arch/ia64/hp/sim/simserial.c

   1 /*
   2  * Simulated Serial Driver (fake serial)
   3  *
   4  * This driver is mostly used for bringup purposes and will go away.
   5  * It has a strong dependency on the system console. All outputs
   6  * are rerouted to the same facility as the one used by printk which, in our
   7  * case means sys_sim.c console (goes via the simulator).
   8  *
   9  * Copyright (C) 1999-2000, 2002-2003 Hewlett-Packard Co
  10  *      Stephane Eranian <eranian@hpl.hp.com>
  11  *      David Mosberger-Tang <davidm@hpl.hp.com>
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/errno.h>
  16 #include <linux/sched.h>
  17 #include <linux/tty.h>
  18 #include <linux/tty_flip.h>
  19 #include <linux/major.h>
  20 #include <linux/fcntl.h>
  21 #include <linux/mm.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/slab.h>
  24 #include <linux/capability.h>
  25 #include <linux/circ_buf.h>
  26 #include <linux/console.h>
  27 #include <linux/irq.h>
  28 #include <linux/module.h>
  29 #include <linux/serial.h>
  30 #include <linux/sysrq.h>
  31 #include <linux/uaccess.h>
  32
  33 #include <asm/hpsim.h>
  34
  35 #include "hpsim_ssc.h"
  36
  37 #undef SIMSERIAL_DEBUG  /* define this to get some debug information */
  38
  39 #define KEYBOARD_INTR   3       /* must match with simulator! */
  40
  41 #define NR_PORTS        1       /* only one port for now */
  42
  43 struct serial_state {
  44         struct tty_port port;
  45         struct circ_buf xmit;
  46         int irq;
  47         int x_char;
  48 };
  49
  50 static struct serial_state rs_table[NR_PORTS];
  51
  52 struct tty_driver *hp_simserial_driver;
  53
  54 static struct console *console;
  55
  56 static void receive_chars(struct tty_port *port)
  57 {
  58         unsigned char ch;
  59         static unsigned char seen_esc = 0;
  60
  61         while ( (ch = ia64_ssc(0, 0, 0, 0, SSC_GETCHAR)) ) {
  62                 if (ch == 27 && seen_esc == 0) {
  63                         seen_esc = 1;
  64                         continue;
  65                 } else if (seen_esc == 1 && ch == 'O') {
  66                         seen_esc = 2;
  67                         continue;
  68                 } else if (seen_esc == 2) {
  69                         if (ch == 'P') /* F1 */
  70                                 show_state();
  71 #ifdef CONFIG_MAGIC_SYSRQ
  72                         if (ch == 'S') { /* F4 */
  73                                 do {
  74                                         ch = ia64_ssc(0, 0, 0, 0, SSC_GETCHAR);
  75                                 } while (!ch);
  76                                 handle_sysrq(ch);
  77                         }
  78 #endif
  79                         seen_esc = 0;
  80                         continue;
  81                 }
  82                 seen_esc = 0;
  83
  84                 if (tty_insert_flip_char(port, ch, TTY_NORMAL) == 0)
  85                         break;
  86         }
  87         tty_flip_buffer_push(port);
  88 }
  89
  90 /*
  91  * This is the serial driver's interrupt routine for a single port
  92  */
  93 static irqreturn_t rs_interrupt_single(int irq, void *dev_id)
  94 {
  95         struct serial_state *info = dev_id;
  96
  97         receive_chars(&info->port);
  98
  99         return IRQ_HANDLED;
 100 }
 101
 102 /*
 103  * -------------------------------------------------------------------
 104  * Here ends the serial interrupt routines.
 105  * -------------------------------------------------------------------
 106  */
 107
 108 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
 109 {
 110         struct serial_state *info = tty->driver_data;
 111         unsigned long flags;
 112
 113         if (!info->xmit.buf)
 114                 return 0;
 115
 116         local_irq_save(flags);
 117         if (CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE) == 0) {
 118                 local_irq_restore(flags);
 119                 return 0;
 120         }
 121         info->xmit.buf[info->xmit.head] = ch;
 122         info->xmit.head = (info->xmit.head + 1) & (SERIAL_XMIT_SIZE-1);
 123         local_irq_restore(flags);
 124         return 1;
 125 }
 126
 127 static void transmit_chars(struct tty_struct *tty, struct serial_state *info,
 128                 int *intr_done)
 129 {
 130         int count;
 131         unsigned long flags;
 132
 133         local_irq_save(flags);
 134
 135         if (info->x_char) {
 136                 char c = info->x_char;
 137
 138                 console->write(console, &c, 1);
 139
 140                 info->x_char = 0;
 141
 142                 goto out;
 143         }
 144
 145         if (info->xmit.head == info->xmit.tail || tty->stopped ||
 146                         tty->hw_stopped) {
 147 #ifdef SIMSERIAL_DEBUG
 148                 printk("transmit_chars: head=%d, tail=%d, stopped=%d\n",
 149                        info->xmit.head, info->xmit.tail, tty->stopped);
 150 #endif
 151                 goto out;
 152         }
 153         /*
 154          * We removed the loop and try to do it in to chunks. We need
 155          * 2 operations maximum because it's a ring buffer.
 156          *
 157          * First from current to tail if possible.
 158          * Then from the beginning of the buffer until necessary
 159          */
 160
 161         count = min(CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE),
 162                     SERIAL_XMIT_SIZE - info->xmit.tail);
 163         console->write(console, info->xmit.buf+info->xmit.tail, count);
 164
 165         info->xmit.tail = (info->xmit.tail+count) & (SERIAL_XMIT_SIZE-1);
 166
 167         /*
 168          * We have more at the beginning of the buffer
 169          */
 170         count = CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 171         if (count) {
 172                 console->write(console, info->xmit.buf, count);
 173                 info->xmit.tail += count;
 174         }
 175 out:
 176         local_irq_restore(flags);
 177 }
 178
 179 static void rs_flush_chars(struct tty_struct *tty)
 180 {
 181         struct serial_state *info = tty->driver_data;
 182
 183         if (info->xmit.head == info->xmit.tail || tty->stopped ||
 184                         tty->hw_stopped || !info->xmit.buf)
 185                 return;
 186
 187         transmit_chars(tty, info, NULL);
 188 }
 189
 190 static int rs_write(struct tty_struct * tty,
 191                     const unsigned char *buf, int count)
 192 {
 193         struct serial_state *info = tty->driver_data;
 194         int     c, ret = 0;
 195         unsigned long flags;
 196
 197         if (!info->xmit.buf)
 198                 return 0;
 199
 200         local_irq_save(flags);
 201         while (1) {
 202                 c = CIRC_SPACE_TO_END(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 203                 if (count < c)
 204                         c = count;
 205                 if (c <= 0) {
 206                         break;
 207                 }
 208                 memcpy(info->xmit.buf + info->xmit.head, buf, c);
 209                 info->xmit.head = ((info->xmit.head + c) &
 210                                    (SERIAL_XMIT_SIZE-1));
 211                 buf += c;
 212                 count -= c;
 213                 ret += c;
 214         }
 215         local_irq_restore(flags);
 216         /*
 217          * Hey, we transmit directly from here in our case
 218          */
 219         if (CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE) &&
 220                         !tty->stopped && !tty->hw_stopped)
 221                 transmit_chars(tty, info, NULL);
 222
 223         return ret;
 224 }
 225
 226 static int rs_write_room(struct tty_struct *tty)
 227 {
 228         struct serial_state *info = tty->driver_data;
 229
 230         return CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 231 }
 232
 233 static int rs_chars_in_buffer(struct tty_struct *tty)
 234 {
 235         struct serial_state *info = tty->driver_data;
 236
 237         return CIRC_CNT(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);
 238 }
 239
 240 static void rs_flush_buffer(struct tty_struct *tty)
 241 {
 242         struct serial_state *info = tty->driver_data;
 243         unsigned long flags;
 244
 245         local_irq_save(flags);
 246         info->xmit.head = info->xmit.tail = 0;
 247         local_irq_restore(flags);
 248
 249         tty_wakeup(tty);
 250 }
 251
 252 /*
 253  * This function is used to send a high-priority XON/XOFF character to
 254  * the device
 255  */
 256 static void rs_send_xchar(struct tty_struct *tty, char ch)
 257 {
 258         struct serial_state *info = tty->driver_data;
 259
 260         info->x_char = ch;
 261         if (ch) {
 262                 /*
 263                  * I guess we could call console->write() directly but
 264                  * let's do that for now.
 265                  */
 266                 transmit_chars(tty, info, NULL);
 267         }
 268 }
 269
 270 /*
 271  * ------------------------------------------------------------
 272  * rs_throttle()
 273  *
 274  * This routine is called by the upper-layer tty layer to signal that
 275  * incoming characters should be throttled.
 276  * ------------------------------------------------------------
 277  */
 278 static void rs_throttle(struct tty_struct * tty)
 279 {
 280         if (I_IXOFF(tty))
 281                 rs_send_xchar(tty, STOP_CHAR(tty));
 282
 283         printk(KERN_INFO "simrs_throttle called\n");
 284 }
 285
 286 static void rs_unthrottle(struct tty_struct * tty)
 287 {
 288         struct serial_state *info = tty->driver_data;
 289
 290         if (I_IXOFF(tty)) {
 291                 if (info->x_char)
 292                         info->x_char = 0;
 293                 else
 294                         rs_send_xchar(tty, START_CHAR(tty));
 295         }
 296         printk(KERN_INFO "simrs_unthrottle called\n");
 297 }
 298
 299 static int rs_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
 300 {
 301         if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
 302             (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
 303             (cmd != TIOCMIWAIT)) {
 304                 if (tty->flags & (1 << TTY_IO_ERROR))
 305                     return -EIO;
 306         }
 307
 308         switch (cmd) {
 309         case TIOCGSERIAL:
 310         case TIOCSSERIAL:
 311         case TIOCSERGSTRUCT:
 312         case TIOCMIWAIT:
 313                 return 0;
 314         case TIOCSERCONFIG:
 315         case TIOCSERGETLSR: /* Get line status register */
 316                 return -EINVAL;
 317         case TIOCSERGWILD:
 318         case TIOCSERSWILD:
 319                 /* "setserial -W" is called in Debian boot */
 320                 printk (KERN_INFO "TIOCSER?WILD ioctl obsolete, ignored.\n");
 321                 return 0;
 322         }
 323         return -ENOIOCTLCMD;
 324 }
 325
 326 #define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
 327
 328 static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
 329 {
 330         /* Handle turning off CRTSCTS */
 331         if ((old_termios->c_cflag & CRTSCTS) &&
 332             !(tty->termios.c_cflag & CRTSCTS)) {
 333                 tty->hw_stopped = 0;
 334         }
 335 }
 336 /*
 337  * This routine will shutdown a serial port; interrupts are disabled, and
 338  * DTR is dropped if the hangup on close termio flag is on.
 339  */
 340 static void shutdown(struct tty_port *port)
 341 {
 342         struct serial_state *info = container_of(port, struct serial_state,
 343                         port);
 344         unsigned long flags;
 345
 346         local_irq_save(flags);
 347         if (info->irq)
 348                 free_irq(info->irq, info);
 349
 350         if (info->xmit.buf) {
 351                 free_page((unsigned long) info->xmit.buf);
 352                 info->xmit.buf = NULL;
 353         }
 354         local_irq_restore(flags);
 355 }
 356
 357 static void rs_close(struct tty_struct *tty, struct file * filp)
 358 {
 359         struct serial_state *info = tty->driver_data;
 360
 361         tty_port_close(&info->port, tty, filp);
 362 }
 363
 364 static void rs_hangup(struct tty_struct *tty)
 365 {
 366         struct serial_state *info = tty->driver_data;
 367
 368         rs_flush_buffer(tty);
 369         tty_port_hangup(&info->port);
 370 }
 371
 372 static int activate(struct tty_port *port, struct tty_struct *tty)
 373 {
 374         struct serial_state *state = container_of(port, struct serial_state,
 375                         port);
 376         unsigned long flags, page;
 377         int retval = 0;
 378
 379         page = get_zeroed_page(GFP_KERNEL);
 380         if (!page)
 381                 return -ENOMEM;
 382
 383         local_irq_save(flags);
 384
 385         if (state->xmit.buf)
 386                 free_page(page);
 387         else
 388                 state->xmit.buf = (unsigned char *) page;
 389
 390         if (state->irq) {
 391                 retval = request_irq(state->irq, rs_interrupt_single, 0,
 392                                 "simserial", state);
 393                 if (retval)
 394                         goto errout;
 395         }
 396
 397         state->xmit.head = state->xmit.tail = 0;
 398
 399         /*
 400          * Set up the tty->alt_speed kludge
 401          */
 402         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
 403                 tty->alt_speed = 57600;
 404         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
 405                 tty->alt_speed = 115200;
 406         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
 407                 tty->alt_speed = 230400;
 408         if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
 409                 tty->alt_speed = 460800;
 410
 411 errout:
 412         local_irq_restore(flags);
 413         return retval;
 414 }
 415
 416
 417 /*
 418  * This routine is called whenever a serial port is opened.  It
 419  * enables interrupts for a serial port, linking in its async structure into
 420  * the IRQ chain.   It also performs the serial-specific
 421  * initialization for the tty structure.
 422  */
 423 static int rs_open(struct tty_struct *tty, struct file * filp)
 424 {
 425         struct serial_state *info = rs_table + tty->index;
 426         struct tty_port *port = &info->port;
 427
 428         tty->driver_data = info;
 429         port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 430
 431         /*
 432          * figure out which console to use (should be one already)
 433          */
 434         console = console_drivers;
 435         while (console) {
 436                 if ((console->flags & CON_ENABLED) && console->write) break;
 437                 console = console->next;
 438         }
 439
 440         return tty_port_open(port, tty, filp);
 441 }
 442
 443 /*
 444  * /proc fs routines....
 445  */
 446
 447 static int rs_proc_show(struct seq_file *m, void *v)
 448 {
 449         int i;
 450
 451         seq_printf(m, "simserinfo:1.0\n");
 452         for (i = 0; i < NR_PORTS; i++)
 453                 seq_printf(m, "%d: uart:16550 port:3F8 irq:%d\n",
 454                        i, rs_table[i].irq);
 455         return 0;
 456 }
 457
 458 static int rs_proc_open(struct inode *inode, struct file *file)
 459 {
 460         return single_open(file, rs_proc_show, NULL);
 461 }
 462
 463 static const struct file_operations rs_proc_fops = {
 464         .owner          = THIS_MODULE,
 465         .open           = rs_proc_open,
 466         .read           = seq_read,
 467         .llseek         = seq_lseek,
 468         .release        = single_release,
 469 };
 470
 471 static const struct tty_operations hp_ops = {
 472         .open = rs_open,
 473         .close = rs_close,
 474         .write = rs_write,
 475         .put_char = rs_put_char,
 476         .flush_chars = rs_flush_chars,
 477         .write_room = rs_write_room,
 478         .chars_in_buffer = rs_chars_in_buffer,
 479         .flush_buffer = rs_flush_buffer,
 480         .ioctl = rs_ioctl,
 481         .throttle = rs_throttle,
 482         .unthrottle = rs_unthrottle,
 483         .send_xchar = rs_send_xchar,
 484         .set_termios = rs_set_termios,
 485         .hangup = rs_hangup,
 486         .proc_fops = &rs_proc_fops,
 487 };
 488
 489 static const struct tty_port_operations hp_port_ops = {
 490         .activate = activate,
 491         .shutdown = shutdown,
 492 };
 493
 494 static int __init simrs_init(void)
 495 {
 496         struct serial_state *state;
 497         int retval;
 498
 499         if (!ia64_platform_is("hpsim"))
 500                 return -ENODEV;
 501
 502         hp_simserial_driver = alloc_tty_driver(NR_PORTS);
 503         if (!hp_simserial_driver)
 504                 return -ENOMEM;
 505
 506         printk(KERN_INFO "SimSerial driver with no serial options enabled\n");
 507
 508         /* Initialize the tty_driver structure */
 509
 510         hp_simserial_driver->driver_name = "simserial";
 511         hp_simserial_driver->name = "ttyS";
 512         hp_simserial_driver->major = TTY_MAJOR;
 513         hp_simserial_driver->minor_start = 64;
 514         hp_simserial_driver->type = TTY_DRIVER_TYPE_SERIAL;
 515         hp_simserial_driver->subtype = SERIAL_TYPE_NORMAL;
 516         hp_simserial_driver->init_termios = tty_std_termios;
 517         hp_simserial_driver->init_termios.c_cflag =
 518                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 519         hp_simserial_driver->flags = TTY_DRIVER_REAL_RAW;
 520         tty_set_operations(hp_simserial_driver, &hp_ops);
 521
 522         state = rs_table;
 523         tty_port_init(&state->port);
 524         state->port.ops = &hp_port_ops;
 525         state->port.close_delay = 0; /* XXX really 0? */
 526
 527         retval = hpsim_get_irq(KEYBOARD_INTR);
 528         if (retval < 0) {
 529                 printk(KERN_ERR "%s: out of interrupt vectors!\n",
 530                                 __func__);
 531                 goto err_free_tty;
 532         }
 533
 534         state->irq = retval;
 535
 536         /* the port is imaginary */
 537         printk(KERN_INFO "ttyS0 at 0x03f8 (irq = %d) is a 16550\n", state->irq);
 538
 539         tty_port_link_device(&state->port, hp_simserial_driver, 0);
 540         retval = tty_register_driver(hp_simserial_driver);
 541         if (retval) {
 542                 printk(KERN_ERR "Couldn't register simserial driver\n");
 543                 goto err_free_tty;
 544         }
 545
 546         return 0;
 547 err_free_tty:
 548         put_tty_driver(hp_simserial_driver);
 549         tty_port_destroy(&state->port);
 550         return retval;
 551 }
 552
 553 #ifndef MODULE
 554 __initcall(simrs_init);
 555 #endif