drivers/tty/serial/altera_jtaguart.c

   1 /*
   2  * altera_jtaguart.c -- Altera JTAG UART driver
   3  *
   4  * Based on mcf.c -- Freescale ColdFire UART driver
   5  *
   6  * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
   7  * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
   8  * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/init.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/module.h>
  20 #include <linux/console.h>
  21 #include <linux/of.h>
  22 #include <linux/tty.h>
  23 #include <linux/tty_flip.h>
  24 #include <linux/serial.h>
  25 #include <linux/serial_core.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/io.h>
  28 #include <linux/altera_jtaguart.h>
  29
  30 #define DRV_NAME "altera_jtaguart"
  31
  32 /*
  33  * Altera JTAG UART register definitions according to the Altera JTAG UART
  34  * datasheet: http://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf
  35  */
  36
  37 #define ALTERA_JTAGUART_SIZE                    8
  38
  39 #define ALTERA_JTAGUART_DATA_REG                0
  40
  41 #define ALTERA_JTAGUART_DATA_DATA_MSK           0x000000FF
  42 #define ALTERA_JTAGUART_DATA_RVALID_MSK         0x00008000
  43 #define ALTERA_JTAGUART_DATA_RAVAIL_MSK         0xFFFF0000
  44 #define ALTERA_JTAGUART_DATA_RAVAIL_OFF         16
  45
  46 #define ALTERA_JTAGUART_CONTROL_REG             4
  47
  48 #define ALTERA_JTAGUART_CONTROL_RE_MSK          0x00000001
  49 #define ALTERA_JTAGUART_CONTROL_WE_MSK          0x00000002
  50 #define ALTERA_JTAGUART_CONTROL_RI_MSK          0x00000100
  51 #define ALTERA_JTAGUART_CONTROL_RI_OFF          8
  52 #define ALTERA_JTAGUART_CONTROL_WI_MSK          0x00000200
  53 #define ALTERA_JTAGUART_CONTROL_AC_MSK          0x00000400
  54 #define ALTERA_JTAGUART_CONTROL_WSPACE_MSK      0xFFFF0000
  55 #define ALTERA_JTAGUART_CONTROL_WSPACE_OFF      16
  56
  57 /*
  58  * Local per-uart structure.
  59  */
  60 struct altera_jtaguart {
  61         struct uart_port port;
  62         unsigned int sigs;      /* Local copy of line sigs */
  63         unsigned long imr;      /* Local IMR mirror */
  64 };
  65
  66 static unsigned int altera_jtaguart_tx_empty(struct uart_port *port)
  67 {
  68         return (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
  69                 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) ? TIOCSER_TEMT : 0;
  70 }
  71
  72 static unsigned int altera_jtaguart_get_mctrl(struct uart_port *port)
  73 {
  74         return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
  75 }
  76
  77 static void altera_jtaguart_set_mctrl(struct uart_port *port, unsigned int sigs)
  78 {
  79 }
  80
  81 static void altera_jtaguart_start_tx(struct uart_port *port)
  82 {
  83         struct altera_jtaguart *pp =
  84             container_of(port, struct altera_jtaguart, port);
  85
  86         pp->imr |= ALTERA_JTAGUART_CONTROL_WE_MSK;
  87         writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
  88 }
  89
  90 static void altera_jtaguart_stop_tx(struct uart_port *port)
  91 {
  92         struct altera_jtaguart *pp =
  93             container_of(port, struct altera_jtaguart, port);
  94
  95         pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
  96         writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
  97 }
  98
  99 static void altera_jtaguart_stop_rx(struct uart_port *port)
 100 {
 101         struct altera_jtaguart *pp =
 102             container_of(port, struct altera_jtaguart, port);
 103
 104         pp->imr &= ~ALTERA_JTAGUART_CONTROL_RE_MSK;
 105         writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 106 }
 107
 108 static void altera_jtaguart_break_ctl(struct uart_port *port, int break_state)
 109 {
 110 }
 111
 112 static void altera_jtaguart_enable_ms(struct uart_port *port)
 113 {
 114 }
 115
 116 static void altera_jtaguart_set_termios(struct uart_port *port,
 117                                         struct ktermios *termios,
 118                                         struct ktermios *old)
 119 {
 120         /* Just copy the old termios settings back */
 121         if (old)
 122                 tty_termios_copy_hw(termios, old);
 123 }
 124
 125 static void altera_jtaguart_rx_chars(struct altera_jtaguart *pp)
 126 {
 127         struct uart_port *port = &pp->port;
 128         unsigned char ch, flag;
 129         unsigned long status;
 130
 131         while ((status = readl(port->membase + ALTERA_JTAGUART_DATA_REG)) &
 132                ALTERA_JTAGUART_DATA_RVALID_MSK) {
 133                 ch = status & ALTERA_JTAGUART_DATA_DATA_MSK;
 134                 flag = TTY_NORMAL;
 135                 port->icount.rx++;
 136
 137                 if (uart_handle_sysrq_char(port, ch))
 138                         continue;
 139                 uart_insert_char(port, 0, 0, ch, flag);
 140         }
 141
 142         spin_unlock(&port->lock);
 143         tty_flip_buffer_push(&port->state->port);
 144         spin_lock(&port->lock);
 145 }
 146
 147 static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp)
 148 {
 149         struct uart_port *port = &pp->port;
 150         struct circ_buf *xmit = &port->state->xmit;
 151         unsigned int pending, count;
 152
 153         if (port->x_char) {
 154                 /* Send special char - probably flow control */
 155                 writel(port->x_char, port->membase + ALTERA_JTAGUART_DATA_REG);
 156                 port->x_char = 0;
 157                 port->icount.tx++;
 158                 return;
 159         }
 160
 161         pending = uart_circ_chars_pending(xmit);
 162         if (pending > 0) {
 163                 count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
 164                                 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >>
 165                         ALTERA_JTAGUART_CONTROL_WSPACE_OFF;
 166                 if (count > pending)
 167                         count = pending;
 168                 if (count > 0) {
 169                         pending -= count;
 170                         while (count--) {
 171                                 writel(xmit->buf[xmit->tail],
 172                                        port->membase + ALTERA_JTAGUART_DATA_REG);
 173                                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 174                                 port->icount.tx++;
 175                         }
 176                         if (pending < WAKEUP_CHARS)
 177                                 uart_write_wakeup(port);
 178                 }
 179         }
 180
 181         if (pending == 0) {
 182                 pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
 183                 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 184         }
 185 }
 186
 187 static irqreturn_t altera_jtaguart_interrupt(int irq, void *data)
 188 {
 189         struct uart_port *port = data;
 190         struct altera_jtaguart *pp =
 191             container_of(port, struct altera_jtaguart, port);
 192         unsigned int isr;
 193
 194         isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >>
 195                ALTERA_JTAGUART_CONTROL_RI_OFF) & pp->imr;
 196
 197         spin_lock(&port->lock);
 198
 199         if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK)
 200                 altera_jtaguart_rx_chars(pp);
 201         if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK)
 202                 altera_jtaguart_tx_chars(pp);
 203
 204         spin_unlock(&port->lock);
 205
 206         return IRQ_RETVAL(isr);
 207 }
 208
 209 static void altera_jtaguart_config_port(struct uart_port *port, int flags)
 210 {
 211         port->type = PORT_ALTERA_JTAGUART;
 212
 213         /* Clear mask, so no surprise interrupts. */
 214         writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 215 }
 216
 217 static int altera_jtaguart_startup(struct uart_port *port)
 218 {
 219         struct altera_jtaguart *pp =
 220             container_of(port, struct altera_jtaguart, port);
 221         unsigned long flags;
 222         int ret;
 223
 224         ret = request_irq(port->irq, altera_jtaguart_interrupt, 0,
 225                         DRV_NAME, port);
 226         if (ret) {
 227                 pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d "
 228                        "interrupt vector=%d\n", port->line, port->irq);
 229                 return ret;
 230         }
 231
 232         spin_lock_irqsave(&port->lock, flags);
 233
 234         /* Enable RX interrupts now */
 235         pp->imr = ALTERA_JTAGUART_CONTROL_RE_MSK;
 236         writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 237
 238         spin_unlock_irqrestore(&port->lock, flags);
 239
 240         return 0;
 241 }
 242
 243 static void altera_jtaguart_shutdown(struct uart_port *port)
 244 {
 245         struct altera_jtaguart *pp =
 246             container_of(port, struct altera_jtaguart, port);
 247         unsigned long flags;
 248
 249         spin_lock_irqsave(&port->lock, flags);
 250
 251         /* Disable all interrupts now */
 252         pp->imr = 0;
 253         writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 254
 255         spin_unlock_irqrestore(&port->lock, flags);
 256
 257         free_irq(port->irq, port);
 258 }
 259
 260 static const char *altera_jtaguart_type(struct uart_port *port)
 261 {
 262         return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL;
 263 }
 264
 265 static int altera_jtaguart_request_port(struct uart_port *port)
 266 {
 267         /* UARTs always present */
 268         return 0;
 269 }
 270
 271 static void altera_jtaguart_release_port(struct uart_port *port)
 272 {
 273         /* Nothing to release... */
 274 }
 275
 276 static int altera_jtaguart_verify_port(struct uart_port *port,
 277                                        struct serial_struct *ser)
 278 {
 279         if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART)
 280                 return -EINVAL;
 281         return 0;
 282 }
 283
 284 /*
 285  *      Define the basic serial functions we support.
 286  */
 287 static struct uart_ops altera_jtaguart_ops = {
 288         .tx_empty       = altera_jtaguart_tx_empty,
 289         .get_mctrl      = altera_jtaguart_get_mctrl,
 290         .set_mctrl      = altera_jtaguart_set_mctrl,
 291         .start_tx       = altera_jtaguart_start_tx,
 292         .stop_tx        = altera_jtaguart_stop_tx,
 293         .stop_rx        = altera_jtaguart_stop_rx,
 294         .enable_ms      = altera_jtaguart_enable_ms,
 295         .break_ctl      = altera_jtaguart_break_ctl,
 296         .startup        = altera_jtaguart_startup,
 297         .shutdown       = altera_jtaguart_shutdown,
 298         .set_termios    = altera_jtaguart_set_termios,
 299         .type           = altera_jtaguart_type,
 300         .request_port   = altera_jtaguart_request_port,
 301         .release_port   = altera_jtaguart_release_port,
 302         .config_port    = altera_jtaguart_config_port,
 303         .verify_port    = altera_jtaguart_verify_port,
 304 };
 305
 306 #define ALTERA_JTAGUART_MAXPORTS 1
 307 static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS];
 308
 309 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)
 310
 311 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
 312 static void altera_jtaguart_console_putc(struct console *co, const char c)
 313 {
 314         struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
 315         unsigned long status;
 316         unsigned long flags;
 317
 318         spin_lock_irqsave(&port->lock, flags);
 319         while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) &
 320                 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
 321                 if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) {
 322                         spin_unlock_irqrestore(&port->lock, flags);
 323                         return; /* no connection activity */
 324                 }
 325                 spin_unlock_irqrestore(&port->lock, flags);
 326                 cpu_relax();
 327                 spin_lock_irqsave(&port->lock, flags);
 328         }
 329         writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
 330         spin_unlock_irqrestore(&port->lock, flags);
 331 }
 332 #else
 333 static void altera_jtaguart_console_putc(struct console *co, const char c)
 334 {
 335         struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
 336         unsigned long flags;
 337
 338         spin_lock_irqsave(&port->lock, flags);
 339         while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
 340                 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
 341                 spin_unlock_irqrestore(&port->lock, flags);
 342                 cpu_relax();
 343                 spin_lock_irqsave(&port->lock, flags);
 344         }
 345         writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
 346         spin_unlock_irqrestore(&port->lock, flags);
 347 }
 348 #endif
 349
 350 static void altera_jtaguart_console_write(struct console *co, const char *s,
 351                                           unsigned int count)
 352 {
 353         for (; count; count--, s++) {
 354                 altera_jtaguart_console_putc(co, *s);
 355                 if (*s == '\n')
 356                         altera_jtaguart_console_putc(co, '\r');
 357         }
 358 }
 359
 360 static int __init altera_jtaguart_console_setup(struct console *co,
 361                                                 char *options)
 362 {
 363         struct uart_port *port;
 364
 365         if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS)
 366                 return -EINVAL;
 367         port = &altera_jtaguart_ports[co->index].port;
 368         if (port->membase == NULL)
 369                 return -ENODEV;
 370         return 0;
 371 }
 372
 373 static struct uart_driver altera_jtaguart_driver;
 374
 375 static struct console altera_jtaguart_console = {
 376         .name   = "ttyJ",
 377         .write  = altera_jtaguart_console_write,
 378         .device = uart_console_device,
 379         .setup  = altera_jtaguart_console_setup,
 380         .flags  = CON_PRINTBUFFER,
 381         .index  = -1,
 382         .data   = &altera_jtaguart_driver,
 383 };
 384
 385 static int __init altera_jtaguart_console_init(void)
 386 {
 387         register_console(&altera_jtaguart_console);
 388         return 0;
 389 }
 390
 391 console_initcall(altera_jtaguart_console_init);
 392
 393 #define ALTERA_JTAGUART_CONSOLE (&altera_jtaguart_console)
 394
 395 #else
 396
 397 #define ALTERA_JTAGUART_CONSOLE NULL
 398
 399 #endif /* CONFIG_ALTERA_JTAGUART_CONSOLE */
 400
 401 static struct uart_driver altera_jtaguart_driver = {
 402         .owner          = THIS_MODULE,
 403         .driver_name    = "altera_jtaguart",
 404         .dev_name       = "ttyJ",
 405         .major          = ALTERA_JTAGUART_MAJOR,
 406         .minor          = ALTERA_JTAGUART_MINOR,
 407         .nr             = ALTERA_JTAGUART_MAXPORTS,
 408         .cons           = ALTERA_JTAGUART_CONSOLE,
 409 };
 410
 411 static int altera_jtaguart_probe(struct platform_device *pdev)
 412 {
 413         struct altera_jtaguart_platform_uart *platp =
 414                         dev_get_platdata(&pdev->dev);
 415         struct uart_port *port;
 416         struct resource *res_irq, *res_mem;
 417         int i = pdev->id;
 418
 419         /* -1 emphasizes that the platform must have one port, no .N suffix */
 420         if (i == -1)
 421                 i = 0;
 422
 423         if (i >= ALTERA_JTAGUART_MAXPORTS)
 424                 return -EINVAL;
 425
 426         port = &altera_jtaguart_ports[i].port;
 427
 428         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 429         if (res_mem)
 430                 port->mapbase = res_mem->start;
 431         else if (platp)
 432                 port->mapbase = platp->mapbase;
 433         else
 434                 return -ENODEV;
 435
 436         res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 437         if (res_irq)
 438                 port->irq = res_irq->start;
 439         else if (platp)
 440                 port->irq = platp->irq;
 441         else
 442                 return -ENODEV;
 443
 444         port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE);
 445         if (!port->membase)
 446                 return -ENOMEM;
 447
 448         port->line = i;
 449         port->type = PORT_ALTERA_JTAGUART;
 450         port->iotype = SERIAL_IO_MEM;
 451         port->ops = &altera_jtaguart_ops;
 452         port->flags = UPF_BOOT_AUTOCONF;
 453
 454         uart_add_one_port(&altera_jtaguart_driver, port);
 455
 456         return 0;
 457 }
 458
 459 static int altera_jtaguart_remove(struct platform_device *pdev)
 460 {
 461         struct uart_port *port;
 462         int i = pdev->id;
 463
 464         if (i == -1)
 465                 i = 0;
 466
 467         port = &altera_jtaguart_ports[i].port;
 468         uart_remove_one_port(&altera_jtaguart_driver, port);
 469
 470         return 0;
 471 }
 472
 473 #ifdef CONFIG_OF
 474 static struct of_device_id altera_jtaguart_match[] = {
 475         { .compatible = "ALTR,juart-1.0", },
 476         { .compatible = "altr,juart-1.0", },
 477         {},
 478 };
 479 MODULE_DEVICE_TABLE(of, altera_jtaguart_match);
 480 #endif /* CONFIG_OF */
 481
 482 static struct platform_driver altera_jtaguart_platform_driver = {
 483         .probe  = altera_jtaguart_probe,
 484         .remove = altera_jtaguart_remove,
 485         .driver = {
 486                 .name           = DRV_NAME,
 487                 .owner          = THIS_MODULE,
 488                 .of_match_table = of_match_ptr(altera_jtaguart_match),
 489         },
 490 };
 491
 492 static int __init altera_jtaguart_init(void)
 493 {
 494         int rc;
 495
 496         rc = uart_register_driver(&altera_jtaguart_driver);
 497         if (rc)
 498                 return rc;
 499         rc = platform_driver_register(&altera_jtaguart_platform_driver);
 500         if (rc)
 501                 uart_unregister_driver(&altera_jtaguart_driver);
 502         return rc;
 503 }
 504
 505 static void __exit altera_jtaguart_exit(void)
 506 {
 507         platform_driver_unregister(&altera_jtaguart_platform_driver);
 508         uart_unregister_driver(&altera_jtaguart_driver);
 509 }
 510
 511 module_init(altera_jtaguart_init);
 512 module_exit(altera_jtaguart_exit);
 513
 514 MODULE_DESCRIPTION("Altera JTAG UART driver");
 515 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
 516 MODULE_LICENSE("GPL");
 517 MODULE_ALIAS("platform:" DRV_NAME);