/*
* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
* JZ4740 Watchdog driver
*
* 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.
*
* 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.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <asm/mach-jz4740/timer.h>
#define JZ_REG_WDT_TIMER_DATA 0x0
#define JZ_REG_WDT_COUNTER_ENABLE 0x4
#define JZ_REG_WDT_TIMER_COUNTER 0x8
#define JZ_REG_WDT_TIMER_CONTROL 0xC
#define JZ_WDT_CLOCK_PCLK 0x1
#define JZ_WDT_CLOCK_RTC 0x2
#define JZ_WDT_CLOCK_EXT 0x4
#define JZ_WDT_CLOCK_DIV_SHIFT 3
#define JZ_WDT_CLOCK_DIV_1 (0 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_4 (1 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_16 (2 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_64 (3 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_256 (4 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
#define DEFAULT_HEARTBEAT 5
#define MAX_HEARTBEAT 2048
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static unsigned int heartbeat = DEFAULT_HEARTBEAT;
module_param(heartbeat, uint, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
struct jz4740_wdt_drvdata {
struct watchdog_device wdt;
void __iomem *base;
struct clk *rtc_clk;
};
static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
return 0;
}
static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int new_timeout)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
unsigned int rtc_clk_rate;
unsigned int timeout_value;
unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
timeout_value = rtc_clk_rate * new_timeout;
while (timeout_value > 0xffff) {
if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
/* Requested timeout too high;
* use highest possible value. */
timeout_value = 0xffff;
break;
}
timeout_value >>= 2;
clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
}
writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
writew(clock_div, drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
writew((u16)timeout_value, drvdata->base + JZ_REG_WDT_TIMER_DATA);
writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
writew(clock_div | JZ_WDT_CLOCK_RTC,
drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
writeb(0x1, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
wdt_dev->timeout = new_timeout;
return 0;
}
static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
{
jz4740_timer_enable_watchdog();
jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
return 0;
}
static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
jz4740_timer_disable_watchdog();
writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
return 0;
}
static const struct watchdog_info jz4740_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "jz4740 Watchdog",
};
static const struct watchdog_ops jz4740_wdt_ops = {
.owner = THIS_MODULE,
.start = jz4740_wdt_start,
.stop = jz4740_wdt_stop,
.ping = jz4740_wdt_ping,
.set_timeout = jz4740_wdt_set_timeout,
};
static int jz4740_wdt_probe(struct platform_device *pdev)
{
struct jz4740_wdt_drvdata *drvdata;
struct watchdog_device *jz4740_wdt;
struct resource *res;
int ret;
drvdata = devm_kzalloc(&pdev->dev, sizeof(struct jz4740_wdt_drvdata),
GFP_KERNEL);
if (!drvdata) {
dev_err(&pdev->dev, "Unable to alloacate watchdog device\n");
return -ENOMEM;
}
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
jz4740_wdt = &drvdata->wdt;
jz4740_wdt->info = &jz4740_wdt_info;
jz4740_wdt->ops = &jz4740_wdt_ops;
jz4740_wdt->timeout = heartbeat;
jz4740_wdt->min_timeout = 1;
jz4740_wdt->max_timeout = MAX_HEARTBEAT;
watchdog_set_nowayout(jz4740_wdt, nowayout);
watchdog_set_drvdata(jz4740_wdt, drvdata);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
drvdata->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(drvdata->base)) {
ret = PTR_ERR(drvdata->base);
goto err_out;
}
drvdata->rtc_clk = clk_get(NULL, "rtc");
if (IS_ERR(drvdata->rtc_clk)) {
dev_err(&pdev->dev, "cannot find RTC clock\n");
ret = PTR_ERR(drvdata->rtc_clk);
goto err_out;
}
ret = watchdog_register_device(&drvdata->wdt);
if (ret < 0)
goto err_disable_clk;
platform_set_drvdata(pdev, drvdata);
return 0;
err_disable_clk:
clk_put(drvdata->rtc_clk);
err_out:
return ret;
}
static int jz4740_wdt_remove(struct platform_device *pdev)
{
struct jz4740_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
jz4740_wdt_stop(&drvdata->wdt);
watchdog_unregister_device(&drvdata->wdt);
clk_put(drvdata->rtc_clk);
return 0;
}
static struct platform_driver jz4740_wdt_driver = {
.probe = jz4740_wdt_probe,
.remove = jz4740_wdt_remove,
.driver = {
.name = "jz4740-wdt",
.owner = THIS_MODULE,
},
};
module_platform_driver(jz4740_wdt_driver);
MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
MODULE_DESCRIPTION("jz4740 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:jz4740-wdt");
