arch/parisc/kernel/pdc_cons.c

   1 /*
   2  *    PDC Console support - ie use firmware to dump text via boot console
   3  *
   4  *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
   5  *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
   6  *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
   7  *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
   8  *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
   9  *    Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
  10  *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
  11  *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
  12  *    Copyright (C) 2001 Helge Deller <deller at parisc-linux.org>
  13  *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
  14  *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
  15  *    Copyright (C) 2010 Guy Martin <gmsoft at tuxicoman.be>
  16  *
  17  *
  18  *    This program is free software; you can redistribute it and/or modify
  19  *    it under the terms of the GNU General Public License as published by
  20  *    the Free Software Foundation; either version 2 of the License, or
  21  *    (at your option) any later version.
  22  *
  23  *    This program is distributed in the hope that it will be useful,
  24  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  25  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  26  *    GNU General Public License for more details.
  27  *
  28  *    You should have received a copy of the GNU General Public License
  29  *    along with this program; if not, write to the Free Software
  30  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  31  */
  32
  33 /*
  34  *  The PDC console is a simple console, which can be used for debugging
  35  *  boot related problems on HP PA-RISC machines. It is also useful when no
  36  *  other console works.
  37  *
  38  *  This code uses the ROM (=PDC) based functions to read and write characters
  39  *  from and to PDC's boot path.
  40  */
  41
  42 /* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems.
  43  * On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
  44 #define EARLY_BOOTUP_DEBUG
  45
  46
  47 #include <linux/kernel.h>
  48 #include <linux/console.h>
  49 #include <linux/string.h>
  50 #include <linux/init.h>
  51 #include <linux/major.h>
  52 #include <linux/tty.h>
  53 #include <asm/pdc.h>            /* for iodc_call() proto and friends */
  54
  55 static DEFINE_SPINLOCK(pdc_console_lock);
  56 static struct console pdc_cons;
  57
  58 static void pdc_console_write(struct console *co, const char *s, unsigned count)
  59 {
  60         int i = 0;
  61         unsigned long flags;
  62
  63         spin_lock_irqsave(&pdc_console_lock, flags);
  64         do {
  65                 i += pdc_iodc_print(s + i, count - i);
  66         } while (i < count);
  67         spin_unlock_irqrestore(&pdc_console_lock, flags);
  68 }
  69
  70 int pdc_console_poll_key(struct console *co)
  71 {
  72         int c;
  73         unsigned long flags;
  74
  75         spin_lock_irqsave(&pdc_console_lock, flags);
  76         c = pdc_iodc_getc();
  77         spin_unlock_irqrestore(&pdc_console_lock, flags);
  78
  79         return c;
  80 }
  81
  82 static int pdc_console_setup(struct console *co, char *options)
  83 {
  84         return 0;
  85 }
  86
  87 #if defined(CONFIG_PDC_CONSOLE)
  88 #include <linux/vt_kern.h>
  89 #include <linux/tty_flip.h>
  90
  91 #define PDC_CONS_POLL_DELAY (30 * HZ / 1000)
  92
  93 static struct timer_list pdc_console_timer;
  94
  95 static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
  96 {
  97
  98         mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
  99
 100         return 0;
 101 }
 102
 103 static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
 104 {
 105         if (!tty->count)
 106                 del_timer(&pdc_console_timer);
 107 }
 108
 109 static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 110 {
 111         pdc_console_write(NULL, buf, count);
 112         return count;
 113 }
 114
 115 static int pdc_console_tty_write_room(struct tty_struct *tty)
 116 {
 117         return 32768; /* no limit, no buffer used */
 118 }
 119
 120 static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
 121 {
 122         return 0; /* no buffer */
 123 }
 124
 125 static struct tty_driver *pdc_console_tty_driver;
 126
 127 static const struct tty_operations pdc_console_tty_ops = {
 128         .open = pdc_console_tty_open,
 129         .close = pdc_console_tty_close,
 130         .write = pdc_console_tty_write,
 131         .write_room = pdc_console_tty_write_room,
 132         .chars_in_buffer = pdc_console_tty_chars_in_buffer,
 133 };
 134
 135 static void pdc_console_poll(unsigned long unused)
 136 {
 137
 138         int data, count = 0;
 139
 140         struct tty_struct *tty = pdc_console_tty_driver->ttys[0];
 141
 142         if (!tty)
 143                 return;
 144
 145         while (1) {
 146                 data = pdc_console_poll_key(NULL);
 147                 if (data == -1)
 148                         break;
 149                 tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
 150                 count ++;
 151         }
 152
 153         if (count)
 154                 tty_flip_buffer_push(tty);
 155
 156         if (tty->count && (pdc_cons.flags & CON_ENABLED))
 157                 mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 158 }
 159
 160 static int __init pdc_console_tty_driver_init(void)
 161 {
 162
 163         int err;
 164         struct tty_driver *drv;
 165
 166         /* Check if the console driver is still registered.
 167          * It is unregistered if the pdc console was not selected as the
 168          * primary console. */
 169
 170         struct console *tmp;
 171
 172         console_lock();
 173         for_each_console(tmp)
 174                 if (tmp == &pdc_cons)
 175                         break;
 176         console_unlock();
 177
 178         if (!tmp) {
 179                 printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
 180                 return -ENODEV;
 181         }
 182
 183         printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
 184         pdc_cons.flags &= ~CON_BOOT;
 185
 186         drv = alloc_tty_driver(1);
 187
 188         if (!drv)
 189                 return -ENOMEM;
 190
 191         drv->driver_name = "pdc_cons";
 192         drv->name = "ttyB";
 193         drv->major = MUX_MAJOR;
 194         drv->minor_start = 0;
 195         drv->type = TTY_DRIVER_TYPE_SYSTEM;
 196         drv->init_termios = tty_std_termios;
 197         drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
 198         tty_set_operations(drv, &pdc_console_tty_ops);
 199
 200         err = tty_register_driver(drv);
 201         if (err) {
 202                 printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
 203                 return err;
 204         }
 205
 206         pdc_console_tty_driver = drv;
 207
 208         /* No need to initialize the pdc_console_timer if tty isn't allocated */
 209         init_timer(&pdc_console_timer);
 210         pdc_console_timer.function = pdc_console_poll;
 211
 212         return 0;
 213 }
 214
 215 module_init(pdc_console_tty_driver_init);
 216
 217 static struct tty_driver * pdc_console_device (struct console *c, int *index)
 218 {
 219         *index = c->index;
 220         return pdc_console_tty_driver;
 221 }
 222 #else
 223 #define pdc_console_device NULL
 224 #endif
 225
 226 static struct console pdc_cons = {
 227         .name =         "ttyB",
 228         .write =        pdc_console_write,
 229         .device =       pdc_console_device,
 230         .setup =        pdc_console_setup,
 231         .flags =        CON_BOOT | CON_PRINTBUFFER,
 232         .index =        -1,
 233 };
 234
 235 static int pdc_console_initialized;
 236
 237 static void pdc_console_init_force(void)
 238 {
 239         if (pdc_console_initialized)
 240                 return;
 241         ++pdc_console_initialized;
 242
 243         /* If the console is duplex then copy the COUT parameters to CIN. */
 244         if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
 245                 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
 246
 247         /* register the pdc console */
 248         register_console(&pdc_cons);
 249 }
 250
 251 void __init pdc_console_init(void)
 252 {
 253 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 254         pdc_console_init_force();
 255 #endif
 256 #ifdef EARLY_BOOTUP_DEBUG
 257         printk(KERN_INFO "Initialized PDC Console for debugging.\n");
 258 #endif
 259 }
 260
 261
 262 /*
 263  * Used for emergencies. Currently only used if an HPMC occurs. If an
 264  * HPMC occurs, it is possible that the current console may not be
 265  * properly initialised after the PDC IO reset. This routine unregisters
 266  * all of the current consoles, reinitializes the pdc console and
 267  * registers it.
 268  */
 269
 270 void pdc_console_restart(void)
 271 {
 272         struct console *console;
 273
 274         if (pdc_console_initialized)
 275                 return;
 276
 277         /* If we've already seen the output, don't bother to print it again */
 278         if (console_drivers != NULL)
 279                 pdc_cons.flags &= ~CON_PRINTBUFFER;
 280
 281         while ((console = console_drivers) != NULL)
 282                 unregister_console(console_drivers);
 283
 284         /* force registering the pdc console */
 285         pdc_console_init_force();
 286 }