drivers/tty/serial/arc

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
arc_serial_stop_rx
arc_serial_stop_tx
arc_serial_tx_empty
arc_serial_tx_chars
arc_serial_start_tx
arc_serial_rx_chars
arc_serial_isr
arc_serial_get_mctrl
arc_serial_set_mctrl
arc_serial_break_ctl
arc_serial_startup
arc_serial_shutdown
arc_serial_set_termios
arc_serial_type
arc_serial_release_port
arc_serial_request_port
arc_serial_verify_port
arc_serial_config_port
arc_serial_poll_putchar
arc_serial_poll_getchar
arc_serial_console_setup
arc_serial_console_putchar
arc_serial_console_write
arc_early_serial_write
arc_early_console_setup
arc_serial_probe
arc_serial_remove
arc_serial_init
arc_serial_exit
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * ARC On-Chip(fpga) UART Driver
   4  *
   5  * Copyright (C) 2010-2012 Synopsys, Inc. (www.synopsys.com)
   6  *
   7  * vineetg: July 10th 2012
   8  *  -Decoupled the driver from arch/arc
   9  *    +Using platform_get_resource() for irq/membase (thx to bfin_uart.c)
  10  *    +Using early_platform_xxx() for early console (thx to mach-shmobile/xxx)
  11  *
  12  * Vineetg: Aug 21st 2010
  13  *  -Is uart_tx_stopped() not done in tty write path as it has already been
  14  *   taken care of, in serial core
  15  *
  16  * Vineetg: Aug 18th 2010
  17  *  -New Serial Core based ARC UART driver
  18  *  -Derived largely from blackfin driver albiet with some major tweaks
  19  *
  20  * TODO:
  21  *  -check if sysreq works
  22  */
  23 
  24 #if defined(CONFIG_SERIAL_ARC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  25 #define SUPPORT_SYSRQ
  26 #endif
  27 
  28 #include <linux/module.h>
  29 #include <linux/serial.h>
  30 #include <linux/console.h>
  31 #include <linux/sysrq.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/tty.h>
  34 #include <linux/tty_flip.h>
  35 #include <linux/serial_core.h>
  36 #include <linux/io.h>
  37 #include <linux/of_irq.h>
  38 #include <linux/of_address.h>
  39 
  40 /*************************************
  41  * ARC UART Hardware Specs
  42  ************************************/
  43 #define ARC_UART_TX_FIFO_SIZE  1
  44 
  45 /*
  46  * UART Register set (this is not a Standards Compliant IP)
  47  * Also each reg is Word aligned, but only 8 bits wide
  48  */
  49 #define R_ID0   0
  50 #define R_ID1   4
  51 #define R_ID2   8
  52 #define R_ID3   12
  53 #define R_DATA  16
  54 #define R_STS   20
  55 #define R_BAUDL 24
  56 #define R_BAUDH 28
  57 
  58 /* Bits for UART Status Reg (R/W) */
  59 #define RXIENB  0x04    /* Receive Interrupt Enable */
  60 #define TXIENB  0x40    /* Transmit Interrupt Enable */
  61 
  62 #define RXEMPTY 0x20    /* Receive FIFO Empty: No char receivede */
  63 #define TXEMPTY 0x80    /* Transmit FIFO Empty, thus char can be written into */
  64 
  65 #define RXFULL  0x08    /* Receive FIFO full */
  66 #define RXFULL1 0x10    /* Receive FIFO has space for 1 char (tot space=4) */
  67 
  68 #define RXFERR  0x01    /* Frame Error: Stop Bit not detected */
  69 #define RXOERR  0x02    /* OverFlow Err: Char recv but RXFULL still set */
  70 
  71 /* Uart bit fiddling helpers: lowest level */
  72 #define RBASE(port, reg)      (port->membase + reg)
  73 #define UART_REG_SET(u, r, v) writeb((v), RBASE(u, r))
  74 #define UART_REG_GET(u, r)    readb(RBASE(u, r))
  75 
  76 #define UART_REG_OR(u, r, v)  UART_REG_SET(u, r, UART_REG_GET(u, r) | (v))
  77 #define UART_REG_CLR(u, r, v) UART_REG_SET(u, r, UART_REG_GET(u, r) & ~(v))
  78 
  79 /* Uart bit fiddling helpers: API level */
  80 #define UART_SET_DATA(uart, val)   UART_REG_SET(uart, R_DATA, val)
  81 #define UART_GET_DATA(uart)        UART_REG_GET(uart, R_DATA)
  82 
  83 #define UART_SET_BAUDH(uart, val)  UART_REG_SET(uart, R_BAUDH, val)
  84 #define UART_SET_BAUDL(uart, val)  UART_REG_SET(uart, R_BAUDL, val)
  85 
  86 #define UART_CLR_STATUS(uart, val) UART_REG_CLR(uart, R_STS, val)
  87 #define UART_GET_STATUS(uart)      UART_REG_GET(uart, R_STS)
  88 
  89 #define UART_ALL_IRQ_DISABLE(uart) UART_REG_CLR(uart, R_STS, RXIENB|TXIENB)
  90 #define UART_RX_IRQ_DISABLE(uart)  UART_REG_CLR(uart, R_STS, RXIENB)
  91 #define UART_TX_IRQ_DISABLE(uart)  UART_REG_CLR(uart, R_STS, TXIENB)
  92 
  93 #define UART_ALL_IRQ_ENABLE(uart)  UART_REG_OR(uart, R_STS, RXIENB|TXIENB)
  94 #define UART_RX_IRQ_ENABLE(uart)   UART_REG_OR(uart, R_STS, RXIENB)
  95 #define UART_TX_IRQ_ENABLE(uart)   UART_REG_OR(uart, R_STS, TXIENB)
  96 
  97 #define ARC_SERIAL_DEV_NAME     "ttyARC"
  98 
  99 struct arc_uart_port {
 100         struct uart_port port;
 101         unsigned long baud;
 102 };
 103 
 104 #define to_arc_port(uport)  container_of(uport, struct arc_uart_port, port)
 105 
 106 static struct arc_uart_port arc_uart_ports[CONFIG_SERIAL_ARC_NR_PORTS];
 107 
 108 #ifdef CONFIG_SERIAL_ARC_CONSOLE
 109 static struct console arc_console;
 110 #endif
 111 
 112 #define DRIVER_NAME     "arc-uart"
 113 
 114 static struct uart_driver arc_uart_driver = {
 115         .owner          = THIS_MODULE,
 116         .driver_name    = DRIVER_NAME,
 117         .dev_name       = ARC_SERIAL_DEV_NAME,
 118         .major          = 0,
 119         .minor          = 0,
 120         .nr             = CONFIG_SERIAL_ARC_NR_PORTS,
 121 #ifdef CONFIG_SERIAL_ARC_CONSOLE
 122         .cons           = &arc_console,
 123 #endif
 124 };
 125 
 126 static void arc_serial_stop_rx(struct uart_port *port)
 127 {
 128         UART_RX_IRQ_DISABLE(port);
 129 }
 130 
 131 static void arc_serial_stop_tx(struct uart_port *port)
 132 {
 133         while (!(UART_GET_STATUS(port) & TXEMPTY))
 134                 cpu_relax();
 135 
 136         UART_TX_IRQ_DISABLE(port);
 137 }
 138 
 139 /*
 140  * Return TIOCSER_TEMT when transmitter is not busy.
 141  */
 142 static unsigned int arc_serial_tx_empty(struct uart_port *port)
 143 {
 144         unsigned int stat;
 145 
 146         stat = UART_GET_STATUS(port);
 147         if (stat & TXEMPTY)
 148                 return TIOCSER_TEMT;
 149 
 150         return 0;
 151 }
 152 
 153 /*
 154  * Driver internal routine, used by both tty(serial core) as well as tx-isr
 155  *  -Called under spinlock in either cases
 156  *  -also tty->stopped has already been checked
 157  *     = by uart_start( ) before calling us
 158  *     = tx_ist checks that too before calling
 159  */
 160 static void arc_serial_tx_chars(struct uart_port *port)
 161 {
 162         struct circ_buf *xmit = &port->state->xmit;
 163         int sent = 0;
 164         unsigned char ch;
 165 
 166         if (unlikely(port->x_char)) {
 167                 UART_SET_DATA(port, port->x_char);
 168                 port->icount.tx++;
 169                 port->x_char = 0;
 170                 sent = 1;
 171         } else if (!uart_circ_empty(xmit)) {
 172                 ch = xmit->buf[xmit->tail];
 173                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 174                 port->icount.tx++;
 175                 while (!(UART_GET_STATUS(port) & TXEMPTY))
 176                         cpu_relax();
 177                 UART_SET_DATA(port, ch);
 178                 sent = 1;
 179         }
 180 
 181         /*
 182          * If num chars in xmit buffer are too few, ask tty layer for more.
 183          * By Hard ISR to schedule processing in software interrupt part
 184          */
 185         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 186                 uart_write_wakeup(port);
 187 
 188         if (sent)
 189                 UART_TX_IRQ_ENABLE(port);
 190 }
 191 
 192 /*
 193  * port is locked and interrupts are disabled
 194  * uart_start( ) calls us under the port spinlock irqsave
 195  */
 196 static void arc_serial_start_tx(struct uart_port *port)
 197 {
 198         arc_serial_tx_chars(port);
 199 }
 200 
 201 static void arc_serial_rx_chars(struct uart_port *port, unsigned int status)
 202 {
 203         unsigned int ch, flg = 0;
 204 
 205         /*
 206          * UART has 4 deep RX-FIFO. Driver's recongnition of this fact
 207          * is very subtle. Here's how ...
 208          * Upon getting a RX-Intr, such that RX-EMPTY=0, meaning data available,
 209          * driver reads the DATA Reg and keeps doing that in a loop, until
 210          * RX-EMPTY=1. Multiple chars being avail, with a single Interrupt,
 211          * before RX-EMPTY=0, implies some sort of buffering going on in the
 212          * controller, which is indeed the Rx-FIFO.
 213          */
 214         do {
 215                 /*
 216                  * This could be an Rx Intr for err (no data),
 217                  * so check err and clear that Intr first
 218                  */
 219                 if (unlikely(status & (RXOERR | RXFERR))) {
 220                         if (status & RXOERR) {
 221                                 port->icount.overrun++;
 222                                 flg = TTY_OVERRUN;
 223                                 UART_CLR_STATUS(port, RXOERR);
 224                         }
 225 
 226                         if (status & RXFERR) {
 227                                 port->icount.frame++;
 228                                 flg = TTY_FRAME;
 229                                 UART_CLR_STATUS(port, RXFERR);
 230                         }
 231                 } else
 232                         flg = TTY_NORMAL;
 233 
 234                 if (status & RXEMPTY)
 235                         continue;
 236 
 237                 ch = UART_GET_DATA(port);
 238                 port->icount.rx++;
 239 
 240                 if (!(uart_handle_sysrq_char(port, ch)))
 241                         uart_insert_char(port, status, RXOERR, ch, flg);
 242 
 243                 spin_unlock(&port->lock);
 244                 tty_flip_buffer_push(&port->state->port);
 245                 spin_lock(&port->lock);
 246         } while (!((status = UART_GET_STATUS(port)) & RXEMPTY));
 247 }
 248 
 249 /*
 250  * A note on the Interrupt handling state machine of this driver
 251  *
 252  * kernel printk writes funnel thru the console driver framework and in order
 253  * to keep things simple as well as efficient, it writes to UART in polled
 254  * mode, in one shot, and exits.
 255  *
 256  * OTOH, Userland output (via tty layer), uses interrupt based writes as there
 257  * can be undeterministic delay between char writes.
 258  *
 259  * Thus Rx-interrupts are always enabled, while tx-interrupts are by default
 260  * disabled.
 261  *
 262  * When tty has some data to send out, serial core calls driver's start_tx
 263  * which
 264  *   -checks-if-tty-buffer-has-char-to-send
 265  *   -writes-data-to-uart
 266  *   -enable-tx-intr
 267  *
 268  * Once data bits are pushed out, controller raises the Tx-room-avail-Interrupt.
 269  * The first thing Tx ISR does is disable further Tx interrupts (as this could
 270  * be the last char to send, before settling down into the quiet polled mode).
 271  * It then calls the exact routine used by tty layer write to send out any
 272  * more char in tty buffer. In case of sending, it re-enables Tx-intr. In case
 273  * of no data, it remains disabled.
 274  * This is how the transmit state machine is dynamically switched on/off
 275  */
 276 
 277 static irqreturn_t arc_serial_isr(int irq, void *dev_id)
 278 {
 279         struct uart_port *port = dev_id;
 280         unsigned int status;
 281 
 282         status = UART_GET_STATUS(port);
 283 
 284         /*
 285          * Single IRQ for both Rx (data available) Tx (room available) Interrupt
 286          * notifications from the UART Controller.
 287          * To demultiplex between the two, we check the relevant bits
 288          */
 289         if (status & RXIENB) {
 290 
 291                 /* already in ISR, no need of xx_irqsave */
 292                 spin_lock(&port->lock);
 293                 arc_serial_rx_chars(port, status);
 294                 spin_unlock(&port->lock);
 295         }
 296 
 297         if ((status & TXIENB) && (status & TXEMPTY)) {
 298 
 299                 /* Unconditionally disable further Tx-Interrupts.
 300                  * will be enabled by tx_chars() if needed.
 301                  */
 302                 UART_TX_IRQ_DISABLE(port);
 303 
 304                 spin_lock(&port->lock);
 305 
 306                 if (!uart_tx_stopped(port))
 307                         arc_serial_tx_chars(port);
 308 
 309                 spin_unlock(&port->lock);
 310         }
 311 
 312         return IRQ_HANDLED;
 313 }
 314 
 315 static unsigned int arc_serial_get_mctrl(struct uart_port *port)
 316 {
 317         /*
 318          * Pretend we have a Modem status reg and following bits are
 319          *  always set, to satify the serial core state machine
 320          *  (DSR) Data Set Ready
 321          *  (CTS) Clear To Send
 322          *  (CAR) Carrier Detect
 323          */
 324         return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 325 }
 326 
 327 static void arc_serial_set_mctrl(struct uart_port *port, unsigned int mctrl)
 328 {
 329         /* MCR not present */
 330 }
 331 
 332 static void arc_serial_break_ctl(struct uart_port *port, int break_state)
 333 {
 334         /* ARC UART doesn't support sending Break signal */
 335 }
 336 
 337 static int arc_serial_startup(struct uart_port *port)
 338 {
 339         /* Before we hook up the ISR, Disable all UART Interrupts */
 340         UART_ALL_IRQ_DISABLE(port);
 341 
 342         if (request_irq(port->irq, arc_serial_isr, 0, "arc uart rx-tx", port)) {
 343                 dev_warn(port->dev, "Unable to attach ARC UART intr\n");
 344                 return -EBUSY;
 345         }
 346 
 347         UART_RX_IRQ_ENABLE(port); /* Only Rx IRQ enabled to begin with */
 348 
 349         return 0;
 350 }
 351 
 352 /* This is not really needed */
 353 static void arc_serial_shutdown(struct uart_port *port)
 354 {
 355         free_irq(port->irq, port);
 356 }
 357 
 358 static void
 359 arc_serial_set_termios(struct uart_port *port, struct ktermios *new,
 360                        struct ktermios *old)
 361 {
 362         struct arc_uart_port *uart = to_arc_port(port);
 363         unsigned int baud, uartl, uarth, hw_val;
 364         unsigned long flags;
 365 
 366         /*
 367          * Use the generic handler so that any specially encoded baud rates
 368          * such as SPD_xx flags or "%B0" can be handled
 369          * Max Baud I suppose will not be more than current 115K * 4
 370          * Formula for ARC UART is: hw-val = ((CLK/(BAUD*4)) -1)
 371          * spread over two 8-bit registers
 372          */
 373         baud = uart_get_baud_rate(port, new, old, 0, 460800);
 374 
 375         hw_val = port->uartclk / (uart->baud * 4) - 1;
 376         uartl = hw_val & 0xFF;
 377         uarth = (hw_val >> 8) & 0xFF;
 378 
 379         spin_lock_irqsave(&port->lock, flags);
 380 
 381         UART_ALL_IRQ_DISABLE(port);
 382 
 383         UART_SET_BAUDL(port, uartl);
 384         UART_SET_BAUDH(port, uarth);
 385 
 386         UART_RX_IRQ_ENABLE(port);
 387 
 388         /*
 389          * UART doesn't support Parity/Hardware Flow Control;
 390          * Only supports 8N1 character size
 391          */
 392         new->c_cflag &= ~(CMSPAR|CRTSCTS|CSIZE);
 393         new->c_cflag |= CS8;
 394 
 395         if (old)
 396                 tty_termios_copy_hw(new, old);
 397 
 398         /* Don't rewrite B0 */
 399         if (tty_termios_baud_rate(new))
 400                 tty_termios_encode_baud_rate(new, baud, baud);
 401 
 402         uart_update_timeout(port, new->c_cflag, baud);
 403 
 404         spin_unlock_irqrestore(&port->lock, flags);
 405 }
 406 
 407 static const char *arc_serial_type(struct uart_port *port)
 408 {
 409         return port->type == PORT_ARC ? DRIVER_NAME : NULL;
 410 }
 411 
 412 static void arc_serial_release_port(struct uart_port *port)
 413 {
 414 }
 415 
 416 static int arc_serial_request_port(struct uart_port *port)
 417 {
 418         return 0;
 419 }
 420 
 421 /*
 422  * Verify the new serial_struct (for TIOCSSERIAL).
 423  */
 424 static int
 425 arc_serial_verify_port(struct uart_port *port, struct serial_struct *ser)
 426 {
 427         if (port->type != PORT_UNKNOWN && ser->type != PORT_ARC)
 428                 return -EINVAL;
 429 
 430         return 0;
 431 }
 432 
 433 /*
 434  * Configure/autoconfigure the port.
 435  */
 436 static void arc_serial_config_port(struct uart_port *port, int flags)
 437 {
 438         if (flags & UART_CONFIG_TYPE)
 439                 port->type = PORT_ARC;
 440 }
 441 
 442 #ifdef CONFIG_CONSOLE_POLL
 443 
 444 static void arc_serial_poll_putchar(struct uart_port *port, unsigned char chr)
 445 {
 446         while (!(UART_GET_STATUS(port) & TXEMPTY))
 447                 cpu_relax();
 448 
 449         UART_SET_DATA(port, chr);
 450 }
 451 
 452 static int arc_serial_poll_getchar(struct uart_port *port)
 453 {
 454         unsigned char chr;
 455 
 456         while (!(UART_GET_STATUS(port) & RXEMPTY))
 457                 cpu_relax();
 458 
 459         chr = UART_GET_DATA(port);
 460         return chr;
 461 }
 462 #endif
 463 
 464 static const struct uart_ops arc_serial_pops = {
 465         .tx_empty       = arc_serial_tx_empty,
 466         .set_mctrl      = arc_serial_set_mctrl,
 467         .get_mctrl      = arc_serial_get_mctrl,
 468         .stop_tx        = arc_serial_stop_tx,
 469         .start_tx       = arc_serial_start_tx,
 470         .stop_rx        = arc_serial_stop_rx,
 471         .break_ctl      = arc_serial_break_ctl,
 472         .startup        = arc_serial_startup,
 473         .shutdown       = arc_serial_shutdown,
 474         .set_termios    = arc_serial_set_termios,
 475         .type           = arc_serial_type,
 476         .release_port   = arc_serial_release_port,
 477         .request_port   = arc_serial_request_port,
 478         .config_port    = arc_serial_config_port,
 479         .verify_port    = arc_serial_verify_port,
 480 #ifdef CONFIG_CONSOLE_POLL
 481         .poll_put_char = arc_serial_poll_putchar,
 482         .poll_get_char = arc_serial_poll_getchar,
 483 #endif
 484 };
 485 
 486 #ifdef CONFIG_SERIAL_ARC_CONSOLE
 487 
 488 static int arc_serial_console_setup(struct console *co, char *options)
 489 {
 490         struct uart_port *port;
 491         int baud = 115200;
 492         int bits = 8;
 493         int parity = 'n';
 494         int flow = 'n';
 495 
 496         if (co->index < 0 || co->index >= CONFIG_SERIAL_ARC_NR_PORTS)
 497                 return -ENODEV;
 498 
 499         /*
 500          * The uart port backing the console (e.g. ttyARC1) might not have been
 501          * init yet. If so, defer the console setup to after the port.
 502          */
 503         port = &arc_uart_ports[co->index].port;
 504         if (!port->membase)
 505                 return -ENODEV;
 506 
 507         if (options)
 508                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 509 
 510         /*
 511          * Serial core will call port->ops->set_termios( )
 512          * which will set the baud reg
 513          */
 514         return uart_set_options(port, co, baud, parity, bits, flow);
 515 }
 516 
 517 static void arc_serial_console_putchar(struct uart_port *port, int ch)
 518 {
 519         while (!(UART_GET_STATUS(port) & TXEMPTY))
 520                 cpu_relax();
 521 
 522         UART_SET_DATA(port, (unsigned char)ch);
 523 }
 524 
 525 /*
 526  * Interrupts are disabled on entering
 527  */
 528 static void arc_serial_console_write(struct console *co, const char *s,
 529                                      unsigned int count)
 530 {
 531         struct uart_port *port = &arc_uart_ports[co->index].port;
 532         unsigned long flags;
 533 
 534         spin_lock_irqsave(&port->lock, flags);
 535         uart_console_write(port, s, count, arc_serial_console_putchar);
 536         spin_unlock_irqrestore(&port->lock, flags);
 537 }
 538 
 539 static struct console arc_console = {
 540         .name   = ARC_SERIAL_DEV_NAME,
 541         .write  = arc_serial_console_write,
 542         .device = uart_console_device,
 543         .setup  = arc_serial_console_setup,
 544         .flags  = CON_PRINTBUFFER,
 545         .index  = -1,
 546         .data   = &arc_uart_driver
 547 };
 548 
 549 static void arc_early_serial_write(struct console *con, const char *s,
 550                                    unsigned int n)
 551 {
 552         struct earlycon_device *dev = con->data;
 553 
 554         uart_console_write(&dev->port, s, n, arc_serial_console_putchar);
 555 }
 556 
 557 static int __init arc_early_console_setup(struct earlycon_device *dev,
 558                                           const char *opt)
 559 {
 560         struct uart_port *port = &dev->port;
 561         unsigned int l, h, hw_val;
 562 
 563         if (!dev->port.membase)
 564                 return -ENODEV;
 565 
 566         hw_val = port->uartclk / (dev->baud * 4) - 1;
 567         l = hw_val & 0xFF;
 568         h = (hw_val >> 8) & 0xFF;
 569 
 570         UART_SET_BAUDL(port, l);
 571         UART_SET_BAUDH(port, h);
 572 
 573         dev->con->write = arc_early_serial_write;
 574         return 0;
 575 }
 576 OF_EARLYCON_DECLARE(arc_uart, "snps,arc-uart", arc_early_console_setup);
 577 
 578 #endif  /* CONFIG_SERIAL_ARC_CONSOLE */
 579 
 580 static int arc_serial_probe(struct platform_device *pdev)
 581 {
 582         struct device_node *np = pdev->dev.of_node;
 583         struct arc_uart_port *uart;
 584         struct uart_port *port;
 585         int dev_id;
 586         u32 val;
 587 
 588         /* no device tree device */
 589         if (!np)
 590                 return -ENODEV;
 591 
 592         dev_id = of_alias_get_id(np, "serial");
 593         if (dev_id < 0)
 594                 dev_id = 0;
 595 
 596         if (dev_id >= ARRAY_SIZE(arc_uart_ports)) {
 597                 dev_err(&pdev->dev, "serial%d out of range\n", dev_id);
 598                 return -EINVAL;
 599         }
 600 
 601         uart = &arc_uart_ports[dev_id];
 602         port = &uart->port;
 603 
 604         if (of_property_read_u32(np, "clock-frequency", &val)) {
 605                 dev_err(&pdev->dev, "clock-frequency property NOTset\n");
 606                 return -EINVAL;
 607         }
 608         port->uartclk = val;
 609 
 610         if (of_property_read_u32(np, "current-speed", &val)) {
 611                 dev_err(&pdev->dev, "current-speed property NOT set\n");
 612                 return -EINVAL;
 613         }
 614         uart->baud = val;
 615 
 616         port->membase = of_iomap(np, 0);
 617         if (!port->membase)
 618                 /* No point of dev_err since UART itself is hosed here */
 619                 return -ENXIO;
 620 
 621         port->irq = irq_of_parse_and_map(np, 0);
 622 
 623         port->dev = &pdev->dev;
 624         port->iotype = UPIO_MEM;
 625         port->flags = UPF_BOOT_AUTOCONF;
 626         port->line = dev_id;
 627         port->ops = &arc_serial_pops;
 628 
 629         port->fifosize = ARC_UART_TX_FIFO_SIZE;
 630 
 631         /*
 632          * uart_insert_char( ) uses it in decideding whether to ignore a
 633          * char or not. Explicitly setting it here, removes the subtelty
 634          */
 635         port->ignore_status_mask = 0;
 636 
 637         return uart_add_one_port(&arc_uart_driver, &arc_uart_ports[dev_id].port);
 638 }
 639 
 640 static int arc_serial_remove(struct platform_device *pdev)
 641 {
 642         /* This will never be called */
 643         return 0;
 644 }
 645 
 646 static const struct of_device_id arc_uart_dt_ids[] = {
 647         { .compatible = "snps,arc-uart" },
 648         { /* Sentinel */ }
 649 };
 650 MODULE_DEVICE_TABLE(of, arc_uart_dt_ids);
 651 
 652 static struct platform_driver arc_platform_driver = {
 653         .probe = arc_serial_probe,
 654         .remove = arc_serial_remove,
 655         .driver = {
 656                 .name = DRIVER_NAME,
 657                 .of_match_table  = arc_uart_dt_ids,
 658          },
 659 };
 660 
 661 static int __init arc_serial_init(void)
 662 {
 663         int ret;
 664 
 665         ret = uart_register_driver(&arc_uart_driver);
 666         if (ret)
 667                 return ret;
 668 
 669         ret = platform_driver_register(&arc_platform_driver);
 670         if (ret)
 671                 uart_unregister_driver(&arc_uart_driver);
 672 
 673         return ret;
 674 }
 675 
 676 static void __exit arc_serial_exit(void)
 677 {
 678         platform_driver_unregister(&arc_platform_driver);
 679         uart_unregister_driver(&arc_uart_driver);
 680 }
 681 
 682 module_init(arc_serial_init);
 683 module_exit(arc_serial_exit);
 684 
 685 MODULE_LICENSE("GPL");
 686 MODULE_ALIAS("platform:" DRIVER_NAME);
 687 MODULE_AUTHOR("Vineet Gupta");
 688 MODULE_DESCRIPTION("ARC(Synopsys) On-Chip(fpga) serial driver");
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/tty/serial/arc_uart.c

DEFINITIONS
