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// SPDX-License-Identifier: GPL-2.0+
/*
* Watchdog driver for the SA11x0/PXA2xx
*
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
* Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* Neither Oleg Drokin nor iXcelerator.com admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
*
* 27/11/2000 Initial release
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/clk.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <linux/timex.h>
#define REG_OSMR0 0x0000 /* OS timer Match Reg. 0 */
#define REG_OSMR1 0x0004 /* OS timer Match Reg. 1 */
#define REG_OSMR2 0x0008 /* OS timer Match Reg. 2 */
#define REG_OSMR3 0x000c /* OS timer Match Reg. 3 */
#define REG_OSCR 0x0010 /* OS timer Counter Reg. */
#define REG_OSSR 0x0014 /* OS timer Status Reg. */
#define REG_OWER 0x0018 /* OS timer Watch-dog Enable Reg. */
#define REG_OIER 0x001C /* OS timer Interrupt Enable Reg. */
#define OSSR_M3 (1 << 3) /* Match status channel 3 */
#define OSSR_M2 (1 << 2) /* Match status channel 2 */
#define OSSR_M1 (1 << 1) /* Match status channel 1 */
#define OSSR_M0 (1 << 0) /* Match status channel 0 */
#define OWER_WME (1 << 0) /* Watchdog Match Enable */
#define OIER_E3 (1 << 3) /* Interrupt enable channel 3 */
#define OIER_E2 (1 << 2) /* Interrupt enable channel 2 */
#define OIER_E1 (1 << 1) /* Interrupt enable channel 1 */
#define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */
static unsigned long oscr_freq;
static unsigned long sa1100wdt_users;
static unsigned int pre_margin;
static int boot_status;
static void __iomem *reg_base;
static inline void sa1100_wr(u32 val, u32 offset)
{
writel_relaxed(val, reg_base + offset);
}
static inline u32 sa1100_rd(u32 offset)
{
return readl_relaxed(reg_base + offset);
}
/*
* Allow only one person to hold it open
*/
static int sa1100dog_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(1, &sa1100wdt_users))
return -EBUSY;
/* Activate SA1100 Watchdog timer */
sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
sa1100_wr(OSSR_M3, REG_OSSR);
sa1100_wr(OWER_WME, REG_OWER);
sa1100_wr(sa1100_rd(REG_OIER) | OIER_E3, REG_OIER);
return stream_open(inode, file);
}
/*
* The watchdog cannot be disabled.
*
* Previous comments suggested that turning off the interrupt by
* clearing REG_OIER[E3] would prevent the watchdog timing out but this
* does not appear to be true (at least on the PXA255).
*/
static int sa1100dog_release(struct inode *inode, struct file *file)
{
pr_crit("Device closed - timer will not stop\n");
clear_bit(1, &sa1100wdt_users);
return 0;
}
static ssize_t sa1100dog_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
if (len)
/* Refresh OSMR3 timer. */
sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT
| WDIOF_KEEPALIVEPING,
.identity = "SA1100/PXA255 Watchdog",
.firmware_version = 1,
};
static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
int time;
void __user *argp = (void __user *)arg;
int __user *p = argp;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user(argp, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, p);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, p);
break;
case WDIOC_KEEPALIVE:
sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, p);
if (ret)
break;
if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) {
ret = -EINVAL;
break;
}
pre_margin = oscr_freq * time;
sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3);
fallthrough;
case WDIOC_GETTIMEOUT:
ret = put_user(pre_margin / oscr_freq, p);
break;
}
return ret;
}
static const struct file_operations sa1100dog_fops = {
.owner = THIS_MODULE,
.write = sa1100dog_write,
.unlocked_ioctl = sa1100dog_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = sa1100dog_open,
.release = sa1100dog_release,
};
static struct miscdevice sa1100dog_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &sa1100dog_fops,
};
static int margin = 60; /* (secs) Default is 1 minute */
static struct clk *clk;
static int sa1100dog_probe(struct platform_device *pdev)
{
int ret;
int *platform_data;
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENXIO;
reg_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!reg_base)
return -ENOMEM;
clk = clk_get(NULL, "OSTIMER0");
if (IS_ERR(clk)) {
pr_err("SA1100/PXA2xx Watchdog Timer: clock not found: %d\n",
(int) PTR_ERR(clk));
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("SA1100/PXA2xx Watchdog Timer: clock failed to prepare+enable: %d\n",
ret);
goto err;
}
oscr_freq = clk_get_rate(clk);
platform_data = pdev->dev.platform_data;
if (platform_data && *platform_data)
boot_status = WDIOF_CARDRESET;
pre_margin = oscr_freq * margin;
ret = misc_register(&sa1100dog_miscdev);
if (ret == 0) {
pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
margin);
return 0;
}
clk_disable_unprepare(clk);
err:
clk_put(clk);
return ret;
}
static void sa1100dog_remove(struct platform_device *pdev)
{
misc_deregister(&sa1100dog_miscdev);
clk_disable_unprepare(clk);
clk_put(clk);
}
static struct platform_driver sa1100dog_driver = {
.driver.name = "sa1100_wdt",
.probe = sa1100dog_probe,
.remove = sa1100dog_remove,
};
module_platform_driver(sa1100dog_driver);
MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
MODULE_LICENSE("GPL");
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