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/sched/debug.h>
  18 #include <linux/tty.h>
  19 #include <linux/tty_flip.h>
  20 #include <linux/major.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/mm.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/slab.h>
  25 #include <linux/capability.h>
  26 #include <linux/circ_buf.h>
  27 #include <linux/console.h>
  28 #include <linux/irq.h>
  29 #include <linux/module.h>
  30 #include <linux/serial.h>
  31 #include <linux/sysrq.h>
  32 #include <linux/uaccess.h>
  33
  34 #include <asm/hpsim.h>
  35
  36 #include "hpsim_ssc.h"
  37
  38 #undef SIMSERIAL_DEBUG  /* define this to get some debug information */
  39
  40 #define KEYBOARD_INTR   3       /* must match with simulator! */
  41
  42 #define NR_PORTS        1       /* only one port for now */
  43
  44 struct serial_state {
  45         struct tty_port port;
  46         struct circ_buf xmit;
  47         int irq;
  48         int x_char;
  49 };
  50
  51 static struct serial_state rs_table[NR_PORTS];
  52
  53 struct tty_driver *hp_simserial_driver;
  54
  55 static struct console *console;
  56
  57 static void receive_chars(struct tty_port *port)
  58 {
  59         unsigned char ch;
  60         static unsigned char seen_esc = 0;
  61
  62         while ( (ch = ia64_ssc(0, 0, 0, 0, SSC_GETCHAR)) ) {
  63                 if (ch == 27 && seen_esc == 0) {
  64                         seen_esc = 1;
  65                         continue;
  66                 } else if (seen_esc == 1 && ch == 'O') {
  67                         seen_esc = 2;
  68                         continue;
  69                 } else if (seen_esc == 2) {
  70                         if (ch == 'P') /* F1 */
  71                                 show_state();
  72 #ifdef CONFIG_MAGIC_SYSRQ
  73                         if (ch == 'S') { /* F4 */
  74                                 do {
  75                                         ch = ia64_ssc(0, 0, 0, 0, SSC_GETCHAR);
  76                                 } while (!ch);
  77                                 handle_sysrq(ch);
  78                         }
  79 #endif
  80                         seen_esc = 0;
  81                         continue;
  82                 }
  83                 seen_esc = 0;
  84
  85                 if (tty_insert_flip_char(port, ch, TTY_NORMAL) == 0)
  86                         break;
  87         }
  88         tty_flip_buffer_push(port);
  89 }
  90
  91 /*
  92  * This is the serial driver's interrupt routine for a single port
  93  */
  94 static irqreturn_t rs_interrupt_single(int irq, void *dev_id)
  95 {
  96         struct serial_state *info = dev_id;
  97
  98         receive_chars(&info->port);
  99
 100         return IRQ_HANDLED;
 101 }
 102
 103 /*
 104  * -------------------------------------------------------------------
 105  * Here ends the serial interrupt routines.
 106  * -------------------------------------------------------------------
 107  */
 108
 109 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
 110 {
 111         struct serial_state *info = tty->driver_data;
 112         unsigned long flags;
 113
 114         if (!info->xmit.buf)
 115                 return 0;
 116
 117         local_irq_save(flags);
 118         if (CIRC_SPACE(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE) == 0) {
 119                 local_irq_restore(flags);
 120                 return 0;
 121         }
 122         info->xmit.buf[info->xmit.head] = ch;
 123         info->xmit.head = (info->xmit.head + 1) & (SERIAL_XMIT_SIZE-1);
 124         local_irq_restore(flags);
 125         return 1;
 126 }
 127
 128 static void transmit_chars(struct tty_struct *tty, struct serial_state *info,
 129                 int *intr_done)
 130 {
 131         int count;
 132         unsigned long flags;
 133
 134         local_irq_save(flags);
 135
 136         if (info->x_char) {
 137                 char c = info->x_char;
 138
 139                 console->write(console, &c, 1);
 140
 141                 info->x_char = 0;
 142
 143                 goto out;
 144         }
 145
 146         if (info->xmit.head == info->xmit.tail || tty->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                         !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)
 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_io_error(tty))
 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 /*
 329  * This routine will shutdown a serial port; interrupts are disabled, and
 330  * DTR is dropped if the hangup on close termio flag is on.
 331  */
 332 static void shutdown(struct tty_port *port)
 333 {
 334         struct serial_state *info = container_of(port, struct serial_state,
 335                         port);
 336         unsigned long flags;
 337
 338         local_irq_save(flags);
 339         if (info->irq)
 340                 free_irq(info->irq, info);
 341
 342         if (info->xmit.buf) {
 343                 free_page((unsigned long) info->xmit.buf);
 344                 info->xmit.buf = NULL;
 345         }
 346         local_irq_restore(flags);
 347 }
 348
 349 static void rs_close(struct tty_struct *tty, struct file * filp)
 350 {
 351         struct serial_state *info = tty->driver_data;
 352
 353         tty_port_close(&info->port, tty, filp);
 354 }
 355
 356 static void rs_hangup(struct tty_struct *tty)
 357 {
 358         struct serial_state *info = tty->driver_data;
 359
 360         rs_flush_buffer(tty);
 361         tty_port_hangup(&info->port);
 362 }
 363
 364 static int activate(struct tty_port *port, struct tty_struct *tty)
 365 {
 366         struct serial_state *state = container_of(port, struct serial_state,
 367                         port);
 368         unsigned long flags, page;
 369         int retval = 0;
 370
 371         page = get_zeroed_page(GFP_KERNEL);
 372         if (!page)
 373                 return -ENOMEM;
 374
 375         local_irq_save(flags);
 376
 377         if (state->xmit.buf)
 378                 free_page(page);
 379         else
 380                 state->xmit.buf = (unsigned char *) page;
 381
 382         if (state->irq) {
 383                 retval = request_irq(state->irq, rs_interrupt_single, 0,
 384                                 "simserial", state);
 385                 if (retval)
 386                         goto errout;
 387         }
 388
 389         state->xmit.head = state->xmit.tail = 0;
 390 errout:
 391         local_irq_restore(flags);
 392         return retval;
 393 }
 394
 395
 396 /*
 397  * This routine is called whenever a serial port is opened.  It
 398  * enables interrupts for a serial port, linking in its async structure into
 399  * the IRQ chain.   It also performs the serial-specific
 400  * initialization for the tty structure.
 401  */
 402 static int rs_open(struct tty_struct *tty, struct file * filp)
 403 {
 404         struct serial_state *info = rs_table + tty->index;
 405         struct tty_port *port = &info->port;
 406
 407         tty->driver_data = info;
 408         port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 409
 410         /*
 411          * figure out which console to use (should be one already)
 412          */
 413         console = console_drivers;
 414         while (console) {
 415                 if ((console->flags & CON_ENABLED) && console->write) break;
 416                 console = console->next;
 417         }
 418
 419         return tty_port_open(port, tty, filp);
 420 }
 421
 422 /*
 423  * /proc fs routines....
 424  */
 425
 426 static int rs_proc_show(struct seq_file *m, void *v)
 427 {
 428         int i;
 429
 430         seq_printf(m, "simserinfo:1.0\n");
 431         for (i = 0; i < NR_PORTS; i++)
 432                 seq_printf(m, "%d: uart:16550 port:3F8 irq:%d\n",
 433                        i, rs_table[i].irq);
 434         return 0;
 435 }
 436
 437 static int rs_proc_open(struct inode *inode, struct file *file)
 438 {
 439         return single_open(file, rs_proc_show, NULL);
 440 }
 441
 442 static const struct file_operations rs_proc_fops = {
 443         .owner          = THIS_MODULE,
 444         .open           = rs_proc_open,
 445         .read           = seq_read,
 446         .llseek         = seq_lseek,
 447         .release        = single_release,
 448 };
 449
 450 static const struct tty_operations hp_ops = {
 451         .open = rs_open,
 452         .close = rs_close,
 453         .write = rs_write,
 454         .put_char = rs_put_char,
 455         .flush_chars = rs_flush_chars,
 456         .write_room = rs_write_room,
 457         .chars_in_buffer = rs_chars_in_buffer,
 458         .flush_buffer = rs_flush_buffer,
 459         .ioctl = rs_ioctl,
 460         .throttle = rs_throttle,
 461         .unthrottle = rs_unthrottle,
 462         .send_xchar = rs_send_xchar,
 463         .hangup = rs_hangup,
 464         .proc_fops = &rs_proc_fops,
 465 };
 466
 467 static const struct tty_port_operations hp_port_ops = {
 468         .activate = activate,
 469         .shutdown = shutdown,
 470 };
 471
 472 static int __init simrs_init(void)
 473 {
 474         struct serial_state *state;
 475         int retval;
 476
 477         if (!ia64_platform_is("hpsim"))
 478                 return -ENODEV;
 479
 480         hp_simserial_driver = alloc_tty_driver(NR_PORTS);
 481         if (!hp_simserial_driver)
 482                 return -ENOMEM;
 483
 484         printk(KERN_INFO "SimSerial driver with no serial options enabled\n");
 485
 486         /* Initialize the tty_driver structure */
 487
 488         hp_simserial_driver->driver_name = "simserial";
 489         hp_simserial_driver->name = "ttyS";
 490         hp_simserial_driver->major = TTY_MAJOR;
 491         hp_simserial_driver->minor_start = 64;
 492         hp_simserial_driver->type = TTY_DRIVER_TYPE_SERIAL;
 493         hp_simserial_driver->subtype = SERIAL_TYPE_NORMAL;
 494         hp_simserial_driver->init_termios = tty_std_termios;
 495         hp_simserial_driver->init_termios.c_cflag =
 496                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 497         hp_simserial_driver->flags = TTY_DRIVER_REAL_RAW;
 498         tty_set_operations(hp_simserial_driver, &hp_ops);
 499
 500         state = rs_table;
 501         tty_port_init(&state->port);
 502         state->port.ops = &hp_port_ops;
 503         state->port.close_delay = 0; /* XXX really 0? */
 504
 505         retval = hpsim_get_irq(KEYBOARD_INTR);
 506         if (retval < 0) {
 507                 printk(KERN_ERR "%s: out of interrupt vectors!\n",
 508                                 __func__);
 509                 goto err_free_tty;
 510         }
 511
 512         state->irq = retval;
 513
 514         /* the port is imaginary */
 515         printk(KERN_INFO "ttyS0 at 0x03f8 (irq = %d) is a 16550\n", state->irq);
 516
 517         tty_port_link_device(&state->port, hp_simserial_driver, 0);
 518         retval = tty_register_driver(hp_simserial_driver);
 519         if (retval) {
 520                 printk(KERN_ERR "Couldn't register simserial driver\n");
 521                 goto err_free_tty;
 522         }
 523
 524         return 0;
 525 err_free_tty:
 526         put_tty_driver(hp_simserial_driver);
 527         tty_port_destroy(&state->port);
 528         return retval;
 529 }
 530
 531 #ifndef MODULE
 532 __initcall(simrs_init);
 533 #endif