drivers/tty/serial/uartlite.c

   1 /*
   2  * uartlite.c: Serial driver for Xilinx uartlite serial controller
   3  *
   4  * Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk>
   5  * Copyright (C) 2007 Secret Lab Technologies Ltd.
   6  *
   7  * This file is licensed under the terms of the GNU General Public License
   8  * version 2.  This program is licensed "as is" without any warranty of any
   9  * kind, whether express or implied.
  10  */
  11
  12 #include <linux/platform_device.h>
  13 #include <linux/module.h>
  14 #include <linux/console.h>
  15 #include <linux/serial.h>
  16 #include <linux/serial_core.h>
  17 #include <linux/tty.h>
  18 #include <linux/delay.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/init.h>
  21 #include <asm/io.h>
  22 #include <linux/of.h>
  23 #include <linux/of_address.h>
  24 #include <linux/of_device.h>
  25 #include <linux/of_platform.h>
  26
  27 #define ULITE_NAME              "ttyUL"
  28 #define ULITE_MAJOR             204
  29 #define ULITE_MINOR             187
  30 #define ULITE_NR_UARTS          4
  31
  32 /* ---------------------------------------------------------------------
  33  * Register definitions
  34  *
  35  * For register details see datasheet:
  36  * http://www.xilinx.com/support/documentation/ip_documentation/opb_uartlite.pdf
  37  */
  38
  39 #define ULITE_RX                0x00
  40 #define ULITE_TX                0x04
  41 #define ULITE_STATUS            0x08
  42 #define ULITE_CONTROL           0x0c
  43
  44 #define ULITE_REGION            16
  45
  46 #define ULITE_STATUS_RXVALID    0x01
  47 #define ULITE_STATUS_RXFULL     0x02
  48 #define ULITE_STATUS_TXEMPTY    0x04
  49 #define ULITE_STATUS_TXFULL     0x08
  50 #define ULITE_STATUS_IE         0x10
  51 #define ULITE_STATUS_OVERRUN    0x20
  52 #define ULITE_STATUS_FRAME      0x40
  53 #define ULITE_STATUS_PARITY     0x80
  54
  55 #define ULITE_CONTROL_RST_TX    0x01
  56 #define ULITE_CONTROL_RST_RX    0x02
  57 #define ULITE_CONTROL_IE        0x10
  58
  59
  60 static struct uart_port ulite_ports[ULITE_NR_UARTS];
  61
  62 /* ---------------------------------------------------------------------
  63  * Core UART driver operations
  64  */
  65
  66 static int ulite_receive(struct uart_port *port, int stat)
  67 {
  68         struct tty_struct *tty = port->state->port.tty;
  69         unsigned char ch = 0;
  70         char flag = TTY_NORMAL;
  71
  72         if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
  73                      | ULITE_STATUS_FRAME)) == 0)
  74                 return 0;
  75
  76         /* stats */
  77         if (stat & ULITE_STATUS_RXVALID) {
  78                 port->icount.rx++;
  79                 ch = ioread32be(port->membase + ULITE_RX);
  80
  81                 if (stat & ULITE_STATUS_PARITY)
  82                         port->icount.parity++;
  83         }
  84
  85         if (stat & ULITE_STATUS_OVERRUN)
  86                 port->icount.overrun++;
  87
  88         if (stat & ULITE_STATUS_FRAME)
  89                 port->icount.frame++;
  90
  91
  92         /* drop byte with parity error if IGNPAR specificed */
  93         if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
  94                 stat &= ~ULITE_STATUS_RXVALID;
  95
  96         stat &= port->read_status_mask;
  97
  98         if (stat & ULITE_STATUS_PARITY)
  99                 flag = TTY_PARITY;
 100
 101
 102         stat &= ~port->ignore_status_mask;
 103
 104         if (stat & ULITE_STATUS_RXVALID)
 105                 tty_insert_flip_char(tty, ch, flag);
 106
 107         if (stat & ULITE_STATUS_FRAME)
 108                 tty_insert_flip_char(tty, 0, TTY_FRAME);
 109
 110         if (stat & ULITE_STATUS_OVERRUN)
 111                 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 112
 113         return 1;
 114 }
 115
 116 static int ulite_transmit(struct uart_port *port, int stat)
 117 {
 118         struct circ_buf *xmit  = &port->state->xmit;
 119
 120         if (stat & ULITE_STATUS_TXFULL)
 121                 return 0;
 122
 123         if (port->x_char) {
 124                 iowrite32be(port->x_char, port->membase + ULITE_TX);
 125                 port->x_char = 0;
 126                 port->icount.tx++;
 127                 return 1;
 128         }
 129
 130         if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 131                 return 0;
 132
 133         iowrite32be(xmit->buf[xmit->tail], port->membase + ULITE_TX);
 134         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
 135         port->icount.tx++;
 136
 137         /* wake up */
 138         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 139                 uart_write_wakeup(port);
 140
 141         return 1;
 142 }
 143
 144 static irqreturn_t ulite_isr(int irq, void *dev_id)
 145 {
 146         struct uart_port *port = dev_id;
 147         int busy, n = 0;
 148
 149         do {
 150                 int stat = ioread32be(port->membase + ULITE_STATUS);
 151                 busy  = ulite_receive(port, stat);
 152                 busy |= ulite_transmit(port, stat);
 153                 n++;
 154         } while (busy);
 155
 156         /* work done? */
 157         if (n > 1) {
 158                 tty_flip_buffer_push(port->state->port.tty);
 159                 return IRQ_HANDLED;
 160         } else {
 161                 return IRQ_NONE;
 162         }
 163 }
 164
 165 static unsigned int ulite_tx_empty(struct uart_port *port)
 166 {
 167         unsigned long flags;
 168         unsigned int ret;
 169
 170         spin_lock_irqsave(&port->lock, flags);
 171         ret = ioread32be(port->membase + ULITE_STATUS);
 172         spin_unlock_irqrestore(&port->lock, flags);
 173
 174         return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
 175 }
 176
 177 static unsigned int ulite_get_mctrl(struct uart_port *port)
 178 {
 179         return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 180 }
 181
 182 static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
 183 {
 184         /* N/A */
 185 }
 186
 187 static void ulite_stop_tx(struct uart_port *port)
 188 {
 189         /* N/A */
 190 }
 191
 192 static void ulite_start_tx(struct uart_port *port)
 193 {
 194         ulite_transmit(port, ioread32be(port->membase + ULITE_STATUS));
 195 }
 196
 197 static void ulite_stop_rx(struct uart_port *port)
 198 {
 199         /* don't forward any more data (like !CREAD) */
 200         port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
 201                 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 202 }
 203
 204 static void ulite_enable_ms(struct uart_port *port)
 205 {
 206         /* N/A */
 207 }
 208
 209 static void ulite_break_ctl(struct uart_port *port, int ctl)
 210 {
 211         /* N/A */
 212 }
 213
 214 static int ulite_startup(struct uart_port *port)
 215 {
 216         int ret;
 217
 218         ret = request_irq(port->irq, ulite_isr,
 219                           IRQF_SHARED | IRQF_SAMPLE_RANDOM, "uartlite", port);
 220         if (ret)
 221                 return ret;
 222
 223         iowrite32be(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
 224                port->membase + ULITE_CONTROL);
 225         iowrite32be(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
 226
 227         return 0;
 228 }
 229
 230 static void ulite_shutdown(struct uart_port *port)
 231 {
 232         iowrite32be(0, port->membase + ULITE_CONTROL);
 233         ioread32be(port->membase + ULITE_CONTROL); /* dummy */
 234         free_irq(port->irq, port);
 235 }
 236
 237 static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
 238                               struct ktermios *old)
 239 {
 240         unsigned long flags;
 241         unsigned int baud;
 242
 243         spin_lock_irqsave(&port->lock, flags);
 244
 245         port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
 246                 | ULITE_STATUS_TXFULL;
 247
 248         if (termios->c_iflag & INPCK)
 249                 port->read_status_mask |=
 250                         ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
 251
 252         port->ignore_status_mask = 0;
 253         if (termios->c_iflag & IGNPAR)
 254                 port->ignore_status_mask |= ULITE_STATUS_PARITY
 255                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 256
 257         /* ignore all characters if CREAD is not set */
 258         if ((termios->c_cflag & CREAD) == 0)
 259                 port->ignore_status_mask |=
 260                         ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
 261                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 262
 263         /* update timeout */
 264         baud = uart_get_baud_rate(port, termios, old, 0, 460800);
 265         uart_update_timeout(port, termios->c_cflag, baud);
 266
 267         spin_unlock_irqrestore(&port->lock, flags);
 268 }
 269
 270 static const char *ulite_type(struct uart_port *port)
 271 {
 272         return port->type == PORT_UARTLITE ? "uartlite" : NULL;
 273 }
 274
 275 static void ulite_release_port(struct uart_port *port)
 276 {
 277         release_mem_region(port->mapbase, ULITE_REGION);
 278         iounmap(port->membase);
 279         port->membase = NULL;
 280 }
 281
 282 static int ulite_request_port(struct uart_port *port)
 283 {
 284         pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
 285                  port, (unsigned long long) port->mapbase);
 286
 287         if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
 288                 dev_err(port->dev, "Memory region busy\n");
 289                 return -EBUSY;
 290         }
 291
 292         port->membase = ioremap(port->mapbase, ULITE_REGION);
 293         if (!port->membase) {
 294                 dev_err(port->dev, "Unable to map registers\n");
 295                 release_mem_region(port->mapbase, ULITE_REGION);
 296                 return -EBUSY;
 297         }
 298
 299         return 0;
 300 }
 301
 302 static void ulite_config_port(struct uart_port *port, int flags)
 303 {
 304         if (!ulite_request_port(port))
 305                 port->type = PORT_UARTLITE;
 306 }
 307
 308 static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
 309 {
 310         /* we don't want the core code to modify any port params */
 311         return -EINVAL;
 312 }
 313
 314 #ifdef CONFIG_CONSOLE_POLL
 315 static int ulite_get_poll_char(struct uart_port *port)
 316 {
 317         if (!(ioread32be(port->membase + ULITE_STATUS)
 318                                                 & ULITE_STATUS_RXVALID))
 319                 return NO_POLL_CHAR;
 320
 321         return ioread32be(port->membase + ULITE_RX);
 322 }
 323
 324 static void ulite_put_poll_char(struct uart_port *port, unsigned char ch)
 325 {
 326         while (ioread32be(port->membase + ULITE_STATUS) & ULITE_STATUS_TXFULL)
 327                 cpu_relax();
 328
 329         /* write char to device */
 330         iowrite32be(ch, port->membase + ULITE_TX);
 331 }
 332 #endif
 333
 334 static struct uart_ops ulite_ops = {
 335         .tx_empty       = ulite_tx_empty,
 336         .set_mctrl      = ulite_set_mctrl,
 337         .get_mctrl      = ulite_get_mctrl,
 338         .stop_tx        = ulite_stop_tx,
 339         .start_tx       = ulite_start_tx,
 340         .stop_rx        = ulite_stop_rx,
 341         .enable_ms      = ulite_enable_ms,
 342         .break_ctl      = ulite_break_ctl,
 343         .startup        = ulite_startup,
 344         .shutdown       = ulite_shutdown,
 345         .set_termios    = ulite_set_termios,
 346         .type           = ulite_type,
 347         .release_port   = ulite_release_port,
 348         .request_port   = ulite_request_port,
 349         .config_port    = ulite_config_port,
 350         .verify_port    = ulite_verify_port,
 351 #ifdef CONFIG_CONSOLE_POLL
 352         .poll_get_char  = ulite_get_poll_char,
 353         .poll_put_char  = ulite_put_poll_char,
 354 #endif
 355 };
 356
 357 /* ---------------------------------------------------------------------
 358  * Console driver operations
 359  */
 360
 361 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
 362 static void ulite_console_wait_tx(struct uart_port *port)
 363 {
 364         int i;
 365         u8 val;
 366
 367         /* Spin waiting for TX fifo to have space available */
 368         for (i = 0; i < 100000; i++) {
 369                 val = ioread32be(port->membase + ULITE_STATUS);
 370                 if ((val & ULITE_STATUS_TXFULL) == 0)
 371                         break;
 372                 cpu_relax();
 373         }
 374 }
 375
 376 static void ulite_console_putchar(struct uart_port *port, int ch)
 377 {
 378         ulite_console_wait_tx(port);
 379         iowrite32be(ch, port->membase + ULITE_TX);
 380 }
 381
 382 static void ulite_console_write(struct console *co, const char *s,
 383                                 unsigned int count)
 384 {
 385         struct uart_port *port = &ulite_ports[co->index];
 386         unsigned long flags;
 387         unsigned int ier;
 388         int locked = 1;
 389
 390         if (oops_in_progress) {
 391                 locked = spin_trylock_irqsave(&port->lock, flags);
 392         } else
 393                 spin_lock_irqsave(&port->lock, flags);
 394
 395         /* save and disable interrupt */
 396         ier = ioread32be(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
 397         iowrite32be(0, port->membase + ULITE_CONTROL);
 398
 399         uart_console_write(port, s, count, ulite_console_putchar);
 400
 401         ulite_console_wait_tx(port);
 402
 403         /* restore interrupt state */
 404         if (ier)
 405                 iowrite32be(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
 406
 407         if (locked)
 408                 spin_unlock_irqrestore(&port->lock, flags);
 409 }
 410
 411 static int __devinit ulite_console_setup(struct console *co, char *options)
 412 {
 413         struct uart_port *port;
 414         int baud = 9600;
 415         int bits = 8;
 416         int parity = 'n';
 417         int flow = 'n';
 418
 419         if (co->index < 0 || co->index >= ULITE_NR_UARTS)
 420                 return -EINVAL;
 421
 422         port = &ulite_ports[co->index];
 423
 424         /* Has the device been initialized yet? */
 425         if (!port->mapbase) {
 426                 pr_debug("console on ttyUL%i not present\n", co->index);
 427                 return -ENODEV;
 428         }
 429
 430         /* not initialized yet? */
 431         if (!port->membase) {
 432                 if (ulite_request_port(port))
 433                         return -ENODEV;
 434         }
 435
 436         if (options)
 437                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 438
 439         return uart_set_options(port, co, baud, parity, bits, flow);
 440 }
 441
 442 static struct uart_driver ulite_uart_driver;
 443
 444 static struct console ulite_console = {
 445         .name   = ULITE_NAME,
 446         .write  = ulite_console_write,
 447         .device = uart_console_device,
 448         .setup  = ulite_console_setup,
 449         .flags  = CON_PRINTBUFFER,
 450         .index  = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
 451         .data   = &ulite_uart_driver,
 452 };
 453
 454 static int __init ulite_console_init(void)
 455 {
 456         register_console(&ulite_console);
 457         return 0;
 458 }
 459
 460 console_initcall(ulite_console_init);
 461
 462 #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
 463
 464 static struct uart_driver ulite_uart_driver = {
 465         .owner          = THIS_MODULE,
 466         .driver_name    = "uartlite",
 467         .dev_name       = ULITE_NAME,
 468         .major          = ULITE_MAJOR,
 469         .minor          = ULITE_MINOR,
 470         .nr             = ULITE_NR_UARTS,
 471 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
 472         .cons           = &ulite_console,
 473 #endif
 474 };
 475
 476 /* ---------------------------------------------------------------------
 477  * Port assignment functions (mapping devices to uart_port structures)
 478  */
 479
 480 /** ulite_assign: register a uartlite device with the driver
 481  *
 482  * @dev: pointer to device structure
 483  * @id: requested id number.  Pass -1 for automatic port assignment
 484  * @base: base address of uartlite registers
 485  * @irq: irq number for uartlite
 486  *
 487  * Returns: 0 on success, <0 otherwise
 488  */
 489 static int __devinit ulite_assign(struct device *dev, int id, u32 base, int irq)
 490 {
 491         struct uart_port *port;
 492         int rc;
 493
 494         /* if id = -1; then scan for a free id and use that */
 495         if (id < 0) {
 496                 for (id = 0; id < ULITE_NR_UARTS; id++)
 497                         if (ulite_ports[id].mapbase == 0)
 498                                 break;
 499         }
 500         if (id < 0 || id >= ULITE_NR_UARTS) {
 501                 dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
 502                 return -EINVAL;
 503         }
 504
 505         if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
 506                 dev_err(dev, "cannot assign to %s%i; it is already in use\n",
 507                         ULITE_NAME, id);
 508                 return -EBUSY;
 509         }
 510
 511         port = &ulite_ports[id];
 512
 513         spin_lock_init(&port->lock);
 514         port->fifosize = 16;
 515         port->regshift = 2;
 516         port->iotype = UPIO_MEM;
 517         port->iobase = 1; /* mark port in use */
 518         port->mapbase = base;
 519         port->membase = NULL;
 520         port->ops = &ulite_ops;
 521         port->irq = irq;
 522         port->flags = UPF_BOOT_AUTOCONF;
 523         port->dev = dev;
 524         port->type = PORT_UNKNOWN;
 525         port->line = id;
 526
 527         dev_set_drvdata(dev, port);
 528
 529         /* Register the port */
 530         rc = uart_add_one_port(&ulite_uart_driver, port);
 531         if (rc) {
 532                 dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
 533                 port->mapbase = 0;
 534                 dev_set_drvdata(dev, NULL);
 535                 return rc;
 536         }
 537
 538         return 0;
 539 }
 540
 541 /** ulite_release: register a uartlite device with the driver
 542  *
 543  * @dev: pointer to device structure
 544  */
 545 static int __devexit ulite_release(struct device *dev)
 546 {
 547         struct uart_port *port = dev_get_drvdata(dev);
 548         int rc = 0;
 549
 550         if (port) {
 551                 rc = uart_remove_one_port(&ulite_uart_driver, port);
 552                 dev_set_drvdata(dev, NULL);
 553                 port->mapbase = 0;
 554         }
 555
 556         return rc;
 557 }
 558
 559 /* ---------------------------------------------------------------------
 560  * Platform bus binding
 561  */
 562
 563 #if defined(CONFIG_OF)
 564 /* Match table for of_platform binding */
 565 static struct of_device_id ulite_of_match[] __devinitdata = {
 566         { .compatible = "xlnx,opb-uartlite-1.00.b", },
 567         { .compatible = "xlnx,xps-uartlite-1.00.a", },
 568         {}
 569 };
 570 MODULE_DEVICE_TABLE(of, ulite_of_match);
 571 #else /* CONFIG_OF */
 572 #define ulite_of_match NULL
 573 #endif /* CONFIG_OF */
 574
 575 static int __devinit ulite_probe(struct platform_device *pdev)
 576 {
 577         struct resource *res, *res2;
 578         int id = pdev->id;
 579 #ifdef CONFIG_OF
 580         const __be32 *prop;
 581
 582         prop = of_get_property(pdev->dev.of_node, "port-number", NULL);
 583         if (prop)
 584                 id = be32_to_cpup(prop);
 585 #endif
 586
 587         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 588         if (!res)
 589                 return -ENODEV;
 590
 591         res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 592         if (!res2)
 593                 return -ENODEV;
 594
 595         return ulite_assign(&pdev->dev, id, res->start, res2->start);
 596 }
 597
 598 static int __devexit ulite_remove(struct platform_device *pdev)
 599 {
 600         return ulite_release(&pdev->dev);
 601 }
 602
 603 /* work with hotplug and coldplug */
 604 MODULE_ALIAS("platform:uartlite");
 605
 606 static struct platform_driver ulite_platform_driver = {
 607         .probe = ulite_probe,
 608         .remove = __devexit_p(ulite_remove),
 609         .driver = {
 610                 .owner = THIS_MODULE,
 611                 .name  = "uartlite",
 612                 .of_match_table = ulite_of_match,
 613         },
 614 };
 615
 616 /* ---------------------------------------------------------------------
 617  * Module setup/teardown
 618  */
 619
 620 int __init ulite_init(void)
 621 {
 622         int ret;
 623
 624         pr_debug("uartlite: calling uart_register_driver()\n");
 625         ret = uart_register_driver(&ulite_uart_driver);
 626         if (ret)
 627                 goto err_uart;
 628
 629         pr_debug("uartlite: calling platform_driver_register()\n");
 630         ret = platform_driver_register(&ulite_platform_driver);
 631         if (ret)
 632                 goto err_plat;
 633
 634         return 0;
 635
 636 err_plat:
 637         uart_unregister_driver(&ulite_uart_driver);
 638 err_uart:
 639         printk(KERN_ERR "registering uartlite driver failed: err=%i", ret);
 640         return ret;
 641 }
 642
 643 void __exit ulite_exit(void)
 644 {
 645         platform_driver_unregister(&ulite_platform_driver);
 646         uart_unregister_driver(&ulite_uart_driver);
 647 }
 648
 649 module_init(ulite_init);
 650 module_exit(ulite_exit);
 651
 652 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
 653 MODULE_DESCRIPTION("Xilinx uartlite serial driver");
 654 MODULE_LICENSE("GPL");