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/*
* drivers/watchdog/orion_wdt.c
*
* Watchdog driver for Orion/Kirkwood processors
*
* Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <mach/bridge-regs.h>
/*
* Watchdog timer block registers.
*/
#define TIMER_CTRL 0x0000
#define WDT_EN 0x0010
#define WDT_VAL 0x0024
#define WDT_MAX_CYCLE_COUNT 0xffffffff
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
static bool nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = -1; /* module parameter (seconds) */
static unsigned int wdt_max_duration; /* (seconds) */
static struct clk *clk;
static unsigned int wdt_tclk;
static void __iomem *wdt_reg;
static DEFINE_SPINLOCK(wdt_lock);
static int orion_wdt_ping(struct watchdog_device *wdt_dev)
{
spin_lock(&wdt_lock);
/* Reload watchdog duration */
writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
spin_unlock(&wdt_lock);
return 0;
}
static int orion_wdt_start(struct watchdog_device *wdt_dev)
{
u32 reg;
spin_lock(&wdt_lock);
/* Set watchdog duration */
writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
/* Clear watchdog timer interrupt */
reg = readl(BRIDGE_CAUSE);
reg &= ~WDT_INT_REQ;
writel(reg, BRIDGE_CAUSE);
/* Enable watchdog timer */
reg = readl(wdt_reg + TIMER_CTRL);
reg |= WDT_EN;
writel(reg, wdt_reg + TIMER_CTRL);
/* Enable reset on watchdog */
reg = readl(RSTOUTn_MASK);
reg |= WDT_RESET_OUT_EN;
writel(reg, RSTOUTn_MASK);
spin_unlock(&wdt_lock);
return 0;
}
static int orion_wdt_stop(struct watchdog_device *wdt_dev)
{
u32 reg;
spin_lock(&wdt_lock);
/* Disable reset on watchdog */
reg = readl(RSTOUTn_MASK);
reg &= ~WDT_RESET_OUT_EN;
writel(reg, RSTOUTn_MASK);
/* Disable watchdog timer */
reg = readl(wdt_reg + TIMER_CTRL);
reg &= ~WDT_EN;
writel(reg, wdt_reg + TIMER_CTRL);
spin_unlock(&wdt_lock);
return 0;
}
static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev)
{
unsigned int time_left;
spin_lock(&wdt_lock);
time_left = readl(wdt_reg + WDT_VAL) / wdt_tclk;
spin_unlock(&wdt_lock);
return time_left;
}
static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int timeout)
{
wdt_dev->timeout = timeout;
return 0;
}
static const struct watchdog_info orion_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "Orion Watchdog",
};
static const struct watchdog_ops orion_wdt_ops = {
.owner = THIS_MODULE,
.start = orion_wdt_start,
.stop = orion_wdt_stop,
.ping = orion_wdt_ping,
.set_timeout = orion_wdt_set_timeout,
.get_timeleft = orion_wdt_get_timeleft,
};
static struct watchdog_device orion_wdt = {
.info = &orion_wdt_info,
.ops = &orion_wdt_ops,
};
static int __devinit orion_wdt_probe(struct platform_device *pdev)
{
struct resource *res;
int ret;
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "Orion Watchdog missing clock\n");
return -ENODEV;
}
clk_prepare_enable(clk);
wdt_tclk = clk_get_rate(clk);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt_reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!wdt_reg)
return -ENOMEM;
wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
if ((heartbeat < 1) || (heartbeat > wdt_max_duration))
heartbeat = wdt_max_duration;
orion_wdt.timeout = heartbeat;
orion_wdt.min_timeout = 1;
orion_wdt.max_timeout = wdt_max_duration;
watchdog_set_nowayout(&orion_wdt, nowayout);
ret = watchdog_register_device(&orion_wdt);
if (ret) {
clk_disable_unprepare(clk);
return ret;
}
pr_info("Initial timeout %d sec%s\n",
heartbeat, nowayout ? ", nowayout" : "");
return 0;
}
static int __devexit orion_wdt_remove(struct platform_device *pdev)
{
watchdog_unregister_device(&orion_wdt);
clk_disable_unprepare(clk);
return 0;
}
static void orion_wdt_shutdown(struct platform_device *pdev)
{
orion_wdt_stop(&orion_wdt);
}
static struct platform_driver orion_wdt_driver = {
.probe = orion_wdt_probe,
.remove = __devexit_p(orion_wdt_remove),
.shutdown = orion_wdt_shutdown,
.driver = {
.owner = THIS_MODULE,
.name = "orion_wdt",
},
};
module_platform_driver(orion_wdt_driver);
MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
MODULE_DESCRIPTION("Orion Processor Watchdog");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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