drivers/serial/clps711x.c

   1 /*
   2  *  linux/drivers/char/clps711x.c
   3  *
   4  *  Driver for CLPS711x serial ports
   5  *
   6  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   7  *
   8  *  Copyright 1999 ARM Limited
   9  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24  *
  25  *  $Id: clps711x.c,v 1.42 2002/07/28 10:03:28 rmk Exp $
  26  *
  27  */
  28 #include <linux/config.h>
  29 #include <linux/module.h>
  30 #include <linux/tty.h>
  31 #include <linux/ioport.h>
  32 #include <linux/init.h>
  33 #include <linux/serial.h>
  34 #include <linux/console.h>
  35 #include <linux/sysrq.h>
  36 #include <linux/spinlock.h>
  37
  38 #include <asm/hardware.h>
  39 #include <asm/io.h>
  40 #include <asm/irq.h>
  41
  42 #if defined(CONFIG_SERIAL_CLPS711X_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  43 #define SUPPORT_SYSRQ
  44 #endif
  45
  46 #include <linux/serial_core.h>
  47
  48 #include <asm/hardware/clps7111.h>
  49
  50 #define UART_NR         2
  51
  52 #ifndef CONFIG_SERIAL_CLPS711X_OLD_NAME
  53 #define SERIAL_CLPS711X_MAJOR   204
  54 #define SERIAL_CLPS711X_MINOR   40
  55 #define SERIAL_CLPS711X_NR      UART_NR
  56
  57 #else
  58 #warning The old names/device number for this driver if compatabity is needed
  59 #define SERIAL_CLPS711X_MAJOR   204
  60 #define SERIAL_CLPS711X_MINOR   16
  61 #define SERIAL_CLPS711X_NR      UART_NR
  62
  63 #endif
  64
  65 /*
  66  * We use the relevant SYSCON register as a base address for these ports.
  67  */
  68 #define UBRLCR(port)            ((port)->iobase + UBRLCR1 - SYSCON1)
  69 #define UARTDR(port)            ((port)->iobase + UARTDR1 - SYSCON1)
  70 #define SYSFLG(port)            ((port)->iobase + SYSFLG1 - SYSCON1)
  71 #define SYSCON(port)            ((port)->iobase + SYSCON1 - SYSCON1)
  72
  73 #define TX_IRQ(port)            ((port)->irq)
  74 #define RX_IRQ(port)            ((port)->irq + 1)
  75
  76 #define UART_ANY_ERR            (UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR)
  77
  78 #define tx_enabled(port)        ((port)->unused[0])
  79
  80 static void
  81 clps711xuart_stop_tx(struct uart_port *port, unsigned int tty_stop)
  82 {
  83         if (tx_enabled(port)) {
  84                 disable_irq(TX_IRQ(port));
  85                 tx_enabled(port) = 0;
  86         }
  87 }
  88
  89 static void
  90 clps711xuart_start_tx(struct uart_port *port, unsigned int tty_start)
  91 {
  92         if (!tx_enabled(port)) {
  93                 enable_irq(TX_IRQ(port));
  94                 tx_enabled(port) = 1;
  95         }
  96 }
  97
  98 static void clps711xuart_stop_rx(struct uart_port *port)
  99 {
 100         disable_irq(RX_IRQ(port));
 101 }
 102
 103 static void clps711xuart_enable_ms(struct uart_port *port)
 104 {
 105 }
 106
 107 static void clps711xuart_int_rx(int irq, void *dev_id, struct pt_regs *regs)
 108 {
 109         struct uart_port *port = dev_id;
 110         struct tty_struct *tty = port->info->tty;
 111         unsigned int status, ch, flg, ignored = 0;
 112
 113         status = clps_readl(SYSFLG(port));
 114         while (!(status & SYSFLG_URXFE)) {
 115                 ch = clps_readl(UARTDR(port));
 116
 117                 if (tty->flip.count >= TTY_FLIPBUF_SIZE)
 118                         goto ignore_char;
 119                 port->icount.rx++;
 120
 121                 flg = TTY_NORMAL;
 122
 123                 /*
 124                  * Note that the error handling code is
 125                  * out of the main execution path
 126                  */
 127                 if (ch & UART_ANY_ERR)
 128                         goto handle_error;
 129
 130                 if (uart_handle_sysrq_char(port, ch, regs))
 131                         goto ignore_char;
 132
 133         error_return:
 134                 *tty->flip.flag_buf_ptr++ = flg;
 135                 *tty->flip.char_buf_ptr++ = ch;
 136                 tty->flip.count++;
 137         ignore_char:
 138                 status = clps_readl(SYSFLG(port));
 139         }
 140  out:
 141         tty_flip_buffer_push(tty);
 142         return;
 143
 144  handle_error:
 145         if (ch & UARTDR_PARERR)
 146                 port->icount.parity++;
 147         else if (ch & UARTDR_FRMERR)
 148                 port->icount.frame++;
 149         if (ch & UARTDR_OVERR)
 150                 port->icount.overrun++;
 151
 152         if (ch & port->ignore_status_mask) {
 153                 if (++ignored > 100)
 154                         goto out;
 155                 goto ignore_char;
 156         }
 157         ch &= port->read_status_mask;
 158
 159         if (ch & UARTDR_PARERR)
 160                 flg = TTY_PARITY;
 161         else if (ch & UARTDR_FRMERR)
 162                 flg = TTY_FRAME;
 163
 164         if (ch & UARTDR_OVERR) {
 165                 /*
 166                  * CHECK: does overrun affect the current character?
 167                  * ASSUMPTION: it does not.
 168                  */
 169                 *tty->flip.flag_buf_ptr++ = flg;
 170                 *tty->flip.char_buf_ptr++ = ch;
 171                 tty->flip.count++;
 172                 if (tty->flip.count >= TTY_FLIPBUF_SIZE)
 173                         goto ignore_char;
 174                 ch = 0;
 175                 flg = TTY_OVERRUN;
 176         }
 177 #ifdef SUPPORT_SYSRQ
 178         port->sysrq = 0;
 179 #endif
 180         goto error_return;
 181 }
 182
 183 static void clps711xuart_int_tx(int irq, void *dev_id, struct pt_regs *regs)
 184 {
 185         struct uart_port *port = dev_id;
 186         struct circ_buf *xmit = &port->info->xmit;
 187         int count;
 188
 189         if (port->x_char) {
 190                 clps_writel(port->x_char, UARTDR(port));
 191                 port->icount.tx++;
 192                 port->x_char = 0;
 193                 return;
 194         }
 195         if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 196                 clps711xuart_stop_tx(port, 0);
 197                 return;
 198         }
 199
 200         count = port->fifosize >> 1;
 201         do {
 202                 clps_writel(xmit->buf[xmit->tail], UARTDR(port));
 203                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 204                 port->icount.tx++;
 205                 if (uart_circ_empty(xmit))
 206                         break;
 207         } while (--count > 0);
 208
 209         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 210                 uart_write_wakeup(port);
 211
 212         if (uart_circ_empty(xmit))
 213                 clps711xuart_stop_tx(port, 0);
 214 }
 215
 216 static unsigned int clps711xuart_tx_empty(struct uart_port *port)
 217 {
 218         unsigned int status = clps_readl(SYSFLG(port));
 219         return status & SYSFLG_UBUSY ? 0 : TIOCSER_TEMT;
 220 }
 221
 222 static unsigned int clps711xuart_get_mctrl(struct uart_port *port)
 223 {
 224         unsigned int port_addr;
 225         unsigned int result = 0;
 226         unsigned int status;
 227
 228         port_addr = SYSFLG(port);
 229         if (port_addr == SYSFLG1) {
 230                 status = clps_readl(SYSFLG1);
 231                 if (status & SYSFLG1_DCD)
 232                         result |= TIOCM_CAR;
 233                 if (status & SYSFLG1_DSR)
 234                         result |= TIOCM_DSR;
 235                 if (status & SYSFLG1_CTS)
 236                         result |= TIOCM_CTS;
 237         }
 238
 239         return result;
 240 }
 241
 242 static void
 243 clps711xuart_set_mctrl_null(struct uart_port *port, unsigned int mctrl)
 244 {
 245 }
 246
 247 static void clps711xuart_break_ctl(struct uart_port *port, int break_state)
 248 {
 249         unsigned long flags;
 250         unsigned int ubrlcr;
 251
 252         spin_lock_irqsave(&port->lock, flags);
 253         ubrlcr = clps_readl(UBRLCR(port));
 254         if (break_state == -1)
 255                 ubrlcr |= UBRLCR_BREAK;
 256         else
 257                 ubrlcr &= ~UBRLCR_BREAK;
 258         clps_writel(ubrlcr, UBRLCR(port));
 259         spin_unlock_irqrestore(&port->lock, flags);
 260 }
 261
 262 static int clps711xuart_startup(struct uart_port *port)
 263 {
 264         unsigned int syscon;
 265         int retval;
 266
 267         tx_enabled(port) = 1;
 268
 269         /*
 270          * Allocate the IRQs
 271          */
 272         retval = request_irq(TX_IRQ(port), clps711xuart_int_tx, 0,
 273                              "clps711xuart_tx", port);
 274         if (retval)
 275                 return retval;
 276
 277         retval = request_irq(RX_IRQ(port), clps711xuart_int_rx, 0,
 278                              "clps711xuart_rx", port);
 279         if (retval) {
 280                 free_irq(TX_IRQ(port), port);
 281                 return retval;
 282         }
 283
 284         /*
 285          * enable the port
 286          */
 287         syscon = clps_readl(SYSCON(port));
 288         syscon |= SYSCON_UARTEN;
 289         clps_writel(syscon, SYSCON(port));
 290
 291         return 0;
 292 }
 293
 294 static void clps711xuart_shutdown(struct uart_port *port)
 295 {
 296         unsigned int ubrlcr, syscon;
 297
 298         /*
 299          * Free the interrupt
 300          */
 301         free_irq(TX_IRQ(port), port);   /* TX interrupt */
 302         free_irq(RX_IRQ(port), port);   /* RX interrupt */
 303
 304         /*
 305          * disable the port
 306          */
 307         syscon = clps_readl(SYSCON(port));
 308         syscon &= ~SYSCON_UARTEN;
 309         clps_writel(syscon, SYSCON(port));
 310
 311         /*
 312          * disable break condition and fifos
 313          */
 314         ubrlcr = clps_readl(UBRLCR(port));
 315         ubrlcr &= ~(UBRLCR_FIFOEN | UBRLCR_BREAK);
 316         clps_writel(ubrlcr, UBRLCR(port));
 317 }
 318
 319 static void
 320 clps711xuart_set_termios(struct uart_port *port, struct termios *termios,
 321                          struct termios *old)
 322 {
 323         unsigned int ubrlcr, baud, quot;
 324         unsigned long flags;
 325
 326         /*
 327          * We don't implement CREAD.
 328          */
 329         termios->c_cflag |= CREAD;
 330
 331         /*
 332          * Ask the core to calculate the divisor for us.
 333          */
 334         baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
 335         quot = uart_get_divisor(port, baud);
 336
 337         switch (termios->c_cflag & CSIZE) {
 338         case CS5:
 339                 ubrlcr = UBRLCR_WRDLEN5;
 340                 break;
 341         case CS6:
 342                 ubrlcr = UBRLCR_WRDLEN6;
 343                 break;
 344         case CS7:
 345                 ubrlcr = UBRLCR_WRDLEN7;
 346                 break;
 347         default: // CS8
 348                 ubrlcr = UBRLCR_WRDLEN8;
 349                 break;
 350         }
 351         if (termios->c_cflag & CSTOPB)
 352                 ubrlcr |= UBRLCR_XSTOP;
 353         if (termios->c_cflag & PARENB) {
 354                 ubrlcr |= UBRLCR_PRTEN;
 355                 if (!(termios->c_cflag & PARODD))
 356                         ubrlcr |= UBRLCR_EVENPRT;
 357         }
 358         if (port->fifosize > 1)
 359                 ubrlcr |= UBRLCR_FIFOEN;
 360
 361         spin_lock_irqsave(&port->lock, flags);
 362
 363         /*
 364          * Update the per-port timeout.
 365          */
 366         uart_update_timeout(port, termios->c_cflag, baud);
 367
 368         port->read_status_mask = UARTDR_OVERR;
 369         if (termios->c_iflag & INPCK)
 370                 port->read_status_mask |= UARTDR_PARERR | UARTDR_FRMERR;
 371
 372         /*
 373          * Characters to ignore
 374          */
 375         port->ignore_status_mask = 0;
 376         if (termios->c_iflag & IGNPAR)
 377                 port->ignore_status_mask |= UARTDR_FRMERR | UARTDR_PARERR;
 378         if (termios->c_iflag & IGNBRK) {
 379                 /*
 380                  * If we're ignoring parity and break indicators,
 381                  * ignore overruns to (for real raw support).
 382                  */
 383                 if (termios->c_iflag & IGNPAR)
 384                         port->ignore_status_mask |= UARTDR_OVERR;
 385         }
 386
 387         quot -= 1;
 388
 389         clps_writel(ubrlcr | quot, UBRLCR(port));
 390
 391         spin_unlock_irqrestore(&port->lock, flags);
 392 }
 393
 394 static const char *clps711xuart_type(struct uart_port *port)
 395 {
 396         return port->type == PORT_CLPS711X ? "CLPS711x" : NULL;
 397 }
 398
 399 /*
 400  * Configure/autoconfigure the port.
 401  */
 402 static void clps711xuart_config_port(struct uart_port *port, int flags)
 403 {
 404         if (flags & UART_CONFIG_TYPE)
 405                 port->type = PORT_CLPS711X;
 406 }
 407
 408 static void clps711xuart_release_port(struct uart_port *port)
 409 {
 410 }
 411
 412 static int clps711xuart_request_port(struct uart_port *port)
 413 {
 414         return 0;
 415 }
 416
 417 static struct uart_ops clps711x_pops = {
 418         .tx_empty       = clps711xuart_tx_empty,
 419         .set_mctrl      = clps711xuart_set_mctrl_null,
 420         .get_mctrl      = clps711xuart_get_mctrl,
 421         .stop_tx        = clps711xuart_stop_tx,
 422         .start_tx       = clps711xuart_start_tx,
 423         .stop_rx        = clps711xuart_stop_rx,
 424         .enable_ms      = clps711xuart_enable_ms,
 425         .break_ctl      = clps711xuart_break_ctl,
 426         .startup        = clps711xuart_startup,
 427         .shutdown       = clps711xuart_shutdown,
 428         .set_termios    = clps711xuart_set_termios,
 429         .type           = clps711xuart_type,
 430         .config_port    = clps711xuart_config_port,
 431         .release_port   = clps711xuart_release_port,
 432         .request_port   = clps711xuart_request_port,
 433 };
 434
 435 static struct uart_port clps711x_ports[UART_NR] = {
 436         {
 437                 .iobase         = SYSCON1,
 438                 .irq            = IRQ_UTXINT1, /* IRQ_URXINT1, IRQ_UMSINT */
 439                 .uartclk        = 3686400,
 440                 .fifosize       = 16,
 441                 .ops            = &clps711x_pops,
 442                 .line           = 0,
 443                 .flags          = ASYNC_BOOT_AUTOCONF,
 444         },
 445         {
 446                 .iobase         = SYSCON2,
 447                 .irq            = IRQ_UTXINT2, /* IRQ_URXINT2 */
 448                 .uartclk        = 3686400,
 449                 .fifosize       = 16,
 450                 .ops            = &clps711x_pops,
 451                 .line           = 1,
 452                 .flags          = ASYNC_BOOT_AUTOCONF,
 453         }
 454 };
 455
 456 #ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
 457 /*
 458  *      Print a string to the serial port trying not to disturb
 459  *      any possible real use of the port...
 460  *
 461  *      The console_lock must be held when we get here.
 462  *
 463  *      Note that this is called with interrupts already disabled
 464  */
 465 static void
 466 clps711xuart_console_write(struct console *co, const char *s,
 467                            unsigned int count)
 468 {
 469         struct uart_port *port = clps711x_ports + co->index;
 470         unsigned int status, syscon;
 471         int i;
 472
 473         /*
 474          *      Ensure that the port is enabled.
 475          */
 476         syscon = clps_readl(SYSCON(port));
 477         clps_writel(syscon | SYSCON_UARTEN, SYSCON(port));
 478
 479         /*
 480          *      Now, do each character
 481          */
 482         for (i = 0; i < count; i++) {
 483                 do {
 484                         status = clps_readl(SYSFLG(port));
 485                 } while (status & SYSFLG_UTXFF);
 486                 clps_writel(s[i], UARTDR(port));
 487                 if (s[i] == '\n') {
 488                         do {
 489                                 status = clps_readl(SYSFLG(port));
 490                         } while (status & SYSFLG_UTXFF);
 491                         clps_writel('\r', UARTDR(port));
 492                 }
 493         }
 494
 495         /*
 496          *      Finally, wait for transmitter to become empty
 497          *      and restore the uart state.
 498          */
 499         do {
 500                 status = clps_readl(SYSFLG(port));
 501         } while (status & SYSFLG_UBUSY);
 502
 503         clps_writel(syscon, SYSCON(port));
 504 }
 505
 506 static void __init
 507 clps711xuart_console_get_options(struct uart_port *port, int *baud,
 508                                  int *parity, int *bits)
 509 {
 510         if (clps_readl(SYSCON(port)) & SYSCON_UARTEN) {
 511                 unsigned int ubrlcr, quot;
 512
 513                 ubrlcr = clps_readl(UBRLCR(port));
 514
 515                 *parity = 'n';
 516                 if (ubrlcr & UBRLCR_PRTEN) {
 517                         if (ubrlcr & UBRLCR_EVENPRT)
 518                                 *parity = 'e';
 519                         else
 520                                 *parity = 'o';
 521                 }
 522
 523                 if ((ubrlcr & UBRLCR_WRDLEN_MASK) == UBRLCR_WRDLEN7)
 524                         *bits = 7;
 525                 else
 526                         *bits = 8;
 527
 528                 quot = ubrlcr & UBRLCR_BAUD_MASK;
 529                 *baud = port->uartclk / (16 * (quot + 1));
 530         }
 531 }
 532
 533 static int __init clps711xuart_console_setup(struct console *co, char *options)
 534 {
 535         struct uart_port *port;
 536         int baud = 38400;
 537         int bits = 8;
 538         int parity = 'n';
 539         int flow = 'n';
 540
 541         /*
 542          * Check whether an invalid uart number has been specified, and
 543          * if so, search for the first available port that does have
 544          * console support.
 545          */
 546         port = uart_get_console(clps711x_ports, UART_NR, co);
 547
 548         if (options)
 549                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 550         else
 551                 clps711xuart_console_get_options(port, &baud, &parity, &bits);
 552
 553         return uart_set_options(port, co, baud, parity, bits, flow);
 554 }
 555
 556 extern struct uart_driver clps711x_reg;
 557 static struct console clps711x_console = {
 558         .name           = "ttyCL",
 559         .write          = clps711xuart_console_write,
 560         .device         = uart_console_device,
 561         .setup          = clps711xuart_console_setup,
 562         .flags          = CON_PRINTBUFFER,
 563         .index          = -1,
 564         .data           = &clps711x_reg,
 565 };
 566
 567 static int __init clps711xuart_console_init(void)
 568 {
 569         register_console(&clps711x_console);
 570         return 0;
 571 }
 572 console_initcall(clps711xuart_console_init);
 573
 574 #define CLPS711X_CONSOLE        &clps711x_console
 575 #else
 576 #define CLPS711X_CONSOLE        NULL
 577 #endif
 578
 579 static struct uart_driver clps711x_reg = {
 580         .driver_name            = "ttyCL",
 581         .dev_name               = "ttyCL",
 582         .major                  = SERIAL_CLPS711X_MAJOR,
 583         .minor                  = SERIAL_CLPS711X_MINOR,
 584         .nr                     = UART_NR,
 585
 586         .cons                   = CLPS711X_CONSOLE,
 587 };
 588
 589 static int __init clps711xuart_init(void)
 590 {
 591         int ret, i;
 592
 593         printk(KERN_INFO "Serial: CLPS711x driver $Revision: 1.42 $\n");
 594
 595         ret = uart_register_driver(&clps711x_reg);
 596         if (ret)
 597                 return ret;
 598
 599         for (i = 0; i < UART_NR; i++)
 600                 uart_add_one_port(&clps711x_reg, &clps711x_ports[i]);
 601
 602         return 0;
 603 }
 604
 605 static void __exit clps711xuart_exit(void)
 606 {
 607         int i;
 608
 609         for (i = 0; i < UART_NR; i++)
 610                 uart_remove_one_port(&clps711x_reg, &clps711x_ports[i]);
 611
 612         uart_unregister_driver(&clps711x_reg);
 613 }
 614
 615 module_init(clps711xuart_init);
 616 module_exit(clps711xuart_exit);
 617
 618 MODULE_AUTHOR("Deep Blue Solutions Ltd");
 619 MODULE_DESCRIPTION("CLPS-711x generic serial driver $Revision: 1.42 $");
 620 MODULE_LICENSE("GPL");