/* linux/drivers/char/watchdog/s3c2410_wdt.c * * Copyright (c) 2004 Simtec Electronics * Ben Dooks * * S3C2410 Watchdog Timer Support * * Based on, softdog.c by Alan Cox, * (c) Copyright 1996 Alan Cox * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include /* for MODULE_ALIAS_MISCDEV */ #include #include #include #include #include #include #include #include #include #include #include #define S3C2410_WTCON 0x00 #define S3C2410_WTDAT 0x04 #define S3C2410_WTCNT 0x08 #define S3C2410_WTCON_RSTEN (1 << 0) #define S3C2410_WTCON_INTEN (1 << 2) #define S3C2410_WTCON_ENABLE (1 << 5) #define S3C2410_WTCON_DIV16 (0 << 3) #define S3C2410_WTCON_DIV32 (1 << 3) #define S3C2410_WTCON_DIV64 (2 << 3) #define S3C2410_WTCON_DIV128 (3 << 3) #define S3C2410_WTCON_PRESCALE(x) ((x) << 8) #define S3C2410_WTCON_PRESCALE_MASK (0xff << 8) #define CONFIG_S3C2410_WATCHDOG_ATBOOT (0) #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15) static bool nowayout = WATCHDOG_NOWAYOUT; static int tmr_margin; static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT; static int soft_noboot; static int debug; module_param(tmr_margin, int, 0); module_param(tmr_atboot, int, 0); module_param(nowayout, bool, 0); module_param(soft_noboot, int, 0); module_param(debug, int, 0); MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. (default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")"); MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT)); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, " "0 to reboot (default 0)"); MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug (default 0)"); struct s3c2410_wdt { struct device *dev; struct clk *clock; void __iomem *reg_base; unsigned int count; spinlock_t lock; unsigned long wtcon_save; unsigned long wtdat_save; struct watchdog_device wdt_device; struct notifier_block freq_transition; }; /* watchdog control routines */ #define DBG(fmt, ...) \ do { \ if (debug) \ pr_info(fmt, ##__VA_ARGS__); \ } while (0) /* functions */ static inline struct s3c2410_wdt *freq_to_wdt(struct notifier_block *nb) { return container_of(nb, struct s3c2410_wdt, freq_transition); } static int s3c2410wdt_keepalive(struct watchdog_device *wdd) { struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd); spin_lock(&wdt->lock); writel(wdt->count, wdt->reg_base + S3C2410_WTCNT); spin_unlock(&wdt->lock); return 0; } static void __s3c2410wdt_stop(struct s3c2410_wdt *wdt) { unsigned long wtcon; wtcon = readl(wdt->reg_base + S3C2410_WTCON); wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN); writel(wtcon, wdt->reg_base + S3C2410_WTCON); } static int s3c2410wdt_stop(struct watchdog_device *wdd) { struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd); spin_lock(&wdt->lock); __s3c2410wdt_stop(wdt); spin_unlock(&wdt->lock); return 0; } static int s3c2410wdt_start(struct watchdog_device *wdd) { unsigned long wtcon; struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd); spin_lock(&wdt->lock); __s3c2410wdt_stop(wdt); wtcon = readl(wdt->reg_base + S3C2410_WTCON); wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128; if (soft_noboot) { wtcon |= S3C2410_WTCON_INTEN; wtcon &= ~S3C2410_WTCON_RSTEN; } else { wtcon &= ~S3C2410_WTCON_INTEN; wtcon |= S3C2410_WTCON_RSTEN; } DBG("%s: count=0x%08x, wtcon=%08lx\n", __func__, wdt->count, wtcon); writel(wdt->count, wdt->reg_base + S3C2410_WTDAT); writel(wdt->count, wdt->reg_base + S3C2410_WTCNT); writel(wtcon, wdt->reg_base + S3C2410_WTCON); spin_unlock(&wdt->lock); return 0; } static inline int s3c2410wdt_is_running(struct s3c2410_wdt *wdt) { return readl(wdt->reg_base + S3C2410_WTCON) & S3C2410_WTCON_ENABLE; } static int s3c2410wdt_set_heartbeat(struct watchdog_device *wdd, unsigned timeout) { struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd); unsigned long freq = clk_get_rate(wdt->clock); unsigned int count; unsigned int divisor = 1; unsigned long wtcon; if (timeout < 1) return -EINVAL; freq /= 128; count = timeout * freq; DBG("%s: count=%d, timeout=%d, freq=%lu\n", __func__, count, timeout, freq); /* if the count is bigger than the watchdog register, then work out what we need to do (and if) we can actually make this value */ if (count >= 0x10000) { for (divisor = 1; divisor <= 0x100; divisor++) { if ((count / divisor) < 0x10000) break; } if ((count / divisor) >= 0x10000) { dev_err(wdt->dev, "timeout %d too big\n", timeout); return -EINVAL; } } DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n", __func__, timeout, divisor, count, count/divisor); count /= divisor; wdt->count = count; /* update the pre-scaler */ wtcon = readl(wdt->reg_base + S3C2410_WTCON); wtcon &= ~S3C2410_WTCON_PRESCALE_MASK; wtcon |= S3C2410_WTCON_PRESCALE(divisor-1); writel(count, wdt->reg_base + S3C2410_WTDAT); writel(wtcon, wdt->reg_base + S3C2410_WTCON); wdd->timeout = (count * divisor) / freq; return 0; } #define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) static const struct watchdog_info s3c2410_wdt_ident = { .options = OPTIONS, .firmware_version = 0, .identity = "S3C2410 Watchdog", }; static struct watchdog_ops s3c2410wdt_ops = { .owner = THIS_MODULE, .start = s3c2410wdt_start, .stop = s3c2410wdt_stop, .ping = s3c2410wdt_keepalive, .set_timeout = s3c2410wdt_set_heartbeat, }; static struct watchdog_device s3c2410_wdd = { .info = &s3c2410_wdt_ident, .ops = &s3c2410wdt_ops, .timeout = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME, }; /* interrupt handler code */ static irqreturn_t s3c2410wdt_irq(int irqno, void *param) { struct s3c2410_wdt *wdt = platform_get_drvdata(param); dev_info(wdt->dev, "watchdog timer expired (irq)\n"); s3c2410wdt_keepalive(&wdt->wdt_device); return IRQ_HANDLED; } #ifdef CONFIG_CPU_FREQ static int s3c2410wdt_cpufreq_transition(struct notifier_block *nb, unsigned long val, void *data) { int ret; struct s3c2410_wdt *wdt = freq_to_wdt(nb); if (!s3c2410wdt_is_running(wdt)) goto done; if (val == CPUFREQ_PRECHANGE) { /* To ensure that over the change we don't cause the * watchdog to trigger, we perform an keep-alive if * the watchdog is running. */ s3c2410wdt_keepalive(&wdt->wdt_device); } else if (val == CPUFREQ_POSTCHANGE) { s3c2410wdt_stop(&wdt->wdt_device); ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device, wdt->wdt_device.timeout); if (ret >= 0) s3c2410wdt_start(&wdt->wdt_device); else goto err; } done: return 0; err: dev_err(wdt->dev, "cannot set new value for timeout %d\n", wdt->wdt_device.timeout); return ret; } static inline int s3c2410wdt_cpufreq_register(struct s3c2410_wdt *wdt) { wdt->freq_transition.notifier_call = s3c2410wdt_cpufreq_transition; return cpufreq_register_notifier(&wdt->freq_transition, CPUFREQ_TRANSITION_NOTIFIER); } static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt) { wdt->freq_transition.notifier_call = s3c2410wdt_cpufreq_transition; cpufreq_unregister_notifier(&wdt->freq_transition, CPUFREQ_TRANSITION_NOTIFIER); } #else static inline int s3c2410wdt_cpufreq_register(struct s3c2410_wdt *wdt) { return 0; } static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt) { } #endif static int s3c2410wdt_probe(struct platform_device *pdev) { struct device *dev; struct s3c2410_wdt *wdt; struct resource *wdt_mem; struct resource *wdt_irq; unsigned int wtcon; int started = 0; int ret; DBG("%s: probe=%p\n", __func__, pdev); dev = &pdev->dev; wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; wdt->dev = &pdev->dev; spin_lock_init(&wdt->lock); wdt->wdt_device = s3c2410_wdd; wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (wdt_mem == NULL) { dev_err(dev, "no memory resource specified\n"); return -ENOENT; } wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (wdt_irq == NULL) { dev_err(dev, "no irq resource specified\n"); ret = -ENOENT; goto err; } /* get the memory region for the watchdog timer */ wdt->reg_base = devm_ioremap_resource(dev, wdt_mem); if (IS_ERR(wdt->reg_base)) { ret = PTR_ERR(wdt->reg_base); goto err; } DBG("probe: mapped reg_base=%p\n", wdt->reg_base); wdt->clock = devm_clk_get(dev, "watchdog"); if (IS_ERR(wdt->clock)) { dev_err(dev, "failed to find watchdog clock source\n"); ret = PTR_ERR(wdt->clock); goto err; } clk_prepare_enable(wdt->clock); ret = s3c2410wdt_cpufreq_register(wdt); if (ret < 0) { dev_err(dev, "failed to register cpufreq\n"); goto err_clk; } watchdog_set_drvdata(&wdt->wdt_device, wdt); /* see if we can actually set the requested timer margin, and if * not, try the default value */ watchdog_init_timeout(&wdt->wdt_device, tmr_margin, &pdev->dev); ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device, wdt->wdt_device.timeout); if (ret) { started = s3c2410wdt_set_heartbeat(&wdt->wdt_device, CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); if (started == 0) dev_info(dev, "tmr_margin value out of range, default %d used\n", CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); else dev_info(dev, "default timer value is out of range, " "cannot start\n"); } ret = devm_request_irq(dev, wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev); if (ret != 0) { dev_err(dev, "failed to install irq (%d)\n", ret); goto err_cpufreq; } watchdog_set_nowayout(&wdt->wdt_device, nowayout); ret = watchdog_register_device(&wdt->wdt_device); if (ret) { dev_err(dev, "cannot register watchdog (%d)\n", ret); goto err_cpufreq; } if (tmr_atboot && started == 0) { dev_info(dev, "starting watchdog timer\n"); s3c2410wdt_start(&wdt->wdt_device); } else if (!tmr_atboot) { /* if we're not enabling the watchdog, then ensure it is * disabled if it has been left running from the bootloader * or other source */ s3c2410wdt_stop(&wdt->wdt_device); } platform_set_drvdata(pdev, wdt); /* print out a statement of readiness */ wtcon = readl(wdt->reg_base + S3C2410_WTCON); dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n", (wtcon & S3C2410_WTCON_ENABLE) ? "" : "in", (wtcon & S3C2410_WTCON_RSTEN) ? "en" : "dis", (wtcon & S3C2410_WTCON_INTEN) ? "en" : "dis"); return 0; err_cpufreq: s3c2410wdt_cpufreq_deregister(wdt); err_clk: clk_disable_unprepare(wdt->clock); wdt->clock = NULL; err: return ret; } static int s3c2410wdt_remove(struct platform_device *dev) { struct s3c2410_wdt *wdt = platform_get_drvdata(dev); watchdog_unregister_device(&wdt->wdt_device); s3c2410wdt_cpufreq_deregister(wdt); clk_disable_unprepare(wdt->clock); wdt->clock = NULL; return 0; } static void s3c2410wdt_shutdown(struct platform_device *dev) { struct s3c2410_wdt *wdt = platform_get_drvdata(dev); s3c2410wdt_stop(&wdt->wdt_device); } #ifdef CONFIG_PM_SLEEP static int s3c2410wdt_suspend(struct device *dev) { struct s3c2410_wdt *wdt = dev_get_drvdata(dev); /* Save watchdog state, and turn it off. */ wdt->wtcon_save = readl(wdt->reg_base + S3C2410_WTCON); wdt->wtdat_save = readl(wdt->reg_base + S3C2410_WTDAT); /* Note that WTCNT doesn't need to be saved. */ s3c2410wdt_stop(&wdt->wdt_device); return 0; } static int s3c2410wdt_resume(struct device *dev) { struct s3c2410_wdt *wdt = dev_get_drvdata(dev); /* Restore watchdog state. */ writel(wdt->wtdat_save, wdt->reg_base + S3C2410_WTDAT); writel(wdt->wtdat_save, wdt->reg_base + S3C2410_WTCNT);/* Reset count */ writel(wdt->wtcon_save, wdt->reg_base + S3C2410_WTCON); dev_info(dev, "watchdog %sabled\n", (wdt->wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis"); return 0; } #endif static SIMPLE_DEV_PM_OPS(s3c2410wdt_pm_ops, s3c2410wdt_suspend, s3c2410wdt_resume); #ifdef CONFIG_OF static const struct of_device_id s3c2410_wdt_match[] = { { .compatible = "samsung,s3c2410-wdt" }, {}, }; MODULE_DEVICE_TABLE(of, s3c2410_wdt_match); #endif static struct platform_driver s3c2410wdt_driver = { .probe = s3c2410wdt_probe, .remove = s3c2410wdt_remove, .shutdown = s3c2410wdt_shutdown, .driver = { .owner = THIS_MODULE, .name = "s3c2410-wdt", .pm = &s3c2410wdt_pm_ops, .of_match_table = of_match_ptr(s3c2410_wdt_match), }, }; module_platform_driver(s3c2410wdt_driver); MODULE_AUTHOR("Ben Dooks , " "Dimitry Andric "); MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); MODULE_ALIAS("platform:s3c2410-wdt");