rt2880_wdt.c
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/*
* Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer
*
* Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2013 John Crispin <blogic@openwrt.org>
*
* This driver was based on: drivers/watchdog/softdog.c
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/reset.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <asm/mach-ralink/ralink_regs.h>
#define SYSC_RSTSTAT 0x38
#define WDT_RST_CAUSE BIT(1)
#define RALINK_WDT_TIMEOUT 30
#define RALINK_WDT_PRESCALE 65536
#define TIMER_REG_TMR1LOAD 0x00
#define TIMER_REG_TMR1CTL 0x08
#define TMRSTAT_TMR1RST BIT(5)
#define TMR1CTL_ENABLE BIT(7)
#define TMR1CTL_MODE_SHIFT 4
#define TMR1CTL_MODE_MASK 0x3
#define TMR1CTL_MODE_FREE_RUNNING 0x0
#define TMR1CTL_MODE_PERIODIC 0x1
#define TMR1CTL_MODE_TIMEOUT 0x2
#define TMR1CTL_MODE_WDT 0x3
#define TMR1CTL_PRESCALE_MASK 0xf
#define TMR1CTL_PRESCALE_65536 0xf
static struct clk *rt288x_wdt_clk;
static unsigned long rt288x_wdt_freq;
static void __iomem *rt288x_wdt_base;
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 inline void rt_wdt_w32(unsigned reg, u32 val)
{
iowrite32(val, rt288x_wdt_base + reg);
}
static inline u32 rt_wdt_r32(unsigned reg)
{
return ioread32(rt288x_wdt_base + reg);
}
static int rt288x_wdt_ping(struct watchdog_device *w)
{
rt_wdt_w32(TIMER_REG_TMR1LOAD, w->timeout * rt288x_wdt_freq);
return 0;
}
static int rt288x_wdt_start(struct watchdog_device *w)
{
u32 t;
t = rt_wdt_r32(TIMER_REG_TMR1CTL);
t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |
TMR1CTL_PRESCALE_MASK);
t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |
TMR1CTL_PRESCALE_65536);
rt_wdt_w32(TIMER_REG_TMR1CTL, t);
rt288x_wdt_ping(w);
t = rt_wdt_r32(TIMER_REG_TMR1CTL);
t |= TMR1CTL_ENABLE;
rt_wdt_w32(TIMER_REG_TMR1CTL, t);
return 0;
}
static int rt288x_wdt_stop(struct watchdog_device *w)
{
u32 t;
rt288x_wdt_ping(w);
t = rt_wdt_r32(TIMER_REG_TMR1CTL);
t &= ~TMR1CTL_ENABLE;
rt_wdt_w32(TIMER_REG_TMR1CTL, t);
return 0;
}
static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t)
{
w->timeout = t;
rt288x_wdt_ping(w);
return 0;
}
static int rt288x_wdt_bootcause(void)
{
if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
return WDIOF_CARDRESET;
return 0;
}
static struct watchdog_info rt288x_wdt_info = {
.identity = "Ralink Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static struct watchdog_ops rt288x_wdt_ops = {
.owner = THIS_MODULE,
.start = rt288x_wdt_start,
.stop = rt288x_wdt_stop,
.ping = rt288x_wdt_ping,
.set_timeout = rt288x_wdt_set_timeout,
};
static struct watchdog_device rt288x_wdt_dev = {
.info = &rt288x_wdt_info,
.ops = &rt288x_wdt_ops,
.min_timeout = 1,
};
static int rt288x_wdt_probe(struct platform_device *pdev)
{
struct resource *res;
int ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rt288x_wdt_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rt288x_wdt_base))
return PTR_ERR(rt288x_wdt_base);
rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(rt288x_wdt_clk))
return PTR_ERR(rt288x_wdt_clk);
device_reset(&pdev->dev);
rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE;
rt288x_wdt_dev.dev = &pdev->dev;
rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();
rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
rt288x_wdt_dev.timeout = rt288x_wdt_dev.max_timeout;
watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);
ret = watchdog_register_device(&rt288x_wdt_dev);
if (!ret)
dev_info(&pdev->dev, "Initialized\n");
return 0;
}
static int rt288x_wdt_remove(struct platform_device *pdev)
{
watchdog_unregister_device(&rt288x_wdt_dev);
return 0;
}
static void rt288x_wdt_shutdown(struct platform_device *pdev)
{
rt288x_wdt_stop(&rt288x_wdt_dev);
}
static const struct of_device_id rt288x_wdt_match[] = {
{ .compatible = "ralink,rt2880-wdt" },
{},
};
MODULE_DEVICE_TABLE(of, rt288x_wdt_match);
static struct platform_driver rt288x_wdt_driver = {
.probe = rt288x_wdt_probe,
.remove = rt288x_wdt_remove,
.shutdown = rt288x_wdt_shutdown,
.driver = {
.name = KBUILD_MODNAME,
.owner = THIS_MODULE,
.of_match_table = rt288x_wdt_match,
},
};
module_platform_driver(rt288x_wdt_driver);
MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
MODULE_LICENSE("GPL v2");