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remarkable-linux/drivers/watchdog/pnx4008_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

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8.2 KiB
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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 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 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;
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)
{
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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