diff options
Diffstat (limited to 'drivers/watchdog/rt2880_wdt.c')
| -rw-r--r-- | drivers/watchdog/rt2880_wdt.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/drivers/watchdog/rt2880_wdt.c b/drivers/watchdog/rt2880_wdt.c new file mode 100644 index 000000000..db7c57d82 --- /dev/null +++ b/drivers/watchdog/rt2880_wdt.c @@ -0,0 +1,209 @@ +/* + * 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 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); + + rt288x_wdt_reset = devm_reset_control_get_exclusive(&pdev->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 = &pdev->dev; + + watchdog_init_timeout(&rt288x_wdt_dev, rt288x_wdt_dev.max_timeout, + &pdev->dev); + 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, + .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"); |