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linux/drivers/char/watchdog/pnx4008_wdt.c

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/*
* drivers/char/watchdog/pnx4008_wdt.c
*
* Watchdog driver for PNX4008 board
*
* Authors: Dmitry Chigirev <source@mvista.com>,
* Vitaly Wool <vitalywool@gmail.com>
* Based on sa1100 driver,
* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* 2005-2006 (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/ioport.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/spinlock.h>
#include <asm/hardware.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define MODULE_NAME "PNX4008-WDT: "
/* WatchDog Timer - Chapter 23 Page 207 */
#define DEFAULT_HEARTBEAT 19
#define MAX_HEARTBEAT 60
/* Watchdog timer register set definition */
#define WDTIM_INT(p) ((p) + 0x0)
#define WDTIM_CTRL(p) ((p) + 0x4)
#define WDTIM_COUNTER(p) ((p) + 0x8)
#define WDTIM_MCTRL(p) ((p) + 0xC)
#define WDTIM_MATCH0(p) ((p) + 0x10)
#define WDTIM_EMR(p) ((p) + 0x14)
#define WDTIM_PULSE(p) ((p) + 0x18)
#define WDTIM_RES(p) ((p) + 0x1C)
/* WDTIM_INT bit definitions */
#define MATCH_INT 1
/* WDTIM_CTRL bit definitions */
#define COUNT_ENAB 1
#define RESET_COUNT (1<<1)
#define DEBUG_EN (1<<2)
/* WDTIM_MCTRL bit definitions */
#define MR0_INT 1
#undef RESET_COUNT0
#define RESET_COUNT0 (1<<2)
#define STOP_COUNT0 (1<<2)
#define M_RES1 (1<<3)
#define M_RES2 (1<<4)
#define RESFRC1 (1<<5)
#define RESFRC2 (1<<6)
/* WDTIM_EMR bit definitions */
#define EXT_MATCH0 1
#define MATCH_OUTPUT_HIGH (2<<4) /*a MATCH_CTRL setting */
/* WDTIM_RES bit definitions */
#define WDOG_RESET 1 /* read only */
#define WDOG_COUNTER_RATE 13000000 /*the counter clock is 13 MHz fixed */
static int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = DEFAULT_HEARTBEAT;
static spinlock_t 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 unsigned long boot_status;
static struct resource *wdt_mem;
static void __iomem *wdt_base;
struct clk *wdt_clk;
static void wdt_enable(void)
{
spin_lock(&io_lock);
if (wdt_clk)
clk_set_rate(wdt_clk, 1);
/* stop counter, initiate counter reset */
__raw_writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
/*wait for reset to complete. 100% guarantee event */
while (__raw_readl(WDTIM_COUNTER(wdt_base)))
cpu_relax();
/* internal and external reset, stop after that */
__raw_writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0,
WDTIM_MCTRL(wdt_base));
/* configure match output */
__raw_writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
/* clear interrupt, just in case */
__raw_writel(MATCH_INT, WDTIM_INT(wdt_base));
/* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
__raw_writel(0xFFFF, WDTIM_PULSE(wdt_base));
__raw_writel(heartbeat * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
/*enable counter, stop when debugger active */
__raw_writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
spin_unlock(&io_lock);
}
static void wdt_disable(void)
{
spin_lock(&io_lock);
__raw_writel(0, WDTIM_CTRL(wdt_base)); /*stop counter */
if (wdt_clk)
clk_set_rate(wdt_clk, 0);
spin_unlock(&io_lock);
}
static int pnx4008_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
wdt_enable();
return nonseekable_open(inode, file);
}
static ssize_t
pnx4008_wdt_write(struct file *file, const char *data, size_t len,
loff_t * ppos)
{
if (len) {
if (!nowayout) {
size_t i;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
}
}
wdt_enable();
}
return len;
}
static struct watchdog_info ident = {
.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "PNX4008 Watchdog",
};
static int
pnx4008_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, (int *)arg);
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > MAX_HEARTBEAT) {
ret = -EINVAL;
break;
}
heartbeat = time;
wdt_enable();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
}
return ret;
}
static int pnx4008_wdt_release(struct inode *inode, struct file *file)
{
if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status))
printk(KERN_WARNING "WATCHDOG: Device closed unexpectdly\n");
wdt_disable();
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations pnx4008_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = pnx4008_wdt_write,
.ioctl = pnx4008_wdt_ioctl,
.open = pnx4008_wdt_open,
.release = pnx4008_wdt_release,
};
static struct miscdevice pnx4008_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &pnx4008_wdt_fops,
};
static int pnx4008_wdt_probe(struct platform_device *pdev)
{
int ret = 0, size;
struct resource *res;
spin_lock_init(&io_lock);
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
printk(KERN_INFO MODULE_NAME
"PNX4008 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 resouce\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 *)IO_ADDRESS(res->start);
wdt_clk = clk_get(&pdev->dev, "wdt_ck");
if (IS_ERR(wdt_clk)) {
ret = PTR_ERR(wdt_clk);
release_resource(wdt_mem);
kfree(wdt_mem);
goto out;
} else
clk_set_rate(wdt_clk, 1);
ret = misc_register(&pnx4008_wdt_miscdev);
if (ret < 0) {
printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
release_resource(wdt_mem);
kfree(wdt_mem);
clk_set_rate(wdt_clk, 0);
} else {
boot_status = (__raw_readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
WDIOF_CARDRESET : 0;
wdt_disable(); /*disable for now */
set_bit(WDT_DEVICE_INITED, &wdt_status);
}
out:
return ret;
}
static int pnx4008_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&pnx4008_wdt_miscdev);
if (wdt_clk) {
clk_set_rate(wdt_clk, 0);
clk_put(wdt_clk);
wdt_clk = NULL;
}
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 = pnx4008_wdt_probe,
.remove = pnx4008_wdt_remove,
};
static int __init pnx4008_wdt_init(void)
{
return platform_driver_register(&platform_wdt_driver);
}
static void __exit pnx4008_wdt_exit(void)
{
return platform_driver_unregister(&platform_wdt_driver);
}
module_init(pnx4008_wdt_init);
module_exit(pnx4008_wdt_exit);
MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
MODULE_DESCRIPTION("PNX4008 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_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
"Set to 1 to keep watchdog running after device release");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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