drivers/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 #if defined(CONFIG_OF) && (defined(CONFIG_PPC32) || defined(CONFIG_MICROBLAZE))
  23 #include <linux/of.h>
  24 #include <linux/of_address.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_platform.h>
  27
  28 /* Match table for of_platform binding */
  29 static struct of_device_id ulite_of_match[] __devinitdata = {
  30         { .compatible = "xlnx,opb-uartlite-1.00.b", },
  31         { .compatible = "xlnx,xps-uartlite-1.00.a", },
  32         {}
  33 };
  34 MODULE_DEVICE_TABLE(of, ulite_of_match);
  35
  36 #endif
  37
  38 #define ULITE_NAME              "ttyUL"
  39 #define ULITE_MAJOR             204
  40 #define ULITE_MINOR             187
  41 #define ULITE_NR_UARTS          4
  42
  43 /* ---------------------------------------------------------------------
  44  * Register definitions
  45  *
  46  * For register details see datasheet:
  47  * http://www.xilinx.com/support/documentation/ip_documentation/opb_uartlite.pdf
  48  */
  49
  50 #define ULITE_RX                0x00
  51 #define ULITE_TX                0x04
  52 #define ULITE_STATUS            0x08
  53 #define ULITE_CONTROL           0x0c
  54
  55 #define ULITE_REGION            16
  56
  57 #define ULITE_STATUS_RXVALID    0x01
  58 #define ULITE_STATUS_RXFULL     0x02
  59 #define ULITE_STATUS_TXEMPTY    0x04
  60 #define ULITE_STATUS_TXFULL     0x08
  61 #define ULITE_STATUS_IE         0x10
  62 #define ULITE_STATUS_OVERRUN    0x20
  63 #define ULITE_STATUS_FRAME      0x40
  64 #define ULITE_STATUS_PARITY     0x80
  65
  66 #define ULITE_CONTROL_RST_TX    0x01
  67 #define ULITE_CONTROL_RST_RX    0x02
  68 #define ULITE_CONTROL_IE        0x10
  69
  70
  71 static struct uart_port ulite_ports[ULITE_NR_UARTS];
  72
  73 /* ---------------------------------------------------------------------
  74  * Core UART driver operations
  75  */
  76
  77 static int ulite_receive(struct uart_port *port, int stat)
  78 {
  79         struct tty_struct *tty = port->state->port.tty;
  80         unsigned char ch = 0;
  81         char flag = TTY_NORMAL;
  82
  83         if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
  84                      | ULITE_STATUS_FRAME)) == 0)
  85                 return 0;
  86
  87         /* stats */
  88         if (stat & ULITE_STATUS_RXVALID) {
  89                 port->icount.rx++;
  90                 ch = ioread32be(port->membase + ULITE_RX);
  91
  92                 if (stat & ULITE_STATUS_PARITY)
  93                         port->icount.parity++;
  94         }
  95
  96         if (stat & ULITE_STATUS_OVERRUN)
  97                 port->icount.overrun++;
  98
  99         if (stat & ULITE_STATUS_FRAME)
 100                 port->icount.frame++;
 101
 102
 103         /* drop byte with parity error if IGNPAR specificed */
 104         if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
 105                 stat &= ~ULITE_STATUS_RXVALID;
 106
 107         stat &= port->read_status_mask;
 108
 109         if (stat & ULITE_STATUS_PARITY)
 110                 flag = TTY_PARITY;
 111
 112
 113         stat &= ~port->ignore_status_mask;
 114
 115         if (stat & ULITE_STATUS_RXVALID)
 116                 tty_insert_flip_char(tty, ch, flag);
 117
 118         if (stat & ULITE_STATUS_FRAME)
 119                 tty_insert_flip_char(tty, 0, TTY_FRAME);
 120
 121         if (stat & ULITE_STATUS_OVERRUN)
 122                 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 123
 124         return 1;
 125 }
 126
 127 static int ulite_transmit(struct uart_port *port, int stat)
 128 {
 129         struct circ_buf *xmit  = &port->state->xmit;
 130
 131         if (stat & ULITE_STATUS_TXFULL)
 132                 return 0;
 133
 134         if (port->x_char) {
 135                 iowrite32be(port->x_char, port->membase + ULITE_TX);
 136                 port->x_char = 0;
 137                 port->icount.tx++;
 138                 return 1;
 139         }
 140
 141         if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 142                 return 0;
 143
 144         iowrite32be(xmit->buf[xmit->tail], port->membase + ULITE_TX);
 145         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
 146         port->icount.tx++;
 147
 148         /* wake up */
 149         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 150                 uart_write_wakeup(port);
 151
 152         return 1;
 153 }
 154
 155 static irqreturn_t ulite_isr(int irq, void *dev_id)
 156 {
 157         struct uart_port *port = dev_id;
 158         int busy, n = 0;
 159
 160         do {
 161                 int stat = ioread32be(port->membase + ULITE_STATUS);
 162                 busy  = ulite_receive(port, stat);
 163                 busy |= ulite_transmit(port, stat);
 164                 n++;
 165         } while (busy);
 166
 167         /* work done? */
 168         if (n > 1) {
 169                 tty_flip_buffer_push(port->state->port.tty);
 170                 return IRQ_HANDLED;
 171         } else {
 172                 return IRQ_NONE;
 173         }
 174 }
 175
 176 static unsigned int ulite_tx_empty(struct uart_port *port)
 177 {
 178         unsigned long flags;
 179         unsigned int ret;
 180
 181         spin_lock_irqsave(&port->lock, flags);
 182         ret = ioread32be(port->membase + ULITE_STATUS);
 183         spin_unlock_irqrestore(&port->lock, flags);
 184
 185         return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
 186 }
 187
 188 static unsigned int ulite_get_mctrl(struct uart_port *port)
 189 {
 190         return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 191 }
 192
 193 static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
 194 {
 195         /* N/A */
 196 }
 197
 198 static void ulite_stop_tx(struct uart_port *port)
 199 {
 200         /* N/A */
 201 }
 202
 203 static void ulite_start_tx(struct uart_port *port)
 204 {
 205         ulite_transmit(port, ioread32be(port->membase + ULITE_STATUS));
 206 }
 207
 208 static void ulite_stop_rx(struct uart_port *port)
 209 {
 210         /* don't forward any more data (like !CREAD) */
 211         port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
 212                 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 213 }
 214
 215 static void ulite_enable_ms(struct uart_port *port)
 216 {
 217         /* N/A */
 218 }
 219
 220 static void ulite_break_ctl(struct uart_port *port, int ctl)
 221 {
 222         /* N/A */
 223 }
 224
 225 static int ulite_startup(struct uart_port *port)
 226 {
 227         int ret;
 228
 229         ret = request_irq(port->irq, ulite_isr,
 230                           IRQF_SHARED | IRQF_SAMPLE_RANDOM, "uartlite", port);
 231         if (ret)
 232                 return ret;
 233
 234         iowrite32be(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
 235                port->membase + ULITE_CONTROL);
 236         iowrite32be(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
 237
 238         return 0;
 239 }
 240
 241 static void ulite_shutdown(struct uart_port *port)
 242 {
 243         iowrite32be(0, port->membase + ULITE_CONTROL);
 244         ioread32be(port->membase + ULITE_CONTROL); /* dummy */
 245         free_irq(port->irq, port);
 246 }
 247
 248 static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
 249                               struct ktermios *old)
 250 {
 251         unsigned long flags;
 252         unsigned int baud;
 253
 254         spin_lock_irqsave(&port->lock, flags);
 255
 256         port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
 257                 | ULITE_STATUS_TXFULL;
 258
 259         if (termios->c_iflag & INPCK)
 260                 port->read_status_mask |=
 261                         ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
 262
 263         port->ignore_status_mask = 0;
 264         if (termios->c_iflag & IGNPAR)
 265                 port->ignore_status_mask |= ULITE_STATUS_PARITY
 266                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 267
 268         /* ignore all characters if CREAD is not set */
 269         if ((termios->c_cflag & CREAD) == 0)
 270                 port->ignore_status_mask |=
 271                         ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
 272                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 273
 274         /* update timeout */
 275         baud = uart_get_baud_rate(port, termios, old, 0, 460800);
 276         uart_update_timeout(port, termios->c_cflag, baud);
 277
 278         spin_unlock_irqrestore(&port->lock, flags);
 279 }
 280
 281 static const char *ulite_type(struct uart_port *port)
 282 {
 283         return port->type == PORT_UARTLITE ? "uartlite" : NULL;
 284 }
 285
 286 static void ulite_release_port(struct uart_port *port)
 287 {
 288         release_mem_region(port->mapbase, ULITE_REGION);
 289         iounmap(port->membase);
 290         port->membase = NULL;
 291 }
 292
 293 static int ulite_request_port(struct uart_port *port)
 294 {
 295         pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
 296                  port, (unsigned long long) port->mapbase);
 297
 298         if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
 299                 dev_err(port->dev, "Memory region busy\n");
 300                 return -EBUSY;
 301         }
 302
 303         port->membase = ioremap(port->mapbase, ULITE_REGION);
 304         if (!port->membase) {
 305                 dev_err(port->dev, "Unable to map registers\n");
 306                 release_mem_region(port->mapbase, ULITE_REGION);
 307                 return -EBUSY;
 308         }
 309
 310         return 0;
 311 }
 312
 313 static void ulite_config_port(struct uart_port *port, int flags)
 314 {
 315         if (!ulite_request_port(port))
 316                 port->type = PORT_UARTLITE;
 317 }
 318
 319 static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
 320 {
 321         /* we don't want the core code to modify any port params */
 322         return -EINVAL;
 323 }
 324
 325 static struct uart_ops ulite_ops = {
 326         .tx_empty       = ulite_tx_empty,
 327         .set_mctrl      = ulite_set_mctrl,
 328         .get_mctrl      = ulite_get_mctrl,
 329         .stop_tx        = ulite_stop_tx,
 330         .start_tx       = ulite_start_tx,
 331         .stop_rx        = ulite_stop_rx,
 332         .enable_ms      = ulite_enable_ms,
 333         .break_ctl      = ulite_break_ctl,
 334         .startup        = ulite_startup,
 335         .shutdown       = ulite_shutdown,
 336         .set_termios    = ulite_set_termios,
 337         .type           = ulite_type,
 338         .release_port   = ulite_release_port,
 339         .request_port   = ulite_request_port,
 340         .config_port    = ulite_config_port,
 341         .verify_port    = ulite_verify_port
 342 };
 343
 344 /* ---------------------------------------------------------------------
 345  * Console driver operations
 346  */
 347
 348 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
 349 static void ulite_console_wait_tx(struct uart_port *port)
 350 {
 351         int i;
 352         u8 val;
 353
 354         /* Spin waiting for TX fifo to have space available */
 355         for (i = 0; i < 100000; i++) {
 356                 val = ioread32be(port->membase + ULITE_STATUS);
 357                 if ((val & ULITE_STATUS_TXFULL) == 0)
 358                         break;
 359                 cpu_relax();
 360         }
 361 }
 362
 363 static void ulite_console_putchar(struct uart_port *port, int ch)
 364 {
 365         ulite_console_wait_tx(port);
 366         iowrite32be(ch, port->membase + ULITE_TX);
 367 }
 368
 369 static void ulite_console_write(struct console *co, const char *s,
 370                                 unsigned int count)
 371 {
 372         struct uart_port *port = &ulite_ports[co->index];
 373         unsigned long flags;
 374         unsigned int ier;
 375         int locked = 1;
 376
 377         if (oops_in_progress) {
 378                 locked = spin_trylock_irqsave(&port->lock, flags);
 379         } else
 380                 spin_lock_irqsave(&port->lock, flags);
 381
 382         /* save and disable interrupt */
 383         ier = ioread32be(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
 384         iowrite32be(0, port->membase + ULITE_CONTROL);
 385
 386         uart_console_write(port, s, count, ulite_console_putchar);
 387
 388         ulite_console_wait_tx(port);
 389
 390         /* restore interrupt state */
 391         if (ier)
 392                 iowrite32be(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
 393
 394         if (locked)
 395                 spin_unlock_irqrestore(&port->lock, flags);
 396 }
 397
 398 static int __devinit ulite_console_setup(struct console *co, char *options)
 399 {
 400         struct uart_port *port;
 401         int baud = 9600;
 402         int bits = 8;
 403         int parity = 'n';
 404         int flow = 'n';
 405
 406         if (co->index < 0 || co->index >= ULITE_NR_UARTS)
 407                 return -EINVAL;
 408
 409         port = &ulite_ports[co->index];
 410
 411         /* Has the device been initialized yet? */
 412         if (!port->mapbase) {
 413                 pr_debug("console on ttyUL%i not present\n", co->index);
 414                 return -ENODEV;
 415         }
 416
 417         /* not initialized yet? */
 418         if (!port->membase) {
 419                 if (ulite_request_port(port))
 420                         return -ENODEV;
 421         }
 422
 423         if (options)
 424                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 425
 426         return uart_set_options(port, co, baud, parity, bits, flow);
 427 }
 428
 429 static struct uart_driver ulite_uart_driver;
 430
 431 static struct console ulite_console = {
 432         .name   = ULITE_NAME,
 433         .write  = ulite_console_write,
 434         .device = uart_console_device,
 435         .setup  = ulite_console_setup,
 436         .flags  = CON_PRINTBUFFER,
 437         .index  = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
 438         .data   = &ulite_uart_driver,
 439 };
 440
 441 static int __init ulite_console_init(void)
 442 {
 443         register_console(&ulite_console);
 444         return 0;
 445 }
 446
 447 console_initcall(ulite_console_init);
 448
 449 #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
 450
 451 static struct uart_driver ulite_uart_driver = {
 452         .owner          = THIS_MODULE,
 453         .driver_name    = "uartlite",
 454         .dev_name       = ULITE_NAME,
 455         .major          = ULITE_MAJOR,
 456         .minor          = ULITE_MINOR,
 457         .nr             = ULITE_NR_UARTS,
 458 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
 459         .cons           = &ulite_console,
 460 #endif
 461 };
 462
 463 /* ---------------------------------------------------------------------
 464  * Port assignment functions (mapping devices to uart_port structures)
 465  */
 466
 467 /** ulite_assign: register a uartlite device with the driver
 468  *
 469  * @dev: pointer to device structure
 470  * @id: requested id number.  Pass -1 for automatic port assignment
 471  * @base: base address of uartlite registers
 472  * @irq: irq number for uartlite
 473  *
 474  * Returns: 0 on success, <0 otherwise
 475  */
 476 static int __devinit ulite_assign(struct device *dev, int id, u32 base, int irq)
 477 {
 478         struct uart_port *port;
 479         int rc;
 480
 481         /* if id = -1; then scan for a free id and use that */
 482         if (id < 0) {
 483                 for (id = 0; id < ULITE_NR_UARTS; id++)
 484                         if (ulite_ports[id].mapbase == 0)
 485                                 break;
 486         }
 487         if (id < 0 || id >= ULITE_NR_UARTS) {
 488                 dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
 489                 return -EINVAL;
 490         }
 491
 492         if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
 493                 dev_err(dev, "cannot assign to %s%i; it is already in use\n",
 494                         ULITE_NAME, id);
 495                 return -EBUSY;
 496         }
 497
 498         port = &ulite_ports[id];
 499
 500         spin_lock_init(&port->lock);
 501         port->fifosize = 16;
 502         port->regshift = 2;
 503         port->iotype = UPIO_MEM;
 504         port->iobase = 1; /* mark port in use */
 505         port->mapbase = base;
 506         port->membase = NULL;
 507         port->ops = &ulite_ops;
 508         port->irq = irq;
 509         port->flags = UPF_BOOT_AUTOCONF;
 510         port->dev = dev;
 511         port->type = PORT_UNKNOWN;
 512         port->line = id;
 513
 514         dev_set_drvdata(dev, port);
 515
 516         /* Register the port */
 517         rc = uart_add_one_port(&ulite_uart_driver, port);
 518         if (rc) {
 519                 dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
 520                 port->mapbase = 0;
 521                 dev_set_drvdata(dev, NULL);
 522                 return rc;
 523         }
 524
 525         return 0;
 526 }
 527
 528 /** ulite_release: register a uartlite device with the driver
 529  *
 530  * @dev: pointer to device structure
 531  */
 532 static int __devexit ulite_release(struct device *dev)
 533 {
 534         struct uart_port *port = dev_get_drvdata(dev);
 535         int rc = 0;
 536
 537         if (port) {
 538                 rc = uart_remove_one_port(&ulite_uart_driver, port);
 539                 dev_set_drvdata(dev, NULL);
 540                 port->mapbase = 0;
 541         }
 542
 543         return rc;
 544 }
 545
 546 /* ---------------------------------------------------------------------
 547  * Platform bus binding
 548  */
 549
 550 static int __devinit ulite_probe(struct platform_device *pdev)
 551 {
 552         struct resource *res, *res2;
 553
 554         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 555         if (!res)
 556                 return -ENODEV;
 557
 558         res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 559         if (!res2)
 560                 return -ENODEV;
 561
 562         return ulite_assign(&pdev->dev, pdev->id, res->start, res2->start);
 563 }
 564
 565 static int __devexit ulite_remove(struct platform_device *pdev)
 566 {
 567         return ulite_release(&pdev->dev);
 568 }
 569
 570 /* work with hotplug and coldplug */
 571 MODULE_ALIAS("platform:uartlite");
 572
 573 static struct platform_driver ulite_platform_driver = {
 574         .probe  = ulite_probe,
 575         .remove = __devexit_p(ulite_remove),
 576         .driver = {
 577                    .owner = THIS_MODULE,
 578                    .name  = "uartlite",
 579                    },
 580 };
 581
 582 /* ---------------------------------------------------------------------
 583  * OF bus bindings
 584  */
 585 #if defined(CONFIG_OF) && (defined(CONFIG_PPC32) || defined(CONFIG_MICROBLAZE))
 586 static int __devinit
 587 ulite_of_probe(struct of_device *op, const struct of_device_id *match)
 588 {
 589         struct resource res;
 590         const unsigned int *id;
 591         int irq, rc;
 592
 593         dev_dbg(&op->dev, "%s(%p, %p)\n", __func__, op, match);
 594
 595         rc = of_address_to_resource(op->dev.of_node, 0, &res);
 596         if (rc) {
 597                 dev_err(&op->dev, "invalid address\n");
 598                 return rc;
 599         }
 600
 601         irq = irq_of_parse_and_map(op->dev.of_node, 0);
 602
 603         id = of_get_property(op->dev.of_node, "port-number", NULL);
 604
 605         return ulite_assign(&op->dev, id ? *id : -1, res.start, irq);
 606 }
 607
 608 static int __devexit ulite_of_remove(struct of_device *op)
 609 {
 610         return ulite_release(&op->dev);
 611 }
 612
 613 static struct of_platform_driver ulite_of_driver = {
 614         .probe = ulite_of_probe,
 615         .remove = __devexit_p(ulite_of_remove),
 616         .driver = {
 617                 .name = "uartlite",
 618                 .owner = THIS_MODULE,
 619                 .of_match_table = ulite_of_match,
 620         },
 621 };
 622
 623 /* Registration helpers to keep the number of #ifdefs to a minimum */
 624 static inline int __init ulite_of_register(void)
 625 {
 626         pr_debug("uartlite: calling of_register_platform_driver()\n");
 627         return of_register_platform_driver(&ulite_of_driver);
 628 }
 629
 630 static inline void __exit ulite_of_unregister(void)
 631 {
 632         of_unregister_platform_driver(&ulite_of_driver);
 633 }
 634 #else /* CONFIG_OF && (CONFIG_PPC32 || CONFIG_MICROBLAZE) */
 635 /* Appropriate config not enabled; do nothing helpers */
 636 static inline int __init ulite_of_register(void) { return 0; }
 637 static inline void __exit ulite_of_unregister(void) { }
 638 #endif /* CONFIG_OF && (CONFIG_PPC32 || CONFIG_MICROBLAZE) */
 639
 640 /* ---------------------------------------------------------------------
 641  * Module setup/teardown
 642  */
 643
 644 int __init ulite_init(void)
 645 {
 646         int ret;
 647
 648         pr_debug("uartlite: calling uart_register_driver()\n");
 649         ret = uart_register_driver(&ulite_uart_driver);
 650         if (ret)
 651                 goto err_uart;
 652
 653         ret = ulite_of_register();
 654         if (ret)
 655                 goto err_of;
 656
 657         pr_debug("uartlite: calling platform_driver_register()\n");
 658         ret = platform_driver_register(&ulite_platform_driver);
 659         if (ret)
 660                 goto err_plat;
 661
 662         return 0;
 663
 664 err_plat:
 665         ulite_of_unregister();
 666 err_of:
 667         uart_unregister_driver(&ulite_uart_driver);
 668 err_uart:
 669         printk(KERN_ERR "registering uartlite driver failed: err=%i", ret);
 670         return ret;
 671 }
 672
 673 void __exit ulite_exit(void)
 674 {
 675         platform_driver_unregister(&ulite_platform_driver);
 676         ulite_of_unregister();
 677         uart_unregister_driver(&ulite_uart_driver);
 678 }
 679
 680 module_init(ulite_init);
 681 module_exit(ulite_exit);
 682
 683 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
 684 MODULE_DESCRIPTION("Xilinx uartlite serial driver");
 685 MODULE_LICENSE("GPL");