/*
* linux/drivers/char/watchdog/omap_wdt.c
*
* Watchdog driver for the TI OMAP 16xx & 24xx 32KHz (non-secure) watchdog
*
* Author: MontaVista Software, Inc.
* <gdavis@mvista.com> or <source@mvista.com>
*
* 2003 (c) MontaVista Software, Inc. This file is licensed under the
* terms of the GNU General Public License version 2. This program is
* licensed "as is" without any warranty of any kind, whether express
* or implied.
*
* History:
*
* 20030527: George G. Davis <gdavis@mvista.com>
* Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
* Based on SoftDog driver by Alan Cox <alan@redhat.com>
*
* Copyright (c) 2004 Texas Instruments.
* 1. Modified to support OMAP1610 32-KHz watchdog timer
* 2. Ported to 2.6 kernel
*
* Copyright (c) 2005 David Brownell
* Use the driver model and standard identifiers; handle bigger timeouts.
*/
#include <linux/module.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/moduleparam.h>
#include <linux/clk.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/hardware.h>
#include <asm/bitops.h>
#include <asm/arch/prcm.h>
#include "omap_wdt.h"
static unsigned timer_margin;
module_param(timer_margin, uint, 0);
MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
static int omap_wdt_users;
static struct clk *armwdt_ck = NULL;
static struct clk *mpu_wdt_ick = NULL;
static struct clk *mpu_wdt_fck = NULL;
static unsigned int wdt_trgr_pattern = 0x1234;
static void omap_wdt_ping(void)
{
/* wait for posted write to complete */
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
cpu_relax();
wdt_trgr_pattern = ~wdt_trgr_pattern;
omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
/* wait for posted write to complete */
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
cpu_relax();
/* reloaded WCRR from WLDR */
}
static void omap_wdt_enable(void)
{
/* Sequence to enable the watchdog */
omap_writel(0xBBBB, OMAP_WATCHDOG_SPR);
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
cpu_relax();
omap_writel(0x4444, OMAP_WATCHDOG_SPR);
while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
cpu_relax();
}
static void omap_wdt_disable(void)
{
/* sequence required to disable watchdog */
omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
cpu_relax();
omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
cpu_relax();
}
static void omap_wdt_adjust_timeout(unsigned new_timeout)
{
if (new_timeout < TIMER_MARGIN_MIN)
new_timeout = TIMER_MARGIN_DEFAULT;
if (new_timeout > TIMER_MARGIN_MAX)
new_timeout = TIMER_MARGIN_MAX;
timer_margin = new_timeout;
}
static void omap_wdt_set_timeout(void)
{
u32 pre_margin = GET_WLDR_VAL(timer_margin);
/* just count up at 32 KHz */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
cpu_relax();
omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
cpu_relax();
}
/*
* Allow only one task to hold it open
*/
static int omap_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
return -EBUSY;
if (cpu_is_omap16xx())
clk_enable(armwdt_ck); /* Enable the clock */
if (cpu_is_omap24xx()) {
clk_enable(mpu_wdt_ick); /* Enable the interface clock */
clk_enable(mpu_wdt_fck); /* Enable the functional clock */
}
/* initialize prescaler */
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
cpu_relax();
omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
cpu_relax();
omap_wdt_set_timeout();
omap_wdt_enable();
return 0;
}
static int omap_wdt_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer unless NOWAYOUT is defined.
*/
#ifndef CONFIG_WATCHDOG_NOWAYOUT
omap_wdt_disable();
if (cpu_is_omap16xx()) {
clk_disable(armwdt_ck); /* Disable the clock */
clk_put(armwdt_ck);
armwdt_ck = NULL;
}
if (cpu_is_omap24xx()) {
clk_disable(mpu_wdt_ick); /* Disable the clock */
clk_disable(mpu_wdt_fck); /* Disable the clock */
clk_put(mpu_wdt_ick);
clk_put(mpu_wdt_fck);
mpu_wdt_ick = NULL;
mpu_wdt_fck = NULL;
}
#else
printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
#endif
omap_wdt_users = 0;
return 0;
}
static ssize_t
omap_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* Refresh LOAD_TIME. */
if (len)
omap_wdt_ping();
return len;
}
static int
omap_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int new_margin;
static struct watchdog_info ident = {
.identity = "OMAP Watchdog",
.options = WDIOF_SETTIMEOUT,
.firmware_version = 0,
};
switch (cmd) {
default:
return -ENOIOCTLCMD;
case WDIOC_GETSUPPORT:
return copy_to_user((struct watchdog_info __user *)arg, &ident,
sizeof(ident));
case WDIOC_GETSTATUS:
return put_user(0, (int __user *)arg);
case WDIOC_GETBOOTSTATUS:
if (cpu_is_omap16xx())
return put_user(omap_readw(ARM_SYSST),
(int __user *)arg);
if (cpu_is_omap24xx())
return put_user(omap_prcm_get_reset_sources(),
(int __user *)arg);
case WDIOC_KEEPALIVE:
omap_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, (int __user *)arg))
return -EFAULT;
omap_wdt_adjust_timeout(new_margin);
omap_wdt_disable();
omap_wdt_set_timeout();
omap_wdt_enable();
omap_wdt_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timer_margin, (int __user *)arg);
}
}
static struct file_operations omap_wdt_fops = {
.owner = THIS_MODULE,
.write = omap_wdt_write,
.ioctl = omap_wdt_ioctl,
.open = omap_wdt_open,
.release = omap_wdt_release,
};
static struct miscdevice omap_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &omap_wdt_fops
};
static int __init omap_wdt_probe(struct platform_device *pdev)
{
struct resource *res, *mem;
int ret;
/* reserve static register mappings */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENOENT;
mem = request_mem_region(res->start, res->end - res->start + 1,
pdev->name);
if (mem == NULL)
return -EBUSY;
platform_set_drvdata(pdev, mem);
omap_wdt_users = 0;
if (cpu_is_omap16xx()) {
armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
if (IS_ERR(armwdt_ck)) {
ret = PTR_ERR(armwdt_ck);
armwdt_ck = NULL;
goto fail;
}
}
if (cpu_is_omap24xx()) {
mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
if (IS_ERR(mpu_wdt_ick)) {
ret = PTR_ERR(mpu_wdt_ick);
mpu_wdt_ick = NULL;
goto fail;
}
mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
if (IS_ERR(mpu_wdt_fck)) {
ret = PTR_ERR(mpu_wdt_fck);
mpu_wdt_fck = NULL;
goto fail;
}
}
omap_wdt_disable();
omap_wdt_adjust_timeout(timer_margin);
omap_wdt_miscdev.dev = &pdev->dev;
ret = misc_register(&omap_wdt_miscdev);
if (ret)
goto fail;
pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);
/* autogate OCP interface clock */
omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
return 0;
fail:
if (armwdt_ck)
clk_put(armwdt_ck);
if (mpu_wdt_ick)
clk_put(mpu_wdt_ick);
if (mpu_wdt_fck)
clk_put(mpu_wdt_fck);
release_resource(mem);
return ret;
}
static void omap_wdt_shutdown(struct platform_device *pdev)
{
omap_wdt_disable();
}
static int omap_wdt_remove(struct platform_device *pdev)
{
struct resource *mem = platform_get_drvdata(pdev);
misc_deregister(&omap_wdt_miscdev);
release_resource(mem);
if (armwdt_ck)
clk_put(armwdt_ck);
if (mpu_wdt_ick)
clk_put(mpu_wdt_ick);
if (mpu_wdt_fck)
clk_put(mpu_wdt_fck);
return 0;
}
#ifdef CONFIG_PM
/* REVISIT ... not clear this is the best way to handle system suspend; and
* it's very inappropriate for selective device suspend (e.g. suspending this
* through sysfs rather than by stopping the watchdog daemon). Also, this
* may not play well enough with NOWAYOUT...
*/
static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
{
if (omap_wdt_users)
omap_wdt_disable();
return 0;
}
static int omap_wdt_resume(struct platform_device *pdev)
{
if (omap_wdt_users) {
omap_wdt_enable();
omap_wdt_ping();
}
return 0;
}
#else
#define omap_wdt_suspend NULL
#define omap_wdt_resume NULL
#endif
static struct platform_driver omap_wdt_driver = {
.probe = omap_wdt_probe,
.remove = omap_wdt_remove,
.shutdown = omap_wdt_shutdown,
.suspend = omap_wdt_suspend,
.resume = omap_wdt_resume,
.driver = {
.owner = THIS_MODULE,
.name = "omap_wdt",
},
};
static int __init omap_wdt_init(void)
{
return platform_driver_register(&omap_wdt_driver);
}
static void __exit omap_wdt_exit(void)
{
platform_driver_unregister(&omap_wdt_driver);
}
module_init(omap_wdt_init);
module_exit(omap_wdt_exit);
MODULE_AUTHOR("George G. Davis");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
