linux/arch/parisc/kernel/pdc_cons.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* 
   3 *    PDC Console support - ie use firmware to dump text via boot console
   4 *
   5 *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
   6 *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
   7 *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
   8 *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
   9 *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
  10 *    Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
  11 *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
  12 *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
  13 *    Copyright (C) 2001 Helge Deller <deller at parisc-linux.org>
  14 *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
  15 *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
  16 *    Copyright (C) 2010 Guy Martin <gmsoft at tuxicoman.be>
  17 */
  18
  19/*
  20 *  The PDC console is a simple console, which can be used for debugging 
  21 *  boot related problems on HP PA-RISC machines. It is also useful when no
  22 *  other console works.
  23 *
  24 *  This code uses the ROM (=PDC) based functions to read and write characters
  25 *  from and to PDC's boot path.
  26 */
  27
  28/* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems. 
  29 * On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
  30#define EARLY_BOOTUP_DEBUG
  31
  32
  33#include <linux/kernel.h>
  34#include <linux/console.h>
  35#include <linux/string.h>
  36#include <linux/init.h>
  37#include <linux/major.h>
  38#include <linux/tty.h>
  39#include <asm/page.h>           /* for PAGE0 */
  40#include <asm/pdc.h>            /* for iodc_call() proto and friends */
  41
  42static DEFINE_SPINLOCK(pdc_console_lock);
  43static struct console pdc_cons;
  44
  45static void pdc_console_write(struct console *co, const char *s, unsigned count)
  46{
  47        int i = 0;
  48        unsigned long flags;
  49
  50        spin_lock_irqsave(&pdc_console_lock, flags);
  51        do {
  52                i += pdc_iodc_print(s + i, count - i);
  53        } while (i < count);
  54        spin_unlock_irqrestore(&pdc_console_lock, flags);
  55}
  56
  57int pdc_console_poll_key(struct console *co)
  58{
  59        int c;
  60        unsigned long flags;
  61
  62        spin_lock_irqsave(&pdc_console_lock, flags);
  63        c = pdc_iodc_getc();
  64        spin_unlock_irqrestore(&pdc_console_lock, flags);
  65
  66        return c;
  67}
  68
  69static int pdc_console_setup(struct console *co, char *options)
  70{
  71        return 0;
  72}
  73
  74#if defined(CONFIG_PDC_CONSOLE)
  75#include <linux/vt_kern.h>
  76#include <linux/tty_flip.h>
  77
  78#define PDC_CONS_POLL_DELAY (30 * HZ / 1000)
  79
  80static void pdc_console_poll(struct timer_list *unused);
  81static DEFINE_TIMER(pdc_console_timer, pdc_console_poll);
  82static struct tty_port tty_port;
  83
  84static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
  85{
  86        tty_port_tty_set(&tty_port, tty);
  87        mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
  88
  89        return 0;
  90}
  91
  92static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
  93{
  94        if (tty->count == 1) {
  95                del_timer_sync(&pdc_console_timer);
  96                tty_port_tty_set(&tty_port, NULL);
  97        }
  98}
  99
 100static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
 101{
 102        pdc_console_write(NULL, buf, count);
 103        return count;
 104}
 105
 106static unsigned int pdc_console_tty_write_room(struct tty_struct *tty)
 107{
 108        return 32768; /* no limit, no buffer used */
 109}
 110
 111static const struct tty_operations pdc_console_tty_ops = {
 112        .open = pdc_console_tty_open,
 113        .close = pdc_console_tty_close,
 114        .write = pdc_console_tty_write,
 115        .write_room = pdc_console_tty_write_room,
 116};
 117
 118static void pdc_console_poll(struct timer_list *unused)
 119{
 120        int data, count = 0;
 121
 122        while (1) {
 123                data = pdc_console_poll_key(NULL);
 124                if (data == -1)
 125                        break;
 126                tty_insert_flip_char(&tty_port, data & 0xFF, TTY_NORMAL);
 127                count ++;
 128        }
 129
 130        if (count)
 131                tty_flip_buffer_push(&tty_port);
 132
 133        if (pdc_cons.flags & CON_ENABLED)
 134                mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
 135}
 136
 137static struct tty_driver *pdc_console_tty_driver;
 138
 139static int __init pdc_console_tty_driver_init(void)
 140{
 141        int err;
 142
 143        /* Check if the console driver is still registered.
 144         * It is unregistered if the pdc console was not selected as the
 145         * primary console. */
 146
 147        struct console *tmp;
 148
 149        console_lock();
 150        for_each_console(tmp)
 151                if (tmp == &pdc_cons)
 152                        break;
 153        console_unlock();
 154
 155        if (!tmp) {
 156                printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
 157                return -ENODEV;
 158        }
 159
 160        printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
 161        pdc_cons.flags &= ~CON_BOOT;
 162
 163        pdc_console_tty_driver = alloc_tty_driver(1);
 164
 165        if (!pdc_console_tty_driver)
 166                return -ENOMEM;
 167
 168        tty_port_init(&tty_port);
 169
 170        pdc_console_tty_driver->driver_name = "pdc_cons";
 171        pdc_console_tty_driver->name = "ttyB";
 172        pdc_console_tty_driver->major = MUX_MAJOR;
 173        pdc_console_tty_driver->minor_start = 0;
 174        pdc_console_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
 175        pdc_console_tty_driver->init_termios = tty_std_termios;
 176        pdc_console_tty_driver->flags = TTY_DRIVER_REAL_RAW |
 177                TTY_DRIVER_RESET_TERMIOS;
 178        tty_set_operations(pdc_console_tty_driver, &pdc_console_tty_ops);
 179        tty_port_link_device(&tty_port, pdc_console_tty_driver, 0);
 180
 181        err = tty_register_driver(pdc_console_tty_driver);
 182        if (err) {
 183                printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
 184                tty_port_destroy(&tty_port);
 185                return err;
 186        }
 187
 188        return 0;
 189}
 190device_initcall(pdc_console_tty_driver_init);
 191
 192static struct tty_driver * pdc_console_device (struct console *c, int *index)
 193{
 194        *index = c->index;
 195        return pdc_console_tty_driver;
 196}
 197#else
 198#define pdc_console_device NULL
 199#endif
 200
 201static struct console pdc_cons = {
 202        .name =         "ttyB",
 203        .write =        pdc_console_write,
 204        .device =       pdc_console_device,
 205        .setup =        pdc_console_setup,
 206        .flags =        CON_BOOT | CON_PRINTBUFFER,
 207        .index =        -1,
 208};
 209
 210static int pdc_console_initialized;
 211
 212static void pdc_console_init_force(void)
 213{
 214        if (pdc_console_initialized)
 215                return;
 216        ++pdc_console_initialized;
 217        
 218        /* If the console is duplex then copy the COUT parameters to CIN. */
 219        if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
 220                memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
 221
 222        /* register the pdc console */
 223        register_console(&pdc_cons);
 224}
 225
 226void __init pdc_console_init(void)
 227{
 228#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
 229        pdc_console_init_force();
 230#endif
 231#ifdef EARLY_BOOTUP_DEBUG
 232        printk(KERN_INFO "Initialized PDC Console for debugging.\n");
 233#endif
 234}
 235
 236
 237/*
 238 * Used for emergencies. Currently only used if an HPMC occurs. If an
 239 * HPMC occurs, it is possible that the current console may not be
 240 * properly initialised after the PDC IO reset. This routine unregisters
 241 * all of the current consoles, reinitializes the pdc console and
 242 * registers it.
 243 */
 244
 245void pdc_console_restart(void)
 246{
 247        struct console *console;
 248
 249        if (pdc_console_initialized)
 250                return;
 251
 252        /* If we've already seen the output, don't bother to print it again */
 253        if (console_drivers != NULL)
 254                pdc_cons.flags &= ~CON_PRINTBUFFER;
 255
 256        while ((console = console_drivers) != NULL)
 257                unregister_console(console_drivers);
 258
 259        /* force registering the pdc console */
 260        pdc_console_init_force();
 261}
 262