// SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (c) 2004 Simtec Electronics * Ben Dooks * * S3C2410 Watchdog Timer Support * * Based on, softdog.c by Alan Cox, * (c) Copyright 1996 Alan Cox */ #include #include #include #include #include #include #include #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_WTCLRINT 0x0c #define S3C2410_WTCNT_MAXCNT 0xffff #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_MAXDIV 0x80 #define S3C2410_WTCON_PRESCALE(x) ((x) << 8) #define S3C2410_WTCON_PRESCALE_MASK (0xff << 8) #define S3C2410_WTCON_PRESCALE_MAX 0xff #define S3C2410_WATCHDOG_ATBOOT (0) #define S3C2410_WATCHDOG_DEFAULT_TIME (15) #define EXYNOS5_RST_STAT_REG_OFFSET 0x0404 #define EXYNOS5_WDT_DISABLE_REG_OFFSET 0x0408 #define EXYNOS5_WDT_MASK_RESET_REG_OFFSET 0x040c #define QUIRK_HAS_PMU_CONFIG (1 << 0) #define QUIRK_HAS_RST_STAT (1 << 1) #define QUIRK_HAS_WTCLRINT_REG (1 << 2) /* These quirks require that we have a PMU register map */ #define QUIRKS_HAVE_PMUREG (QUIRK_HAS_PMU_CONFIG | \ QUIRK_HAS_RST_STAT) static bool nowayout = WATCHDOG_NOWAYOUT; static int tmr_margin; static int tmr_atboot = S3C2410_WATCHDOG_ATBOOT; static int soft_noboot; module_param(tmr_margin, int, 0); module_param(tmr_atboot, int, 0); module_param(nowayout, bool, 0); module_param(soft_noboot, int, 0); MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. (default=" __MODULE_STRING(S3C2410_WATCHDOG_DEFAULT_TIME) ")"); MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(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)"); /** * struct s3c2410_wdt_variant - Per-variant config data * * @disable_reg: Offset in pmureg for the register that disables the watchdog * timer reset functionality. * @mask_reset_reg: Offset in pmureg for the register that masks the watchdog * timer reset functionality. * @mask_bit: Bit number for the watchdog timer in the disable register and the * mask reset register. * @rst_stat_reg: Offset in pmureg for the register that has the reset status. * @rst_stat_bit: Bit number in the rst_stat register indicating a watchdog * reset. * @quirks: A bitfield of quirks. */ struct s3c2410_wdt_variant { int disable_reg; int mask_reset_reg; int mask_bit; int rst_stat_reg; int rst_stat_bit; u32 quirks; }; 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; const struct s3c2410_wdt_variant *drv_data; struct regmap *pmureg; }; static const struct s3c2410_wdt_variant drv_data_s3c2410 = { .quirks = 0 }; #ifdef CONFIG_OF static const struct s3c2410_wdt_variant drv_data_s3c6410 = { .quirks = QUIRK_HAS_WTCLRINT_REG, }; static const struct s3c2410_wdt_variant drv_data_exynos5250 = { .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET, .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET, .mask_bit = 20, .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET, .rst_stat_bit = 20, .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \ | QUIRK_HAS_WTCLRINT_REG, }; static const struct s3c2410_wdt_variant drv_data_exynos5420 = { .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET, .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET, .mask_bit = 0, .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET, .rst_stat_bit = 9, .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \ | QUIRK_HAS_WTCLRINT_REG, }; static const struct s3c2410_wdt_variant drv_data_exynos7 = { .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET, .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET, .mask_bit = 23, .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET, .rst_stat_bit = 23, /* A57 WDTRESET */ .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \ | QUIRK_HAS_WTCLRINT_REG, }; static const struct of_device_id s3c2410_wdt_match[] = { { .compatible = "samsung,s3c2410-wdt", .data = &drv_data_s3c2410 }, { .compatible = "samsung,s3c6410-wdt", .data = &drv_data_s3c6410 }, { .compatible = "samsung,exynos5250-wdt", .data = &drv_data_exynos5250 }, { .compatible = "samsung,exynos5420-wdt", .data = &drv_data_exynos5420 }, { .compatible = "samsung,exynos7-wdt", .data = &drv_data_exynos7 }, {}, }; MODULE_DEVICE_TABLE(of, s3c2410_wdt_match); #endif static const struct platform_device_id s3c2410_wdt_ids[] = { { .name = "s3c2410-wdt", .driver_data = (unsigned long)&drv_data_s3c2410, }, {} }; MODULE_DEVICE_TABLE(platform, s3c2410_wdt_ids); /* functions */ static inline unsigned int s3c2410wdt_max_timeout(struct clk *clock) { unsigned long freq = clk_get_rate(clock); return S3C2410_WTCNT_MAXCNT / (freq / (S3C2410_WTCON_PRESCALE_MAX + 1) / S3C2410_WTCON_MAXDIV); } static inline struct s3c2410_wdt *freq_to_wdt(struct notifier_block *nb) { return container_of(nb, struct s3c2410_wdt, freq_transition); } static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask) { int ret; u32 mask_val = 1 << wdt->drv_data->mask_bit; u32 val = 0; /* No need to do anything if no PMU CONFIG needed */ if (!(wdt->drv_data->quirks & QUIRK_HAS_PMU_CONFIG)) return 0; if (mask) val = mask_val; ret = regmap_update_bits(wdt->pmureg, wdt->drv_data->disable_reg, mask_val, val); if (ret < 0) goto error; ret = regmap_update_bits(wdt->pmureg, wdt->drv_data->mask_reset_reg, mask_val, val); error: if (ret < 0) dev_err(wdt->dev, "failed to update reg(%d)\n", ret); return ret; } 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; } dev_dbg(wdt->dev, "Starting watchdog: count=0x%08x, wtcon=%08lx\n", 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 int 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 = DIV_ROUND_UP(freq, 128); count = timeout * freq; dev_dbg(wdt->dev, "Heartbeat: count=%d, timeout=%d, freq=%lu\n", 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) { divisor = DIV_ROUND_UP(count, 0xffff); if (divisor > 0x100) { dev_err(wdt->dev, "timeout %d too big\n", timeout); return -EINVAL; } } dev_dbg(wdt->dev, "Heartbeat: timeout=%d, divisor=%d, count=%d (%08x)\n", timeout, divisor, count, DIV_ROUND_UP(count, divisor)); count = DIV_ROUND_UP(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; } static int s3c2410wdt_restart(struct watchdog_device *wdd, unsigned long action, void *data) { struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd); void __iomem *wdt_base = wdt->reg_base; /* disable watchdog, to be safe */ writel(0, wdt_base + S3C2410_WTCON); /* put initial values into count and data */ writel(0x80, wdt_base + S3C2410_WTCNT); writel(0x80, wdt_base + S3C2410_WTDAT); /* set the watchdog to go and reset... */ writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 | S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20), wdt_base + S3C2410_WTCON); /* wait for reset to assert... */ mdelay(500); 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 const struct watchdog_ops s3c2410wdt_ops = { .owner = THIS_MODULE, .start = s3c2410wdt_start, .stop = s3c2410wdt_stop, .ping = s3c2410wdt_keepalive, .set_timeout = s3c2410wdt_set_heartbeat, .restart = s3c2410wdt_restart, }; static const struct watchdog_device s3c2410_wdd = { .info = &s3c2410_wdt_ident, .ops = &s3c2410wdt_ops, .timeout = 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); if (wdt->drv_data->quirks & QUIRK_HAS_WTCLRINT_REG) writel(0x1, wdt->reg_base + S3C2410_WTCLRINT); return IRQ_HANDLED; } #ifdef CONFIG_ARM_S3C24XX_CPUFREQ 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 inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt) { unsigned int rst_stat; int ret; if (!(wdt->drv_data->quirks & QUIRK_HAS_RST_STAT)) return 0; ret = regmap_read(wdt->pmureg, wdt->drv_data->rst_stat_reg, &rst_stat); if (ret) dev_warn(wdt->dev, "Couldn't get RST_STAT register\n"); else if (rst_stat & BIT(wdt->drv_data->rst_stat_bit)) return WDIOF_CARDRESET; return 0; } static inline const struct s3c2410_wdt_variant * s3c2410_get_wdt_drv_data(struct platform_device *pdev) { const struct s3c2410_wdt_variant *variant; variant = of_device_get_match_data(&pdev->dev); if (!variant) { /* Device matched by platform_device_id */ variant = (struct s3c2410_wdt_variant *) platform_get_device_id(pdev)->driver_data; } return variant; } static int s3c2410wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct s3c2410_wdt *wdt; struct resource *wdt_irq; unsigned int wtcon; int started = 0; int ret; wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; wdt->dev = dev; spin_lock_init(&wdt->lock); wdt->wdt_device = s3c2410_wdd; wdt->drv_data = s3c2410_get_wdt_drv_data(pdev); if (wdt->drv_data->quirks & QUIRKS_HAVE_PMUREG) { wdt->pmureg = syscon_regmap_lookup_by_phandle(dev->of_node, "samsung,syscon-phandle"); if (IS_ERR(wdt->pmureg)) { dev_err(dev, "syscon regmap lookup failed.\n"); return PTR_ERR(wdt->pmureg); } } 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_platform_ioremap_resource(pdev, 0); if (IS_ERR(wdt->reg_base)) { ret = PTR_ERR(wdt->reg_base); goto err; } 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; } ret = clk_prepare_enable(wdt->clock); if (ret < 0) { dev_err(dev, "failed to enable clock\n"); return ret; } wdt->wdt_device.min_timeout = 1; wdt->wdt_device.max_timeout = s3c2410wdt_max_timeout(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, dev); ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device, wdt->wdt_device.timeout); if (ret) { started = s3c2410wdt_set_heartbeat(&wdt->wdt_device, S3C2410_WATCHDOG_DEFAULT_TIME); if (started == 0) dev_info(dev, "tmr_margin value out of range, default %d used\n", 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); watchdog_set_restart_priority(&wdt->wdt_device, 128); wdt->wdt_device.bootstatus = s3c2410wdt_get_bootstatus(wdt); wdt->wdt_device.parent = dev; ret = watchdog_register_device(&wdt->wdt_device); if (ret) goto err_cpufreq; ret = s3c2410wdt_mask_and_disable_reset(wdt, false); if (ret < 0) goto err_unregister; 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_unregister: watchdog_unregister_device(&wdt->wdt_device); err_cpufreq: s3c2410wdt_cpufreq_deregister(wdt); err_clk: clk_disable_unprepare(wdt->clock); err: return ret; } static int s3c2410wdt_remove(struct platform_device *dev) { int ret; struct s3c2410_wdt *wdt = platform_get_drvdata(dev); ret = s3c2410wdt_mask_and_disable_reset(wdt, true); if (ret < 0) return ret; watchdog_unregister_device(&wdt->wdt_device); s3c2410wdt_cpufreq_deregister(wdt); clk_disable_unprepare(wdt->clock); return 0; } static void s3c2410wdt_shutdown(struct platform_device *dev) { struct s3c2410_wdt *wdt = platform_get_drvdata(dev); s3c2410wdt_mask_and_disable_reset(wdt, true); s3c2410wdt_stop(&wdt->wdt_device); } #ifdef CONFIG_PM_SLEEP static int s3c2410wdt_suspend(struct device *dev) { int ret; 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); ret = s3c2410wdt_mask_and_disable_reset(wdt, true); if (ret < 0) return ret; /* Note that WTCNT doesn't need to be saved. */ s3c2410wdt_stop(&wdt->wdt_device); return 0; } static int s3c2410wdt_resume(struct device *dev) { int ret; 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); ret = s3c2410wdt_mask_and_disable_reset(wdt, false); if (ret < 0) return ret; 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); static struct platform_driver s3c2410wdt_driver = { .probe = s3c2410wdt_probe, .remove = s3c2410wdt_remove, .shutdown = s3c2410wdt_shutdown, .id_table = s3c2410_wdt_ids, .driver = { .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");