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 void pdc_console_poll(unsigned long unused);
  94 static DEFINE_TIMER(pdc_console_timer, pdc_console_poll, 0, 0);
  95
  96 static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
  97 {
  98
  99         mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 100
 101         return 0;
 102 }
 103
 104 static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
 105 {
 106         if (!tty->count)
 107                 del_timer_sync(&pdc_console_timer);
 108 }
 109
 110 static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 111 {
 112         pdc_console_write(NULL, buf, count);
 113         return count;
 114 }
 115
 116 static int pdc_console_tty_write_room(struct tty_struct *tty)
 117 {
 118         return 32768; /* no limit, no buffer used */
 119 }
 120
 121 static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
 122 {
 123         return 0; /* no buffer */
 124 }
 125
 126 static struct tty_driver *pdc_console_tty_driver;
 127
 128 static const struct tty_operations pdc_console_tty_ops = {
 129         .open = pdc_console_tty_open,
 130         .close = pdc_console_tty_close,
 131         .write = pdc_console_tty_write,
 132         .write_room = pdc_console_tty_write_room,
 133         .chars_in_buffer = pdc_console_tty_chars_in_buffer,
 134 };
 135
 136 static void pdc_console_poll(unsigned long unused)
 137 {
 138
 139         int data, count = 0;
 140
 141         struct tty_struct *tty = pdc_console_tty_driver->ttys[0];
 142
 143         if (!tty)
 144                 return;
 145
 146         while (1) {
 147                 data = pdc_console_poll_key(NULL);
 148                 if (data == -1)
 149                         break;
 150                 tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
 151                 count ++;
 152         }
 153
 154         if (count)
 155                 tty_flip_buffer_push(tty);
 156
 157         if (pdc_cons.flags & CON_ENABLED)
 158                 mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 159 }
 160
 161 static int __init pdc_console_tty_driver_init(void)
 162 {
 163
 164         int err;
 165         struct tty_driver *drv;
 166
 167         /* Check if the console driver is still registered.
 168          * It is unregistered if the pdc console was not selected as the
 169          * primary console. */
 170
 171         struct console *tmp;
 172
 173         console_lock();
 174         for_each_console(tmp)
 175                 if (tmp == &pdc_cons)
 176                         break;
 177         console_unlock();
 178
 179         if (!tmp) {
 180                 printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
 181                 return -ENODEV;
 182         }
 183
 184         printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
 185         pdc_cons.flags &= ~CON_BOOT;
 186
 187         drv = alloc_tty_driver(1);
 188
 189         if (!drv)
 190                 return -ENOMEM;
 191
 192         drv->driver_name = "pdc_cons";
 193         drv->name = "ttyB";
 194         drv->major = MUX_MAJOR;
 195         drv->minor_start = 0;
 196         drv->type = TTY_DRIVER_TYPE_SYSTEM;
 197         drv->init_termios = tty_std_termios;
 198         drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
 199         tty_set_operations(drv, &pdc_console_tty_ops);
 200
 201         err = tty_register_driver(drv);
 202         if (err) {
 203                 printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
 204                 return err;
 205         }
 206
 207         pdc_console_tty_driver = drv;
 208
 209         return 0;
 210 }
 211
 212 module_init(pdc_console_tty_driver_init);
 213
 214 static struct tty_driver * pdc_console_device (struct console *c, int *index)
 215 {
 216         *index = c->index;
 217         return pdc_console_tty_driver;
 218 }
 219 #else
 220 #define pdc_console_device NULL
 221 #endif
 222
 223 static struct console pdc_cons = {
 224         .name =         "ttyB",
 225         .write =        pdc_console_write,
 226         .device =       pdc_console_device,
 227         .setup =        pdc_console_setup,
 228         .flags =        CON_BOOT | CON_PRINTBUFFER,
 229         .index =        -1,
 230 };
 231
 232 static int pdc_console_initialized;
 233
 234 static void pdc_console_init_force(void)
 235 {
 236         if (pdc_console_initialized)
 237                 return;
 238         ++pdc_console_initialized;
 239
 240         /* If the console is duplex then copy the COUT parameters to CIN. */
 241         if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
 242                 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
 243
 244         /* register the pdc console */
 245         register_console(&pdc_cons);
 246 }
 247
 248 void __init pdc_console_init(void)
 249 {
 250 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 251         pdc_console_init_force();
 252 #endif
 253 #ifdef EARLY_BOOTUP_DEBUG
 254         printk(KERN_INFO "Initialized PDC Console for debugging.\n");
 255 #endif
 256 }
 257
 258
 259 /*
 260  * Used for emergencies. Currently only used if an HPMC occurs. If an
 261  * HPMC occurs, it is possible that the current console may not be
 262  * properly initialised after the PDC IO reset. This routine unregisters
 263  * all of the current consoles, reinitializes the pdc console and
 264  * registers it.
 265  */
 266
 267 void pdc_console_restart(void)
 268 {
 269         struct console *console;
 270
 271         if (pdc_console_initialized)
 272                 return;
 273
 274         /* If we've already seen the output, don't bother to print it again */
 275         if (console_drivers != NULL)
 276                 pdc_cons.flags &= ~CON_PRINTBUFFER;
 277
 278         while ((console = console_drivers) != NULL)
 279                 unregister_console(console_drivers);
 280
 281         /* force registering the pdc console */
 282         pdc_console_init_force();
 283 }