linux/arch/parisc/kernel/pdc_cons.c
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   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
  55static DEFINE_SPINLOCK(pdc_console_lock);
  56static struct console pdc_cons;
  57
  58static 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
  70int 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
  82static 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
  93static struct timer_list pdc_console_timer;
  94
  95extern struct console * console_drivers;
  96
  97static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
  98{
  99
 100        mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 101
 102        return 0;
 103}
 104
 105static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
 106{
 107        if (!tty->count)
 108                del_timer(&pdc_console_timer);
 109}
 110
 111static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 112{
 113        pdc_console_write(NULL, buf, count);
 114        return count;
 115}
 116
 117static int pdc_console_tty_write_room(struct tty_struct *tty)
 118{
 119        return 32768; /* no limit, no buffer used */
 120}
 121
 122static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
 123{
 124        return 0; /* no buffer */
 125}
 126
 127static struct tty_driver *pdc_console_tty_driver;
 128
 129static const struct tty_operations pdc_console_tty_ops = {
 130        .open = pdc_console_tty_open,
 131        .close = pdc_console_tty_close,
 132        .write = pdc_console_tty_write,
 133        .write_room = pdc_console_tty_write_room,
 134        .chars_in_buffer = pdc_console_tty_chars_in_buffer,
 135};
 136
 137static void pdc_console_poll(unsigned long unused)
 138{
 139
 140        int data, count = 0;
 141
 142        struct tty_struct *tty = pdc_console_tty_driver->ttys[0];
 143
 144        if (!tty)
 145                return;
 146
 147        while (1) {
 148                data = pdc_console_poll_key(NULL);
 149                if (data == -1)
 150                        break;
 151                tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
 152                count ++;
 153        }
 154
 155        if (count)
 156                tty_flip_buffer_push(tty);
 157
 158        if (tty->count && (pdc_cons.flags & CON_ENABLED))
 159                mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 160}
 161
 162static int __init pdc_console_tty_driver_init(void)
 163{
 164
 165        int err;
 166        struct tty_driver *drv;
 167
 168        /* Check if the console driver is still registered.
 169         * It is unregistered if the pdc console was not selected as the
 170         * primary console. */
 171
 172        struct console *tmp = console_drivers;
 173
 174        for (tmp = console_drivers; tmp; tmp = tmp->next)
 175                if (tmp == &pdc_cons)
 176                        break;
 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
 215module_init(pdc_console_tty_driver_init);
 216
 217static 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
 226static 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
 235static int pdc_console_initialized;
 236
 237static 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
 251void __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
 270void 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}
 287