1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
135 lines
2.9 KiB
C
135 lines
2.9 KiB
C
/*
|
||
* arch/v850/kernel/memcons.c -- Console I/O to a memory buffer
|
||
*
|
||
* Copyright (C) 2001,02 NEC Corporation
|
||
* Copyright (C) 2001,02 Miles Bader <miles@gnu.org>
|
||
*
|
||
* This file is subject to the terms and conditions of the GNU General
|
||
* Public License. See the file COPYING in the main directory of this
|
||
* archive for more details.
|
||
*
|
||
* Written by Miles Bader <miles@gnu.org>
|
||
*/
|
||
|
||
#include <linux/kernel.h>
|
||
#include <linux/console.h>
|
||
#include <linux/tty.h>
|
||
#include <linux/tty_driver.h>
|
||
#include <linux/init.h>
|
||
|
||
/* If this device is enabled, the linker map should define start and
|
||
end points for its buffer. */
|
||
extern char memcons_output[], memcons_output_end;
|
||
|
||
/* Current offset into the buffer. */
|
||
static unsigned long memcons_offs = 0;
|
||
|
||
/* Spinlock protecting memcons_offs. */
|
||
static DEFINE_SPINLOCK(memcons_lock);
|
||
|
||
|
||
static size_t write (const char *buf, size_t len)
|
||
{
|
||
int flags;
|
||
char *point;
|
||
|
||
spin_lock_irqsave (memcons_lock, flags);
|
||
|
||
point = memcons_output + memcons_offs;
|
||
if (point + len >= &memcons_output_end) {
|
||
len = &memcons_output_end - point;
|
||
memcons_offs = 0;
|
||
} else
|
||
memcons_offs += len;
|
||
|
||
spin_unlock_irqrestore (memcons_lock, flags);
|
||
|
||
memcpy (point, buf, len);
|
||
|
||
return len;
|
||
}
|
||
|
||
|
||
/* Low-level console. */
|
||
|
||
static void memcons_write (struct console *co, const char *buf, unsigned len)
|
||
{
|
||
while (len > 0)
|
||
len -= write (buf, len);
|
||
}
|
||
|
||
static struct tty_driver *tty_driver;
|
||
|
||
static struct tty_driver *memcons_device (struct console *co, int *index)
|
||
{
|
||
*index = co->index;
|
||
return tty_driver;
|
||
}
|
||
|
||
static struct console memcons =
|
||
{
|
||
.name = "memcons",
|
||
.write = memcons_write,
|
||
.device = memcons_device,
|
||
.flags = CON_PRINTBUFFER,
|
||
.index = -1,
|
||
};
|
||
|
||
void memcons_setup (void)
|
||
{
|
||
register_console (&memcons);
|
||
printk (KERN_INFO "Console: static memory buffer (memcons)\n");
|
||
}
|
||
|
||
/* Higher level TTY interface. */
|
||
|
||
int memcons_tty_open (struct tty_struct *tty, struct file *filp)
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
int memcons_tty_write (struct tty_struct *tty, const unsigned char *buf, int len)
|
||
{
|
||
return write (buf, len);
|
||
}
|
||
|
||
int memcons_tty_write_room (struct tty_struct *tty)
|
||
{
|
||
return &memcons_output_end - (memcons_output + memcons_offs);
|
||
}
|
||
|
||
int memcons_tty_chars_in_buffer (struct tty_struct *tty)
|
||
{
|
||
/* We have no buffer. */
|
||
return 0;
|
||
}
|
||
|
||
static struct tty_operations ops = {
|
||
.open = memcons_tty_open,
|
||
.write = memcons_tty_write,
|
||
.write_room = memcons_tty_write_room,
|
||
.chars_in_buffer = memcons_tty_chars_in_buffer,
|
||
};
|
||
|
||
int __init memcons_tty_init (void)
|
||
{
|
||
int err;
|
||
struct tty_driver *driver = alloc_tty_driver(1);
|
||
if (!driver)
|
||
return -ENOMEM;
|
||
|
||
driver->name = "memcons";
|
||
driver->major = TTY_MAJOR;
|
||
driver->minor_start = 64;
|
||
driver->type = TTY_DRIVER_TYPE_SYSCONS;
|
||
driver->init_termios = tty_std_termios;
|
||
tty_set_operations(driver, &ops);
|
||
err = tty_register_driver(driver);
|
||
if (err) {
|
||
put_tty_driver(driver);
|
||
return err;
|
||
}
|
||
tty_driver = driver;
|
||
return 0;
|
||
}
|
||
__initcall (memcons_tty_init);
|