LXR linux/arch/parisc/kernel/pdc

   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 *
  16 *
  17 *    This program is free software; you can redistribute it and/or modify
  18 *    it under the terms of the GNU General Public License as published by
  19 *    the Free Software Foundation; either version 2 of the License, or
  20 *    (at your option) any later version.
  21 *
  22 *    This program is distributed in the hope that it will be useful,
  23 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  24 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25 *    GNU General Public License for more details.
  26 *
  27 *    You should have received a copy of the GNU General Public License
  28 *    along with this program; if not, write to the Free Software
  29 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  30 */
  31
  32/*
  33 *  The PDC console is a simple console, which can be used for debugging 
  34 *  boot related problems on HP PA-RISC machines.
  35 *
  36 *  This code uses the ROM (=PDC) based functions to read and write characters
  37 *  from and to PDC's boot path.
  38 *  Since all character read from that path must be polled, this code never
  39 *  can or will be a fully functional linux console.
  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);
  56
  57static void pdc_console_write(struct console *co, const char *s, unsigned count)
  58{
  59        int i = 0;
  60        unsigned long flags;
  61
  62        spin_lock_irqsave(&pdc_console_lock, flags);
  63        do {
  64                i += pdc_iodc_print(s + i, count - i);
  65        } while (i < count);
  66        spin_unlock_irqrestore(&pdc_console_lock, flags);
  67}
  68
  69int pdc_console_poll_key(struct console *co)
  70{
  71        int c;
  72        unsigned long flags;
  73
  74        spin_lock_irqsave(&pdc_console_lock, flags);
  75        c = pdc_iodc_getc();
  76        spin_unlock_irqrestore(&pdc_console_lock, flags);
  77
  78        return c;
  79}
  80
  81static int pdc_console_setup(struct console *co, char *options)
  82{
  83        return 0;
  84}
  85
  86#if defined(CONFIG_PDC_CONSOLE)
  87#include <linux/vt_kern.h>
  88
  89static struct tty_driver * pdc_console_device (struct console *c, int *index)
  90{
  91        extern struct tty_driver console_driver;
  92        *index = c->index ? c->index-1 : fg_console;
  93        return &console_driver;
  94}
  95#else
  96#define pdc_console_device NULL
  97#endif
  98
  99static struct console pdc_cons = {
 100        .name =         "ttyB",
 101        .write =        pdc_console_write,
 102        .device =       pdc_console_device,
 103        .setup =        pdc_console_setup,
 104        .flags =        CON_BOOT | CON_PRINTBUFFER | CON_ENABLED,
 105        .index =        -1,
 106};
 107
 108static int pdc_console_initialized;
 109
 110static void pdc_console_init_force(void)
 111{
 112        if (pdc_console_initialized)
 113                return;
 114        ++pdc_console_initialized;
 115        
 116        /* If the console is duplex then copy the COUT parameters to CIN. */
 117        if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
 118                memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
 119
 120        /* register the pdc console */
 121        register_console(&pdc_cons);
 122}
 123
 124void __init pdc_console_init(void)
 125{
 126#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 127        pdc_console_init_force();
 128#endif
 129#ifdef EARLY_BOOTUP_DEBUG
 130        printk(KERN_INFO "Initialized PDC Console for debugging.\n");
 131#endif
 132}
 133
 134
 135/*
 136 * Used for emergencies. Currently only used if an HPMC occurs. If an
 137 * HPMC occurs, it is possible that the current console may not be
 138 * properly initialised after the PDC IO reset. This routine unregisters
 139 * all of the current consoles, reinitializes the pdc console and
 140 * registers it.
 141 */
 142
 143void pdc_console_restart(void)
 144{
 145        struct console *console;
 146
 147        if (pdc_console_initialized)
 148                return;
 149
 150        /* If we've already seen the output, don't bother to print it again */
 151        if (console_drivers != NULL)
 152                pdc_cons.flags &= ~CON_PRINTBUFFER;
 153
 154        while ((console = console_drivers) != NULL)
 155                unregister_console(console_drivers);
 156
 157        /* force registering the pdc console */
 158        pdc_console_init_force();
 159}
 160