/*
* mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
*
* Author: James Chapman <jchapman@katalix.com>
*
* Platform-specific setup code should configure the dog to generate
* interrupt or reset as required. This code only enables/disables
* and services the watchdog.
*
* Derived from mpc8xx_wdt.c, with the following copyright.
*
* 2002 (c) Florian Schirmer <jolt@tuxbox.org> 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/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/mv643xx.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define MV64x60_WDT_WDC_OFFSET 0
/* MV64x60 WDC (config) register access definitions */
#define MV64x60_WDC_CTL1_MASK (3 << 24)
#define MV64x60_WDC_CTL1(val) ((val & 3) << 24)
#define MV64x60_WDC_CTL2_MASK (3 << 26)
#define MV64x60_WDC_CTL2(val) ((val & 3) << 26)
/* Flags bits */
#define MV64x60_WDOG_FLAG_OPENED 0
#define MV64x60_WDOG_FLAG_ENABLED 1
static unsigned long wdt_flags;
static int wdt_status;
static void __iomem *mv64x60_wdt_regs;
static int mv64x60_wdt_timeout;
static unsigned int bus_clk;
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static void mv64x60_wdt_reg_write(u32 val)
{
/* Allow write only to CTL1 / CTL2 fields, retaining values in
* other fields.
*/
u32 data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);
data |= val;
writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
}
static void mv64x60_wdt_service(void)
{
/* Write 01 followed by 10 to CTL2 */
mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01));
mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02));
}
static void mv64x60_wdt_handler_disable(void)
{
if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
/* Write 01 followed by 10 to CTL1 */
mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
}
}
static void mv64x60_wdt_handler_enable(void)
{
if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
/* Write 01 followed by 10 to CTL1 */
mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
}
}
static void mv64x60_wdt_set_timeout(int timeout)
{
/* maximum bus cycle count is 0xFFFFFFFF */
if (timeout > 0xFFFFFFFF / bus_clk)
timeout = 0xFFFFFFFF / bus_clk;
mv64x60_wdt_timeout = timeout;
writel((timeout * bus_clk) >> 8,
mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
mv64x60_wdt_service();
}
static int mv64x60_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
mv64x60_wdt_service();
mv64x60_wdt_handler_enable();
return nonseekable_open(inode, file);
}
static int mv64x60_wdt_release(struct inode *inode, struct file *file)
{
mv64x60_wdt_service();
if (!nowayout)
mv64x60_wdt_handler_disable();
clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
return 0;
}
static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t * ppos)
{
if (len)
mv64x60_wdt_service();
return len;
}
static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int timeout;
int options;
void __user *argp = (void __user *)arg;
static struct watchdog_info info = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING,
.firmware_version = 0,
.identity = "MV64x60 watchdog",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &info, sizeof(info)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
if (put_user(wdt_status, (int __user *)argp))
return -EFAULT;
wdt_status &= ~WDIOF_KEEPALIVEPING;
break;
case WDIOC_GETTEMP:
return -EOPNOTSUPP;
case WDIOC_SETOPTIONS:
if (get_user(options, (int __user *)argp))
return -EFAULT;
if (options & WDIOS_DISABLECARD)
mv64x60_wdt_handler_disable();
if (options & WDIOS_ENABLECARD)
mv64x60_wdt_handler_enable();
break;
case WDIOC_KEEPALIVE:
mv64x60_wdt_service();
wdt_status |= WDIOF_KEEPALIVEPING;
break;
case WDIOC_SETTIMEOUT:
if (get_user(timeout, (int __user *)argp))
return -EFAULT;
mv64x60_wdt_set_timeout(timeout);
/* Fall through */
case WDIOC_GETTIMEOUT:
if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
return -EFAULT;
break;
default:
return -ENOTTY;
}
return 0;
}
static const struct file_operations mv64x60_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = mv64x60_wdt_write,
.ioctl = mv64x60_wdt_ioctl,
.open = mv64x60_wdt_open,
.release = mv64x60_wdt_release,
};
static struct miscdevice mv64x60_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &mv64x60_wdt_fops,
};
static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
{
struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
struct resource *r;
int timeout = 10;
bus_clk = 133; /* in MHz */
if (pdata) {
timeout = pdata->timeout;
bus_clk = pdata->bus_clk;
}
/* Since bus_clk is truncated MHz, actual frequency could be
* up to 1MHz higher. Round up, since it's better to time out
* too late than too soon.
*/
bus_clk++;
bus_clk *= 1000000; /* convert to Hz */
r = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (!r)
return -ENODEV;
mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
if (mv64x60_wdt_regs == NULL)
return -ENOMEM;
mv64x60_wdt_set_timeout(timeout);
return misc_register(&mv64x60_wdt_miscdev);
}
static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
{
misc_deregister(&mv64x60_wdt_miscdev);
mv64x60_wdt_service();
mv64x60_wdt_handler_disable();
iounmap(mv64x60_wdt_regs);
return 0;
}
static struct platform_driver mv64x60_wdt_driver = {
.probe = mv64x60_wdt_probe,
.remove = __devexit_p(mv64x60_wdt_remove),
.driver = {
.owner = THIS_MODULE,
.name = MV64x60_WDT_NAME,
},
};
static int __init mv64x60_wdt_init(void)
{
printk(KERN_INFO "MV64x60 watchdog driver\n");
return platform_driver_register(&mv64x60_wdt_driver);
}
static void __exit mv64x60_wdt_exit(void)
{
platform_driver_unregister(&mv64x60_wdt_driver);
}
module_init(mv64x60_wdt_init);
module_exit(mv64x60_wdt_exit);
MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("MV64x60 watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
