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  *
  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/config.h>
  48 #include <linux/kernel.h>
  49 #include <linux/console.h>
  50 #include <linux/string.h>
  51 #include <linux/init.h>
  52 #include <linux/major.h>
  53 #include <linux/tty.h>
  54 #include <asm/pdc.h>            /* for iodc_call() proto and friends */
  55
  56
  57 static void pdc_console_write(struct console *co, const char *s, unsigned count)
  58 {
  59         while(count--)
  60                 pdc_iodc_putc(*s++);
  61 }
  62
  63 void pdc_outc(unsigned char c)
  64 {
  65         pdc_iodc_outc(c);
  66 }
  67
  68 void pdc_printf(const char *fmt, ...)
  69 {
  70         va_list args;
  71         char buf[1024];
  72         int i, len;
  73
  74         va_start(args, fmt);
  75         len = vscnprintf(buf, sizeof(buf), fmt, args);
  76         va_end(args);
  77
  78         for (i = 0; i < len; i++)
  79                 pdc_iodc_outc(buf[i]);
  80 }
  81
  82 int pdc_console_poll_key(struct console *co)
  83 {
  84         return pdc_iodc_getc();
  85 }
  86
  87 static int pdc_console_setup(struct console *co, char *options)
  88 {
  89         return 0;
  90 }
  91
  92 #if defined(CONFIG_PDC_CONSOLE)
  93 static struct tty_driver * pdc_console_device (struct console *c, int *index)
  94 {
  95         extern struct tty_driver console_driver;
  96         *index = c->index ? c->index-1 : fg_console;
  97         return &console_driver;
  98 }
  99 #else
 100 #define pdc_console_device NULL
 101 #endif
 102
 103 static struct console pdc_cons = {
 104         .name =         "ttyB",
 105         .write =        pdc_console_write,
 106         .device =       pdc_console_device,
 107         .setup =        pdc_console_setup,
 108         .flags =        CON_BOOT | CON_PRINTBUFFER | CON_ENABLED,
 109         .index =        -1,
 110 };
 111
 112 static int pdc_console_initialized;
 113
 114 static void pdc_console_init_force(void)
 115 {
 116         if (pdc_console_initialized)
 117                 return;
 118         ++pdc_console_initialized;
 119
 120         /* If the console is duplex then copy the COUT parameters to CIN. */
 121         if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
 122                 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
 123
 124         /* register the pdc console */
 125         register_console(&pdc_cons);
 126 }
 127
 128 void __init pdc_console_init(void)
 129 {
 130 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 131         pdc_console_init_force();
 132 #endif
 133 #ifdef EARLY_BOOTUP_DEBUG
 134         printk(KERN_INFO "Initialized PDC Console for debugging.\n");
 135 #endif
 136 }
 137
 138
 139 /*
 140  * Used for emergencies. Currently only used if an HPMC occurs. If an
 141  * HPMC occurs, it is possible that the current console may not be
 142  * properly initialised after the PDC IO reset. This routine unregisters
 143  * all of the current consoles, reinitializes the pdc console and
 144  * registers it.
 145  */
 146
 147 void pdc_console_restart(void)
 148 {
 149         struct console *console;
 150
 151         if (pdc_console_initialized)
 152                 return;
 153
 154         /* If we've already seen the output, don't bother to print it again */
 155         if (console_drivers != NULL)
 156                 pdc_cons.flags &= ~CON_PRINTBUFFER;
 157
 158         while ((console = console_drivers) != NULL)
 159                 unregister_console(console_drivers);
 160
 161         /* force registering the pdc console */
 162         pdc_console_init_force();
 163 }