linux/arch/xtensa/platforms/iss/console.c
Marc Gauthier c865415838 [XTENSA] Prevent inlining ISS platform asm constructs
The simcall asm macro assumes Windowed ABI parameter passing
in registers, and doesn't work if its containing function gets
inlined.  This fix prevents that from happening.

Signed-off-by: Marc Gauthier <marc@tensilica.com>
2008-02-13 17:04:56 -08:00

297 lines
6.8 KiB
C

/*
* arch/xtensa/platform-iss/console.c
*
* 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.
*
* Copyright (C) 2001-2005 Tensilica Inc.
* Authors Christian Zankel, Joe Taylor
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/param.h>
#include <linux/serial.h>
#include <linux/serialP.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/platform/simcall.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#ifdef SERIAL_INLINE
#define _INLINE_ inline
#endif
#define SERIAL_MAX_NUM_LINES 1
#define SERIAL_TIMER_VALUE (20 * HZ)
static struct tty_driver *serial_driver;
static struct timer_list serial_timer;
static DEFINE_SPINLOCK(timer_lock);
int errno;
static int __simc (int a, int b, int c, int d, int e, int f) __attribute__((__noinline__));
static int __simc (int a, int b, int c, int d, int e, int f)
{
int ret;
__asm__ __volatile__ ("simcall\n"
"mov %0, a2\n"
"mov %1, a3\n" : "=a" (ret), "=a" (errno)
: : "a2", "a3");
return ret;
}
static char *serial_version = "0.1";
static char *serial_name = "ISS serial driver";
/*
* This routine is called whenever a serial port is opened. It
* enables interrupts for a serial port, linking in its async structure into
* the IRQ chain. It also performs the serial-specific
* initialization for the tty structure.
*/
static void rs_poll(unsigned long);
static int rs_open(struct tty_struct *tty, struct file * filp)
{
int line = tty->index;
if ((line < 0) || (line >= SERIAL_MAX_NUM_LINES))
return -ENODEV;
spin_lock(&timer_lock);
if (tty->count == 1) {
init_timer(&serial_timer);
serial_timer.data = (unsigned long) tty;
serial_timer.function = rs_poll;
mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
}
spin_unlock(&timer_lock);
return 0;
}
/*
* ------------------------------------------------------------
* iss_serial_close()
*
* This routine is called when the serial port gets closed. First, we
* wait for the last remaining data to be sent. Then, we unlink its
* async structure from the interrupt chain if necessary, and we free
* that IRQ if nothing is left in the chain.
* ------------------------------------------------------------
*/
static void rs_close(struct tty_struct *tty, struct file * filp)
{
spin_lock(&timer_lock);
if (tty->count == 1)
del_timer_sync(&serial_timer);
spin_unlock(&timer_lock);
}
static int rs_write(struct tty_struct * tty,
const unsigned char *buf, int count)
{
/* see drivers/char/serialX.c to reference original version */
__simc (SYS_write, 1, (unsigned long)buf, count, 0, 0);
return count;
}
static void rs_poll(unsigned long priv)
{
struct tty_struct* tty = (struct tty_struct*) priv;
struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
int i = 0;
unsigned char c;
spin_lock(&timer_lock);
while (__simc(SYS_select_one, 0, XTISS_SELECT_ONE_READ, (int)&tv,0,0)){
__simc (SYS_read, 0, (unsigned long)&c, 1, 0, 0);
tty_insert_flip_char(tty, c, TTY_NORMAL);
i++;
}
if (i)
tty_flip_buffer_push(tty);
mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
spin_unlock(&timer_lock);
}
static void rs_put_char(struct tty_struct *tty, unsigned char ch)
{
char buf[2];
if (!tty)
return;
buf[0] = ch;
buf[1] = '\0'; /* Is this NULL necessary? */
__simc (SYS_write, 1, (unsigned long) buf, 1, 0, 0);
}
static void rs_flush_chars(struct tty_struct *tty)
{
}
static int rs_write_room(struct tty_struct *tty)
{
/* Let's say iss can always accept 2K characters.. */
return 2 * 1024;
}
static int rs_chars_in_buffer(struct tty_struct *tty)
{
/* the iss doesn't buffer characters */
return 0;
}
static void rs_hangup(struct tty_struct *tty)
{
/* Stub, once again.. */
}
static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
{
/* Stub, once again.. */
}
static int rs_read_proc(char *page, char **start, off_t off, int count,
int *eof, void *data)
{
int len = 0;
off_t begin = 0;
len += sprintf(page, "serinfo:1.0 driver:%s\n", serial_version);
*eof = 1;
if (off >= len + begin)
return 0;
*start = page + (off - begin);
return ((count < begin + len - off) ? count : begin + len - off);
}
static struct tty_operations serial_ops = {
.open = rs_open,
.close = rs_close,
.write = rs_write,
.put_char = rs_put_char,
.flush_chars = rs_flush_chars,
.write_room = rs_write_room,
.chars_in_buffer = rs_chars_in_buffer,
.hangup = rs_hangup,
.wait_until_sent = rs_wait_until_sent,
.read_proc = rs_read_proc
};
int __init rs_init(void)
{
serial_driver = alloc_tty_driver(1);
printk ("%s %s\n", serial_name, serial_version);
/* Initialize the tty_driver structure */
serial_driver->owner = THIS_MODULE;
serial_driver->driver_name = "iss_serial";
serial_driver->name = "ttyS";
serial_driver->major = TTY_MAJOR;
serial_driver->minor_start = 64;
serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
serial_driver->subtype = SERIAL_TYPE_NORMAL;
serial_driver->init_termios = tty_std_termios;
serial_driver->init_termios.c_cflag =
B9600 | CS8 | CREAD | HUPCL | CLOCAL;
serial_driver->flags = TTY_DRIVER_REAL_RAW;
tty_set_operations(serial_driver, &serial_ops);
if (tty_register_driver(serial_driver))
panic("Couldn't register serial driver\n");
return 0;
}
static __exit void rs_exit(void)
{
int error;
if ((error = tty_unregister_driver(serial_driver)))
printk("ISS_SERIAL: failed to unregister serial driver (%d)\n",
error);
put_tty_driver(serial_driver);
}
/* We use `late_initcall' instead of just `__initcall' as a workaround for
* the fact that (1) simcons_tty_init can't be called before tty_init,
* (2) tty_init is called via `module_init', (3) if statically linked,
* module_init == device_init, and (4) there's no ordering of init lists.
* We can do this easily because simcons is always statically linked, but
* other tty drivers that depend on tty_init and which must use
* `module_init' to declare their init routines are likely to be broken.
*/
late_initcall(rs_init);
#ifdef CONFIG_SERIAL_CONSOLE
static void iss_console_write(struct console *co, const char *s, unsigned count)
{
int len = strlen(s);
if (s != 0 && *s != 0)
__simc (SYS_write, 1, (unsigned long)s,
count < len ? count : len,0,0);
}
static struct tty_driver* iss_console_device(struct console *c, int *index)
{
*index = c->index;
return serial_driver;
}
static struct console sercons = {
.name = "ttyS",
.write = iss_console_write,
.device = iss_console_device,
.flags = CON_PRINTBUFFER,
.index = -1
};
static int __init iss_console_init(void)
{
register_console(&sercons);
return 0;
}
console_initcall(iss_console_init);
#endif /* CONFIG_SERIAL_CONSOLE */