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