208 lines
4.9 KiB
C
208 lines
4.9 KiB
C
/*
|
|
* Moschip MCS814x Watchdog driver
|
|
*
|
|
* Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/io.h>
|
|
#include <linux/err.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/of.h>
|
|
|
|
#define WDT_COUNT 0x00
|
|
#define WDT_CTRL 0x04
|
|
#define WDT_CTRL_EN 0x1
|
|
|
|
/* watchdog frequency */
|
|
#define WDT_MAX_VALUE (0xffffffff)
|
|
|
|
struct mcs814x_wdt {
|
|
void __iomem *regs;
|
|
spinlock_t lock;
|
|
struct watchdog_device wdt_dev;
|
|
struct clk *clk;
|
|
};
|
|
|
|
static int mcs814x_wdt_start(struct watchdog_device *dev)
|
|
{
|
|
struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
|
|
u32 reg;
|
|
|
|
spin_lock(&wdt->lock);
|
|
reg = readl_relaxed(wdt->regs + WDT_CTRL);
|
|
reg |= WDT_CTRL_EN;
|
|
writel_relaxed(reg, wdt->regs + WDT_CTRL);
|
|
spin_unlock(&wdt->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mcs814x_wdt_stop(struct watchdog_device *dev)
|
|
{
|
|
struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
|
|
u32 reg;
|
|
|
|
spin_lock(&wdt->lock);
|
|
reg = readl_relaxed(wdt->regs + WDT_CTRL);
|
|
reg &= ~WDT_CTRL_EN;
|
|
writel_relaxed(reg, wdt->regs + WDT_CTRL);
|
|
spin_unlock(&wdt->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mcs814x_wdt_set_timeout(struct watchdog_device *dev,
|
|
unsigned int new_timeout)
|
|
{
|
|
struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
|
|
|
|
spin_lock(&wdt->lock);
|
|
/* watchdog counts upward and rollover (0xfffffff -> 0)
|
|
* triggers the reboot
|
|
*/
|
|
writel_relaxed(WDT_MAX_VALUE - (new_timeout * clk_get_rate(wdt->clk)),
|
|
wdt->regs + WDT_COUNT);
|
|
spin_unlock(&wdt->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int mcs814x_wdt_ping(struct watchdog_device *dev)
|
|
{
|
|
/* restart the watchdog */
|
|
mcs814x_wdt_stop(dev);
|
|
mcs814x_wdt_set_timeout(dev, dev->timeout);
|
|
mcs814x_wdt_start(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct watchdog_info mcs814x_wdt_ident = {
|
|
.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT |
|
|
WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
|
|
.identity = "MCS814x Watchdog",
|
|
};
|
|
|
|
static struct watchdog_ops mcs814x_wdt_ops = {
|
|
.owner = THIS_MODULE,
|
|
.start = mcs814x_wdt_start,
|
|
.stop = mcs814x_wdt_stop,
|
|
.set_timeout = mcs814x_wdt_set_timeout,
|
|
.ping = mcs814x_wdt_ping,
|
|
};
|
|
|
|
static int mcs814x_wdt_probe(struct platform_device *pdev)
|
|
{
|
|
struct resource *res;
|
|
struct mcs814x_wdt *wdt;
|
|
int ret;
|
|
struct clk *clk;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
if (!res)
|
|
return -ENODEV;
|
|
|
|
clk = clk_get(NULL, "wdt");
|
|
if (IS_ERR_OR_NULL(clk)) {
|
|
dev_err(&pdev->dev, "failed to get watchdog clock\n");
|
|
return PTR_ERR(clk);
|
|
}
|
|
|
|
wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
|
|
if (!wdt) {
|
|
ret = -ENOMEM;
|
|
goto out_clk;
|
|
}
|
|
|
|
spin_lock_init(&wdt->lock);
|
|
wdt->clk = clk;
|
|
wdt->wdt_dev.info = &mcs814x_wdt_ident;
|
|
wdt->wdt_dev.ops = &mcs814x_wdt_ops;
|
|
wdt->wdt_dev.min_timeout = 1;
|
|
/* approximately 10995 secs */
|
|
wdt->wdt_dev.max_timeout = (WDT_MAX_VALUE / clk_get_rate(clk));
|
|
|
|
platform_set_drvdata(pdev, wdt);
|
|
|
|
/* only ioremap registers, because the register is shared */
|
|
wdt->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res));
|
|
if (!wdt->regs) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
watchdog_set_drvdata(&wdt->wdt_dev, wdt);
|
|
|
|
ret = watchdog_register_device(&wdt->wdt_dev);
|
|
if (ret) {
|
|
dev_err(&pdev->dev, "cannot register watchdog: %d\n", ret);
|
|
goto out;
|
|
}
|
|
|
|
dev_info(&pdev->dev, "registered\n");
|
|
return 0;
|
|
|
|
out:
|
|
platform_set_drvdata(pdev, NULL);
|
|
kfree(wdt);
|
|
out_clk:
|
|
clk_put(clk);
|
|
return ret;
|
|
}
|
|
|
|
static int mcs814x_wdt_remove(struct platform_device *pdev)
|
|
{
|
|
struct mcs814x_wdt *wdt = platform_get_drvdata(pdev);
|
|
|
|
clk_put(wdt->clk);
|
|
watchdog_unregister_device(&wdt->wdt_dev);
|
|
watchdog_set_drvdata(&wdt->wdt_dev, NULL);
|
|
kfree(wdt);
|
|
platform_set_drvdata(pdev, NULL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id mcs814x_wdt_ids[] = {
|
|
{ .compatible = "moschip,mcs814x-wdt", },
|
|
{ /* sentinel */ },
|
|
};
|
|
|
|
static struct platform_driver mcs814x_wdt_driver = {
|
|
.driver = {
|
|
.name = "mcs814x-wdt",
|
|
.owner = THIS_MODULE,
|
|
.of_match_table = mcs814x_wdt_ids,
|
|
},
|
|
.probe = mcs814x_wdt_probe,
|
|
.remove = mcs814x_wdt_remove,
|
|
};
|
|
|
|
module_platform_driver(mcs814x_wdt_driver);
|
|
|
|
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
|
|
MODULE_DESCRIPTION("Moschip MCS814x Watchdog driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
|
MODULE_ALIAS("platform:mcs814x-wdt");
|