/* * Ralink MT7621/MT7628 built-in hardware watchdog timer * * Copyright (C) 2014 John Crispin <blogic@openwrt.org> * * This driver was based on: drivers/watchdog/rt2880_wdt.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 TIMER_REG_TMRSTAT 0x00 #define TIMER_REG_TMR1LOAD 0x24 #define TIMER_REG_TMR1CTL 0x20 #define TMR1CTL_ENABLE BIT(7) #define TMR1CTL_RESTART BIT(9) #define TMR1CTL_PRESCALE_SHIFT 16 static void __iomem *mt7621_wdt_base; static struct reset_control *mt7621_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, mt7621_wdt_base + reg); } static inline u32 rt_wdt_r32(unsigned reg) { return ioread32(mt7621_wdt_base + reg); } static int mt7621_wdt_ping(struct watchdog_device *w) { rt_wdt_w32(TIMER_REG_TMRSTAT, TMR1CTL_RESTART); return 0; } static int mt7621_wdt_set_timeout(struct watchdog_device *w, unsigned int t) { w->timeout = t; rt_wdt_w32(TIMER_REG_TMR1LOAD, t * 1000); mt7621_wdt_ping(w); return 0; } static int mt7621_wdt_start(struct watchdog_device *w) { u32 t; /* set the prescaler to 1ms == 1000us */ rt_wdt_w32(TIMER_REG_TMR1CTL, 1000 << TMR1CTL_PRESCALE_SHIFT); mt7621_wdt_set_timeout(w, w->timeout); t = rt_wdt_r32(TIMER_REG_TMR1CTL); t |= TMR1CTL_ENABLE; rt_wdt_w32(TIMER_REG_TMR1CTL, t); return 0; } static int mt7621_wdt_stop(struct watchdog_device *w) { u32 t; mt7621_wdt_ping(w); t = rt_wdt_r32(TIMER_REG_TMR1CTL); t &= ~TMR1CTL_ENABLE; rt_wdt_w32(TIMER_REG_TMR1CTL, t); return 0; } static int mt7621_wdt_bootcause(void) { if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE) return WDIOF_CARDRESET; return 0; } static struct watchdog_info mt7621_wdt_info = { .identity = "Mediatek Watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static struct watchdog_ops mt7621_wdt_ops = { .owner = THIS_MODULE, .start = mt7621_wdt_start, .stop = mt7621_wdt_stop, .ping = mt7621_wdt_ping, .set_timeout = mt7621_wdt_set_timeout, }; static struct watchdog_device mt7621_wdt_dev = { .info = &mt7621_wdt_info, .ops = &mt7621_wdt_ops, .min_timeout = 1, .max_timeout = 0xfffful / 1000, }; static int mt7621_wdt_probe(struct platform_device *pdev) { struct resource *res; int ret; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); mt7621_wdt_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(mt7621_wdt_base)) return PTR_ERR(mt7621_wdt_base); mt7621_wdt_reset = devm_reset_control_get(&pdev->dev, NULL); if (!IS_ERR(mt7621_wdt_reset)) reset_control_deassert(mt7621_wdt_reset); mt7621_wdt_dev.dev = &pdev->dev; mt7621_wdt_dev.bootstatus = mt7621_wdt_bootcause(); watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout, &pdev->dev); watchdog_set_nowayout(&mt7621_wdt_dev, nowayout); ret = watchdog_register_device(&mt7621_wdt_dev); return 0; } static int mt7621_wdt_remove(struct platform_device *pdev) { watchdog_unregister_device(&mt7621_wdt_dev); return 0; } static void mt7621_wdt_shutdown(struct platform_device *pdev) { mt7621_wdt_stop(&mt7621_wdt_dev); } static const struct of_device_id mt7621_wdt_match[] = { { .compatible = "mediatek,mt7621-wdt" }, {}, }; MODULE_DEVICE_TABLE(of, mt7621_wdt_match); static struct platform_driver mt7621_wdt_driver = { .probe = mt7621_wdt_probe, .remove = mt7621_wdt_remove, .shutdown = mt7621_wdt_shutdown, .driver = { .name = KBUILD_MODNAME, .of_match_table = mt7621_wdt_match, }, }; module_platform_driver(mt7621_wdt_driver); MODULE_DESCRIPTION("MediaTek MT762x hardware watchdog driver"); MODULE_AUTHOR("John Crispin <blogic@openwrt.org"); MODULE_LICENSE("GPL v2");