/*
* 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 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 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;
spin_lock_init(&io_lock);
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);
