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         tty_flip_buffer_push(port->state->port.tty);
 143 }
 144
 145 static void altera_jtaguart_tx_chars(struct altera_jtaguart *pp)
 146 {
 147         struct uart_port *port = &pp->port;
 148         struct circ_buf *xmit = &port->state->xmit;
 149         unsigned int pending, count;
 150
 151         if (port->x_char) {
 152                 /* Send special char - probably flow control */
 153                 writel(port->x_char, port->membase + ALTERA_JTAGUART_DATA_REG);
 154                 port->x_char = 0;
 155                 port->icount.tx++;
 156                 return;
 157         }
 158
 159         pending = uart_circ_chars_pending(xmit);
 160         if (pending > 0) {
 161                 count = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
 162                                 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) >>
 163                         ALTERA_JTAGUART_CONTROL_WSPACE_OFF;
 164                 if (count > pending)
 165                         count = pending;
 166                 if (count > 0) {
 167                         pending -= count;
 168                         while (count--) {
 169                                 writel(xmit->buf[xmit->tail],
 170                                        port->membase + ALTERA_JTAGUART_DATA_REG);
 171                                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 172                                 port->icount.tx++;
 173                         }
 174                         if (pending < WAKEUP_CHARS)
 175                                 uart_write_wakeup(port);
 176                 }
 177         }
 178
 179         if (pending == 0) {
 180                 pp->imr &= ~ALTERA_JTAGUART_CONTROL_WE_MSK;
 181                 writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 182         }
 183 }
 184
 185 static irqreturn_t altera_jtaguart_interrupt(int irq, void *data)
 186 {
 187         struct uart_port *port = data;
 188         struct altera_jtaguart *pp =
 189             container_of(port, struct altera_jtaguart, port);
 190         unsigned int isr;
 191
 192         isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >>
 193                ALTERA_JTAGUART_CONTROL_RI_OFF) & pp->imr;
 194
 195         spin_lock(&port->lock);
 196
 197         if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK)
 198                 altera_jtaguart_rx_chars(pp);
 199         if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK)
 200                 altera_jtaguart_tx_chars(pp);
 201
 202         spin_unlock(&port->lock);
 203
 204         return IRQ_RETVAL(isr);
 205 }
 206
 207 static void altera_jtaguart_config_port(struct uart_port *port, int flags)
 208 {
 209         port->type = PORT_ALTERA_JTAGUART;
 210
 211         /* Clear mask, so no surprise interrupts. */
 212         writel(0, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 213 }
 214
 215 static int altera_jtaguart_startup(struct uart_port *port)
 216 {
 217         struct altera_jtaguart *pp =
 218             container_of(port, struct altera_jtaguart, port);
 219         unsigned long flags;
 220         int ret;
 221
 222         ret = request_irq(port->irq, altera_jtaguart_interrupt, 0,
 223                         DRV_NAME, port);
 224         if (ret) {
 225                 pr_err(DRV_NAME ": unable to attach Altera JTAG UART %d "
 226                        "interrupt vector=%d\n", port->line, port->irq);
 227                 return ret;
 228         }
 229
 230         spin_lock_irqsave(&port->lock, flags);
 231
 232         /* Enable RX interrupts now */
 233         pp->imr = ALTERA_JTAGUART_CONTROL_RE_MSK;
 234         writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 235
 236         spin_unlock_irqrestore(&port->lock, flags);
 237
 238         return 0;
 239 }
 240
 241 static void altera_jtaguart_shutdown(struct uart_port *port)
 242 {
 243         struct altera_jtaguart *pp =
 244             container_of(port, struct altera_jtaguart, port);
 245         unsigned long flags;
 246
 247         spin_lock_irqsave(&port->lock, flags);
 248
 249         /* Disable all interrupts now */
 250         pp->imr = 0;
 251         writel(pp->imr, port->membase + ALTERA_JTAGUART_CONTROL_REG);
 252
 253         spin_unlock_irqrestore(&port->lock, flags);
 254
 255         free_irq(port->irq, port);
 256 }
 257
 258 static const char *altera_jtaguart_type(struct uart_port *port)
 259 {
 260         return (port->type == PORT_ALTERA_JTAGUART) ? "Altera JTAG UART" : NULL;
 261 }
 262
 263 static int altera_jtaguart_request_port(struct uart_port *port)
 264 {
 265         /* UARTs always present */
 266         return 0;
 267 }
 268
 269 static void altera_jtaguart_release_port(struct uart_port *port)
 270 {
 271         /* Nothing to release... */
 272 }
 273
 274 static int altera_jtaguart_verify_port(struct uart_port *port,
 275                                        struct serial_struct *ser)
 276 {
 277         if (ser->type != PORT_UNKNOWN && ser->type != PORT_ALTERA_JTAGUART)
 278                 return -EINVAL;
 279         return 0;
 280 }
 281
 282 /*
 283  *      Define the basic serial functions we support.
 284  */
 285 static struct uart_ops altera_jtaguart_ops = {
 286         .tx_empty       = altera_jtaguart_tx_empty,
 287         .get_mctrl      = altera_jtaguart_get_mctrl,
 288         .set_mctrl      = altera_jtaguart_set_mctrl,
 289         .start_tx       = altera_jtaguart_start_tx,
 290         .stop_tx        = altera_jtaguart_stop_tx,
 291         .stop_rx        = altera_jtaguart_stop_rx,
 292         .enable_ms      = altera_jtaguart_enable_ms,
 293         .break_ctl      = altera_jtaguart_break_ctl,
 294         .startup        = altera_jtaguart_startup,
 295         .shutdown       = altera_jtaguart_shutdown,
 296         .set_termios    = altera_jtaguart_set_termios,
 297         .type           = altera_jtaguart_type,
 298         .request_port   = altera_jtaguart_request_port,
 299         .release_port   = altera_jtaguart_release_port,
 300         .config_port    = altera_jtaguart_config_port,
 301         .verify_port    = altera_jtaguart_verify_port,
 302 };
 303
 304 #define ALTERA_JTAGUART_MAXPORTS 1
 305 static struct altera_jtaguart altera_jtaguart_ports[ALTERA_JTAGUART_MAXPORTS];
 306
 307 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)
 308
 309 #if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
 310 static void altera_jtaguart_console_putc(struct console *co, const char c)
 311 {
 312         struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
 313         unsigned long status;
 314         unsigned long flags;
 315
 316         spin_lock_irqsave(&port->lock, flags);
 317         while (((status = readl(port->membase + ALTERA_JTAGUART_CONTROL_REG)) &
 318                 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
 319                 if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) {
 320                         spin_unlock_irqrestore(&port->lock, flags);
 321                         return; /* no connection activity */
 322                 }
 323                 spin_unlock_irqrestore(&port->lock, flags);
 324                 cpu_relax();
 325                 spin_lock_irqsave(&port->lock, flags);
 326         }
 327         writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
 328         spin_unlock_irqrestore(&port->lock, flags);
 329 }
 330 #else
 331 static void altera_jtaguart_console_putc(struct console *co, const char c)
 332 {
 333         struct uart_port *port = &(altera_jtaguart_ports + co->index)->port;
 334         unsigned long flags;
 335
 336         spin_lock_irqsave(&port->lock, flags);
 337         while ((readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) &
 338                 ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
 339                 spin_unlock_irqrestore(&port->lock, flags);
 340                 cpu_relax();
 341                 spin_lock_irqsave(&port->lock, flags);
 342         }
 343         writel(c, port->membase + ALTERA_JTAGUART_DATA_REG);
 344         spin_unlock_irqrestore(&port->lock, flags);
 345 }
 346 #endif
 347
 348 static void altera_jtaguart_console_write(struct console *co, const char *s,
 349                                           unsigned int count)
 350 {
 351         for (; count; count--, s++) {
 352                 altera_jtaguart_console_putc(co, *s);
 353                 if (*s == '\n')
 354                         altera_jtaguart_console_putc(co, '\r');
 355         }
 356 }
 357
 358 static int __init altera_jtaguart_console_setup(struct console *co,
 359                                                 char *options)
 360 {
 361         struct uart_port *port;
 362
 363         if (co->index < 0 || co->index >= ALTERA_JTAGUART_MAXPORTS)
 364                 return -EINVAL;
 365         port = &altera_jtaguart_ports[co->index].port;
 366         if (port->membase == NULL)
 367                 return -ENODEV;
 368         return 0;
 369 }
 370
 371 static struct uart_driver altera_jtaguart_driver;
 372
 373 static struct console altera_jtaguart_console = {
 374         .name   = "ttyJ",
 375         .write  = altera_jtaguart_console_write,
 376         .device = uart_console_device,
 377         .setup  = altera_jtaguart_console_setup,
 378         .flags  = CON_PRINTBUFFER,
 379         .index  = -1,
 380         .data   = &altera_jtaguart_driver,
 381 };
 382
 383 static int __init altera_jtaguart_console_init(void)
 384 {
 385         register_console(&altera_jtaguart_console);
 386         return 0;
 387 }
 388
 389 console_initcall(altera_jtaguart_console_init);
 390
 391 #define ALTERA_JTAGUART_CONSOLE (&altera_jtaguart_console)
 392
 393 #else
 394
 395 #define ALTERA_JTAGUART_CONSOLE NULL
 396
 397 #endif /* CONFIG_ALTERA_JTAGUART_CONSOLE */
 398
 399 static struct uart_driver altera_jtaguart_driver = {
 400         .owner          = THIS_MODULE,
 401         .driver_name    = "altera_jtaguart",
 402         .dev_name       = "ttyJ",
 403         .major          = ALTERA_JTAGUART_MAJOR,
 404         .minor          = ALTERA_JTAGUART_MINOR,
 405         .nr             = ALTERA_JTAGUART_MAXPORTS,
 406         .cons           = ALTERA_JTAGUART_CONSOLE,
 407 };
 408
 409 static int __devinit altera_jtaguart_probe(struct platform_device *pdev)
 410 {
 411         struct altera_jtaguart_platform_uart *platp = pdev->dev.platform_data;
 412         struct uart_port *port;
 413         struct resource *res_irq, *res_mem;
 414         int i = pdev->id;
 415
 416         /* -1 emphasizes that the platform must have one port, no .N suffix */
 417         if (i == -1)
 418                 i = 0;
 419
 420         if (i >= ALTERA_JTAGUART_MAXPORTS)
 421                 return -EINVAL;
 422
 423         port = &altera_jtaguart_ports[i].port;
 424
 425         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 426         if (res_mem)
 427                 port->mapbase = res_mem->start;
 428         else if (platp)
 429                 port->mapbase = platp->mapbase;
 430         else
 431                 return -ENODEV;
 432
 433         res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 434         if (res_irq)
 435                 port->irq = res_irq->start;
 436         else if (platp)
 437                 port->irq = platp->irq;
 438         else
 439                 return -ENODEV;
 440
 441         port->membase = ioremap(port->mapbase, ALTERA_JTAGUART_SIZE);
 442         if (!port->membase)
 443                 return -ENOMEM;
 444
 445         port->line = i;
 446         port->type = PORT_ALTERA_JTAGUART;
 447         port->iotype = SERIAL_IO_MEM;
 448         port->ops = &altera_jtaguart_ops;
 449         port->flags = UPF_BOOT_AUTOCONF;
 450
 451         uart_add_one_port(&altera_jtaguart_driver, port);
 452
 453         return 0;
 454 }
 455
 456 static int __devexit altera_jtaguart_remove(struct platform_device *pdev)
 457 {
 458         struct uart_port *port;
 459         int i = pdev->id;
 460
 461         if (i == -1)
 462                 i = 0;
 463
 464         port = &altera_jtaguart_ports[i].port;
 465         uart_remove_one_port(&altera_jtaguart_driver, port);
 466
 467         return 0;
 468 }
 469
 470 #ifdef CONFIG_OF
 471 static struct of_device_id altera_jtaguart_match[] = {
 472         { .compatible = "ALTR,juart-1.0", },
 473         {},
 474 };
 475 MODULE_DEVICE_TABLE(of, altera_jtaguart_match);
 476 #endif /* CONFIG_OF */
 477
 478 static struct platform_driver altera_jtaguart_platform_driver = {
 479         .probe  = altera_jtaguart_probe,
 480         .remove = __devexit_p(altera_jtaguart_remove),
 481         .driver = {
 482                 .name           = DRV_NAME,
 483                 .owner          = THIS_MODULE,
 484                 .of_match_table = of_match_ptr(altera_jtaguart_match),
 485         },
 486 };
 487
 488 static int __init altera_jtaguart_init(void)
 489 {
 490         int rc;
 491
 492         rc = uart_register_driver(&altera_jtaguart_driver);
 493         if (rc)
 494                 return rc;
 495         rc = platform_driver_register(&altera_jtaguart_platform_driver);
 496         if (rc) {
 497                 uart_unregister_driver(&altera_jtaguart_driver);
 498                 return rc;
 499         }
 500         return 0;
 501 }
 502
 503 static void __exit altera_jtaguart_exit(void)
 504 {
 505         platform_driver_unregister(&altera_jtaguart_platform_driver);
 506         uart_unregister_driver(&altera_jtaguart_driver);
 507 }
 508
 509 module_init(altera_jtaguart_init);
 510 module_exit(altera_jtaguart_exit);
 511
 512 MODULE_DESCRIPTION("Altera JTAG UART driver");
 513 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
 514 MODULE_LICENSE("GPL");
 515 MODULE_ALIAS("platform:" DRV_NAME);