drivers/tty/serial/st-asc.c

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This source file includes following definitions.
to_asc_port
asc_in
asc_out
asc_disable_tx_interrupts
asc_enable_tx_interrupts
asc_disable_rx_interrupts
asc_enable_rx_interrupts
asc_txfifo_is_empty
asc_txfifo_is_half_empty
asc_port_name
asc_hw_txroom
asc_transmit_chars
asc_receive_chars
asc_interrupt
asc_tx_empty
asc_set_mctrl
asc_get_mctrl
asc_start_tx
asc_stop_tx
asc_stop_rx
asc_break_ctl
asc_startup
asc_shutdown
asc_pm
asc_set_termios
asc_type
asc_release_port
asc_request_port
asc_config_port
asc_verify_port
asc_get_poll_char
asc_put_poll_char
asc_init_port
asc_of_get_asc_port
asc_serial_probe
asc_serial_remove
asc_serial_suspend
asc_serial_resume
asc_console_putchar
asc_console_write
asc_console_setup
asc_init
asc_exit
   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * st-asc.c: ST Asynchronous serial controller (ASC) driver
   4  *
   5  * Copyright (C) 2003-2013 STMicroelectronics (R&D) Limited
   6  */
   7 
   8 #if defined(CONFIG_SERIAL_ST_ASC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
   9 #define SUPPORT_SYSRQ
  10 #endif
  11 
  12 #include <linux/module.h>
  13 #include <linux/serial.h>
  14 #include <linux/console.h>
  15 #include <linux/sysrq.h>
  16 #include <linux/pinctrl/consumer.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/io.h>
  19 #include <linux/irq.h>
  20 #include <linux/tty.h>
  21 #include <linux/tty_flip.h>
  22 #include <linux/delay.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/pm_runtime.h>
  25 #include <linux/of.h>
  26 #include <linux/of_platform.h>
  27 #include <linux/serial_core.h>
  28 #include <linux/clk.h>
  29 #include <linux/gpio/consumer.h>
  30 
  31 #define DRIVER_NAME "st-asc"
  32 #define ASC_SERIAL_NAME "ttyAS"
  33 #define ASC_FIFO_SIZE 16
  34 #define ASC_MAX_PORTS 8
  35 
  36 /* Pinctrl states */
  37 #define DEFAULT         0
  38 #define NO_HW_FLOWCTRL  1
  39 
  40 struct asc_port {
  41         struct uart_port port;
  42         struct gpio_desc *rts;
  43         struct clk *clk;
  44         struct pinctrl *pinctrl;
  45         struct pinctrl_state *states[2];
  46         unsigned int hw_flow_control:1;
  47         unsigned int force_m1:1;
  48 };
  49 
  50 static struct asc_port asc_ports[ASC_MAX_PORTS];
  51 static struct uart_driver asc_uart_driver;
  52 
  53 /*---- UART Register definitions ------------------------------*/
  54 
  55 /* Register offsets */
  56 
  57 #define ASC_BAUDRATE                    0x00
  58 #define ASC_TXBUF                       0x04
  59 #define ASC_RXBUF                       0x08
  60 #define ASC_CTL                         0x0C
  61 #define ASC_INTEN                       0x10
  62 #define ASC_STA                         0x14
  63 #define ASC_GUARDTIME                   0x18
  64 #define ASC_TIMEOUT                     0x1C
  65 #define ASC_TXRESET                     0x20
  66 #define ASC_RXRESET                     0x24
  67 #define ASC_RETRIES                     0x28
  68 
  69 /* ASC_RXBUF */
  70 #define ASC_RXBUF_PE                    0x100
  71 #define ASC_RXBUF_FE                    0x200
  72 /**
  73  * Some of status comes from higher bits of the character and some come from
  74  * the status register. Combining both of them in to single status using dummy
  75  * bits.
  76  */
  77 #define ASC_RXBUF_DUMMY_RX              0x10000
  78 #define ASC_RXBUF_DUMMY_BE              0x20000
  79 #define ASC_RXBUF_DUMMY_OE              0x40000
  80 
  81 /* ASC_CTL */
  82 
  83 #define ASC_CTL_MODE_MSK                0x0007
  84 #define  ASC_CTL_MODE_8BIT              0x0001
  85 #define  ASC_CTL_MODE_7BIT_PAR          0x0003
  86 #define  ASC_CTL_MODE_9BIT              0x0004
  87 #define  ASC_CTL_MODE_8BIT_WKUP         0x0005
  88 #define  ASC_CTL_MODE_8BIT_PAR          0x0007
  89 #define ASC_CTL_STOP_MSK                0x0018
  90 #define  ASC_CTL_STOP_HALFBIT           0x0000
  91 #define  ASC_CTL_STOP_1BIT              0x0008
  92 #define  ASC_CTL_STOP_1_HALFBIT         0x0010
  93 #define  ASC_CTL_STOP_2BIT              0x0018
  94 #define ASC_CTL_PARITYODD               0x0020
  95 #define ASC_CTL_LOOPBACK                0x0040
  96 #define ASC_CTL_RUN                     0x0080
  97 #define ASC_CTL_RXENABLE                0x0100
  98 #define ASC_CTL_SCENABLE                0x0200
  99 #define ASC_CTL_FIFOENABLE              0x0400
 100 #define ASC_CTL_CTSENABLE               0x0800
 101 #define ASC_CTL_BAUDMODE                0x1000
 102 
 103 /* ASC_GUARDTIME */
 104 
 105 #define ASC_GUARDTIME_MSK               0x00FF
 106 
 107 /* ASC_INTEN */
 108 
 109 #define ASC_INTEN_RBE                   0x0001
 110 #define ASC_INTEN_TE                    0x0002
 111 #define ASC_INTEN_THE                   0x0004
 112 #define ASC_INTEN_PE                    0x0008
 113 #define ASC_INTEN_FE                    0x0010
 114 #define ASC_INTEN_OE                    0x0020
 115 #define ASC_INTEN_TNE                   0x0040
 116 #define ASC_INTEN_TOI                   0x0080
 117 #define ASC_INTEN_RHF                   0x0100
 118 
 119 /* ASC_RETRIES */
 120 
 121 #define ASC_RETRIES_MSK                 0x00FF
 122 
 123 /* ASC_RXBUF */
 124 
 125 #define ASC_RXBUF_MSK                   0x03FF
 126 
 127 /* ASC_STA */
 128 
 129 #define ASC_STA_RBF                     0x0001
 130 #define ASC_STA_TE                      0x0002
 131 #define ASC_STA_THE                     0x0004
 132 #define ASC_STA_PE                      0x0008
 133 #define ASC_STA_FE                      0x0010
 134 #define ASC_STA_OE                      0x0020
 135 #define ASC_STA_TNE                     0x0040
 136 #define ASC_STA_TOI                     0x0080
 137 #define ASC_STA_RHF                     0x0100
 138 #define ASC_STA_TF                      0x0200
 139 #define ASC_STA_NKD                     0x0400
 140 
 141 /* ASC_TIMEOUT */
 142 
 143 #define ASC_TIMEOUT_MSK                 0x00FF
 144 
 145 /* ASC_TXBUF */
 146 
 147 #define ASC_TXBUF_MSK                   0x01FF
 148 
 149 /*---- Inline function definitions ---------------------------*/
 150 
 151 static inline struct asc_port *to_asc_port(struct uart_port *port)
 152 {
 153         return container_of(port, struct asc_port, port);
 154 }
 155 
 156 static inline u32 asc_in(struct uart_port *port, u32 offset)
 157 {
 158 #ifdef readl_relaxed
 159         return readl_relaxed(port->membase + offset);
 160 #else
 161         return readl(port->membase + offset);
 162 #endif
 163 }
 164 
 165 static inline void asc_out(struct uart_port *port, u32 offset, u32 value)
 166 {
 167 #ifdef writel_relaxed
 168         writel_relaxed(value, port->membase + offset);
 169 #else
 170         writel(value, port->membase + offset);
 171 #endif
 172 }
 173 
 174 /*
 175  * Some simple utility functions to enable and disable interrupts.
 176  * Note that these need to be called with interrupts disabled.
 177  */
 178 static inline void asc_disable_tx_interrupts(struct uart_port *port)
 179 {
 180         u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_THE;
 181         asc_out(port, ASC_INTEN, intenable);
 182         (void)asc_in(port, ASC_INTEN);  /* Defeat bus write posting */
 183 }
 184 
 185 static inline void asc_enable_tx_interrupts(struct uart_port *port)
 186 {
 187         u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_THE;
 188         asc_out(port, ASC_INTEN, intenable);
 189 }
 190 
 191 static inline void asc_disable_rx_interrupts(struct uart_port *port)
 192 {
 193         u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_RBE;
 194         asc_out(port, ASC_INTEN, intenable);
 195         (void)asc_in(port, ASC_INTEN);  /* Defeat bus write posting */
 196 }
 197 
 198 static inline void asc_enable_rx_interrupts(struct uart_port *port)
 199 {
 200         u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_RBE;
 201         asc_out(port, ASC_INTEN, intenable);
 202 }
 203 
 204 static inline u32 asc_txfifo_is_empty(struct uart_port *port)
 205 {
 206         return asc_in(port, ASC_STA) & ASC_STA_TE;
 207 }
 208 
 209 static inline u32 asc_txfifo_is_half_empty(struct uart_port *port)
 210 {
 211         return asc_in(port, ASC_STA) & ASC_STA_THE;
 212 }
 213 
 214 static inline const char *asc_port_name(struct uart_port *port)
 215 {
 216         return to_platform_device(port->dev)->name;
 217 }
 218 
 219 /*----------------------------------------------------------------------*/
 220 
 221 /*
 222  * This section contains code to support the use of the ASC as a
 223  * generic serial port.
 224  */
 225 
 226 static inline unsigned asc_hw_txroom(struct uart_port *port)
 227 {
 228         u32 status = asc_in(port, ASC_STA);
 229 
 230         if (status & ASC_STA_THE)
 231                 return port->fifosize / 2;
 232         else if (!(status & ASC_STA_TF))
 233                 return 1;
 234 
 235         return 0;
 236 }
 237 
 238 /*
 239  * Start transmitting chars.
 240  * This is called from both interrupt and task level.
 241  * Either way interrupts are disabled.
 242  */
 243 static void asc_transmit_chars(struct uart_port *port)
 244 {
 245         struct circ_buf *xmit = &port->state->xmit;
 246         int txroom;
 247         unsigned char c;
 248 
 249         txroom = asc_hw_txroom(port);
 250 
 251         if ((txroom != 0) && port->x_char) {
 252                 c = port->x_char;
 253                 port->x_char = 0;
 254                 asc_out(port, ASC_TXBUF, c);
 255                 port->icount.tx++;
 256                 txroom = asc_hw_txroom(port);
 257         }
 258 
 259         if (uart_tx_stopped(port)) {
 260                 /*
 261                  * We should try and stop the hardware here, but I
 262                  * don't think the ASC has any way to do that.
 263                  */
 264                 asc_disable_tx_interrupts(port);
 265                 return;
 266         }
 267 
 268         if (uart_circ_empty(xmit)) {
 269                 asc_disable_tx_interrupts(port);
 270                 return;
 271         }
 272 
 273         if (txroom == 0)
 274                 return;
 275 
 276         do {
 277                 c = xmit->buf[xmit->tail];
 278                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 279                 asc_out(port, ASC_TXBUF, c);
 280                 port->icount.tx++;
 281                 txroom--;
 282         } while ((txroom > 0) && (!uart_circ_empty(xmit)));
 283 
 284         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 285                 uart_write_wakeup(port);
 286 
 287         if (uart_circ_empty(xmit))
 288                 asc_disable_tx_interrupts(port);
 289 }
 290 
 291 static void asc_receive_chars(struct uart_port *port)
 292 {
 293         struct tty_port *tport = &port->state->port;
 294         unsigned long status, mode;
 295         unsigned long c = 0;
 296         char flag;
 297         bool ignore_pe = false;
 298 
 299         /*
 300          * Datasheet states: If the MODE field selects an 8-bit frame then
 301          * this [parity error] bit is undefined. Software should ignore this
 302          * bit when reading 8-bit frames.
 303          */
 304         mode = asc_in(port, ASC_CTL) & ASC_CTL_MODE_MSK;
 305         if (mode == ASC_CTL_MODE_8BIT || mode == ASC_CTL_MODE_8BIT_PAR)
 306                 ignore_pe = true;
 307 
 308         if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
 309                 pm_wakeup_event(tport->tty->dev, 0);
 310 
 311         while ((status = asc_in(port, ASC_STA)) & ASC_STA_RBF) {
 312                 c = asc_in(port, ASC_RXBUF) | ASC_RXBUF_DUMMY_RX;
 313                 flag = TTY_NORMAL;
 314                 port->icount.rx++;
 315 
 316                 if (status & ASC_STA_OE || c & ASC_RXBUF_FE ||
 317                     (c & ASC_RXBUF_PE && !ignore_pe)) {
 318 
 319                         if (c & ASC_RXBUF_FE) {
 320                                 if (c == (ASC_RXBUF_FE | ASC_RXBUF_DUMMY_RX)) {
 321                                         port->icount.brk++;
 322                                         if (uart_handle_break(port))
 323                                                 continue;
 324                                         c |= ASC_RXBUF_DUMMY_BE;
 325                                 } else {
 326                                         port->icount.frame++;
 327                                 }
 328                         } else if (c & ASC_RXBUF_PE) {
 329                                 port->icount.parity++;
 330                         }
 331                         /*
 332                          * Reading any data from the RX FIFO clears the
 333                          * overflow error condition.
 334                          */
 335                         if (status & ASC_STA_OE) {
 336                                 port->icount.overrun++;
 337                                 c |= ASC_RXBUF_DUMMY_OE;
 338                         }
 339 
 340                         c &= port->read_status_mask;
 341 
 342                         if (c & ASC_RXBUF_DUMMY_BE)
 343                                 flag = TTY_BREAK;
 344                         else if (c & ASC_RXBUF_PE)
 345                                 flag = TTY_PARITY;
 346                         else if (c & ASC_RXBUF_FE)
 347                                 flag = TTY_FRAME;
 348                 }
 349 
 350                 if (uart_handle_sysrq_char(port, c & 0xff))
 351                         continue;
 352 
 353                 uart_insert_char(port, c, ASC_RXBUF_DUMMY_OE, c & 0xff, flag);
 354         }
 355 
 356         /* Tell the rest of the system the news. New characters! */
 357         tty_flip_buffer_push(tport);
 358 }
 359 
 360 static irqreturn_t asc_interrupt(int irq, void *ptr)
 361 {
 362         struct uart_port *port = ptr;
 363         u32 status;
 364 
 365         spin_lock(&port->lock);
 366 
 367         status = asc_in(port, ASC_STA);
 368 
 369         if (status & ASC_STA_RBF) {
 370                 /* Receive FIFO not empty */
 371                 asc_receive_chars(port);
 372         }
 373 
 374         if ((status & ASC_STA_THE) &&
 375             (asc_in(port, ASC_INTEN) & ASC_INTEN_THE)) {
 376                 /* Transmitter FIFO at least half empty */
 377                 asc_transmit_chars(port);
 378         }
 379 
 380         spin_unlock(&port->lock);
 381 
 382         return IRQ_HANDLED;
 383 }
 384 
 385 /*----------------------------------------------------------------------*/
 386 
 387 /*
 388  * UART Functions
 389  */
 390 
 391 static unsigned int asc_tx_empty(struct uart_port *port)
 392 {
 393         return asc_txfifo_is_empty(port) ? TIOCSER_TEMT : 0;
 394 }
 395 
 396 static void asc_set_mctrl(struct uart_port *port, unsigned int mctrl)
 397 {
 398         struct asc_port *ascport = to_asc_port(port);
 399 
 400         /*
 401          * This routine is used for seting signals of: DTR, DCD, CTS and RTS.
 402          * We use ASC's hardware for CTS/RTS when hardware flow-control is
 403          * enabled, however if the RTS line is required for another purpose,
 404          * commonly controlled using HUP from userspace, then we need to toggle
 405          * it manually, using GPIO.
 406          *
 407          * Some boards also have DTR and DCD implemented using PIO pins, code to
 408          * do this should be hooked in here.
 409          */
 410 
 411         if (!ascport->rts)
 412                 return;
 413 
 414         /* If HW flow-control is enabled, we can't fiddle with the RTS line */
 415         if (asc_in(port, ASC_CTL) & ASC_CTL_CTSENABLE)
 416                 return;
 417 
 418         gpiod_set_value(ascport->rts, mctrl & TIOCM_RTS);
 419 }
 420 
 421 static unsigned int asc_get_mctrl(struct uart_port *port)
 422 {
 423         /*
 424          * This routine is used for geting signals of: DTR, DCD, DSR, RI,
 425          * and CTS/RTS
 426          */
 427         return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
 428 }
 429 
 430 /* There are probably characters waiting to be transmitted. */
 431 static void asc_start_tx(struct uart_port *port)
 432 {
 433         struct circ_buf *xmit = &port->state->xmit;
 434 
 435         if (!uart_circ_empty(xmit))
 436                 asc_enable_tx_interrupts(port);
 437 }
 438 
 439 /* Transmit stop */
 440 static void asc_stop_tx(struct uart_port *port)
 441 {
 442         asc_disable_tx_interrupts(port);
 443 }
 444 
 445 /* Receive stop */
 446 static void asc_stop_rx(struct uart_port *port)
 447 {
 448         asc_disable_rx_interrupts(port);
 449 }
 450 
 451 /* Handle breaks - ignored by us */
 452 static void asc_break_ctl(struct uart_port *port, int break_state)
 453 {
 454         /* Nothing here yet .. */
 455 }
 456 
 457 /*
 458  * Enable port for reception.
 459  */
 460 static int asc_startup(struct uart_port *port)
 461 {
 462         if (request_irq(port->irq, asc_interrupt, 0,
 463                         asc_port_name(port), port)) {
 464                 dev_err(port->dev, "cannot allocate irq.\n");
 465                 return -ENODEV;
 466         }
 467 
 468         asc_transmit_chars(port);
 469         asc_enable_rx_interrupts(port);
 470 
 471         return 0;
 472 }
 473 
 474 static void asc_shutdown(struct uart_port *port)
 475 {
 476         asc_disable_tx_interrupts(port);
 477         asc_disable_rx_interrupts(port);
 478         free_irq(port->irq, port);
 479 }
 480 
 481 static void asc_pm(struct uart_port *port, unsigned int state,
 482                 unsigned int oldstate)
 483 {
 484         struct asc_port *ascport = to_asc_port(port);
 485         unsigned long flags = 0;
 486         u32 ctl;
 487 
 488         switch (state) {
 489         case UART_PM_STATE_ON:
 490                 clk_prepare_enable(ascport->clk);
 491                 break;
 492         case UART_PM_STATE_OFF:
 493                 /*
 494                  * Disable the ASC baud rate generator, which is as close as
 495                  * we can come to turning it off. Note this is not called with
 496                  * the port spinlock held.
 497                  */
 498                 spin_lock_irqsave(&port->lock, flags);
 499                 ctl = asc_in(port, ASC_CTL) & ~ASC_CTL_RUN;
 500                 asc_out(port, ASC_CTL, ctl);
 501                 spin_unlock_irqrestore(&port->lock, flags);
 502                 clk_disable_unprepare(ascport->clk);
 503                 break;
 504         }
 505 }
 506 
 507 static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
 508                             struct ktermios *old)
 509 {
 510         struct asc_port *ascport = to_asc_port(port);
 511         struct device_node *np = port->dev->of_node;
 512         struct gpio_desc *gpiod;
 513         unsigned int baud;
 514         u32 ctrl_val;
 515         tcflag_t cflag;
 516         unsigned long flags;
 517 
 518         /* Update termios to reflect hardware capabilities */
 519         termios->c_cflag &= ~(CMSPAR |
 520                          (ascport->hw_flow_control ? 0 : CRTSCTS));
 521 
 522         port->uartclk = clk_get_rate(ascport->clk);
 523 
 524         baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
 525         cflag = termios->c_cflag;
 526 
 527         spin_lock_irqsave(&port->lock, flags);
 528 
 529         /* read control register */
 530         ctrl_val = asc_in(port, ASC_CTL);
 531 
 532         /* stop serial port and reset value */
 533         asc_out(port, ASC_CTL, (ctrl_val & ~ASC_CTL_RUN));
 534         ctrl_val = ASC_CTL_RXENABLE | ASC_CTL_FIFOENABLE;
 535 
 536         /* reset fifo rx & tx */
 537         asc_out(port, ASC_TXRESET, 1);
 538         asc_out(port, ASC_RXRESET, 1);
 539 
 540         /* set character length */
 541         if ((cflag & CSIZE) == CS7) {
 542                 ctrl_val |= ASC_CTL_MODE_7BIT_PAR;
 543         } else {
 544                 ctrl_val |= (cflag & PARENB) ?  ASC_CTL_MODE_8BIT_PAR :
 545                                                 ASC_CTL_MODE_8BIT;
 546         }
 547 
 548         /* set stop bit */
 549         ctrl_val |= (cflag & CSTOPB) ? ASC_CTL_STOP_2BIT : ASC_CTL_STOP_1BIT;
 550 
 551         /* odd parity */
 552         if (cflag & PARODD)
 553                 ctrl_val |= ASC_CTL_PARITYODD;
 554 
 555         /* hardware flow control */
 556         if ((cflag & CRTSCTS)) {
 557                 ctrl_val |= ASC_CTL_CTSENABLE;
 558 
 559                 /* If flow-control selected, stop handling RTS manually */
 560                 if (ascport->rts) {
 561                         devm_gpiod_put(port->dev, ascport->rts);
 562                         ascport->rts = NULL;
 563 
 564                         pinctrl_select_state(ascport->pinctrl,
 565                                              ascport->states[DEFAULT]);
 566                 }
 567         } else {
 568                 /* If flow-control disabled, it's safe to handle RTS manually */
 569                 if (!ascport->rts && ascport->states[NO_HW_FLOWCTRL]) {
 570                         pinctrl_select_state(ascport->pinctrl,
 571                                              ascport->states[NO_HW_FLOWCTRL]);
 572 
 573                         gpiod = devm_fwnode_get_gpiod_from_child(port->dev,
 574                                                                  "rts",
 575                                                                  &np->fwnode,
 576                                                                  GPIOD_OUT_LOW,
 577                                                                  np->name);
 578                         if (!IS_ERR(gpiod))
 579                                 ascport->rts = gpiod;
 580                 }
 581         }
 582 
 583         if ((baud < 19200) && !ascport->force_m1) {
 584                 asc_out(port, ASC_BAUDRATE, (port->uartclk / (16 * baud)));
 585         } else {
 586                 /*
 587                  * MODE 1: recommended for high bit rates (above 19.2K)
 588                  *
 589                  *                   baudrate * 16 * 2^16
 590                  * ASCBaudRate =   ------------------------
 591                  *                          inputclock
 592                  *
 593                  * To keep maths inside 64bits, we divide inputclock by 16.
 594                  */
 595                 u64 dividend = (u64)baud * (1 << 16);
 596 
 597                 do_div(dividend, port->uartclk / 16);
 598                 asc_out(port, ASC_BAUDRATE, dividend);
 599                 ctrl_val |= ASC_CTL_BAUDMODE;
 600         }
 601 
 602         uart_update_timeout(port, cflag, baud);
 603 
 604         ascport->port.read_status_mask = ASC_RXBUF_DUMMY_OE;
 605         if (termios->c_iflag & INPCK)
 606                 ascport->port.read_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE;
 607         if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
 608                 ascport->port.read_status_mask |= ASC_RXBUF_DUMMY_BE;
 609 
 610         /*
 611          * Characters to ignore
 612          */
 613         ascport->port.ignore_status_mask = 0;
 614         if (termios->c_iflag & IGNPAR)
 615                 ascport->port.ignore_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE;
 616         if (termios->c_iflag & IGNBRK) {
 617                 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_BE;
 618                 /*
 619                  * If we're ignoring parity and break indicators,
 620                  * ignore overruns too (for real raw support).
 621                  */
 622                 if (termios->c_iflag & IGNPAR)
 623                         ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_OE;
 624         }
 625 
 626         /*
 627          * Ignore all characters if CREAD is not set.
 628          */
 629         if (!(termios->c_cflag & CREAD))
 630                 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_RX;
 631 
 632         /* Set the timeout */
 633         asc_out(port, ASC_TIMEOUT, 20);
 634 
 635         /* write final value and enable port */
 636         asc_out(port, ASC_CTL, (ctrl_val | ASC_CTL_RUN));
 637 
 638         spin_unlock_irqrestore(&port->lock, flags);
 639 }
 640 
 641 static const char *asc_type(struct uart_port *port)
 642 {
 643         return (port->type == PORT_ASC) ? DRIVER_NAME : NULL;
 644 }
 645 
 646 static void asc_release_port(struct uart_port *port)
 647 {
 648 }
 649 
 650 static int asc_request_port(struct uart_port *port)
 651 {
 652         return 0;
 653 }
 654 
 655 /*
 656  * Called when the port is opened, and UPF_BOOT_AUTOCONF flag is set
 657  * Set type field if successful
 658  */
 659 static void asc_config_port(struct uart_port *port, int flags)
 660 {
 661         if ((flags & UART_CONFIG_TYPE))
 662                 port->type = PORT_ASC;
 663 }
 664 
 665 static int
 666 asc_verify_port(struct uart_port *port, struct serial_struct *ser)
 667 {
 668         /* No user changeable parameters */
 669         return -EINVAL;
 670 }
 671 
 672 #ifdef CONFIG_CONSOLE_POLL
 673 /*
 674  * Console polling routines for writing and reading from the uart while
 675  * in an interrupt or debug context (i.e. kgdb).
 676  */
 677 
 678 static int asc_get_poll_char(struct uart_port *port)
 679 {
 680         if (!(asc_in(port, ASC_STA) & ASC_STA_RBF))
 681                 return NO_POLL_CHAR;
 682 
 683         return asc_in(port, ASC_RXBUF);
 684 }
 685 
 686 static void asc_put_poll_char(struct uart_port *port, unsigned char c)
 687 {
 688         while (!asc_txfifo_is_half_empty(port))
 689                 cpu_relax();
 690         asc_out(port, ASC_TXBUF, c);
 691 }
 692 
 693 #endif /* CONFIG_CONSOLE_POLL */
 694 
 695 /*---------------------------------------------------------------------*/
 696 
 697 static const struct uart_ops asc_uart_ops = {
 698         .tx_empty       = asc_tx_empty,
 699         .set_mctrl      = asc_set_mctrl,
 700         .get_mctrl      = asc_get_mctrl,
 701         .start_tx       = asc_start_tx,
 702         .stop_tx        = asc_stop_tx,
 703         .stop_rx        = asc_stop_rx,
 704         .break_ctl      = asc_break_ctl,
 705         .startup        = asc_startup,
 706         .shutdown       = asc_shutdown,
 707         .set_termios    = asc_set_termios,
 708         .type           = asc_type,
 709         .release_port   = asc_release_port,
 710         .request_port   = asc_request_port,
 711         .config_port    = asc_config_port,
 712         .verify_port    = asc_verify_port,
 713         .pm             = asc_pm,
 714 #ifdef CONFIG_CONSOLE_POLL
 715         .poll_get_char = asc_get_poll_char,
 716         .poll_put_char = asc_put_poll_char,
 717 #endif /* CONFIG_CONSOLE_POLL */
 718 };
 719 
 720 static int asc_init_port(struct asc_port *ascport,
 721                           struct platform_device *pdev)
 722 {
 723         struct uart_port *port = &ascport->port;
 724         struct resource *res;
 725         int ret;
 726 
 727         port->iotype    = UPIO_MEM;
 728         port->flags     = UPF_BOOT_AUTOCONF;
 729         port->ops       = &asc_uart_ops;
 730         port->fifosize  = ASC_FIFO_SIZE;
 731         port->dev       = &pdev->dev;
 732         port->irq       = platform_get_irq(pdev, 0);
 733 
 734         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 735         port->membase = devm_ioremap_resource(&pdev->dev, res);
 736         if (IS_ERR(port->membase))
 737                 return PTR_ERR(port->membase);
 738         port->mapbase = res->start;
 739 
 740         spin_lock_init(&port->lock);
 741 
 742         ascport->clk = devm_clk_get(&pdev->dev, NULL);
 743 
 744         if (WARN_ON(IS_ERR(ascport->clk)))
 745                 return -EINVAL;
 746         /* ensure that clk rate is correct by enabling the clk */
 747         clk_prepare_enable(ascport->clk);
 748         ascport->port.uartclk = clk_get_rate(ascport->clk);
 749         WARN_ON(ascport->port.uartclk == 0);
 750         clk_disable_unprepare(ascport->clk);
 751 
 752         ascport->pinctrl = devm_pinctrl_get(&pdev->dev);
 753         if (IS_ERR(ascport->pinctrl)) {
 754                 ret = PTR_ERR(ascport->pinctrl);
 755                 dev_err(&pdev->dev, "Failed to get Pinctrl: %d\n", ret);
 756                 return ret;
 757         }
 758 
 759         ascport->states[DEFAULT] =
 760                 pinctrl_lookup_state(ascport->pinctrl, "default");
 761         if (IS_ERR(ascport->states[DEFAULT])) {
 762                 ret = PTR_ERR(ascport->states[DEFAULT]);
 763                 dev_err(&pdev->dev,
 764                         "Failed to look up Pinctrl state 'default': %d\n", ret);
 765                 return ret;
 766         }
 767 
 768         /* "no-hw-flowctrl" state is optional */
 769         ascport->states[NO_HW_FLOWCTRL] =
 770                 pinctrl_lookup_state(ascport->pinctrl, "no-hw-flowctrl");
 771         if (IS_ERR(ascport->states[NO_HW_FLOWCTRL]))
 772                 ascport->states[NO_HW_FLOWCTRL] = NULL;
 773 
 774         return 0;
 775 }
 776 
 777 static struct asc_port *asc_of_get_asc_port(struct platform_device *pdev)
 778 {
 779         struct device_node *np = pdev->dev.of_node;
 780         int id;
 781 
 782         if (!np)
 783                 return NULL;
 784 
 785         id = of_alias_get_id(np, "serial");
 786         if (id < 0)
 787                 id = of_alias_get_id(np, ASC_SERIAL_NAME);
 788 
 789         if (id < 0)
 790                 id = 0;
 791 
 792         if (WARN_ON(id >= ASC_MAX_PORTS))
 793                 return NULL;
 794 
 795         asc_ports[id].hw_flow_control = of_property_read_bool(np,
 796                                                         "uart-has-rtscts");
 797         asc_ports[id].force_m1 =  of_property_read_bool(np, "st,force_m1");
 798         asc_ports[id].port.line = id;
 799         asc_ports[id].rts = NULL;
 800 
 801         return &asc_ports[id];
 802 }
 803 
 804 #ifdef CONFIG_OF
 805 static const struct of_device_id asc_match[] = {
 806         { .compatible = "st,asc", },
 807         {},
 808 };
 809 
 810 MODULE_DEVICE_TABLE(of, asc_match);
 811 #endif
 812 
 813 static int asc_serial_probe(struct platform_device *pdev)
 814 {
 815         int ret;
 816         struct asc_port *ascport;
 817 
 818         ascport = asc_of_get_asc_port(pdev);
 819         if (!ascport)
 820                 return -ENODEV;
 821 
 822         ret = asc_init_port(ascport, pdev);
 823         if (ret)
 824                 return ret;
 825 
 826         ret = uart_add_one_port(&asc_uart_driver, &ascport->port);
 827         if (ret)
 828                 return ret;
 829 
 830         platform_set_drvdata(pdev, &ascport->port);
 831 
 832         return 0;
 833 }
 834 
 835 static int asc_serial_remove(struct platform_device *pdev)
 836 {
 837         struct uart_port *port = platform_get_drvdata(pdev);
 838 
 839         return uart_remove_one_port(&asc_uart_driver, port);
 840 }
 841 
 842 #ifdef CONFIG_PM_SLEEP
 843 static int asc_serial_suspend(struct device *dev)
 844 {
 845         struct uart_port *port = dev_get_drvdata(dev);
 846 
 847         return uart_suspend_port(&asc_uart_driver, port);
 848 }
 849 
 850 static int asc_serial_resume(struct device *dev)
 851 {
 852         struct uart_port *port = dev_get_drvdata(dev);
 853 
 854         return uart_resume_port(&asc_uart_driver, port);
 855 }
 856 
 857 #endif /* CONFIG_PM_SLEEP */
 858 
 859 /*----------------------------------------------------------------------*/
 860 
 861 #ifdef CONFIG_SERIAL_ST_ASC_CONSOLE
 862 static void asc_console_putchar(struct uart_port *port, int ch)
 863 {
 864         unsigned int timeout = 1000000;
 865 
 866         /* Wait for upto 1 second in case flow control is stopping us. */
 867         while (--timeout && !asc_txfifo_is_half_empty(port))
 868                 udelay(1);
 869 
 870         asc_out(port, ASC_TXBUF, ch);
 871 }
 872 
 873 /*
 874  *  Print a string to the serial port trying not to disturb
 875  *  any possible real use of the port...
 876  */
 877 
 878 static void asc_console_write(struct console *co, const char *s, unsigned count)
 879 {
 880         struct uart_port *port = &asc_ports[co->index].port;
 881         unsigned long flags;
 882         unsigned long timeout = 1000000;
 883         int locked = 1;
 884         u32 intenable;
 885 
 886         if (port->sysrq)
 887                 locked = 0; /* asc_interrupt has already claimed the lock */
 888         else if (oops_in_progress)
 889                 locked = spin_trylock_irqsave(&port->lock, flags);
 890         else
 891                 spin_lock_irqsave(&port->lock, flags);
 892 
 893         /*
 894          * Disable interrupts so we don't get the IRQ line bouncing
 895          * up and down while interrupts are disabled.
 896          */
 897         intenable = asc_in(port, ASC_INTEN);
 898         asc_out(port, ASC_INTEN, 0);
 899         (void)asc_in(port, ASC_INTEN);  /* Defeat bus write posting */
 900 
 901         uart_console_write(port, s, count, asc_console_putchar);
 902 
 903         while (--timeout && !asc_txfifo_is_empty(port))
 904                 udelay(1);
 905 
 906         asc_out(port, ASC_INTEN, intenable);
 907 
 908         if (locked)
 909                 spin_unlock_irqrestore(&port->lock, flags);
 910 }
 911 
 912 static int asc_console_setup(struct console *co, char *options)
 913 {
 914         struct asc_port *ascport;
 915         int baud = 115200;
 916         int bits = 8;
 917         int parity = 'n';
 918         int flow = 'n';
 919 
 920         if (co->index >= ASC_MAX_PORTS)
 921                 return -ENODEV;
 922 
 923         ascport = &asc_ports[co->index];
 924 
 925         /*
 926          * This driver does not support early console initialization
 927          * (use ARM early printk support instead), so we only expect
 928          * this to be called during the uart port registration when the
 929          * driver gets probed and the port should be mapped at that point.
 930          */
 931         if (ascport->port.mapbase == 0 || ascport->port.membase == NULL)
 932                 return -ENXIO;
 933 
 934         if (options)
 935                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 936 
 937         return uart_set_options(&ascport->port, co, baud, parity, bits, flow);
 938 }
 939 
 940 static struct console asc_console = {
 941         .name           = ASC_SERIAL_NAME,
 942         .device         = uart_console_device,
 943         .write          = asc_console_write,
 944         .setup          = asc_console_setup,
 945         .flags          = CON_PRINTBUFFER,
 946         .index          = -1,
 947         .data           = &asc_uart_driver,
 948 };
 949 
 950 #define ASC_SERIAL_CONSOLE (&asc_console)
 951 
 952 #else
 953 #define ASC_SERIAL_CONSOLE NULL
 954 #endif /* CONFIG_SERIAL_ST_ASC_CONSOLE */
 955 
 956 static struct uart_driver asc_uart_driver = {
 957         .owner          = THIS_MODULE,
 958         .driver_name    = DRIVER_NAME,
 959         .dev_name       = ASC_SERIAL_NAME,
 960         .major          = 0,
 961         .minor          = 0,
 962         .nr             = ASC_MAX_PORTS,
 963         .cons           = ASC_SERIAL_CONSOLE,
 964 };
 965 
 966 static const struct dev_pm_ops asc_serial_pm_ops = {
 967         SET_SYSTEM_SLEEP_PM_OPS(asc_serial_suspend, asc_serial_resume)
 968 };
 969 
 970 static struct platform_driver asc_serial_driver = {
 971         .probe          = asc_serial_probe,
 972         .remove         = asc_serial_remove,
 973         .driver = {
 974                 .name   = DRIVER_NAME,
 975                 .pm     = &asc_serial_pm_ops,
 976                 .of_match_table = of_match_ptr(asc_match),
 977         },
 978 };
 979 
 980 static int __init asc_init(void)
 981 {
 982         int ret;
 983         static const char banner[] __initconst =
 984                 KERN_INFO "STMicroelectronics ASC driver initialized\n";
 985 
 986         printk(banner);
 987 
 988         ret = uart_register_driver(&asc_uart_driver);
 989         if (ret)
 990                 return ret;
 991 
 992         ret = platform_driver_register(&asc_serial_driver);
 993         if (ret)
 994                 uart_unregister_driver(&asc_uart_driver);
 995 
 996         return ret;
 997 }
 998 
 999 static void __exit asc_exit(void)
1000 {
1001         platform_driver_unregister(&asc_serial_driver);
1002         uart_unregister_driver(&asc_uart_driver);
1003 }
1004 
1005 module_init(asc_init);
1006 module_exit(asc_exit);
1007 
1008 MODULE_ALIAS("platform:" DRIVER_NAME);
1009 MODULE_AUTHOR("STMicroelectronics (R&D) Limited");
1010 MODULE_DESCRIPTION("STMicroelectronics ASC serial port driver");
1011 MODULE_LICENSE("GPL");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/tty/serial/st-asc.c

DEFINITIONS
