
 253         int retval;
 254 
 255         if (tty_port_initialized(port))
 256                 return 0;
 257 
 258         retval = uart_port_startup(tty, state, init_hw);
 259         if (retval)
 260                 set_bit(TTY_IO_ERROR, &tty->flags);
 261 
 262         return retval;
 263 }
 264 
 265 /*
 266  * This routine will shutdown a serial port; interrupts are disabled, and
 267  * DTR is dropped if the hangup on close termio flag is on.  Calls to
 268  * uart_shutdown are serialised by the per-port semaphore.
 269  *
 270  * uport == NULL if uart_port has already been removed
 271  */
 272 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 273 {
 274         struct uart_port *uport = uart_port_check(state);
 275         struct tty_port *port = &state->port;
 276         unsigned long flags = 0;
 277         char *xmit_buf = NULL;
 278 
 279         /*
 280          * Set the TTY IO error marker
 281          */
 282         if (tty)
 283                 set_bit(TTY_IO_ERROR, &tty->flags);
 284 
 285         if (tty_port_initialized(port)) {
 286                 tty_port_set_initialized(port, 0);
 287 
 288                 /*
 289                  * Turn off DTR and RTS early.
 290                  */
 291                 if (uport && uart_console(uport) && tty)
 292                         uport->cons->cflag = tty->termios.c_cflag;
 293 
 294                 if (!tty || C_HUPCL(tty))
 295                         uart_port_dtr_rts(uport, 0);
 296 
 297                 uart_port_shutdown(port);
 298         }
 299 
 300         /*
 301          * It's possible for shutdown to be called after suspend if we get
 302          * a DCD drop (hangup) at just the right time.  Clear suspended bit so
 303          * we don't try to resume a port that has been shutdown.
 304          */
 305         tty_port_set_suspended(port, 0);
 306 
 307         /*
 308          * Do not free() the transmit buffer page under the port lock since
 309          * this can create various circular locking scenarios. For instance,
 310          * console driver may need to allocate/free a debug object, which
 311          * can endup in printk() recursion.
 312          */
 313         uart_port_lock(state, flags);
 314         xmit_buf = state->xmit.buf;
 315         state->xmit.buf = NULL;
 316         uart_port_unlock(uport, flags);
 317 
 318         if (xmit_buf)
 319                 free_page((unsigned long)xmit_buf);
 320 }
 321 
 322 /**
 323  *      uart_update_timeout - update per-port FIFO timeout.
 324  *      @port:  uart_port structure describing the port
 325  *      @cflag: termios cflag value
 326  *      @baud:  speed of the port
 327  *
 328  *      Set the port FIFO timeout value.  The @cflag value should
 329  *      reflect the actual hardware settings.
 330  */
 331 void
 332 uart_update_timeout(struct uart_port *port, unsigned int cflag,
 333                     unsigned int baud)
 334 {
 335         unsigned int bits;
 336 
 337         /* byte size and parity */
 338         switch (cflag & CSIZE) {
 339         case CS5:
 340                 bits = 7;
 341                 break;
 342         case CS6:
 343                 bits = 8;
 344                 break;
 345         case CS7:
 346                 bits = 9;
 347                 break;
 348         default:
 349                 bits = 10;
 350                 break; /* CS8 */
 351         }
 352 
 353         if (cflag & CSTOPB)
 354                 bits++;
 355         if (cflag & PARENB)
 356                 bits++;
 357 
 358         /*
 359          * The total number of bits to be transmitted in the fifo.
 360          */
 361         bits = bits * port->fifosize;
 362 
 363         /*
 364          * Figure the timeout to send the above number of bits.
 365          * Add .02 seconds of slop
 366          */
 367         port->timeout = (HZ * bits) / baud + HZ/50;
 368 }
 369 
 370 EXPORT_SYMBOL(uart_update_timeout);
 371 
 372 /**
 373  *      uart_get_baud_rate - return baud rate for a particular port
 374  *      @port: uart_port structure describing the port in question.
 375  *      @termios: desired termios settings.
 376  *      @old: old termios (or NULL)
 377  *      @min: minimum acceptable baud rate
 378  *      @max: maximum acceptable baud rate
 379  *
 380  *      Decode the termios structure into a numeric baud rate,
 381  *      taking account of the magic 38400 baud rate (with spd_*
 382  *      flags), and mapping the %B0 rate to 9600 baud.
 383  *
 384  *      If the new baud rate is invalid, try the old termios setting.
 385  *      If it's still invalid, we try 9600 baud.
 386  *
 387  *      Update the @termios structure to reflect the baud rate
 388  *      we're actually going to be using. Don't do this for the case
 389  *      where B0 is requested ("hang up").
 390  */
 391 unsigned int
 392 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 393                    struct ktermios *old, unsigned int min, unsigned int max)
 394 {
 395         unsigned int try;
 396         unsigned int baud;
 397         unsigned int altbaud;
 398         int hung_up = 0;
 399         upf_t flags = port->flags & UPF_SPD_MASK;
 400 
 401         switch (flags) {
 402         case UPF_SPD_HI:
 403                 altbaud = 57600;
 404                 break;
 405         case UPF_SPD_VHI:
 406                 altbaud = 115200;
 407                 break;
 408         case UPF_SPD_SHI:
 409                 altbaud = 230400;
 410                 break;
 411         case UPF_SPD_WARP:
 412                 altbaud = 460800;
 413                 break;
 414         default:
 415                 altbaud = 38400;
 416                 break;
 417         }
 418 
 419         for (try = 0; try < 2; try++) {
 420                 baud = tty_termios_baud_rate(termios);
 421 
 422                 /*
 423                  * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
 424                  * Die! Die! Die!
 425                  */
 426                 if (try == 0 && baud == 38400)
 427                         baud = altbaud;
 428 
 429                 /*
 430                  * Special case: B0 rate.
 431                  */
 432                 if (baud == 0) {
 433                         hung_up = 1;
 434                         baud = 9600;
 435                 }
 436 
 437                 if (baud >= min && baud <= max)
 438                         return baud;
 439 
 440                 /*
 441                  * Oops, the quotient was zero.  Try again with
 442                  * the old baud rate if possible.
 443                  */
 444                 termios->c_cflag &= ~CBAUD;
 445                 if (old) {
 446                         baud = tty_termios_baud_rate(old);
 447                         if (!hung_up)
 448                                 tty_termios_encode_baud_rate(termios,
 449                                                                 baud, baud);
 450                         old = NULL;
 451                         continue;
 452                 }
 453 
 454                 /*
 455                  * As a last resort, if the range cannot be met then clip to
 456                  * the nearest chip supported rate.
 457                  */
 458                 if (!hung_up) {
 459                         if (baud <= min)
 460                                 tty_termios_encode_baud_rate(termios,
 461                                                         min + 1, min + 1);
 462                         else
 463                                 tty_termios_encode_baud_rate(termios,
 464                                                         max - 1, max - 1);
 465                 }
 466         }
 467         /* Should never happen */
 468         WARN_ON(1);
 469         return 0;
 470 }
 471 
 472 EXPORT_SYMBOL(uart_get_baud_rate);
 473 
 474 /**
 475  *      uart_get_divisor - return uart clock divisor
 476  *      @port: uart_port structure describing the port.
 477  *      @baud: desired baud rate
 478  *
 479  *      Calculate the uart clock divisor for the port.
 480  */
 481 unsigned int
 482 uart_get_divisor(struct uart_port *port, unsigned int baud)
 483 {
 484         unsigned int quot;
 485 
 486         /*
 487          * Old custom speed handling.
 488          */
 489         if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
 490                 quot = port->custom_divisor;
 491         else
 492                 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
 493 
 494         return quot;
 495 }
 496 
 497 EXPORT_SYMBOL(uart_get_divisor);
 498 
 499 /* Caller holds port mutex */
 500 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
 501                                         struct ktermios *old_termios)
 502 {
 503         struct uart_port *uport = uart_port_check(state);
 504         struct ktermios *termios;
 505         int hw_stopped;
 506 
 507         /*
 508          * If we have no tty, termios, or the port does not exist,
 509          * then we can't set the parameters for this port.
 510          */
 511         if (!tty || uport->type == PORT_UNKNOWN)
 512                 return;
 513 
 514         termios = &tty->termios;
 515         uport->ops->set_termios(uport, termios, old_termios);
 516 
 517         /*
 518          * Set modem status enables based on termios cflag
 519          */
 520         spin_lock_irq(&uport->lock);
 521         if (termios->c_cflag & CRTSCTS)
 522                 uport->status |= UPSTAT_CTS_ENABLE;
 523         else
 524                 uport->status &= ~UPSTAT_CTS_ENABLE;
 525 
 526         if (termios->c_cflag & CLOCAL)
 527                 uport->status &= ~UPSTAT_DCD_ENABLE;
 528         else
 529                 uport->status |= UPSTAT_DCD_ENABLE;
 530 
 531         /* reset sw-assisted CTS flow control based on (possibly) new mode */
 532         hw_stopped = uport->hw_stopped;
 533         uport->hw_stopped = uart_softcts_mode(uport) &&
 534                                 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
 535         if (uport->hw_stopped) {
 536                 if (!hw_stopped)
 537                         uport->ops->stop_tx(uport);
 538         } else {
 539                 if (hw_stopped)
 540                         __uart_start(tty);
 541         }
 542         spin_unlock_irq(&uport->lock);
 543 }
 544 
 545 static int uart_put_char(struct tty_struct *tty, unsigned char c)
 546 {
 547         struct uart_state *state = tty->driver_data;
 548         struct uart_port *port;
 549         struct circ_buf *circ;
 550         unsigned long flags;
 551         int ret = 0;
 552 
 553         circ = &state->xmit;
 554         port = uart_port_lock(state, flags);
 555         if (!circ->buf) {
 556                 uart_port_unlock(port, flags);
 557                 return 0;
 558         }
 559 
 560         if (port && uart_circ_chars_free(circ) != 0) {
 561                 circ->buf[circ->head] = c;
 562                 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
 563                 ret = 1;
 564         }
 565         uart_port_unlock(port, flags);
 566         return ret;
 567 }
 568 
 569 static void uart_flush_chars(struct tty_struct *tty)
 570 {
 571         uart_start(tty);
 572 }
 573 
 574 static int uart_write(struct tty_struct *tty,
 575                                         const unsigned char *buf, int count)
 576 {
 577         struct uart_state *state = tty->driver_data;
 578         struct uart_port *port;
 579         struct circ_buf *circ;
 580         unsigned long flags;
 581         int c, ret = 0;
 582 
 583         /*
 584          * This means you called this function _after_ the port was
 585          * closed.  No cookie for you.
 586          */
 587         if (!state) {
 588                 WARN_ON(1);
 589                 return -EL3HLT;
 590         }
 591 
 592         port = uart_port_lock(state, flags);
 593         circ = &state->xmit;
 594         if (!circ->buf) {
 595                 uart_port_unlock(port, flags);
 596                 return 0;
 597         }
 598 
 599         while (port) {
 600                 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
 601                 if (count < c)
 602                         c = count;
 603                 if (c <= 0)
 604                         break;
 605                 memcpy(circ->buf + circ->head, buf, c);
 606                 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
 607                 buf += c;
 608                 count -= c;
 609                 ret += c;
 610         }
 611 
 612         __uart_start(tty);
 613         uart_port_unlock(port, flags);
 614         return ret;
 615 }
 616 
 617 static int uart_write_room(struct tty_struct *tty)
 618 {
 619         struct uart_state *state = tty->driver_data;
 620         struct uart_port *port;
 621         unsigned long flags;
 622         int ret;
 623 
 624         port = uart_port_lock(state, flags);
 625         ret = uart_circ_chars_free(&state->xmit);
 626         uart_port_unlock(port, flags);
 627         return ret;
 628 }
 629 
 630 static int uart_chars_in_buffer(struct tty_struct *tty)
 631 {
 632         struct uart_state *state = tty->driver_data;
 633         struct uart_port *port;
 634         unsigned long flags;
 635         int ret;
 636 
 637         port = uart_port_lock(state, flags);
 638         ret = uart_circ_chars_pending(&state->xmit);
 639         uart_port_unlock(port, flags);
 640         return ret;
 641 }
 642 
 643 static void uart_flush_buffer(struct tty_struct *tty)
 644 {
 645         struct uart_state *state = tty->driver_data;
 646         struct uart_port *port;
 647         unsigned long flags;
 648 
 649         /*
 650          * This means you called this function _after_ the port was
 651          * closed.  No cookie for you.
 652          */
 653         if (!state) {
 654                 WARN_ON(1);
 655                 return;
 656         }
 657 
 658         pr_debug("uart_flush_buffer(%d) called\n", tty->index);
 659 
 660         port = uart_port_lock(state, flags);
 661         if (!port)
 662                 return;
 663         uart_circ_clear(&state->xmit);
 664         if (port->ops->flush_buffer)
 665                 port->ops->flush_buffer(port);
 666         uart_port_unlock(port, flags);
 667         tty_port_tty_wakeup(&state->port);
 668 }
 669 
 670 /*
 671  * This function is used to send a high-priority XON/XOFF character to
 672  * the device
 673  */
 674 static void uart_send_xchar(struct tty_struct *tty, char ch)
 675 {
 676         struct uart_state *state = tty->driver_data;
 677         struct uart_port *port;
 678         unsigned long flags;
 679 
 680         port = uart_port_ref(state);
 681         if (!port)
 682                 return;
 683 
 684         if (port->ops->send_xchar)
 685                 port->ops->send_xchar(port, ch);
 686         else {
 687                 spin_lock_irqsave(&port->lock, flags);
 688                 port->x_char = ch;
 689                 if (ch)
 690                         port->ops->start_tx(port);
 691                 spin_unlock_irqrestore(&port->lock, flags);
 692         }
 693         uart_port_deref(port);
 694 }
 695 
 696 static void uart_throttle(struct tty_struct *tty)
 697 {
 698         struct uart_state *state = tty->driver_data;
 699         upstat_t mask = UPSTAT_SYNC_FIFO;
 700         struct uart_port *port;
 701 
 702         port = uart_port_ref(state);
 703         if (!port)
 704                 return;
 705 
 706         if (I_IXOFF(tty))
 707                 mask |= UPSTAT_AUTOXOFF;
 708         if (C_CRTSCTS(tty))
 709                 mask |= UPSTAT_AUTORTS;
 710 
 711         if (port->status & mask) {
 712                 port->ops->throttle(port);
 713                 mask &= ~port->status;
 714         }
 715 
 716         if (mask & UPSTAT_AUTORTS)
 717                 uart_clear_mctrl(port, TIOCM_RTS);
 718 
 719         if (mask & UPSTAT_AUTOXOFF)
 720                 uart_send_xchar(tty, STOP_CHAR(tty));
 721 
 722         uart_port_deref(port);
 723 }
 724 
 725 static void uart_unthrottle(struct tty_struct *tty)
 726 {
 727         struct uart_state *state = tty->driver_data;
 728         upstat_t mask = UPSTAT_SYNC_FIFO;
 729         struct uart_port *port;
 730 
 731         port = uart_port_ref(state);
 732         if (!port)
 733                 return;
 734 
 735         if (I_IXOFF(tty))
 736                 mask |= UPSTAT_AUTOXOFF;
 737         if (C_CRTSCTS(tty))
 738                 mask |= UPSTAT_AUTORTS;
 739 
 740         if (port->status & mask) {
 741                 port->ops->unthrottle(port);
 742                 mask &= ~port->status;
 743         }
 744 
 745         if (mask & UPSTAT_AUTORTS)
 746                 uart_set_mctrl(port, TIOCM_RTS);
 747 
 748         if (mask & UPSTAT_AUTOXOFF)
 749                 uart_send_xchar(tty, START_CHAR(tty));
 750 
 751         uart_port_deref(port);
 752 }
 753 
 754 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
 755 {
 756         struct uart_state *state = container_of(port, struct uart_state, port);
 757         struct uart_port *uport;
 758         int ret = -ENODEV;
 759 
 760         memset(retinfo, 0, sizeof(*retinfo));
 761 
 762         /*
 763          * Ensure the state we copy is consistent and no hardware changes
 764          * occur as we go
 765          */
 766         mutex_lock(&port->mutex);
 767         uport = uart_port_check(state);
 768         if (!uport)
 769                 goto out;
 770 
 771         retinfo->type       = uport->type;
 772         retinfo->line       = uport->line;
 773         retinfo->port       = uport->iobase;
 774         if (HIGH_BITS_OFFSET)
 775                 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
 776         retinfo->irq                = uport->irq;
 777         retinfo->flags      = (__force int)uport->flags;
 778         retinfo->xmit_fifo_size  = uport->fifosize;
 779         retinfo->baud_base          = uport->uartclk / 16;
 780         retinfo->close_delay        = jiffies_to_msecs(port->close_delay) / 10;
 781         retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 782                                 ASYNC_CLOSING_WAIT_NONE :
 783                                 jiffies_to_msecs(port->closing_wait) / 10;
 784         retinfo->custom_divisor  = uport->custom_divisor;
 785         retinfo->hub6       = uport->hub6;
 786         retinfo->io_type         = uport->iotype;
 787         retinfo->iomem_reg_shift = uport->regshift;
 788         retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
 789 
 790         ret = 0;
 791 out:
 792         mutex_unlock(&port->mutex);
 793         return ret;
 794 }
 795 
 796 static int uart_get_info_user(struct tty_struct *tty,
 797                          struct serial_struct *ss)
 798 {
 799         struct uart_state *state = tty->driver_data;
 800         struct tty_port *port = &state->port;
 801 
 802         return uart_get_info(port, ss) < 0 ? -EIO : 0;
 803 }
 804 
 805 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 806                          struct uart_state *state,
 807                          struct serial_struct *new_info)
 808 {
 809         struct uart_port *uport = uart_port_check(state);
 810         unsigned long new_port;
 811         unsigned int change_irq, change_port, closing_wait;
 812         unsigned int old_custom_divisor, close_delay;
 813         upf_t old_flags, new_flags;
 814         int retval = 0;
 815 
 816         if (!uport)
 817                 return -EIO;
 818 
 819         new_port = new_info->port;
 820         if (HIGH_BITS_OFFSET)
 821                 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
 822 
 823         new_info->irq = irq_canonicalize(new_info->irq);
 824         close_delay = msecs_to_jiffies(new_info->close_delay * 10);
 825         closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
 826                         ASYNC_CLOSING_WAIT_NONE :
 827                         msecs_to_jiffies(new_info->closing_wait * 10);
 828 
 829 
 830         change_irq  = !(uport->flags & UPF_FIXED_PORT)
 831                 && new_info->irq != uport->irq;
 832 
 833         /*
 834          * Since changing the 'type' of the port changes its resource
 835          * allocations, we should treat type changes the same as
 836          * IO port changes.
 837          */
 838         change_port = !(uport->flags & UPF_FIXED_PORT)
 839                 && (new_port != uport->iobase ||
 840                     (unsigned long)new_info->iomem_base != uport->mapbase ||
 841                     new_info->hub6 != uport->hub6 ||
 842                     new_info->io_type != uport->iotype ||
 843                     new_info->iomem_reg_shift != uport->regshift ||
 844                     new_info->type != uport->type);
 845 
 846         old_flags = uport->flags;
 847         new_flags = (__force upf_t)new_info->flags;
 848         old_custom_divisor = uport->custom_divisor;
 849 
 850         if (!capable(CAP_SYS_ADMIN)) {
 851                 retval = -EPERM;
 852                 if (change_irq || change_port ||
 853                     (new_info->baud_base != uport->uartclk / 16) ||
 854                     (close_delay != port->close_delay) ||
 855                     (closing_wait != port->closing_wait) ||
 856                     (new_info->xmit_fifo_size &&
 857                      new_info->xmit_fifo_size != uport->fifosize) ||
 858                     (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
 859                         goto exit;
 860                 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
 861                                (new_flags & UPF_USR_MASK));
 862                 uport->custom_divisor = new_info->custom_divisor;
 863                 goto check_and_exit;
 864         }
 865 
 866         retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
 867         if (retval && (change_irq || change_port))
 868                 goto exit;
 869 
 870         /*
 871          * Ask the low level driver to verify the settings.
 872          */
 873         if (uport->ops->verify_port)
 874                 retval = uport->ops->verify_port(uport, new_info);
 875 
 876         if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
 877             (new_info->baud_base < 9600))
 878                 retval = -EINVAL;
 879 
 880         if (retval)
 881                 goto exit;
 882 
 883         if (change_port || change_irq) {
 884                 retval = -EBUSY;
 885 
 886                 /*
 887                  * Make sure that we are the sole user of this port.
 888                  */
 889                 if (tty_port_users(port) > 1)
 890                         goto exit;
 891 
 892                 /*
 893                  * We need to shutdown the serial port at the old
 894                  * port/type/irq combination.
 895                  */
 896                 uart_shutdown(tty, state);
 897         }
 898 
 899         if (change_port) {
 900                 unsigned long old_iobase, old_mapbase;
 901                 unsigned int old_type, old_iotype, old_hub6, old_shift;
 902 
 903                 old_iobase = uport->iobase;
 904                 old_mapbase = uport->mapbase;
 905                 old_type = uport->type;
 906                 old_hub6 = uport->hub6;
 907                 old_iotype = uport->iotype;
 908                 old_shift = uport->regshift;
 909 
 910                 /*
 911                  * Free and release old regions
 912                  */
 913                 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
 914                         uport->ops->release_port(uport);
 915 
 916                 uport->iobase = new_port;
 917                 uport->type = new_info->type;
 918                 uport->hub6 = new_info->hub6;
 919                 uport->iotype = new_info->io_type;
 920                 uport->regshift = new_info->iomem_reg_shift;
 921                 uport->mapbase = (unsigned long)new_info->iomem_base;
 922 
 923                 /*
 924                  * Claim and map the new regions
 925                  */
 926                 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
 927                         retval = uport->ops->request_port(uport);
 928                 } else {
 929                         /* Always success - Jean II */
 930                         retval = 0;
 931                 }
 932 
 933                 /*
 934                  * If we fail to request resources for the
 935                  * new port, try to restore the old settings.
 936                  */
 937                 if (retval) {
 938                         uport->iobase = old_iobase;
 939                         uport->type = old_type;
 940                         uport->hub6 = old_hub6;
 941                         uport->iotype = old_iotype;
 942                         uport->regshift = old_shift;
 943                         uport->mapbase = old_mapbase;
 944 
 945                         if (old_type != PORT_UNKNOWN) {
 946                                 retval = uport->ops->request_port(uport);
 947                                 /*
 948                                  * If we failed to restore the old settings,
 949                                  * we fail like this.
 950                                  */
 951                                 if (retval)
 952                                         uport->type = PORT_UNKNOWN;
 953 
 954                                 /*
 955                                  * We failed anyway.
 956                                  */
 957                                 retval = -EBUSY;
 958                         }
 959 
 960                         /* Added to return the correct error -Ram Gupta */
 961                         goto exit;
 962                 }
 963         }
 964 
 965         if (change_irq)
 966                 uport->irq      = new_info->irq;
 967         if (!(uport->flags & UPF_FIXED_PORT))
 968                 uport->uartclk  = new_info->baud_base * 16;
 969         uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
 970                                  (new_flags & UPF_CHANGE_MASK);
 971         uport->custom_divisor   = new_info->custom_divisor;
 972         port->close_delay     = close_delay;
 973         port->closing_wait    = closing_wait;
 974         if (new_info->xmit_fifo_size)
 975                 uport->fifosize = new_info->xmit_fifo_size;
 976         port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
 977 
 978  check_and_exit:
 979         retval = 0;
 980         if (uport->type == PORT_UNKNOWN)
 981                 goto exit;
 982         if (tty_port_initialized(port)) {
 983                 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
 984                     old_custom_divisor != uport->custom_divisor) {
 985                         /*
 986                          * If they're setting up a custom divisor or speed,
 987                          * instead of clearing it, then bitch about it.
 988                          */
 989                         if (uport->flags & UPF_SPD_MASK) {
 990                                 dev_notice_ratelimited(uport->dev,
 991                                        "%s sets custom speed on %s. This is deprecated.\n",
 992                                       current->comm,
 993                                       tty_name(port->tty));
 994                         }
 995                         uart_change_speed(tty, state, NULL);
 996                 }
 997         } else {
 998                 retval = uart_startup(tty, state, 1);
 999                 if (retval == 0)
1000                         tty_port_set_initialized(port, true);
1001                 if (retval > 0)
1002                         retval = 0;
1003         }
1004  exit:
1005         return retval;
1006 }
1007 
1008 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1009 {
1010         struct uart_state *state = tty->driver_data;
1011         struct tty_port *port = &state->port;
1012         int retval;
1013 
1014         down_write(&tty->termios_rwsem);
1015         /*
1016          * This semaphore protects port->count.  It is also
1017          * very useful to prevent opens.  Also, take the
1018          * port configuration semaphore to make sure that a
1019          * module insertion/removal doesn't change anything
1020          * under us.
1021          */
1022         mutex_lock(&port->mutex);
1023         retval = uart_set_info(tty, port, state, ss);
1024         mutex_unlock(&port->mutex);
1025         up_write(&tty->termios_rwsem);
1026         return retval;
1027 }
1028 
1029 /**
1030  *      uart_get_lsr_info       -       get line status register info
1031  *      @tty: tty associated with the UART
1032  *      @state: UART being queried
1033  *      @value: returned modem value
1034  */
1035 static int uart_get_lsr_info(struct tty_struct *tty,
1036                         struct uart_state *state, unsigned int __user *value)
1037 {
1038         struct uart_port *uport = uart_port_check(state);
1039         unsigned int result;
1040 
1041         result = uport->ops->tx_empty(uport);
1042 
1043         /*
1044          * If we're about to load something into the transmit
1045          * register, we'll pretend the transmitter isn't empty to
1046          * avoid a race condition (depending on when the transmit
1047          * interrupt happens).
1048          */
1049         if (uport->x_char ||
1050             ((uart_circ_chars_pending(&state->xmit) > 0) &&
1051              !uart_tx_stopped(uport)))
1052                 result &= ~TIOCSER_TEMT;
1053 
1054         return put_user(result, value);
1055 }
1056 
1057 static int uart_tiocmget(struct tty_struct *tty)
1058 {
1059         struct uart_state *state = tty->driver_data;
1060         struct tty_port *port = &state->port;
1061         struct uart_port *uport;
1062         int result = -EIO;
1063 
1064         mutex_lock(&port->mutex);
1065         uport = uart_port_check(state);
1066         if (!uport)
1067                 goto out;
1068 
1069         if (!tty_io_error(tty)) {
1070                 result = uport->mctrl;
1071                 spin_lock_irq(&uport->lock);
1072                 result |= uport->ops->get_mctrl(uport);
1073                 spin_unlock_irq(&uport->lock);
1074         }
1075 out:
1076         mutex_unlock(&port->mutex);
1077         return result;
1078 }
1079 
1080 static int
1081 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1082 {
1083         struct uart_state *state = tty->driver_data;
1084         struct tty_port *port = &state->port;
1085         struct uart_port *uport;
1086         int ret = -EIO;
1087 
1088         mutex_lock(&port->mutex);
1089         uport = uart_port_check(state);
1090         if (!uport)
1091                 goto out;
1092 
1093         if (!tty_io_error(tty)) {
1094                 uart_update_mctrl(uport, set, clear);
1095                 ret = 0;
1096         }
1097 out:
1098         mutex_unlock(&port->mutex);
1099         return ret;
1100 }
1101 
1102 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1103 {
1104         struct uart_state *state = tty->driver_data;
1105         struct tty_port *port = &state->port;
1106         struct uart_port *uport;
1107         int ret = -EIO;
1108 
1109         mutex_lock(&port->mutex);
1110         uport = uart_port_check(state);
1111         if (!uport)
1112                 goto out;
1113 
1114         if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1115                 uport->ops->break_ctl(uport, break_state);
1116         ret = 0;
1117 out:
1118         mutex_unlock(&port->mutex);
1119         return ret;
1120 }
1121 
1122 static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
1123 {
1124         struct tty_port *port = &state->port;
1125         struct uart_port *uport;
1126         int flags, ret;
1127 
1128         if (!capable(CAP_SYS_ADMIN))
1129                 return -EPERM;
1130 
1131         /*
1132          * Take the per-port semaphore.  This prevents count from
1133          * changing, and hence any extra opens of the port while
1134          * we're auto-configuring.
1135          */
1136         if (mutex_lock_interruptible(&port->mutex))
1137                 return -ERESTARTSYS;
1138 
1139         uport = uart_port_check(state);
1140         if (!uport) {
1141                 ret = -EIO;
1142                 goto out;
1143         }
1144 
1145         ret = -EBUSY;
1146         if (tty_port_users(port) == 1) {
1147                 uart_shutdown(tty, state);
1148 
1149                 /*
1150                  * If we already have a port type configured,
1151                  * we must release its resources.
1152                  */
1153                 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1154                         uport->ops->release_port(uport);
1155 
1156                 flags = UART_CONFIG_TYPE;
1157                 if (uport->flags & UPF_AUTO_IRQ)
1158                         flags |= UART_CONFIG_IRQ;
1159 
1160                 /*
1161                  * This will claim the ports resources if
1162                  * a port is found.
1163                  */
1164                 uport->ops->config_port(uport, flags);
1165 
1166                 ret = uart_startup(tty, state, 1);
1167                 if (ret == 0)
1168                         tty_port_set_initialized(port, true);
1169                 if (ret > 0)
1170                         ret = 0;
1171         }
1172 out:
1173         mutex_unlock(&port->mutex);
1174         return ret;
1175 }
1176 
1177 static void uart_enable_ms(struct uart_port *uport)
1178 {
1179         /*
1180          * Force modem status interrupts on
1181          */
1182         if (uport->ops->enable_ms)
1183                 uport->ops->enable_ms(uport);
1184 }
1185 
1186 /*
1187  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1188  * - mask passed in arg for lines of interest
1189  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1190  * Caller should use TIOCGICOUNT to see which one it was
1191  *
1192  * FIXME: This wants extracting into a common all driver implementation
1193  * of TIOCMWAIT using tty_port.
1194  */
1195 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1196 {
1197         struct uart_port *uport;
1198         struct tty_port *port = &state->port;
1199         DECLARE_WAITQUEUE(wait, current);
1200         struct uart_icount cprev, cnow;
1201         int ret;
1202 
1203         /*
1204          * note the counters on entry
1205          */
1206         uport = uart_port_ref(state);
1207         if (!uport)
1208                 return -EIO;
1209         spin_lock_irq(&uport->lock);
1210         memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1211         uart_enable_ms(uport);
1212         spin_unlock_irq(&uport->lock);
1213 
1214         add_wait_queue(&port->delta_msr_wait, &wait);
1215         for (;;) {
1216                 spin_lock_irq(&uport->lock);
1217                 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1218                 spin_unlock_irq(&uport->lock);
1219 
1220                 set_current_state(TASK_INTERRUPTIBLE);
1221 
1222                 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1223                     ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1224                     ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1225                     ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1226                         ret = 0;
1227                         break;
1228                 }
1229 
1230                 schedule();
1231 
1232                 /* see if a signal did it */
1233                 if (signal_pending(current)) {
1234                         ret = -ERESTARTSYS;
1235                         break;
1236                 }
1237 
1238                 cprev = cnow;
1239         }
1240         __set_current_state(TASK_RUNNING);
1241         remove_wait_queue(&port->delta_msr_wait, &wait);
1242         uart_port_deref(uport);
1243 
1244         return ret;
1245 }
1246 
1247 /*
1248  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1249  * Return: write counters to the user passed counter struct
1250  * NB: both 1->0 and 0->1 transitions are counted except for
1251  *     RI where only 0->1 is counted.
1252  */
1253 static int uart_get_icount(struct tty_struct *tty,
1254                           struct serial_icounter_struct *icount)
1255 {
1256         struct uart_state *state = tty->driver_data;
1257         struct uart_icount cnow;
1258         struct uart_port *uport;
1259 
1260         uport = uart_port_ref(state);
1261         if (!uport)
1262                 return -EIO;
1263         spin_lock_irq(&uport->lock);
1264         memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1265         spin_unlock_irq(&uport->lock);
1266         uart_port_deref(uport);
1267 
1268         icount->cts         = cnow.cts;
1269         icount->dsr         = cnow.dsr;
1270         icount->rng         = cnow.rng;
1271         icount->dcd         = cnow.dcd;
1272         icount->rx          = cnow.rx;
1273         icount->tx          = cnow.tx;
1274         icount->frame       = cnow.frame;
1275         icount->overrun     = cnow.overrun;
1276         icount->parity      = cnow.parity;
1277         icount->brk         = cnow.brk;
1278         icount->buf_overrun = cnow.buf_overrun;
1279 
1280         return 0;
1281 }
1282 
1283 static int uart_get_rs485_config(struct uart_port *port,
1284                          struct serial_rs485 __user *rs485)
1285 {
1286         unsigned long flags;
1287         struct serial_rs485 aux;
1288 
1289         spin_lock_irqsave(&port->lock, flags);
1290         aux = port->rs485;
1291         spin_unlock_irqrestore(&port->lock, flags);
1292 
1293         if (copy_to_user(rs485, &aux, sizeof(aux)))
1294                 return -EFAULT;
1295 
1296         return 0;
1297 }
1298 
1299 static int uart_set_rs485_config(struct uart_port *port,
1300                          struct serial_rs485 __user *rs485_user)
1301 {
1302         struct serial_rs485 rs485;
1303         int ret;
1304         unsigned long flags;
1305 
1306         if (!port->rs485_config)
1307                 return -ENOIOCTLCMD;
1308 
1309         if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1310                 return -EFAULT;
1311 
1312         spin_lock_irqsave(&port->lock, flags);
1313         ret = port->rs485_config(port, &rs485);
1314         spin_unlock_irqrestore(&port->lock, flags);
1315         if (ret)
1316                 return ret;
1317 
1318         if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1319                 return -EFAULT;
1320 
1321         return 0;
1322 }
1323 
1324 static int uart_get_iso7816_config(struct uart_port *port,
1325                                    struct serial_iso7816 __user *iso7816)
1326 {
1327         unsigned long flags;
1328         struct serial_iso7816 aux;
1329 
1330         if (!port->iso7816_config)
1331                 return -ENOIOCTLCMD;
1332 
1333         spin_lock_irqsave(&port->lock, flags);
1334         aux = port->iso7816;
1335         spin_unlock_irqrestore(&port->lock, flags);
1336 
1337         if (copy_to_user(iso7816, &aux, sizeof(aux)))
1338                 return -EFAULT;
1339 
1340         return 0;
1341 }
1342 
1343 static int uart_set_iso7816_config(struct uart_port *port,
1344                                    struct serial_iso7816 __user *iso7816_user)
1345 {
1346         struct serial_iso7816 iso7816;
1347         int i, ret;
1348         unsigned long flags;
1349 
1350         if (!port->iso7816_config)
1351                 return -ENOIOCTLCMD;
1352 
1353         if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1354                 return -EFAULT;
1355 
1356         /*
1357          * There are 5 words reserved for future use. Check that userspace
1358          * doesn't put stuff in there to prevent breakages in the future.
1359          */
1360         for (i = 0; i < 5; i++)
1361                 if (iso7816.reserved[i])
1362                         return -EINVAL;
1363 
1364         spin_lock_irqsave(&port->lock, flags);
1365         ret = port->iso7816_config(port, &iso7816);
1366         spin_unlock_irqrestore(&port->lock, flags);
1367         if (ret)
1368                 return ret;
1369 
1370         if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1371                 return -EFAULT;
1372 
1373         return 0;
1374 }
1375 
1376 /*
1377  * Called via sys_ioctl.  We can use spin_lock_irq() here.
1378  */
1379 static int
1380 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1381 {
1382         struct uart_state *state = tty->driver_data;
1383         struct tty_port *port = &state->port;
1384         struct uart_port *uport;
1385         void __user *uarg = (void __user *)arg;
1386         int ret = -ENOIOCTLCMD;
1387 
1388 
1389         /*
1390          * These ioctls don't rely on the hardware to be present.
1391          */
1392         switch (cmd) {
1393         case TIOCSERCONFIG:
1394                 down_write(&tty->termios_rwsem);
1395                 ret = uart_do_autoconfig(tty, state);
1396                 up_write(&tty->termios_rwsem);
1397                 break;
1398         }
1399 
1400         if (ret != -ENOIOCTLCMD)
1401                 goto out;
1402 
1403         if (tty_io_error(tty)) {
1404                 ret = -EIO;
1405                 goto out;
1406         }
1407 
1408         /*
1409          * The following should only be used when hardware is present.
1410          */
1411         switch (cmd) {
1412         case TIOCMIWAIT:
1413                 ret = uart_wait_modem_status(state, arg);
1414                 break;
1415         }
1416 
1417         if (ret != -ENOIOCTLCMD)
1418                 goto out;
1419 
1420         mutex_lock(&port->mutex);
1421         uport = uart_port_check(state);
1422 
1423         if (!uport || tty_io_error(tty)) {
1424                 ret = -EIO;
1425                 goto out_up;
1426         }
1427 
1428         /*
1429          * All these rely on hardware being present and need to be
1430          * protected against the tty being hung up.
1431          */
1432 
1433         switch (cmd) {
1434         case TIOCSERGETLSR: /* Get line status register */
1435                 ret = uart_get_lsr_info(tty, state, uarg);
1436                 break;
1437 
1438         case TIOCGRS485:
1439                 ret = uart_get_rs485_config(uport, uarg);
1440                 break;
1441 
1442         case TIOCSRS485:
1443                 ret = uart_set_rs485_config(uport, uarg);
1444                 break;
1445 
1446         case TIOCSISO7816:
1447                 ret = uart_set_iso7816_config(state->uart_port, uarg);
1448                 break;
1449 
1450         case TIOCGISO7816:
1451                 ret = uart_get_iso7816_config(state->uart_port, uarg);
1452                 break;
1453         default:
1454                 if (uport->ops->ioctl)
1455                         ret = uport->ops->ioctl(uport, cmd, arg);
1456                 break;
1457         }
1458 out_up:
1459         mutex_unlock(&port->mutex);
1460 out:
1461         return ret;
1462 }
1463 
1464 static void uart_set_ldisc(struct tty_struct *tty)
1465 {
1466         struct uart_state *state = tty->driver_data;
1467         struct uart_port *uport;
1468 
1469         mutex_lock(&state->port.mutex);
1470         uport = uart_port_check(state);
1471         if (uport && uport->ops->set_ldisc)
1472                 uport->ops->set_ldisc(uport, &tty->termios);
1473         mutex_unlock(&state->port.mutex);
1474 }
1475 
1476 static void uart_set_termios(struct tty_struct *tty,
1477                                                 struct ktermios *old_termios)
1478 {
1479         struct uart_state *state = tty->driver_data;
1480         struct uart_port *uport;
1481         unsigned int cflag = tty->termios.c_cflag;
1482         unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1483         bool sw_changed = false;
1484 
1485         mutex_lock(&state->port.mutex);
1486         uport = uart_port_check(state);
1487         if (!uport)
1488                 goto out;
1489 
1490         /*
1491          * Drivers doing software flow control also need to know
1492          * about changes to these input settings.
1493          */
1494         if (uport->flags & UPF_SOFT_FLOW) {
1495                 iflag_mask |= IXANY|IXON|IXOFF;
1496                 sw_changed =
1497                    tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1498                    tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1499         }
1500 
1501         /*
1502          * These are the bits that are used to setup various
1503          * flags in the low level driver. We can ignore the Bfoo
1504          * bits in c_cflag; c_[io]speed will always be set
1505          * appropriately by set_termios() in tty_ioctl.c
1506          */
1507         if ((cflag ^ old_termios->c_cflag) == 0 &&
1508             tty->termios.c_ospeed == old_termios->c_ospeed &&
1509             tty->termios.c_ispeed == old_termios->c_ispeed &&
1510             ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1511             !sw_changed) {
1512                 goto out;
1513         }
1514 
1515         uart_change_speed(tty, state, old_termios);
1516         /* reload cflag from termios; port driver may have overridden flags */
1517         cflag = tty->termios.c_cflag;
1518 
1519         /* Handle transition to B0 status */
1520         if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1521                 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1522         /* Handle transition away from B0 status */
1523         else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1524                 unsigned int mask = TIOCM_DTR;
1525                 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1526                         mask |= TIOCM_RTS;
1527                 uart_set_mctrl(uport, mask);
1528         }
1529 out:
1530         mutex_unlock(&state->port.mutex);
1531 }
1532 
1533 /*
1534  * Calls to uart_close() are serialised via the tty_lock in
1535  *   drivers/tty/tty_io.c:tty_release()
1536  *   drivers/tty/tty_io.c:do_tty_hangup()
1537  */
1538 static void uart_close(struct tty_struct *tty, struct file *filp)
1539 {
1540         struct uart_state *state = tty->driver_data;
1541 
1542         if (!state) {
1543                 struct uart_driver *drv = tty->driver->driver_state;
1544                 struct tty_port *port;
1545 
1546                 state = drv->state + tty->index;
1547                 port = &state->port;
1548                 spin_lock_irq(&port->lock);
1549                 --port->count;
1550                 spin_unlock_irq(&port->lock);
1551                 return;
1552         }
1553 
1554         pr_debug("uart_close(%d) called\n", tty->index);
1555 
1556         tty_port_close(tty->port, tty, filp);
1557 }
1558 
1559 static void uart_tty_port_shutdown(struct tty_port *port)
1560 {
1561         struct uart_state *state = container_of(port, struct uart_state, port);
1562         struct uart_port *uport = uart_port_check(state);
1563 
1564         /*
1565          * At this point, we stop accepting input.  To do this, we
1566          * disable the receive line status interrupts.
1567          */
1568         if (WARN(!uport, "detached port still initialized!\n"))
1569                 return;
1570 
1571         spin_lock_irq(&uport->lock);
1572         uport->ops->stop_rx(uport);
1573         spin_unlock_irq(&uport->lock);
1574 
1575         uart_port_shutdown(port);
1576 
1577         /*
1578          * It's possible for shutdown to be called after suspend if we get
1579          * a DCD drop (hangup) at just the right time.  Clear suspended bit so
1580          * we don't try to resume a port that has been shutdown.
1581          */
1582         tty_port_set_suspended(port, 0);
1583 
1584         uart_change_pm(state, UART_PM_STATE_OFF);
1585 
1586 }
1587 
1588 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1589 {
1590         struct uart_state *state = tty->driver_data;
1591         struct uart_port *port;
1592         unsigned long char_time, expire;
1593 
1594         port = uart_port_ref(state);
1595         if (!port)
1596                 return;
1597 
1598         if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1599                 uart_port_deref(port);
1600                 return;
1601         }
1602 
1603         /*
1604          * Set the check interval to be 1/5 of the estimated time to
1605          * send a single character, and make it at least 1.  The check
1606          * interval should also be less than the timeout.
1607          *
1608          * Note: we have to use pretty tight timings here to satisfy
1609          * the NIST-PCTS.
1610          */
1611         char_time = (port->timeout - HZ/50) / port->fifosize;
1612         char_time = char_time / 5;
1613         if (char_time == 0)
1614                 char_time = 1;
1615         if (timeout && timeout < char_time)
1616                 char_time = timeout;
1617 
1618         /*
1619          * If the transmitter hasn't cleared in twice the approximate
1620          * amount of time to send the entire FIFO, it probably won't
1621          * ever clear.  This assumes the UART isn't doing flow
1622          * control, which is currently the case.  Hence, if it ever
1623          * takes longer than port->timeout, this is probably due to a
1624          * UART bug of some kind.  So, we clamp the timeout parameter at
1625          * 2*port->timeout.
1626          */
1627         if (timeout == 0 || timeout > 2 * port->timeout)
1628                 timeout = 2 * port->timeout;
1629 
1630         expire = jiffies + timeout;
1631 
1632         pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1633                 port->line, jiffies, expire);
1634 
1635         /*
1636          * Check whether the transmitter is empty every 'char_time'.
1637          * 'timeout' / 'expire' give us the maximum amount of time
1638          * we wait.
1639          */
1640         while (!port->ops->tx_empty(port)) {
1641                 msleep_interruptible(jiffies_to_msecs(char_time));
1642                 if (signal_pending(current))
1643                         break;
1644                 if (time_after(jiffies, expire))
1645                         break;
1646         }
1647         uart_port_deref(port);
1648 }
1649 
1650 /*
1651  * Calls to uart_hangup() are serialised by the tty_lock in
1652  *   drivers/tty/tty_io.c:do_tty_hangup()
1653  * This runs from a workqueue and can sleep for a _short_ time only.
1654  */
1655 static void uart_hangup(struct tty_struct *tty)
1656 {
1657         struct uart_state *state = tty->driver_data;
1658         struct tty_port *port = &state->port;
1659         struct uart_port *uport;
1660         unsigned long flags;
1661 
1662         pr_debug("uart_hangup(%d)\n", tty->index);
1663 
1664         mutex_lock(&port->mutex);
1665         uport = uart_port_check(state);
1666         WARN(!uport, "hangup of detached port!\n");
1667 
1668         if (tty_port_active(port)) {
1669                 uart_flush_buffer(tty);
1670                 uart_shutdown(tty, state);
1671                 spin_lock_irqsave(&port->lock, flags);
1672                 port->count = 0;
1673                 spin_unlock_irqrestore(&port->lock, flags);
1674                 tty_port_set_active(port, 0);
1675                 tty_port_tty_set(port, NULL);
1676                 if (uport && !uart_console(uport))
1677                         uart_change_pm(state, UART_PM_STATE_OFF);
1678                 wake_up_interruptible(&port->open_wait);
1679                 wake_up_interruptible(&port->delta_msr_wait);
1680         }
1681         mutex_unlock(&port->mutex);
1682 }
1683 
1684 /* uport == NULL if uart_port has already been removed */
1685 static void uart_port_shutdown(struct tty_port *port)
1686 {
1687         struct uart_state *state = container_of(port, struct uart_state, port);
1688         struct uart_port *uport = uart_port_check(state);
1689 
1690         /*
1691          * clear delta_msr_wait queue to avoid mem leaks: we may free
1692          * the irq here so the queue might never be woken up.  Note
1693          * that we won't end up waiting on delta_msr_wait again since
1694          * any outstanding file descriptors should be pointing at
1695          * hung_up_tty_fops now.
1696          */
1697         wake_up_interruptible(&port->delta_msr_wait);
1698 
1699         /*
1700          * Free the IRQ and disable the port.
1701          */
1702         if (uport)
1703                 uport->ops->shutdown(uport);
1704 
1705         /*
1706          * Ensure that the IRQ handler isn't running on another CPU.
1707          */
1708         if (uport)
1709                 synchronize_irq(uport->irq);
1710 }
1711 
1712 static int uart_carrier_raised(struct tty_port *port)
1713 {
1714         struct uart_state *state = container_of(port, struct uart_state, port);
1715         struct uart_port *uport;
1716         int mctrl;
1717 
1718         uport = uart_port_ref(state);
1719         /*
1720          * Should never observe uport == NULL since checks for hangup should
1721          * abort the tty_port_block_til_ready() loop before checking for carrier
1722          * raised -- but report carrier raised if it does anyway so open will
1723          * continue and not sleep
1724          */
1725         if (WARN_ON(!uport))
1726                 return 1;
1727         spin_lock_irq(&uport->lock);
1728         uart_enable_ms(uport);
1729         mctrl = uport->ops->get_mctrl(uport);
1730         spin_unlock_irq(&uport->lock);
1731         uart_port_deref(uport);
1732         if (mctrl & TIOCM_CAR)
1733                 return 1;
1734         return 0;
1735 }
1736 
1737 static void uart_dtr_rts(struct tty_port *port, int raise)
1738 {
1739         struct uart_state *state = container_of(port, struct uart_state, port);
1740         struct uart_port *uport;
1741 
1742         uport = uart_port_ref(state);
1743         if (!uport)
1744                 return;
1745         uart_port_dtr_rts(uport, raise);
1746         uart_port_deref(uport);
1747 }
1748 
1749 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1750 {
1751         struct uart_driver *drv = driver->driver_state;
1752         struct uart_state *state = drv->state + tty->index;
1753 
1754         tty->driver_data = state;
1755 
1756         return tty_standard_install(driver, tty);
1757 }
1758 
1759 /*
1760  * Calls to uart_open are serialised by the tty_lock in
1761  *   drivers/tty/tty_io.c:tty_open()
1762  * Note that if this fails, then uart_close() _will_ be called.
1763  *
1764  * In time, we want to scrap the "opening nonpresent ports"
1765  * behaviour and implement an alternative way for setserial
1766  * to set base addresses/ports/types.  This will allow us to
1767  * get rid of a certain amount of extra tests.
1768  */
1769 static int uart_open(struct tty_struct *tty, struct file *filp)
1770 {
1771         struct uart_state *state = tty->driver_data;
1772         int retval;
1773 
1774         retval = tty_port_open(&state->port, tty, filp);
1775         if (retval > 0)
1776                 retval = 0;
1777 
1778         return retval;
1779 }
1780 
1781 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1782 {
1783         struct uart_state *state = container_of(port, struct uart_state, port);
1784         struct uart_port *uport;
1785         int ret;
1786 
1787         uport = uart_port_check(state);
1788         if (!uport || uport->flags & UPF_DEAD)
1789                 return -ENXIO;
1790 
1791         port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
1792 
1793         /*
1794          * Start up the serial port.
1795          */
1796         ret = uart_startup(tty, state, 0);
1797         if (ret > 0)
1798                 tty_port_set_active(port, 1);
1799 
1800         return ret;
1801 }
1802 
1803 static const char *uart_type(struct uart_port *port)
1804 {
1805         const char *str = NULL;
1806 
1807         if (port->ops->type)
1808                 str = port->ops->type(port);
1809 
1810         if (!str)
1811                 str = "unknown";
1812 
1813         return str;
1814 }
1815 
1816 #ifdef CONFIG_PROC_FS
1817 
1818 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1819 {
1820         struct uart_state *state = drv->state + i;
1821         struct tty_port *port = &state->port;
1822         enum uart_pm_state pm_state;
1823         struct uart_port *uport;
1824         char stat_buf[32];
1825         unsigned int status;
1826         int mmio;
1827 
1828         mutex_lock(&port->mutex);
1829         uport = uart_port_check(state);
1830         if (!uport)
1831                 goto out;
1832 
1833         mmio = uport->iotype >= UPIO_MEM;
1834         seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1835                         uport->line, uart_type(uport),
1836                         mmio ? "mmio:0x" : "port:",
1837                         mmio ? (unsigned long long)uport->mapbase
1838                              : (unsigned long long)uport->iobase,
1839                         uport->irq);
1840 
1841         if (uport->type == PORT_UNKNOWN) {
1842                 seq_putc(m, '\n');
1843                 goto out;
1844         }
1845 
1846         if (capable(CAP_SYS_ADMIN)) {
1847                 pm_state = state->pm_state;
1848                 if (pm_state != UART_PM_STATE_ON)
1849                         uart_change_pm(state, UART_PM_STATE_ON);
1850                 spin_lock_irq(&uport->lock);
1851                 status = uport->ops->get_mctrl(uport);
1852                 spin_unlock_irq(&uport->lock);
1853                 if (pm_state != UART_PM_STATE_ON)
1854                         uart_change_pm(state, pm_state);
1855 
1856                 seq_printf(m, " tx:%d rx:%d",
1857                                 uport->icount.tx, uport->icount.rx);
1858                 if (uport->icount.frame)
1859                         seq_printf(m, " fe:%d", uport->icount.frame);
1860                 if (uport->icount.parity)
1861                         seq_printf(m, " pe:%d", uport->icount.parity);
1862                 if (uport->icount.brk)
1863                         seq_printf(m, " brk:%d", uport->icount.brk);
1864                 if (uport->icount.overrun)
1865                         seq_printf(m, " oe:%d", uport->icount.overrun);
1866                 if (uport->icount.buf_overrun)
1867                         seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1868 
1869 #define INFOBIT(bit, str) \
1870         if (uport->mctrl & (bit)) \
1871                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1872                         strlen(stat_buf) - 2)
1873 #define STATBIT(bit, str) \
1874         if (status & (bit)) \
1875                 strncat(stat_buf, (str), sizeof(stat_buf) - \
1876                        strlen(stat_buf) - 2)
1877 
1878                 stat_buf[0] = '\0';
1879                 stat_buf[1] = '\0';
1880                 INFOBIT(TIOCM_RTS, "|RTS");
1881                 STATBIT(TIOCM_CTS, "|CTS");
1882                 INFOBIT(TIOCM_DTR, "|DTR");
1883                 STATBIT(TIOCM_DSR, "|DSR");
1884                 STATBIT(TIOCM_CAR, "|CD");
1885                 STATBIT(TIOCM_RNG, "|RI");
1886                 if (stat_buf[0])
1887                         stat_buf[0] = ' ';
1888 
1889                 seq_puts(m, stat_buf);
1890         }
1891         seq_putc(m, '\n');
1892 #undef STATBIT
1893 #undef INFOBIT
1894 out:
1895         mutex_unlock(&port->mutex);
1896 }
1897 
1898 static int uart_proc_show(struct seq_file *m, void *v)
1899 {
1900         struct tty_driver *ttydrv = m->private;
1901         struct uart_driver *drv = ttydrv->driver_state;
1902         int i;
1903 
1904         seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1905         for (i = 0; i < drv->nr; i++)
1906                 uart_line_info(m, drv, i);
1907         return 0;
1908 }
1909 #endif
1910 
1911 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1912 /**
1913  *      uart_console_write - write a console message to a serial port
1914  *      @port: the port to write the message
1915  *      @s: array of characters
1916  *      @count: number of characters in string to write
1917  *      @putchar: function to write character to port
1918  */
1919 void uart_console_write(struct uart_port *port, const char *s,
1920                         unsigned int count,
1921                         void (*putchar)(struct uart_port *, int))
1922 {
1923         unsigned int i;
1924 
1925         for (i = 0; i < count; i++, s++) {
1926                 if (*s == '\n')
1927                         putchar(port, '\r');
1928                 putchar(port, *s);
1929         }
1930 }
1931 EXPORT_SYMBOL_GPL(uart_console_write);
1932 
1933 /*
1934  *      Check whether an invalid uart number has been specified, and
1935  *      if so, search for the first available port that does have
1936  *      console support.
1937  */
1938 struct uart_port * __init
1939 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1940 {
1941         int idx = co->index;
1942 
1943         if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1944                                      ports[idx].membase == NULL))
1945                 for (idx = 0; idx < nr; idx++)
1946                         if (ports[idx].iobase != 0 ||
1947                             ports[idx].membase != NULL)
1948                                 break;
1949 
1950         co->index = idx;
1951 
1952         return ports + idx;
1953 }
1954 
1955 /**
1956  *      uart_parse_earlycon - Parse earlycon options
1957  *      @p:       ptr to 2nd field (ie., just beyond '<name>,')
1958  *      @iotype:  ptr for decoded iotype (out)
1959  *      @addr:    ptr for decoded mapbase/iobase (out)
1960  *      @options: ptr for <options> field; NULL if not present (out)
1961  *
1962  *      Decodes earlycon kernel command line parameters of the form
1963  *         earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1964  *         console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1965  *
1966  *      The optional form
1967  *
1968  *         earlycon=<name>,0x<addr>,<options>
1969  *         console=<name>,0x<addr>,<options>
1970  *
1971  *      is also accepted; the returned @iotype will be UPIO_MEM.
1972  *
1973  *      Returns 0 on success or -EINVAL on failure
1974  */
1975 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1976                         char **options)
1977 {
1978         if (strncmp(p, "mmio,", 5) == 0) {
1979                 *iotype = UPIO_MEM;
1980                 p += 5;
1981         } else if (strncmp(p, "mmio16,", 7) == 0) {
1982                 *iotype = UPIO_MEM16;
1983                 p += 7;
1984         } else if (strncmp(p, "mmio32,", 7) == 0) {
1985                 *iotype = UPIO_MEM32;
1986                 p += 7;
1987         } else if (strncmp(p, "mmio32be,", 9) == 0) {
1988                 *iotype = UPIO_MEM32BE;
1989                 p += 9;
1990         } else if (strncmp(p, "mmio32native,", 13) == 0) {
1991                 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
1992                         UPIO_MEM32BE : UPIO_MEM32;
1993                 p += 13;
1994         } else if (strncmp(p, "io,", 3) == 0) {
1995                 *iotype = UPIO_PORT;
1996                 p += 3;
1997         } else if (strncmp(p, "0x", 2) == 0) {
1998                 *iotype = UPIO_MEM;
1999         } else {
2000                 return -EINVAL;
2001         }
2002 
2003         /*
2004          * Before you replace it with kstrtoull(), think about options separator
2005          * (',') it will not tolerate
2006          */
2007         *addr = simple_strtoull(p, NULL, 0);
2008         p = strchr(p, ',');
2009         if (p)
2010                 p++;
2011 
2012         *options = p;
2013         return 0;
2014 }
2015 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2016 
2017 /**
2018  *      uart_parse_options - Parse serial port baud/parity/bits/flow control.
2019  *      @options: pointer to option string
2020  *      @baud: pointer to an 'int' variable for the baud rate.
2021  *      @parity: pointer to an 'int' variable for the parity.
2022  *      @bits: pointer to an 'int' variable for the number of data bits.
2023  *      @flow: pointer to an 'int' variable for the flow control character.
2024  *
2025  *      uart_parse_options decodes a string containing the serial console
2026  *      options.  The format of the string is <baud><parity><bits><flow>,
2027  *      eg: 115200n8r
2028  */
2029 void
2030 uart_parse_options(const char *options, int *baud, int *parity,
2031                    int *bits, int *flow)
2032 {
2033         const char *s = options;
2034 
2035         *baud = simple_strtoul(s, NULL, 10);
2036         while (*s >= '0' && *s <= '9')
2037                 s++;
2038         if (*s)
2039                 *parity = *s++;
2040         if (*s)
2041                 *bits = *s++ - '0';
2042         if (*s)
2043                 *flow = *s;
2044 }
2045 EXPORT_SYMBOL_GPL(uart_parse_options);
2046 
2047 /**
2048  *      uart_set_options - setup the serial console parameters
2049  *      @port: pointer to the serial ports uart_port structure
2050  *      @co: console pointer
2051  *      @baud: baud rate
2052  *      @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2053  *      @bits: number of data bits
2054  *      @flow: flow control character - 'r' (rts)
2055  */
2056 int
2057 uart_set_options(struct uart_port *port, struct console *co,
2058                  int baud, int parity, int bits, int flow)
2059 {
2060         struct ktermios termios;
2061         static struct ktermios dummy;
2062 
2063         /*
2064          * Ensure that the serial console lock is initialised
2065          * early.
2066          * If this port is a console, then the spinlock is already
2067          * initialised.
2068          */
2069         if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
2070                 spin_lock_init(&port->lock);
2071                 lockdep_set_class(&port->lock, &port_lock_key);
2072         }
2073 
2074         memset(&termios, 0, sizeof(struct ktermios));
2075 
2076         termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2077         tty_termios_encode_baud_rate(&termios, baud, baud);
2078 
2079         if (bits == 7)
2080                 termios.c_cflag |= CS7;
2081         else
2082                 termios.c_cflag |= CS8;
2083 
2084         switch (parity) {
2085         case 'o': case 'O':
2086                 termios.c_cflag |= PARODD;
2087                 /*fall through*/
2088         case 'e': case 'E':
2089                 termios.c_cflag |= PARENB;
2090                 break;
2091         }
2092 
2093         if (flow == 'r')
2094                 termios.c_cflag |= CRTSCTS;
2095 
2096         /*
2097          * some uarts on other side don't support no flow control.
2098          * So we set * DTR in host uart to make them happy
2099          */
2100         port->mctrl |= TIOCM_DTR;
2101 
2102         port->ops->set_termios(port, &termios, &dummy);
2103         /*
2104          * Allow the setting of the UART parameters with a NULL console
2105          * too:
2106          */
2107         if (co)
2108                 co->cflag = termios.c_cflag;
2109 
2110         return 0;
2111 }
2112 EXPORT_SYMBOL_GPL(uart_set_options);
2113 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2114 
2115 /**
2116  * uart_change_pm - set power state of the port
2117  *
2118  * @state: port descriptor
2119  * @pm_state: new state
2120  *
2121  * Locking: port->mutex has to be held
2122  */
2123 static void uart_change_pm(struct uart_state *state,
2124                            enum uart_pm_state pm_state)
2125 {
2126         struct uart_port *port = uart_port_check(state);
2127 
2128         if (state->pm_state != pm_state) {
2129                 if (port && port->ops->pm)
2130                         port->ops->pm(port, pm_state, state->pm_state);
2131                 state->pm_state = pm_state;
2132         }
2133 }
2134 
2135 struct uart_match {
2136         struct uart_port *port;
2137         struct uart_driver *driver;
2138 };
2139 
2140 static int serial_match_port(struct device *dev, void *data)
2141 {
2142         struct uart_match *match = data;
2143         struct tty_driver *tty_drv = match->driver->tty_driver;
2144         dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2145                 match->port->line;
2146 
2147         return dev->devt == devt; /* Actually, only one tty per port */
2148 }
2149 
2150 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2151 {
2152         struct uart_state *state = drv->state + uport->line;
2153         struct tty_port *port = &state->port;
2154         struct device *tty_dev;
2155         struct uart_match match = {uport, drv};
2156 
2157         mutex_lock(&port->mutex);
2158 
2159         tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2160         if (tty_dev && device_may_wakeup(tty_dev)) {
2161                 enable_irq_wake(uport->irq);
2162                 put_device(tty_dev);
2163                 mutex_unlock(&port->mutex);
2164                 return 0;
2165         }
2166         put_device(tty_dev);
2167 
2168         /* Nothing to do if the console is not suspending */
2169         if (!console_suspend_enabled && uart_console(uport))
2170                 goto unlock;
2171 
2172         uport->suspended = 1;
2173 
2174         if (tty_port_initialized(port)) {
2175                 const struct uart_ops *ops = uport->ops;
2176                 int tries;
2177 
2178                 tty_port_set_suspended(port, 1);
2179                 tty_port_set_initialized(port, 0);
2180 
2181                 spin_lock_irq(&uport->lock);
2182                 ops->stop_tx(uport);
2183                 ops->set_mctrl(uport, 0);
2184                 ops->stop_rx(uport);
2185                 spin_unlock_irq(&uport->lock);
2186 
2187                 /*
2188                  * Wait for the transmitter to empty.
2189                  */
2190                 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2191                         msleep(10);
2192                 if (!tries)
2193                         dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2194                                 uport->name);
2195 
2196                 ops->shutdown(uport);
2197         }
2198 
2199         /*
2200          * Disable the console device before suspending.
2201          */
2202         if (uart_console(uport))
2203                 console_stop(uport->cons);
2204 
2205         uart_change_pm(state, UART_PM_STATE_OFF);
2206 unlock:
2207         mutex_unlock(&port->mutex);
2208 
2209         return 0;
2210 }
2211 
2212 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2213 {
2214         struct uart_state *state = drv->state + uport->line;
2215         struct tty_port *port = &state->port;
2216         struct device *tty_dev;
2217         struct uart_match match = {uport, drv};
2218         struct ktermios termios;
2219 
2220         mutex_lock(&port->mutex);
2221 
2222         tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2223         if (!uport->suspended && device_may_wakeup(tty_dev)) {
2224                 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2225                         disable_irq_wake(uport->irq);
2226                 put_device(tty_dev);
2227                 mutex_unlock(&port->mutex);
2228                 return 0;
2229         }
2230         put_device(tty_dev);
2231         uport->suspended = 0;
2232 
2233         /*
2234          * Re-enable the console device after suspending.
2235          */
2236         if (uart_console(uport)) {
2237                 /*
2238                  * First try to use the console cflag setting.
2239                  */
2240                 memset(&termios, 0, sizeof(struct ktermios));
2241                 termios.c_cflag = uport->cons->cflag;
2242 
2243                 /*
2244                  * If that's unset, use the tty termios setting.
2245                  */
2246                 if (port->tty && termios.c_cflag == 0)
2247                         termios = port->tty->termios;
2248 
2249                 if (console_suspend_enabled)
2250                         uart_change_pm(state, UART_PM_STATE_ON);
2251                 uport->ops->set_termios(uport, &termios, NULL);
2252                 if (console_suspend_enabled)
2253                         console_start(uport->cons);
2254         }
2255 
2256         if (tty_port_suspended(port)) {
2257                 const struct uart_ops *ops = uport->ops;
2258                 int ret;
2259 
2260                 uart_change_pm(state, UART_PM_STATE_ON);
2261                 spin_lock_irq(&uport->lock);
2262                 ops->set_mctrl(uport, 0);
2263                 spin_unlock_irq(&uport->lock);
2264                 if (console_suspend_enabled || !uart_console(uport)) {
2265                         /* Protected by port mutex for now */
2266                         struct tty_struct *tty = port->tty;
2267                         ret = ops->startup(uport);
2268                         if (ret == 0) {
2269                                 if (tty)
2270                                         uart_change_speed(tty, state, NULL);
2271                                 spin_lock_irq(&uport->lock);
2272                                 ops->set_mctrl(uport, uport->mctrl);
2273                                 ops->start_tx(uport);
2274                                 spin_unlock_irq(&uport->lock);
2275                                 tty_port_set_initialized(port, 1);
2276                         } else {
2277                                 /*
2278                                  * Failed to resume - maybe hardware went away?
2279                                  * Clear the "initialized" flag so we won't try
2280                                  * to call the low level drivers shutdown method.
2281                                  */
2282                                 uart_shutdown(tty, state);
2283                         }
2284                 }
2285 
2286                 tty_port_set_suspended(port, 0);
2287         }
2288 
2289         mutex_unlock(&port->mutex);
2290 
2291         return 0;
2292 }
2293 
2294 static inline void
2295 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2296 {
2297         char address[64];
2298 
2299         switch (port->iotype) {
2300         case UPIO_PORT:
2301                 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2302                 break;
2303         case UPIO_HUB6:
2304                 snprintf(address, sizeof(address),
2305                          "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2306                 break;
2307         case UPIO_MEM:
2308         case UPIO_MEM16:
2309         case UPIO_MEM32:
2310         case UPIO_MEM32BE:
2311         case UPIO_AU:
2312         case UPIO_TSI:
2313                 snprintf(address, sizeof(address),
2314                          "MMIO 0x%llx", (unsigned long long)port->mapbase);
2315                 break;
2316         default:
2317                 strlcpy(address, "*unknown*", sizeof(address));
2318                 break;
2319         }
2320 
2321         pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2322                port->dev ? dev_name(port->dev) : "",
2323                port->dev ? ": " : "",
2324                port->name,
2325                address, port->irq, port->uartclk / 16, uart_type(port));
2326 }
2327 
2328 static void
2329 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2330                     struct uart_port *port)
2331 {
2332         unsigned int flags;
2333 
2334         /*
2335          * If there isn't a port here, don't do anything further.
2336          */
2337         if (!port->iobase && !port->mapbase && !port->membase)
2338                 return;
2339 
2340         /*
2341          * Now do the auto configuration stuff.  Note that config_port
2342          * is expected to claim the resources and map the port for us.
2343          */
2344         flags = 0;
2345         if (port->flags & UPF_AUTO_IRQ)
2346                 flags |= UART_CONFIG_IRQ;
2347         if (port->flags & UPF_BOOT_AUTOCONF) {
2348                 if (!(port->flags & UPF_FIXED_TYPE)) {
2349                         port->type = PORT_UNKNOWN;
2350                         flags |= UART_CONFIG_TYPE;
2351                 }
2352                 port->ops->config_port(port, flags);
2353         }
2354 
2355         if (port->type != PORT_UNKNOWN) {
2356                 unsigned long flags;
2357 
2358                 uart_report_port(drv, port);
2359 
2360                 /* Power up port for set_mctrl() */
2361                 uart_change_pm(state, UART_PM_STATE_ON);
2362 
2363                 /*
2364                  * Ensure that the modem control lines are de-activated.
2365                  * keep the DTR setting that is set in uart_set_options()
2366                  * We probably don't need a spinlock around this, but
2367                  */
2368                 spin_lock_irqsave(&port->lock, flags);
2369                 port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2370                 spin_unlock_irqrestore(&port->lock, flags);
2371 
2372                 /*
2373                  * If this driver supports console, and it hasn't been
2374                  * successfully registered yet, try to re-register it.
2375                  * It may be that the port was not available.
2376                  */
2377                 if (port->cons && !(port->cons->flags & CON_ENABLED))
2378                         register_console(port->cons);
2379 
2380                 /*
2381                  * Power down all ports by default, except the
2382                  * console if we have one.
2383                  */
2384                 if (!uart_console(port))
2385                         uart_change_pm(state, UART_PM_STATE_OFF);
2386         }
2387 }
2388 
2389 #ifdef CONFIG_CONSOLE_POLL
2390 
2391 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2392 {
2393         struct uart_driver *drv = driver->driver_state;
2394         struct uart_state *state = drv->state + line;
2395         struct tty_port *tport;
2396         struct uart_port *port;
2397         int baud = 9600;
2398         int bits = 8;
2399         int parity = 'n';
2400         int flow = 'n';
2401         int ret = 0;
2402 
2403         tport = &state->port;
2404         mutex_lock(&tport->mutex);
2405 
2406         port = uart_port_check(state);
2407         if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2408                 ret = -1;
2409                 goto out;
2410         }
2411 
2412         if (port->ops->poll_init) {
2413                 /*
2414                  * We don't set initialized as we only initialized the hw,
2415                  * e.g. state->xmit is still uninitialized.
2416                  */
2417                 if (!tty_port_initialized(tport))
2418                         ret = port->ops->poll_init(port);
2419         }
2420 
2421         if (!ret && options) {
2422                 uart_parse_options(options, &baud, &parity, &bits, &flow);
2423                 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2424         }
2425 out:
2426         mutex_unlock(&tport->mutex);
2427         return ret;
2428 }
2429 
2430 static int uart_poll_get_char(struct tty_driver *driver, int line)
2431 {
2432         struct uart_driver *drv = driver->driver_state;
2433         struct uart_state *state = drv->state + line;
2434         struct uart_port *port;
2435         int ret = -1;
2436 
2437         port = uart_port_ref(state);
2438         if (port) {
2439                 ret = port->ops->poll_get_char(port);
2440                 uart_port_deref(port);
2441         }
2442 
2443         return ret;
2444 }
2445 
2446 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2447 {
2448         struct uart_driver *drv = driver->driver_state;
2449         struct uart_state *state = drv->state + line;
2450         struct uart_port *port;
2451 
2452         port = uart_port_ref(state);
2453         if (!port)
2454                 return;
2455 
2456         if (ch == '\n')
2457                 port->ops->poll_put_char(port, '\r');
2458         port->ops->poll_put_char(port, ch);
2459         uart_port_deref(port);
2460 }
2461 #endif
2462 
2463 static const struct tty_operations uart_ops = {
2464         .install        = uart_install,
2465         .open           = uart_open,
2466         .close          = uart_close,
2467         .write          = uart_write,
2468         .put_char       = uart_put_char,
2469         .flush_chars    = uart_flush_chars,
2470         .write_room     = uart_write_room,
2471         .chars_in_buffer= uart_chars_in_buffer,
2472         .flush_buffer   = uart_flush_buffer,
2473         .ioctl          = uart_ioctl,
2474         .throttle       = uart_throttle,
2475         .unthrottle     = uart_unthrottle,
2476         .send_xchar     = uart_send_xchar,
2477         .set_termios    = uart_set_termios,
2478         .set_ldisc      = uart_set_ldisc,
2479         .stop           = uart_stop,
2480         .start          = uart_start,
2481         .hangup         = uart_hangup,
2482         .break_ctl      = uart_break_ctl,
2483         .wait_until_sent= uart_wait_until_sent,
2484 #ifdef CONFIG_PROC_FS
2485         .proc_show      = uart_proc_show,
2486 #endif
2487         .tiocmget       = uart_tiocmget,
2488         .tiocmset       = uart_tiocmset,
2489         .set_serial     = uart_set_info_user,
2490         .get_serial     = uart_get_info_user,
2491         .get_icount     = uart_get_icount,
2492 #ifdef CONFIG_CONSOLE_POLL
2493         .poll_init      = uart_poll_init,
2494         .poll_get_char  = uart_poll_get_char,
2495         .poll_put_char  = uart_poll_put_char,
2496 #endif
2497 };
2498 
2499 static const struct tty_port_operations uart_port_ops = {
2500         .carrier_raised = uart_carrier_raised,
2501         .dtr_rts        = uart_dtr_rts,
2502         .activate       = uart_port_activate,
2503         .shutdown       = uart_tty_port_shutdown,
2504 };
2505 
2506 /**
2507  *      uart_register_driver - register a driver with the uart core layer
2508  *      @drv: low level driver structure
2509  *
2510  *      Register a uart driver with the core driver.  We in turn register
2511  *      with the tty layer, and initialise the core driver per-port state.
2512  *
2513  *      We have a proc file in /proc/tty/driver which is named after the
2514  *      normal driver.
2515  *
2516  *      drv->port should be NULL, and the per-port structures should be
2517  *      registered using uart_add_one_port after this call has succeeded.
2518  */
2519 int uart_register_driver(struct uart_driver *drv)
2520 {
2521         struct tty_driver *normal;
2522         int i, retval = -ENOMEM;
2523 
2524         BUG_ON(drv->state);
2525 
2526         /*
2527          * Maybe we should be using a slab cache for this, especially if
2528          * we have a large number of ports to handle.
2529          */
2530         drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2531         if (!drv->state)
2532                 goto out;
2533 
2534         normal = alloc_tty_driver(drv->nr);
2535         if (!normal)
2536                 goto out_kfree;
2537 
2538         drv->tty_driver = normal;
2539 
2540         normal->driver_name     = drv->driver_name;
2541         normal->name            = drv->dev_name;
2542         normal->major           = drv->major;
2543         normal->minor_start     = drv->minor;
2544         normal->type            = TTY_DRIVER_TYPE_SERIAL;
2545         normal->subtype         = SERIAL_TYPE_NORMAL;
2546         normal->init_termios    = tty_std_termios;
2547         normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2548         normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2549         normal->flags           = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2550         normal->driver_state    = drv;
2551         tty_set_operations(normal, &uart_ops);
2552 
2553         /*
2554          * Initialise the UART state(s).
2555          */
2556         for (i = 0; i < drv->nr; i++) {
2557                 struct uart_state *state = drv->state + i;
2558                 struct tty_port *port = &state->port;
2559 
2560                 tty_port_init(port);
2561                 port->ops = &uart_port_ops;
2562         }
2563 
2564         retval = tty_register_driver(normal);
2565         if (retval >= 0)
2566                 return retval;
2567 
2568         for (i = 0; i < drv->nr; i++)
2569                 tty_port_destroy(&drv->state[i].port);
2570         put_tty_driver(normal);
2571 out_kfree:
2572         kfree(drv->state);
2573 out:
2574         return retval;
2575 }
2576 
2577 /**
2578  *      uart_unregister_driver - remove a driver from the uart core layer
2579  *      @drv: low level driver structure
2580  *
2581  *      Remove all references to a driver from the core driver.  The low
2582  *      level driver must have removed all its ports via the
2583  *      uart_remove_one_port() if it registered them with uart_add_one_port().
2584  *      (ie, drv->port == NULL)
2585  */
2586 void uart_unregister_driver(struct uart_driver *drv)
2587 {
2588         struct tty_driver *p = drv->tty_driver;
2589         unsigned int i;
2590 
2591         tty_unregister_driver(p);
2592         put_tty_driver(p);
2593         for (i = 0; i < drv->nr; i++)
2594                 tty_port_destroy(&drv->state[i].port);
2595         kfree(drv->state);
2596         drv->state = NULL;
2597         drv->tty_driver = NULL;
2598 }
2599 
2600 struct tty_driver *uart_console_device(struct console *co, int *index)
2601 {
2602         struct uart_driver *p = co->data;
2603         *index = co->index;
2604         return p->tty_driver;
2605 }
2606 
2607 static ssize_t uart_get_attr_uartclk(struct device *dev,
2608         struct device_attribute *attr, char *buf)
2609 {
2610         struct serial_struct tmp;
2611         struct tty_port *port = dev_get_drvdata(dev);
2612 
2613         uart_get_info(port, &tmp);
2614         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.baud_base * 16);
2615 }
2616 
2617 static ssize_t uart_get_attr_type(struct device *dev,
2618         struct device_attribute *attr, char *buf)
2619 {
2620         struct serial_struct tmp;
2621         struct tty_port *port = dev_get_drvdata(dev);
2622 
2623         uart_get_info(port, &tmp);
2624         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.type);
2625 }
2626 static ssize_t uart_get_attr_line(struct device *dev,
2627         struct device_attribute *attr, char *buf)
2628 {
2629         struct serial_struct tmp;
2630         struct tty_port *port = dev_get_drvdata(dev);
2631 
2632         uart_get_info(port, &tmp);
2633         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.line);
2634 }
2635 
2636 static ssize_t uart_get_attr_port(struct device *dev,
2637         struct device_attribute *attr, char *buf)
2638 {
2639         struct serial_struct tmp;
2640         struct tty_port *port = dev_get_drvdata(dev);
2641         unsigned long ioaddr;
2642 
2643         uart_get_info(port, &tmp);
2644         ioaddr = tmp.port;
2645         if (HIGH_BITS_OFFSET)
2646                 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2647         return snprintf(buf, PAGE_SIZE, "0x%lX\n", ioaddr);
2648 }
2649 
2650 static ssize_t uart_get_attr_irq(struct device *dev,
2651         struct device_attribute *attr, char *buf)
2652 {
2653         struct serial_struct tmp;
2654         struct tty_port *port = dev_get_drvdata(dev);
2655 
2656         uart_get_info(port, &tmp);
2657         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.irq);
2658 }
2659 
2660 static ssize_t uart_get_attr_flags(struct device *dev,
2661         struct device_attribute *attr, char *buf)
2662 {
2663         struct serial_struct tmp;
2664         struct tty_port *port = dev_get_drvdata(dev);
2665 
2666         uart_get_info(port, &tmp);
2667         return snprintf(buf, PAGE_SIZE, "0x%X\n", tmp.flags);
2668 }
2669 
2670 static ssize_t uart_get_attr_xmit_fifo_size(struct device *dev,
2671         struct device_attribute *attr, char *buf)
2672 {
2673         struct serial_struct tmp;
2674         struct tty_port *port = dev_get_drvdata(dev);
2675 
2676         uart_get_info(port, &tmp);
2677         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.xmit_fifo_size);
2678 }
2679 
2680 
2681 static ssize_t uart_get_attr_close_delay(struct device *dev,
2682         struct device_attribute *attr, char *buf)
2683 {
2684         struct serial_struct tmp;
2685         struct tty_port *port = dev_get_drvdata(dev);
2686 
2687         uart_get_info(port, &tmp);
2688         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.close_delay);
2689 }
2690 
2691 
2692 static ssize_t uart_get_attr_closing_wait(struct device *dev,
2693         struct device_attribute *attr, char *buf)
2694 {
2695         struct serial_struct tmp;
2696         struct tty_port *port = dev_get_drvdata(dev);
2697 
2698         uart_get_info(port, &tmp);
2699         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.closing_wait);
2700 }
2701 
2702 static ssize_t uart_get_attr_custom_divisor(struct device *dev,
2703         struct device_attribute *attr, char *buf)
2704 {
2705         struct serial_struct tmp;
2706         struct tty_port *port = dev_get_drvdata(dev);
2707 
2708         uart_get_info(port, &tmp);
2709         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.custom_divisor);
2710 }
2711 
2712 static ssize_t uart_get_attr_io_type(struct device *dev,
2713         struct device_attribute *attr, char *buf)
2714 {
2715         struct serial_struct tmp;
2716         struct tty_port *port = dev_get_drvdata(dev);
2717 
2718         uart_get_info(port, &tmp);
2719         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.io_type);
2720 }
2721 
2722 static ssize_t uart_get_attr_iomem_base(struct device *dev,
2723         struct device_attribute *attr, char *buf)
2724 {
2725         struct serial_struct tmp;
2726         struct tty_port *port = dev_get_drvdata(dev);
2727 
2728         uart_get_info(port, &tmp);
2729         return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)tmp.iomem_base);
2730 }
2731 
2732 static ssize_t uart_get_attr_iomem_reg_shift(struct device *dev,
2733         struct device_attribute *attr, char *buf)
2734 {
2735         struct serial_struct tmp;
2736         struct tty_port *port = dev_get_drvdata(dev);
2737 
2738         uart_get_info(port, &tmp);
2739         return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
2740 }
2741 
2742 static DEVICE_ATTR(type, S_IRUSR | S_IRGRP, uart_get_attr_type, NULL);
2743 static DEVICE_ATTR(line, S_IRUSR | S_IRGRP, uart_get_attr_line, NULL);
2744 static DEVICE_ATTR(port, S_IRUSR | S_IRGRP, uart_get_attr_port, NULL);
2745 static DEVICE_ATTR(irq, S_IRUSR | S_IRGRP, uart_get_attr_irq, NULL);
2746 static DEVICE_ATTR(flags, S_IRUSR | S_IRGRP, uart_get_attr_flags, NULL);
2747 static DEVICE_ATTR(xmit_fifo_size, S_IRUSR | S_IRGRP, uart_get_attr_xmit_fifo_size, NULL);
2748 static DEVICE_ATTR(uartclk, S_IRUSR | S_IRGRP, uart_get_attr_uartclk, NULL);
2749 static DEVICE_ATTR(close_delay, S_IRUSR | S_IRGRP, uart_get_attr_close_delay, NULL);
2750 static DEVICE_ATTR(closing_wait, S_IRUSR | S_IRGRP, uart_get_attr_closing_wait, NULL);
2751 static DEVICE_ATTR(custom_divisor, S_IRUSR | S_IRGRP, uart_get_attr_custom_divisor, NULL);
2752 static DEVICE_ATTR(io_type, S_IRUSR | S_IRGRP, uart_get_attr_io_type, NULL);
2753 static DEVICE_ATTR(iomem_base, S_IRUSR | S_IRGRP, uart_get_attr_iomem_base, NULL);
2754 static DEVICE_ATTR(iomem_reg_shift, S_IRUSR | S_IRGRP, uart_get_attr_iomem_reg_shift, NULL);
2755 
2756 static struct attribute *tty_dev_attrs[] = {
2757         &dev_attr_type.attr,
2758         &dev_attr_line.attr,
2759         &dev_attr_port.attr,
2760         &dev_attr_irq.attr,
2761         &dev_attr_flags.attr,
2762         &dev_attr_xmit_fifo_size.attr,
2763         &dev_attr_uartclk.attr,
2764         &dev_attr_close_delay.attr,
2765         &dev_attr_closing_wait.attr,
2766         &dev_attr_custom_divisor.attr,
2767         &dev_attr_io_type.attr,
2768         &dev_attr_iomem_base.attr,
2769         &dev_attr_iomem_reg_shift.attr,
2770         NULL,
2771         };
2772 
2773 static const struct attribute_group tty_dev_attr_group = {
2774         .attrs = tty_dev_attrs,
2775         };
2776 
2777 /**
2778  *      uart_add_one_port - attach a driver-defined port structure
2779  *      @drv: pointer to the uart low level driver structure for this port
2780  *      @uport: uart port structure to use for this port.
2781  *
2782  *      This allows the driver to register its own uart_port structure
2783  *      with the core driver.  The main purpose is to allow the low
2784  *      level uart drivers to expand uart_port, rather than having yet
2785  *      more levels of structures.
2786  */
2787 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2788 {
2789         struct uart_state *state;
2790         struct tty_port *port;
2791         int ret = 0;
2792         struct device *tty_dev;
2793         int num_groups;
2794 
2795         BUG_ON(in_interrupt());
2796 
2797         if (uport->line >= drv->nr)
2798                 return -EINVAL;
2799 
2800         state = drv->state + uport->line;
2801         port = &state->port;
2802 
2803         mutex_lock(&port_mutex);
2804         mutex_lock(&port->mutex);
2805         if (state->uart_port) {
2806                 ret = -EINVAL;
2807                 goto out;
2808         }
2809 
2810         /* Link the port to the driver state table and vice versa */
2811         atomic_set(&state->refcount, 1);
2812         init_waitqueue_head(&state->remove_wait);
2813         state->uart_port = uport;
2814         uport->state = state;
2815 
2816         state->pm_state = UART_PM_STATE_UNDEFINED;
2817         uport->cons = drv->cons;
2818         uport->minor = drv->tty_driver->minor_start + uport->line;
2819         uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2820                                 drv->tty_driver->name_base + uport->line);
2821         if (!uport->name) {
2822                 ret = -ENOMEM;
2823                 goto out;
2824         }
2825 
2826         /*
2827          * If this port is a console, then the spinlock is already
2828          * initialised.
2829          */
2830         if (!(uart_console(uport) && (uport->cons->flags & CON_ENABLED))) {
2831                 spin_lock_init(&uport->lock);
2832                 lockdep_set_class(&uport->lock, &port_lock_key);
2833         }
2834         if (uport->cons && uport->dev)
2835                 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2836 
2837         tty_port_link_device(port, drv->tty_driver, uport->line);
2838         uart_configure_port(drv, state, uport);
2839 
2840         port->console = uart_console(uport);
2841 
2842         num_groups = 2;
2843         if (uport->attr_group)
2844                 num_groups++;
2845 
2846         uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2847                                     GFP_KERNEL);
2848         if (!uport->tty_groups) {
2849                 ret = -ENOMEM;
2850                 goto out;
2851         }
2852         uport->tty_groups[0] = &tty_dev_attr_group;
2853         if (uport->attr_group)
2854                 uport->tty_groups[1] = uport->attr_group;
2855 
2856         /*
2857          * Register the port whether it's detected or not.  This allows
2858          * setserial to be used to alter this port's parameters.
2859          */
2860         tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2861                         uport->line, uport->dev, port, uport->tty_groups);
2862         if (!IS_ERR(tty_dev)) {
2863                 device_set_wakeup_capable(tty_dev, 1);
2864         } else {
2865                 dev_err(uport->dev, "Cannot register tty device on line %d\n",
2866                        uport->line);
2867         }
2868 
2869         /*
2870          * Ensure UPF_DEAD is not set.
2871          */
2872         uport->flags &= ~UPF_DEAD;
2873 
2874  out:
2875         mutex_unlock(&port->mutex);
2876         mutex_unlock(&port_mutex);
2877 
2878         return ret;
2879 }
2880 
2881 /**
2882  *      uart_remove_one_port - detach a driver defined port structure
2883  *      @drv: pointer to the uart low level driver structure for this port
2884  *      @uport: uart port structure for this port
2885  *
2886  *      This unhooks (and hangs up) the specified port structure from the
2887  *      core driver.  No further calls will be made to the low-level code
2888  *      for this port.
2889  */
2890 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2891 {
2892         struct uart_state *state = drv->state + uport->line;
2893         struct tty_port *port = &state->port;
2894         struct uart_port *uart_port;
2895         struct tty_struct *tty;
2896         int ret = 0;
2897 
2898         BUG_ON(in_interrupt());
2899 
2900         mutex_lock(&port_mutex);
2901 
2902         /*
2903          * Mark the port "dead" - this prevents any opens from
2904          * succeeding while we shut down the port.
2905          */
2906         mutex_lock(&port->mutex);
2907         uart_port = uart_port_check(state);
2908         if (uart_port != uport)
2909                 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2910                           uart_port, uport);
2911 
2912         if (!uart_port) {
2913                 mutex_unlock(&port->mutex);
2914                 ret = -EINVAL;
2915                 goto out;
2916         }
2917         uport->flags |= UPF_DEAD;
2918         mutex_unlock(&port->mutex);
2919 
2920         /*
2921          * Remove the devices from the tty layer
2922          */
2923         tty_port_unregister_device(port, drv->tty_driver, uport->line);
2924 
2925         tty = tty_port_tty_get(port);
2926         if (tty) {
2927                 tty_vhangup(port->tty);
2928                 tty_kref_put(tty);
2929         }
2930 
2931         /*
2932          * If the port is used as a console, unregister it
2933          */
2934         if (uart_console(uport))
2935                 unregister_console(uport->cons);
2936 
2937         /*
2938          * Free the port IO and memory resources, if any.
2939          */
2940         if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
2941                 uport->ops->release_port(uport);
2942         kfree(uport->tty_groups);
2943         kfree(uport->name);
2944 
2945         /*
2946          * Indicate that there isn't a port here anymore.
2947          */
2948         uport->type = PORT_UNKNOWN;
2949 
2950         mutex_lock(&port->mutex);
2951         WARN_ON(atomic_dec_return(&state->refcount) < 0);
2952         wait_event(state->remove_wait, !atomic_read(&state->refcount));
2953         state->uart_port = NULL;
2954         mutex_unlock(&port->mutex);
2955 out:
2956         mutex_unlock(&port_mutex);
2957 
2958         return ret;
2959 }
2960 
2961 /*
2962  *      Are the two ports equivalent?
2963  */
2964 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2965 {
2966         if (port1->iotype != port2->iotype)
2967                 return 0;
2968 
2969         switch (port1->iotype) {
2970         case UPIO_PORT:
2971                 return (port1->iobase == port2->iobase);
2972         case UPIO_HUB6:
2973                 return (port1->iobase == port2->iobase) &&
2974                        (port1->hub6   == port2->hub6);
2975         case UPIO_MEM:
2976         case UPIO_MEM16:
2977         case UPIO_MEM32:
2978         case UPIO_MEM32BE:
2979         case UPIO_AU:
2980         case UPIO_TSI:
2981                 return (port1->mapbase == port2->mapbase);
2982         }
2983         return 0;
2984 }
2985 EXPORT_SYMBOL(uart_match_port);
2986 
2987 /**
2988  *      uart_handle_dcd_change - handle a change of carrier detect state
2989  *      @uport: uart_port structure for the open port
2990  *      @status: new carrier detect status, nonzero if active
2991  *
2992  *      Caller must hold uport->lock
2993  */
2994 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
2995 {
2996         struct tty_port *port = &uport->state->port;
2997         struct tty_struct *tty = port->tty;
2998         struct tty_ldisc *ld;
2999 
3000         lockdep_assert_held_once(&uport->lock);
3001 
3002         if (tty) {
3003                 ld = tty_ldisc_ref(tty);
3004                 if (ld) {
3005                         if (ld->ops->dcd_change)
3006                                 ld->ops->dcd_change(tty, status);
3007                         tty_ldisc_deref(ld);
3008                 }
3009         }
3010 
3011         uport->icount.dcd++;
3012 
3013         if (uart_dcd_enabled(uport)) {
3014                 if (status)
3015                         wake_up_interruptible(&port->open_wait);
3016                 else if (tty)
3017                         tty_hangup(tty);
3018         }
3019 }
3020 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3021 
3022 /**
3023  *      uart_handle_cts_change - handle a change of clear-to-send state
3024  *      @uport: uart_port structure for the open port
3025  *      @status: new clear to send status, nonzero if active
3026  *
3027  *      Caller must hold uport->lock
3028  */
3029 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3030 {
3031         lockdep_assert_held_once(&uport->lock);
3032 
3033         uport->icount.cts++;
3034 
3035         if (uart_softcts_mode(uport)) {
3036                 if (uport->hw_stopped) {
3037                         if (status) {
3038                                 uport->hw_stopped = 0;
3039                                 uport->ops->start_tx(uport);
3040                                 uart_write_wakeup(uport);
3041                         }
3042                 } else {
3043                         if (!status) {
3044                                 uport->hw_stopped = 1;
3045                                 uport->ops->stop_tx(uport);
3046                         }
3047                 }
3048 
3049         }
3050 }
3051 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3052 
3053 /**
3054  * uart_insert_char - push a char to the uart layer
3055  *
3056  * User is responsible to call tty_flip_buffer_push when they are done with
3057  * insertion.
3058  *
3059  * @port: corresponding port
3060  * @status: state of the serial port RX buffer (LSR for 8250)
3061  * @overrun: mask of overrun bits in @status
3062  * @ch: character to push
3063  * @flag: flag for the character (see TTY_NORMAL and friends)
3064  */
3065 void uart_insert_char(struct uart_port *port, unsigned int status,
3066                  unsigned int overrun, unsigned int ch, unsigned int flag)
3067 {
3068         struct tty_port *tport = &port->state->port;
3069 
3070         if ((status & port->ignore_status_mask & ~overrun) == 0)
3071                 if (tty_insert_flip_char(tport, ch, flag) == 0)
3072                         ++port->icount.buf_overrun;
3073 
3074         /*
3075          * Overrun is special.  Since it's reported immediately,
3076          * it doesn't affect the current character.
3077          */
3078         if (status & ~port->ignore_status_mask & overrun)
3079                 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3080                         ++port->icount.buf_overrun;
3081 }
3082 EXPORT_SYMBOL_GPL(uart_insert_char);
3083 
3084 EXPORT_SYMBOL(uart_write_wakeup);
3085 EXPORT_SYMBOL(uart_register_driver);
3086 EXPORT_SYMBOL(uart_unregister_driver);
3087 EXPORT_SYMBOL(uart_suspend_port);
3088 EXPORT_SYMBOL(uart_resume_port);
3089 EXPORT_SYMBOL(uart_add_one_port);
3090 EXPORT_SYMBOL(uart_remove_one_port);
3091 
3092 /**
3093  * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3094  * @dev: uart device
3095  * @rs485conf: output parameter
3096  *
3097  * This function implements the device tree binding described in
3098  * Documentation/devicetree/bindings/serial/rs485.txt.
3099  */
3100 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
3101 {
3102         u32 rs485_delay[2];
3103         int ret;
3104 
3105         ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3106                                              rs485_delay, 2);
3107         if (!ret) {
3108                 rs485conf->delay_rts_before_send = rs485_delay[0];
3109                 rs485conf->delay_rts_after_send = rs485_delay[1];
3110         } else {
3111                 rs485conf->delay_rts_before_send = 0;
3112                 rs485conf->delay_rts_after_send = 0;
3113         }
3114 
3115         /*
3116          * Clear full-duplex and enabled flags, set RTS polarity to active high
3117          * to get to a defined state with the following properties:
3118          */
3119         rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3120                               SER_RS485_RTS_AFTER_SEND);
3121         rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3122 
3123         if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3124                 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3125 
3126         if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3127                 rs485conf->flags |= SER_RS485_ENABLED;
3128 
3129         if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3130                 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3131                 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3132         }
3133 }
3134 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3135 
3136 MODULE_DESCRIPTION("Serial driver core");
3137 MODULE_LICENSE("GPL");