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linux-sg2042/arch/parisc/kernel/pdc_cons.c

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/*
* PDC Console support - ie use firmware to dump text via boot console
*
* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
* Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
* Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
* Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
* Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
* Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
* Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
* Copyright (C) 2001 Helge Deller <deller at parisc-linux.org>
* Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
* Copyright (C) 2010 Guy Martin <gmsoft at tuxicoman.be>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* The PDC console is a simple console, which can be used for debugging
* boot related problems on HP PA-RISC machines. It is also useful when no
* other console works.
*
* This code uses the ROM (=PDC) based functions to read and write characters
* from and to PDC's boot path.
*/
/* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems.
* On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
#define EARLY_BOOTUP_DEBUG
#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/major.h>
#include <linux/tty.h>
#include <asm/page.h> /* for PAGE0 */
#include <asm/pdc.h> /* for iodc_call() proto and friends */
static DEFINE_SPINLOCK(pdc_console_lock);
static struct console pdc_cons;
static void pdc_console_write(struct console *co, const char *s, unsigned count)
{
int i = 0;
unsigned long flags;
spin_lock_irqsave(&pdc_console_lock, flags);
do {
i += pdc_iodc_print(s + i, count - i);
} while (i < count);
spin_unlock_irqrestore(&pdc_console_lock, flags);
}
int pdc_console_poll_key(struct console *co)
{
int c;
unsigned long flags;
spin_lock_irqsave(&pdc_console_lock, flags);
c = pdc_iodc_getc();
spin_unlock_irqrestore(&pdc_console_lock, flags);
return c;
}
static int pdc_console_setup(struct console *co, char *options)
{
return 0;
}
#if defined(CONFIG_PDC_CONSOLE)
#include <linux/vt_kern.h>
#include <linux/tty_flip.h>
#define PDC_CONS_POLL_DELAY (30 * HZ / 1000)
static void pdc_console_poll(unsigned long unused);
static DEFINE_TIMER(pdc_console_timer, pdc_console_poll, 0, 0);
static struct tty_port tty_port;
static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
{
tty_port_tty_set(&tty_port, tty);
mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
return 0;
}
static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
{
if (tty->count == 1) {
del_timer_sync(&pdc_console_timer);
tty_port_tty_set(&tty_port, NULL);
}
}
static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
pdc_console_write(NULL, buf, count);
return count;
}
static int pdc_console_tty_write_room(struct tty_struct *tty)
{
return 32768; /* no limit, no buffer used */
}
static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
{
return 0; /* no buffer */
}
static const struct tty_operations pdc_console_tty_ops = {
.open = pdc_console_tty_open,
.close = pdc_console_tty_close,
.write = pdc_console_tty_write,
.write_room = pdc_console_tty_write_room,
.chars_in_buffer = pdc_console_tty_chars_in_buffer,
};
static void pdc_console_poll(unsigned long unused)
{
int data, count = 0;
struct tty_struct *tty = tty_port_tty_get(&tty_port);
if (!tty)
return;
while (1) {
data = pdc_console_poll_key(NULL);
if (data == -1)
break;
tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
count ++;
}
if (count)
tty_flip_buffer_push(tty);
tty_kref_put(tty);
if (pdc_cons.flags & CON_ENABLED)
mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
}
static struct tty_driver *pdc_console_tty_driver;
static int __init pdc_console_tty_driver_init(void)
{
int err;
/* Check if the console driver is still registered.
* It is unregistered if the pdc console was not selected as the
* primary console. */
struct console *tmp;
console_lock();
for_each_console(tmp)
if (tmp == &pdc_cons)
break;
console_unlock();
if (!tmp) {
printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
return -ENODEV;
}
printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
pdc_cons.flags &= ~CON_BOOT;
tty_port_init(&tty_port);
pdc_console_tty_driver = alloc_tty_driver(1);
if (!pdc_console_tty_driver)
return -ENOMEM;
pdc_console_tty_driver->driver_name = "pdc_cons";
pdc_console_tty_driver->name = "ttyB";
pdc_console_tty_driver->major = MUX_MAJOR;
pdc_console_tty_driver->minor_start = 0;
pdc_console_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
pdc_console_tty_driver->init_termios = tty_std_termios;
pdc_console_tty_driver->flags = TTY_DRIVER_REAL_RAW |
TTY_DRIVER_RESET_TERMIOS;
tty_set_operations(pdc_console_tty_driver, &pdc_console_tty_ops);
err = tty_register_driver(pdc_console_tty_driver);
if (err) {
printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
return err;
}
return 0;
}
module_init(pdc_console_tty_driver_init);
static struct tty_driver * pdc_console_device (struct console *c, int *index)
{
*index = c->index;
return pdc_console_tty_driver;
}
#else
#define pdc_console_device NULL
#endif
static struct console pdc_cons = {
.name = "ttyB",
.write = pdc_console_write,
.device = pdc_console_device,
.setup = pdc_console_setup,
.flags = CON_BOOT | CON_PRINTBUFFER,
.index = -1,
};
static int pdc_console_initialized;
static void pdc_console_init_force(void)
{
if (pdc_console_initialized)
return;
++pdc_console_initialized;
/* If the console is duplex then copy the COUT parameters to CIN. */
if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
/* register the pdc console */
register_console(&pdc_cons);
}
void __init pdc_console_init(void)
{
#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
pdc_console_init_force();
#endif
#ifdef EARLY_BOOTUP_DEBUG
printk(KERN_INFO "Initialized PDC Console for debugging.\n");
#endif
}
/*
* Used for emergencies. Currently only used if an HPMC occurs. If an
* HPMC occurs, it is possible that the current console may not be
* properly initialised after the PDC IO reset. This routine unregisters
* all of the current consoles, reinitializes the pdc console and
* registers it.
*/
void pdc_console_restart(void)
{
struct console *console;
if (pdc_console_initialized)
return;
/* If we've already seen the output, don't bother to print it again */
if (console_drivers != NULL)
pdc_cons.flags &= ~CON_PRINTBUFFER;
while ((console = console_drivers) != NULL)
unregister_console(console_drivers);
/* force registering the pdc console */
pdc_console_init_force();
}
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