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linux/drivers/watchdog/ath79_wdt.c
Gabor Juhos 86955e2bcb watchdog: ath79_wdt: flush register writes 
The watchdog register writes required to have a flush
in order to commit the values to the register. Without
the flush, the driver not function correctly on AR934X
SoCs.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Acked-by: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-01-06 15:27:51 +01:00

312 lines
6.8 KiB
C
Raw Blame History

/*
* Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
*
* Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
*
* This driver was based on: drivers/watchdog/ixp4xx_wdt.c
* Author: Deepak Saxena <dsaxena@plexity.net>
* Copyright 2004 (c) MontaVista, Software, Inc.
*
* which again was based on sa1100 driver,
* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
*/
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <asm/mach-ath79/ath79.h>
#include <asm/mach-ath79/ar71xx_regs.h>
#define DRIVER_NAME "ath79-wdt"
#define WDT_TIMEOUT 15 /* seconds */
#define WDOG_CTRL_LAST_RESET BIT(31)
#define WDOG_CTRL_ACTION_MASK 3
#define WDOG_CTRL_ACTION_NONE 0 /* no action */
#define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */
#define WDOG_CTRL_ACTION_NMI 2 /* NMI */
#define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static int timeout = WDT_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
"(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
static unsigned long wdt_flags;
#define WDT_FLAGS_BUSY 0
#define WDT_FLAGS_EXPECT_CLOSE 1
static struct clk *wdt_clk;
static unsigned long wdt_freq;
static int boot_status;
static int max_timeout;
static inline void ath79_wdt_keepalive(void)
{
ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout);
/* flush write */
ath79_reset_rr(AR71XX_RESET_REG_WDOG);
}
static inline void ath79_wdt_enable(void)
{
ath79_wdt_keepalive();
ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
/* flush write */
ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
}
static inline void ath79_wdt_disable(void)
{
ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
/* flush write */
ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
}
static int ath79_wdt_set_timeout(int val)
{
if (val < 1 || val > max_timeout)
return -EINVAL;
timeout = val;
ath79_wdt_keepalive();
return 0;
}
static int ath79_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
return -EBUSY;
clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
ath79_wdt_enable();
return nonseekable_open(inode, file);
}
static int ath79_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
ath79_wdt_disable();
else {
pr_crit(DRIVER_NAME ": device closed unexpectedly, "
"watchdog timer will not stop!\n");
ath79_wdt_keepalive();
}
clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
return 0;
}
static ssize_t ath79_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_FLAGS_EXPECT_CLOSE,
&wdt_flags);
}
}
ath79_wdt_keepalive();
}
return len;
}
static const struct watchdog_info ath79_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
.firmware_version = 0,
.identity = "ATH79 watchdog",
};
static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int err;
int t;
switch (cmd) {
case WDIOC_GETSUPPORT:
err = copy_to_user(argp, &ath79_wdt_info,
sizeof(ath79_wdt_info)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
err = put_user(0, p);
break;
case WDIOC_GETBOOTSTATUS:
err = put_user(boot_status, p);
break;
case WDIOC_KEEPALIVE:
ath79_wdt_keepalive();
err = 0;
break;
case WDIOC_SETTIMEOUT:
err = get_user(t, p);
if (err)
break;
err = ath79_wdt_set_timeout(t);
if (err)
break;
/* fallthrough */
case WDIOC_GETTIMEOUT:
err = put_user(timeout, p);
break;
default:
err = -ENOTTY;
break;
}
return err;
}
static const struct file_operations ath79_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = ath79_wdt_write,
.unlocked_ioctl = ath79_wdt_ioctl,
.open = ath79_wdt_open,
.release = ath79_wdt_release,
};
static struct miscdevice ath79_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ath79_wdt_fops,
};
static int __devinit ath79_wdt_probe(struct platform_device *pdev)
{
u32 ctrl;
int err;
wdt_clk = clk_get(&pdev->dev, "wdt");
if (IS_ERR(wdt_clk))
return PTR_ERR(wdt_clk);
err = clk_enable(wdt_clk);
if (err)
goto err_clk_put;
wdt_freq = clk_get_rate(wdt_clk);
if (!wdt_freq) {
err = -EINVAL;
goto err_clk_disable;
}
max_timeout = (0xfffffffful / wdt_freq);
if (timeout < 1 || timeout > max_timeout) {
timeout = max_timeout;
dev_info(&pdev->dev,
"timeout value must be 0 < timeout < %d, using %d\n",
max_timeout, timeout);
}
ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
err = misc_register(&ath79_wdt_miscdev);
if (err) {
dev_err(&pdev->dev,
"unable to register misc device, err=%d\n", err);
goto err_clk_disable;
}
return 0;
err_clk_disable:
clk_disable(wdt_clk);
err_clk_put:
clk_put(wdt_clk);
return err;
}
static int __devexit ath79_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&ath79_wdt_miscdev);
clk_disable(wdt_clk);
clk_put(wdt_clk);
return 0;
}
static void ath97_wdt_shutdown(struct platform_device *pdev)
{
ath79_wdt_disable();
}
static struct platform_driver ath79_wdt_driver = {
.remove = __devexit_p(ath79_wdt_remove),
.shutdown = ath97_wdt_shutdown,
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
},
};
static int __init ath79_wdt_init(void)
{
return platform_driver_probe(&ath79_wdt_driver, ath79_wdt_probe);
}
module_init(ath79_wdt_init);
static void __exit ath79_wdt_exit(void)
{
platform_driver_unregister(&ath79_wdt_driver);
}
module_exit(ath79_wdt_exit);
MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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