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 #undef 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/delay.h>
  53 #include <linux/sched.h>
  54 #include <linux/interrupt.h>
  55 #include <linux/major.h>
  56 #include <linux/tty.h>
  57 #include <asm/page.h>
  58 #include <asm/types.h>
  59 #include <asm/system.h>
  60 #include <asm/pdc.h>            /* for iodc_call() proto and friends */
  61
  62
  63 static void pdc_console_write(struct console *co, const char *s, unsigned count)
  64 {
  65         while(count--)
  66                 pdc_iodc_putc(*s++);
  67 }
  68
  69 void pdc_outc(unsigned char c)
  70 {
  71         pdc_iodc_outc(c);
  72 }
  73
  74
  75 int pdc_console_poll_key(struct console *co)
  76 {
  77         return pdc_iodc_getc();
  78 }
  79
  80 static int pdc_console_setup(struct console *co, char *options)
  81 {
  82         return 0;
  83 }
  84
  85 #if defined(CONFIG_PDC_CONSOLE)
  86 #define PDC_CONSOLE_DEVICE pdc_console_device
  87 static struct tty_driver * pdc_console_device (struct console *c, int *index)
  88 {
  89         extern struct tty_driver console_driver;
  90         *index = c->index ? c->index-1 : fg_console;
  91         return &console_driver;
  92 }
  93 #else
  94 #define PDC_CONSOLE_DEVICE NULL
  95 #endif
  96
  97 static struct console pdc_cons = {
  98         .name =         "ttyB",
  99         .write =        pdc_console_write,
 100         .device =       PDC_CONSOLE_DEVICE,
 101         .setup =        pdc_console_setup,
 102         .flags =        CON_BOOT|CON_PRINTBUFFER|CON_ENABLED,
 103         .index =        -1,
 104 };
 105
 106 static int pdc_console_initialized;
 107 extern unsigned long con_start; /* kernel/printk.c */
 108 extern unsigned long log_end;   /* kernel/printk.c */
 109
 110
 111 static void pdc_console_init_force(void)
 112 {
 113         if (pdc_console_initialized)
 114                 return;
 115         ++pdc_console_initialized;
 116
 117         /* If the console is duplex then copy the COUT parameters to CIN. */
 118         if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
 119                 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
 120
 121         /* register the pdc console */
 122         register_console(&pdc_cons);
 123 }
 124
 125 void __init pdc_console_init(void)
 126 {
 127 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 128         pdc_console_init_force();
 129 #endif
 130 #ifdef EARLY_BOOTUP_DEBUG
 131         printk(KERN_INFO "Initialized PDC Console for debugging.\n");
 132 #endif
 133 }
 134
 135
 136 /* Unregister the pdc console with the printk console layer */
 137 void pdc_console_die(void)
 138 {
 139         if (!pdc_console_initialized)
 140                 return;
 141         --pdc_console_initialized;
 142
 143         printk(KERN_INFO "Switching from PDC console\n");
 144
 145         /* Don't repeat what we've already printed */
 146         con_start = log_end;
 147
 148         unregister_console(&pdc_cons);
 149 }
 150
 151
 152 /*
 153  * Used for emergencies. Currently only used if an HPMC occurs. If an
 154  * HPMC occurs, it is possible that the current console may not be
 155  * properly initialed after the PDC IO reset. This routine unregisters all
 156  * of the current consoles, reinitializes the pdc console and
 157  * registers it.
 158  */
 159
 160 void pdc_console_restart(void)
 161 {
 162         struct console *console;
 163
 164         if (pdc_console_initialized)
 165                 return;
 166
 167         while ((console = console_drivers) != NULL)
 168                 unregister_console(console_drivers);
 169
 170         /* Don't repeat what we've already printed */
 171         con_start = log_end;
 172
 173         /* force registering the pdc console */
 174         pdc_console_init_force();
 175 }
 176