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/page.h>           /* for PAGE0 */
  54 #include <asm/pdc.h>            /* for iodc_call() proto and friends */
  55
  56 static DEFINE_SPINLOCK(pdc_console_lock);
  57 static struct console pdc_cons;
  58
  59 static void pdc_console_write(struct console *co, const char *s, unsigned count)
  60 {
  61         int i = 0;
  62         unsigned long flags;
  63
  64         spin_lock_irqsave(&pdc_console_lock, flags);
  65         do {
  66                 i += pdc_iodc_print(s + i, count - i);
  67         } while (i < count);
  68         spin_unlock_irqrestore(&pdc_console_lock, flags);
  69 }
  70
  71 int pdc_console_poll_key(struct console *co)
  72 {
  73         int c;
  74         unsigned long flags;
  75
  76         spin_lock_irqsave(&pdc_console_lock, flags);
  77         c = pdc_iodc_getc();
  78         spin_unlock_irqrestore(&pdc_console_lock, flags);
  79
  80         return c;
  81 }
  82
  83 static int pdc_console_setup(struct console *co, char *options)
  84 {
  85         return 0;
  86 }
  87
  88 #if defined(CONFIG_PDC_CONSOLE)
  89 #include <linux/vt_kern.h>
  90 #include <linux/tty_flip.h>
  91
  92 #define PDC_CONS_POLL_DELAY (30 * HZ / 1000)
  93
  94 static void pdc_console_poll(struct timer_list *unused);
  95 static DEFINE_TIMER(pdc_console_timer, pdc_console_poll);
  96 static struct tty_port tty_port;
  97
  98 static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
  99 {
 100         tty_port_tty_set(&tty_port, tty);
 101         mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 102
 103         return 0;
 104 }
 105
 106 static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
 107 {
 108         if (tty->count == 1) {
 109                 del_timer_sync(&pdc_console_timer);
 110                 tty_port_tty_set(&tty_port, NULL);
 111         }
 112 }
 113
 114 static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 115 {
 116         pdc_console_write(NULL, buf, count);
 117         return count;
 118 }
 119
 120 static int pdc_console_tty_write_room(struct tty_struct *tty)
 121 {
 122         return 32768; /* no limit, no buffer used */
 123 }
 124
 125 static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
 126 {
 127         return 0; /* no buffer */
 128 }
 129
 130 static const struct tty_operations pdc_console_tty_ops = {
 131         .open = pdc_console_tty_open,
 132         .close = pdc_console_tty_close,
 133         .write = pdc_console_tty_write,
 134         .write_room = pdc_console_tty_write_room,
 135         .chars_in_buffer = pdc_console_tty_chars_in_buffer,
 136 };
 137
 138 static void pdc_console_poll(struct timer_list *unused)
 139 {
 140         int data, count = 0;
 141
 142         while (1) {
 143                 data = pdc_console_poll_key(NULL);
 144                 if (data == -1)
 145                         break;
 146                 tty_insert_flip_char(&tty_port, data & 0xFF, TTY_NORMAL);
 147                 count ++;
 148         }
 149
 150         if (count)
 151                 tty_flip_buffer_push(&tty_port);
 152
 153         if (pdc_cons.flags & CON_ENABLED)
 154                 mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 155 }
 156
 157 static struct tty_driver *pdc_console_tty_driver;
 158
 159 static int __init pdc_console_tty_driver_init(void)
 160 {
 161         int err;
 162
 163         /* Check if the console driver is still registered.
 164          * It is unregistered if the pdc console was not selected as the
 165          * primary console. */
 166
 167         struct console *tmp;
 168
 169         console_lock();
 170         for_each_console(tmp)
 171                 if (tmp == &pdc_cons)
 172                         break;
 173         console_unlock();
 174
 175         if (!tmp) {
 176                 printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
 177                 return -ENODEV;
 178         }
 179
 180         printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
 181         pdc_cons.flags &= ~CON_BOOT;
 182
 183         pdc_console_tty_driver = alloc_tty_driver(1);
 184
 185         if (!pdc_console_tty_driver)
 186                 return -ENOMEM;
 187
 188         tty_port_init(&tty_port);
 189
 190         pdc_console_tty_driver->driver_name = "pdc_cons";
 191         pdc_console_tty_driver->name = "ttyB";
 192         pdc_console_tty_driver->major = MUX_MAJOR;
 193         pdc_console_tty_driver->minor_start = 0;
 194         pdc_console_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
 195         pdc_console_tty_driver->init_termios = tty_std_termios;
 196         pdc_console_tty_driver->flags = TTY_DRIVER_REAL_RAW |
 197                 TTY_DRIVER_RESET_TERMIOS;
 198         tty_set_operations(pdc_console_tty_driver, &pdc_console_tty_ops);
 199         tty_port_link_device(&tty_port, pdc_console_tty_driver, 0);
 200
 201         err = tty_register_driver(pdc_console_tty_driver);
 202         if (err) {
 203                 printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
 204                 tty_port_destroy(&tty_port);
 205                 return err;
 206         }
 207
 208         return 0;
 209 }
 210 device_initcall(pdc_console_tty_driver_init);
 211
 212 static struct tty_driver * pdc_console_device (struct console *c, int *index)
 213 {
 214         *index = c->index;
 215         return pdc_console_tty_driver;
 216 }
 217 #else
 218 #define pdc_console_device NULL
 219 #endif
 220
 221 static struct console pdc_cons = {
 222         .name =         "ttyB",
 223         .write =        pdc_console_write,
 224         .device =       pdc_console_device,
 225         .setup =        pdc_console_setup,
 226         .flags =        CON_BOOT | CON_PRINTBUFFER,
 227         .index =        -1,
 228 };
 229
 230 static int pdc_console_initialized;
 231
 232 static void pdc_console_init_force(void)
 233 {
 234         if (pdc_console_initialized)
 235                 return;
 236         ++pdc_console_initialized;
 237
 238         /* If the console is duplex then copy the COUT parameters to CIN. */
 239         if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
 240                 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
 241
 242         /* register the pdc console */
 243         register_console(&pdc_cons);
 244 }
 245
 246 void __init pdc_console_init(void)
 247 {
 248 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 249         pdc_console_init_force();
 250 #endif
 251 #ifdef EARLY_BOOTUP_DEBUG
 252         printk(KERN_INFO "Initialized PDC Console for debugging.\n");
 253 #endif
 254 }
 255
 256
 257 /*
 258  * Used for emergencies. Currently only used if an HPMC occurs. If an
 259  * HPMC occurs, it is possible that the current console may not be
 260  * properly initialised after the PDC IO reset. This routine unregisters
 261  * all of the current consoles, reinitializes the pdc console and
 262  * registers it.
 263  */
 264
 265 void pdc_console_restart(void)
 266 {
 267         struct console *console;
 268
 269         if (pdc_console_initialized)
 270                 return;
 271
 272         /* If we've already seen the output, don't bother to print it again */
 273         if (console_drivers != NULL)
 274                 pdc_cons.flags &= ~CON_PRINTBUFFER;
 275
 276         while ((console = console_drivers) != NULL)
 277                 unregister_console(console_drivers);
 278
 279         /* force registering the pdc console */
 280         pdc_console_init_force();
 281 }