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#include <linux/init.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/of_platform.h>
#include <asm/uaccess.h>
#include <asm/mpc52xx.h>
#define GPT_MODE_WDT (1<<15)
#define GPT_MODE_CE (1<<12)
#define GPT_MODE_MS_TIMER (0x4)
struct mpc5200_wdt {
unsigned count; /* timer ticks before watchdog kicks in */
long ipb_freq;
struct miscdevice miscdev;
struct resource mem;
struct mpc52xx_gpt __iomem *regs;
spinlock_t io_lock;
};
/* is_active stores wether or not the /dev/watchdog device is opened */
static unsigned long is_active;
/* misc devices don't provide a way, to get back to 'dev' or 'miscdev' from
* file operations, which sucks. But there can be max 1 watchdog anyway, so...
*/
static struct mpc5200_wdt *wdt_global;
/* helper to calculate timeout in timer counts */
static void mpc5200_wdt_set_timeout(struct mpc5200_wdt *wdt, int timeout)
{
/* use biggest prescaler of 64k */
wdt->count = (wdt->ipb_freq + 0xffff) / 0x10000 * timeout;
if (wdt->count > 0xffff)
wdt->count = 0xffff;
}
/* return timeout in seconds (calculated from timer count) */
static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt)
{
return wdt->count * 0x10000 / wdt->ipb_freq;
}
/* watchdog operations */
static int mpc5200_wdt_start(struct mpc5200_wdt *wdt)
{
spin_lock(&wdt->io_lock);
/* disable */
out_be32(&wdt->regs->mode, 0);
/* set timeout, with maximum prescaler */
out_be32(&wdt->regs->count, 0x0 | wdt->count);
/* enable watchdog */
out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT | GPT_MODE_MS_TIMER);
spin_unlock(&wdt->io_lock);
return 0;
}
static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt)
{
spin_lock(&wdt->io_lock);
/* writing A5 to OCPW resets the watchdog */
out_be32(&wdt->regs->mode, 0xA5000000 | (0xffffff & in_be32(&wdt->regs->mode)));
spin_unlock(&wdt->io_lock);
return 0;
}
static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt)
{
spin_lock(&wdt->io_lock);
/* disable */
out_be32(&wdt->regs->mode, 0);
spin_unlock(&wdt->io_lock);
return 0;
}
/* file operations */
static ssize_t mpc5200_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
struct mpc5200_wdt *wdt = file->private_data;
mpc5200_wdt_ping(wdt);
return 0;
}
static struct watchdog_info mpc5200_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "mpc5200 watchdog on GPT0",
};
static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct mpc5200_wdt *wdt = file->private_data;
int __user *data = (int __user *)arg;
int timeout;
int ret = 0;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user(data, &mpc5200_wdt_info,
sizeof(mpc5200_wdt_info));
if (ret)
ret = -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, data);
break;
case WDIOC_KEEPALIVE:
mpc5200_wdt_ping(wdt);
break;
case WDIOC_SETTIMEOUT:
ret = get_user(timeout, data);
if (ret)
break;
mpc5200_wdt_set_timeout(wdt, timeout);
mpc5200_wdt_start(wdt);
/* fall through and return the timeout */
case WDIOC_GETTIMEOUT:
timeout = mpc5200_wdt_get_timeout(wdt);
ret = put_user(timeout, data);
break;
default:
ret = -ENOTTY;
}
return ret;
}
static int mpc5200_wdt_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &is_active))
return -EBUSY;
/* Set and activate the watchdog */
mpc5200_wdt_set_timeout(wdt_global, 30);
mpc5200_wdt_start(wdt_global);
file->private_data = wdt_global;
return nonseekable_open(inode, file);
}
static int mpc5200_wdt_release(struct inode *inode, struct file *file)
{
#if WATCHDOG_NOWAYOUT == 0
struct mpc5200_wdt *wdt = file->private_data;
mpc5200_wdt_stop(wdt);
wdt->count = 0; /* == disabled */
#endif
clear_bit(0, &is_active);
return 0;
}
static const struct file_operations mpc5200_wdt_fops = {
.owner = THIS_MODULE,
.write = mpc5200_wdt_write,
.ioctl = mpc5200_wdt_ioctl,
.open = mpc5200_wdt_open,
.release = mpc5200_wdt_release,
};
/* module operations */
static int mpc5200_wdt_probe(struct of_device *op, const struct of_device_id *match)
{
struct mpc5200_wdt *wdt;
int err;
const void *has_wdt;
int size;
has_wdt = of_get_property(op->node, "has-wdt", NULL);
if (!has_wdt)
has_wdt = of_get_property(op->node, "fsl,has-wdt", NULL);
if (!has_wdt)
return -ENODEV;
wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->ipb_freq = mpc52xx_find_ipb_freq(op->node);
err = of_address_to_resource(op->node, 0, &wdt->mem);
if (err)
goto out_free;
size = wdt->mem.end - wdt->mem.start + 1;
if (!request_mem_region(wdt->mem.start, size, "mpc5200_wdt")) {
err = -ENODEV;
goto out_free;
}
wdt->regs = ioremap(wdt->mem.start, size);
if (!wdt->regs) {
err = -ENODEV;
goto out_release;
}
dev_set_drvdata(&op->dev, wdt);
spin_lock_init(&wdt->io_lock);
wdt->miscdev = (struct miscdevice) {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &mpc5200_wdt_fops,
.parent = &op->dev,
};
wdt_global = wdt;
err = misc_register(&wdt->miscdev);
if (!err)
return 0;
iounmap(wdt->regs);
out_release:
release_mem_region(wdt->mem.start, size);
out_free:
kfree(wdt);
return err;
}
static int mpc5200_wdt_remove(struct of_device *op)
{
struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
mpc5200_wdt_stop(wdt);
misc_deregister(&wdt->miscdev);
iounmap(wdt->regs);
release_mem_region(wdt->mem.start, wdt->mem.end - wdt->mem.start + 1);
kfree(wdt);
return 0;
}
static int mpc5200_wdt_suspend(struct of_device *op, pm_message_t state)
{
struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
mpc5200_wdt_stop(wdt);
return 0;
}
static int mpc5200_wdt_resume(struct of_device *op)
{
struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
if (wdt->count)
mpc5200_wdt_start(wdt);
return 0;
}
static int mpc5200_wdt_shutdown(struct of_device *op)
{
struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
mpc5200_wdt_stop(wdt);
return 0;
}
static struct of_device_id mpc5200_wdt_match[] = {
{ .compatible = "mpc5200-gpt", },
{ .compatible = "fsl,mpc5200-gpt", },
{},
};
static struct of_platform_driver mpc5200_wdt_driver = {
.owner = THIS_MODULE,
.name = "mpc5200-gpt-wdt",
.match_table = mpc5200_wdt_match,
.probe = mpc5200_wdt_probe,
.remove = mpc5200_wdt_remove,
.suspend = mpc5200_wdt_suspend,
.resume = mpc5200_wdt_resume,
.shutdown = mpc5200_wdt_shutdown,
};
static int __init mpc5200_wdt_init(void)
{
return of_register_platform_driver(&mpc5200_wdt_driver);
}
static void __exit mpc5200_wdt_exit(void)
{
of_unregister_platform_driver(&mpc5200_wdt_driver);
}
module_init(mpc5200_wdt_init);
module_exit(mpc5200_wdt_exit);
MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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