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