drivers/char/hvc_console.c

   1 /*
   2  * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
   3  * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  */
  19
  20 #include <linux/init.h>
  21 #include <linux/module.h>
  22 #include <linux/console.h>
  23 #include <linux/major.h>
  24 #include <linux/kernel.h>
  25 #include <linux/sysrq.h>
  26 #include <linux/tty.h>
  27 #include <linux/tty_flip.h>
  28 #include <linux/sched.h>
  29 #include <linux/kbd_kern.h>
  30 #include <asm/uaccess.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/cpumask.h>
  33
  34 extern int hvc_count(int *);
  35 extern int hvc_get_chars(int index, char *buf, int count);
  36 extern int hvc_put_chars(int index, const char *buf, int count);
  37
  38 #define HVC_MAJOR       229
  39 #define HVC_MINOR       0
  40
  41 #define MAX_NR_HVC_CONSOLES     4
  42
  43 #define TIMEOUT         ((HZ + 99) / 100)
  44
  45 static struct tty_driver *hvc_driver;
  46 static int hvc_offset;
  47 #ifdef CONFIG_MAGIC_SYSRQ
  48 static int sysrq_pressed;
  49 #endif
  50
  51 #define N_OUTBUF        16
  52
  53 #define __ALIGNED__     __attribute__((__aligned__(8)))
  54
  55 struct hvc_struct {
  56         spinlock_t lock;
  57         int index;
  58         struct tty_struct *tty;
  59         unsigned int count;
  60         int do_wakeup;
  61         char outbuf[N_OUTBUF] __ALIGNED__;
  62         int n_outbuf;
  63 };
  64
  65 struct hvc_struct hvc_struct[MAX_NR_HVC_CONSOLES];
  66
  67 static int hvc_open(struct tty_struct *tty, struct file * filp)
  68 {
  69         int line = tty->index;
  70         struct hvc_struct *hp;
  71         unsigned long flags;
  72
  73         if (line < 0 || line >= MAX_NR_HVC_CONSOLES)
  74                 return -ENODEV;
  75         hp = &hvc_struct[line];
  76
  77         tty->driver_data = hp;
  78         spin_lock_irqsave(&hp->lock, flags);
  79         hp->tty = tty;
  80         hp->count++;
  81         spin_unlock_irqrestore(&hp->lock, flags);
  82
  83         return 0;
  84 }
  85
  86 static void hvc_close(struct tty_struct *tty, struct file * filp)
  87 {
  88         struct hvc_struct *hp = tty->driver_data;
  89         unsigned long flags;
  90
  91         if (tty_hung_up_p(filp))
  92                 return;
  93         spin_lock_irqsave(&hp->lock, flags);
  94         if (--hp->count == 0)
  95                 hp->tty = NULL;
  96         else if (hp->count < 0)
  97                 printk(KERN_ERR "hvc_close %lu: oops, count is %d\n",
  98                        hp - hvc_struct, hp->count);
  99         spin_unlock_irqrestore(&hp->lock, flags);
 100 }
 101
 102 static void hvc_hangup(struct tty_struct *tty)
 103 {
 104         struct hvc_struct *hp = tty->driver_data;
 105
 106         hp->count = 0;
 107         hp->tty = NULL;
 108 }
 109
 110 /* called with hp->lock held */
 111 static void hvc_push(struct hvc_struct *hp)
 112 {
 113         int n;
 114
 115         n = hvc_put_chars(hp->index + hvc_offset, hp->outbuf, hp->n_outbuf);
 116         if (n <= 0) {
 117                 if (n == 0)
 118                         return;
 119                 /* throw away output on error; this happens when
 120                    there is no session connected to the vterm. */
 121                 hp->n_outbuf = 0;
 122         } else
 123                 hp->n_outbuf -= n;
 124         if (hp->n_outbuf > 0)
 125                 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
 126         else
 127                 hp->do_wakeup = 1;
 128 }
 129
 130 static int hvc_write(struct tty_struct *tty, int from_user,
 131                      const unsigned char *buf, int count)
 132 {
 133         struct hvc_struct *hp = tty->driver_data;
 134         char *tbuf, *p;
 135         int tbsize, rsize, written = 0;
 136         unsigned long flags;
 137
 138         if (from_user) {
 139                 tbsize = min(count, (int)PAGE_SIZE);
 140                 if (!(tbuf = kmalloc(tbsize, GFP_KERNEL)))
 141                         return -ENOMEM;
 142
 143                 while ((rsize = count - written) > 0) {
 144                         int wsize;
 145                         if (rsize > tbsize)
 146                                 rsize = tbsize;
 147
 148                         p = tbuf;
 149                         rsize -= copy_from_user(p, buf, rsize);
 150                         if (!rsize) {
 151                                 if (written == 0)
 152                                         written = -EFAULT;
 153                                 break;
 154                         }
 155                         buf += rsize;
 156                         written += rsize;
 157
 158                         spin_lock_irqsave(&hp->lock, flags);
 159                         for (wsize = N_OUTBUF - hp->n_outbuf; rsize && wsize;
 160                                         wsize = N_OUTBUF - hp->n_outbuf) {
 161                                 if (wsize > rsize)
 162                                         wsize = rsize;
 163                                 memcpy(hp->outbuf + hp->n_outbuf, p, wsize);
 164                                 hp->n_outbuf += wsize;
 165                                 hvc_push(hp);
 166                                 rsize -= wsize;
 167                                 p += wsize;
 168                         }
 169                         spin_unlock_irqrestore(&hp->lock, flags);
 170
 171                         if (rsize)
 172                                 break;
 173
 174                         if (count < tbsize)
 175                                 tbsize = count;
 176                 }
 177
 178                 kfree(tbuf);
 179         } else {
 180                 spin_lock_irqsave(&hp->lock, flags);
 181                 while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) {
 182                         if (rsize > count)
 183                                 rsize = count;
 184                         memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
 185                         count -= rsize;
 186                         buf += rsize;
 187                         hp->n_outbuf += rsize;
 188                         written += rsize;
 189                         hvc_push(hp);
 190                 }
 191                 spin_unlock_irqrestore(&hp->lock, flags);
 192         }
 193
 194         return written;
 195 }
 196
 197 static int hvc_write_room(struct tty_struct *tty)
 198 {
 199         struct hvc_struct *hp = tty->driver_data;
 200
 201         return N_OUTBUF - hp->n_outbuf;
 202 }
 203
 204 static int hvc_chars_in_buffer(struct tty_struct *tty)
 205 {
 206         struct hvc_struct *hp = tty->driver_data;
 207
 208         return hp->n_outbuf;
 209 }
 210
 211 static void hvc_poll(int index)
 212 {
 213         struct hvc_struct *hp = &hvc_struct[index];
 214         struct tty_struct *tty;
 215         int i, n;
 216         char buf[16] __ALIGNED__;
 217         unsigned long flags;
 218
 219         spin_lock_irqsave(&hp->lock, flags);
 220
 221         if (hp->n_outbuf > 0)
 222                 hvc_push(hp);
 223
 224         tty = hp->tty;
 225         if (tty) {
 226                 for (;;) {
 227                         if (TTY_FLIPBUF_SIZE - tty->flip.count < sizeof(buf))
 228                                 break;
 229                         n = hvc_get_chars(index + hvc_offset, buf, sizeof(buf));
 230                         if (n <= 0)
 231                                 break;
 232                         for (i = 0; i < n; ++i) {
 233 #ifdef CONFIG_MAGIC_SYSRQ               /* Handle the SysRq Hack */
 234                                 if (buf[i] == '\x0f') { /* ^O -- should support a sequence */
 235                                         sysrq_pressed = 1;
 236                                         continue;
 237                                 } else if (sysrq_pressed) {
 238                                         handle_sysrq(buf[i], NULL, tty);
 239                                         sysrq_pressed = 0;
 240                                         continue;
 241                                 }
 242 #endif
 243                                 tty_insert_flip_char(tty, buf[i], 0);
 244                         }
 245                 }
 246                 if (tty->flip.count)
 247                         tty_schedule_flip(tty);
 248
 249                 if (hp->do_wakeup) {
 250                         hp->do_wakeup = 0;
 251                         if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP))
 252                             && tty->ldisc.write_wakeup)
 253                                 (tty->ldisc.write_wakeup)(tty);
 254                         wake_up_interruptible(&tty->write_wait);
 255                 }
 256         }
 257
 258         spin_unlock_irqrestore(&hp->lock, flags);
 259 }
 260
 261 #if defined(CONFIG_XMON) && defined(CONFIG_SMP)
 262 extern cpumask_t cpus_in_xmon;
 263 #else
 264 static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
 265 #endif
 266
 267
 268 int khvcd(void *unused)
 269 {
 270         int i;
 271
 272         daemonize("khvcd");
 273
 274         for (;;) {
 275                 if (cpus_empty(cpus_in_xmon)) {
 276                         for (i = 0; i < MAX_NR_HVC_CONSOLES; ++i)
 277                                 hvc_poll(i);
 278                 }
 279                 set_current_state(TASK_INTERRUPTIBLE);
 280                 schedule_timeout(TIMEOUT);
 281         }
 282 }
 283
 284 static struct tty_operations hvc_ops = {
 285         .open = hvc_open,
 286         .close = hvc_close,
 287         .write = hvc_write,
 288         .hangup = hvc_hangup,
 289         .write_room = hvc_write_room,
 290         .chars_in_buffer = hvc_chars_in_buffer,
 291 };
 292
 293 int __init hvc_init(void)
 294 {
 295         int num = hvc_count(&hvc_offset);
 296         int i;
 297
 298         if (num > MAX_NR_HVC_CONSOLES)
 299                 num = MAX_NR_HVC_CONSOLES;
 300
 301         hvc_driver = alloc_tty_driver(num);
 302         if (!hvc_driver)
 303                 return -ENOMEM;
 304
 305         hvc_driver->owner = THIS_MODULE;
 306         hvc_driver->devfs_name = "hvc/";
 307         hvc_driver->driver_name = "hvc";
 308         hvc_driver->name = "hvc";
 309         hvc_driver->major = HVC_MAJOR;
 310         hvc_driver->minor_start = HVC_MINOR;
 311         hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM;
 312         hvc_driver->init_termios = tty_std_termios;
 313         hvc_driver->flags = TTY_DRIVER_REAL_RAW;
 314         tty_set_operations(hvc_driver, &hvc_ops);
 315         for (i = 0; i < num; i++) {
 316                 hvc_struct[i].lock = SPIN_LOCK_UNLOCKED;
 317                 hvc_struct[i].index = i;
 318         }
 319
 320         if (tty_register_driver(hvc_driver))
 321                 panic("Couldn't register hvc console driver\n");
 322
 323         if (num > 0)
 324                 kernel_thread(khvcd, NULL, CLONE_KERNEL);
 325
 326         return 0;
 327 }
 328
 329 static void __exit hvc_exit(void)
 330 {
 331 }
 332
 333 void hvc_console_print(struct console *co, const char *b, unsigned count)
 334 {
 335         char c[16] __ALIGNED__;
 336         unsigned i, n;
 337         int r, donecr = 0;
 338
 339         i = n = 0;
 340         while (count > 0 || i > 0) {
 341                 if (count > 0 && i < sizeof(c)) {
 342                         if (b[n] == '\n' && !donecr) {
 343                                 c[i++] = '\r';
 344                                 donecr = 1;
 345                         } else {
 346                                 c[i++] = b[n++];
 347                                 donecr = 0;
 348                                 --count;
 349                         }
 350                 } else {
 351                         r = hvc_put_chars(co->index + hvc_offset, c, i);
 352                         if (r < 0) {
 353                                 /* throw away chars on error */
 354                                 i = 0;
 355                         } else if (r > 0) {
 356                                 i -= r;
 357                                 if (i > 0)
 358                                         memmove(c, c+r, i);
 359                         }
 360                 }
 361         }
 362 }
 363
 364 static struct tty_driver *hvc_console_device(struct console *c, int *index)
 365 {
 366         *index = c->index;
 367         return hvc_driver;
 368 }
 369
 370 static int __init hvc_console_setup(struct console *co, char *options)
 371 {
 372         if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES
 373             || co->index >= hvc_count(&hvc_offset))
 374                 return -1;
 375         return 0;
 376 }
 377
 378 struct console hvc_con_driver = {
 379         .name           = "hvc",
 380         .write          = hvc_console_print,
 381         .device         = hvc_console_device,
 382         .setup          = hvc_console_setup,
 383         .flags          = CON_PRINTBUFFER,
 384         .index          = -1,
 385 };
 386
 387 static int __init hvc_console_init(void)
 388 {
 389         register_console(&hvc_con_driver);
 390         return 0;
 391 }
 392 console_initcall(hvc_console_init);
 393
 394 module_init(hvc_init);
 395 module_exit(hvc_exit);