alistair23-linux/drivers/watchdog/rt2880_wdt.c
Guenter Roeck 570927df46 watchdog: rt2880_wdt: Convert to use device managed functions and other improvements
Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.
Other improvements as listed below.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

- Drop empty remove function
- Introduce local variable 'struct device *dev' and use it instead of
  dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device
- Replace shutdown function with call to watchdog_stop_on_reboot()

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-05-05 21:02:36 +02:00

196 lines
4.7 KiB
C

/*
* Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer
*
* Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
* Copyright (C) 2013 John Crispin <john@phrozen.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 <linux/mod_devicetable.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 struct reset_control *rt288x_wdt_reset;
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 const struct watchdog_info rt288x_wdt_info = {
.identity = "Ralink Watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
};
static const 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 device *dev = &pdev->dev;
int ret;
rt288x_wdt_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(rt288x_wdt_base))
return PTR_ERR(rt288x_wdt_base);
rt288x_wdt_clk = devm_clk_get(dev, NULL);
if (IS_ERR(rt288x_wdt_clk))
return PTR_ERR(rt288x_wdt_clk);
rt288x_wdt_reset = devm_reset_control_get_exclusive(dev, NULL);
if (!IS_ERR(rt288x_wdt_reset))
reset_control_deassert(rt288x_wdt_reset);
rt288x_wdt_freq = clk_get_rate(rt288x_wdt_clk) / RALINK_WDT_PRESCALE;
rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();
rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
rt288x_wdt_dev.parent = dev;
watchdog_init_timeout(&rt288x_wdt_dev, rt288x_wdt_dev.max_timeout,
dev);
watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);
watchdog_stop_on_reboot(&rt288x_wdt_dev);
ret = devm_watchdog_register_device(dev, &rt288x_wdt_dev);
if (!ret)
dev_info(dev, "Initialized\n");
return 0;
}
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,
.driver = {
.name = KBUILD_MODNAME,
.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");