linux/drivers/watchdog/davinci_wdt.c
Alexey Dobriyan c7dfd0cca3 [WATCHDOG] spin_lock_init() fixes
Some watchdog drivers initialize global spinlocks in module's init function
which is tolerable, but some do it in PCI probe function.  So, switch to
static initialization to fix theoretical bugs and, more importantly, stop
giving people bad examples.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-11-02 19:09:07 +00:00

279 lines
6.5 KiB
C

/*
* drivers/char/watchdog/davinci_wdt.c
*
* Watchdog driver for DaVinci DM644x/DM646x processors
*
* Copyright (C) 2006 Texas Instruments.
*
* 2007 (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.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <asm/hardware.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define MODULE_NAME "DAVINCI-WDT: "
#define DEFAULT_HEARTBEAT 60
#define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/
/* Timer register set definition */
#define PID12 (0x0)
#define EMUMGT (0x4)
#define TIM12 (0x10)
#define TIM34 (0x14)
#define PRD12 (0x18)
#define PRD34 (0x1C)
#define TCR (0x20)
#define TGCR (0x24)
#define WDTCR (0x28)
/* TCR bit definitions */
#define ENAMODE12_DISABLED (0 << 6)
#define ENAMODE12_ONESHOT (1 << 6)
#define ENAMODE12_PERIODIC (2 << 6)
/* TGCR bit definitions */
#define TIM12RS_UNRESET (1 << 0)
#define TIM34RS_UNRESET (1 << 1)
#define TIMMODE_64BIT_WDOG (2 << 2)
/* WDTCR bit definitions */
#define WDEN (1 << 14)
#define WDFLAG (1 << 15)
#define WDKEY_SEQ0 (0xa5c6 << 16)
#define WDKEY_SEQ1 (0xda7e << 16)
static int heartbeat = DEFAULT_HEARTBEAT;
static DEFINE_SPINLOCK(io_lock);
static unsigned long wdt_status;
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
#define WDT_REGION_INITED 2
#define WDT_DEVICE_INITED 3
static struct resource *wdt_mem;
static void __iomem *wdt_base;
static void wdt_service(void)
{
spin_lock(&io_lock);
/* put watchdog in service state */
davinci_writel(WDKEY_SEQ0, wdt_base + WDTCR);
/* put watchdog in active state */
davinci_writel(WDKEY_SEQ1, wdt_base + WDTCR);
spin_unlock(&io_lock);
}
static void wdt_enable(void)
{
u32 tgcr;
u32 timer_margin;
spin_lock(&io_lock);
/* disable, internal clock source */
davinci_writel(0, wdt_base + TCR);
/* reset timer, set mode to 64-bit watchdog, and unreset */
davinci_writel(0, wdt_base + TGCR);
tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
davinci_writel(tgcr, wdt_base + TGCR);
/* clear counter regs */
davinci_writel(0, wdt_base + TIM12);
davinci_writel(0, wdt_base + TIM34);
/* set timeout period */
timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff);
davinci_writel(timer_margin, wdt_base + PRD12);
timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32);
davinci_writel(timer_margin, wdt_base + PRD34);
/* enable run continuously */
davinci_writel(ENAMODE12_PERIODIC, wdt_base + TCR);
/* Once the WDT is in pre-active state write to
* TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
* write protected (except for the WDKEY field)
*/
/* put watchdog in pre-active state */
davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
/* put watchdog in active state */
davinci_writel(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR);
spin_unlock(&io_lock);
}
static int davinci_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
wdt_enable();
return nonseekable_open(inode, file);
}
static ssize_t
davinci_wdt_write(struct file *file, const char *data, size_t len,
loff_t *ppos)
{
if (len)
wdt_service();
return len;
}
static struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING,
.identity = "DaVinci Watchdog",
};
static int
davinci_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_service();
ret = 0;
break;
}
return ret;
}
static int davinci_wdt_release(struct inode *inode, struct file *file)
{
wdt_service();
clear_bit(WDT_IN_USE, &wdt_status);
return 0;
}
static const struct file_operations davinci_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = davinci_wdt_write,
.ioctl = davinci_wdt_ioctl,
.open = davinci_wdt_open,
.release = davinci_wdt_release,
};
static struct miscdevice davinci_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &davinci_wdt_fops,
};
static int davinci_wdt_probe(struct platform_device *pdev)
{
int ret = 0, size;
struct resource *res;
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
printk(KERN_INFO MODULE_NAME
"DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
printk(KERN_INFO MODULE_NAME
"failed to get memory region resource\n");
return -ENOENT;
}
size = res->end - res->start + 1;
wdt_mem = request_mem_region(res->start, size, pdev->name);
if (wdt_mem == NULL) {
printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
return -ENOENT;
}
wdt_base = (void __iomem *)(res->start);
ret = misc_register(&davinci_wdt_miscdev);
if (ret < 0) {
printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
release_resource(wdt_mem);
kfree(wdt_mem);
} else {
set_bit(WDT_DEVICE_INITED, &wdt_status);
}
return ret;
}
static int davinci_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&davinci_wdt_miscdev);
if (wdt_mem) {
release_resource(wdt_mem);
kfree(wdt_mem);
wdt_mem = NULL;
}
return 0;
}
static struct platform_driver platform_wdt_driver = {
.driver = {
.name = "watchdog",
},
.probe = davinci_wdt_probe,
.remove = davinci_wdt_remove,
};
static int __init davinci_wdt_init(void)
{
return platform_driver_register(&platform_wdt_driver);
}
static void __exit davinci_wdt_exit(void)
{
platform_driver_unregister(&platform_wdt_driver);
}
module_init(davinci_wdt_init);
module_exit(davinci_wdt_exit);
MODULE_AUTHOR("Texas Instruments");
MODULE_DESCRIPTION("DaVinci Watchdog Driver");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);