// SPDX-License-Identifier: GPL-2.0+ /* * Watchdog driver for Marvell Armada 37xx SoCs * * Author: Marek Behún */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* * There are four counters that can be used for watchdog on Armada 37xx. * The addresses for counter control registers are register base plus ID*0x10, * where ID is 0, 1, 2 or 3. * * In this driver we use IDs 0 and 1. Counter ID 1 is used as watchdog counter, * while counter ID 0 is used to implement pinging the watchdog: counter ID 1 is * set to restart counting from initial value on counter ID 0 end count event. * Pinging is done by forcing immediate end count event on counter ID 0. * If only one counter was used, pinging would have to be implemented by * disabling and enabling the counter, leaving the system in a vulnerable state * for a (really) short period of time. * * Counters ID 2 and 3 are enabled by default even before U-Boot loads, * therefore this driver does not provide a way to use them, eg. by setting a * property in device tree. */ #define CNTR_ID_RETRIGGER 0 #define CNTR_ID_WDOG 1 /* relative to cpu_misc */ #define WDT_TIMER_SELECT 0x64 #define WDT_TIMER_SELECT_MASK 0xf #define WDT_TIMER_SELECT_VAL BIT(CNTR_ID_WDOG) /* relative to reg */ #define CNTR_CTRL(id) ((id) * 0x10) #define CNTR_CTRL_ENABLE 0x0001 #define CNTR_CTRL_ACTIVE 0x0002 #define CNTR_CTRL_MODE_MASK 0x000c #define CNTR_CTRL_MODE_ONESHOT 0x0000 #define CNTR_CTRL_MODE_HWSIG 0x000c #define CNTR_CTRL_TRIG_SRC_MASK 0x00f0 #define CNTR_CTRL_TRIG_SRC_PREV_CNTR 0x0050 #define CNTR_CTRL_PRESCALE_MASK 0xff00 #define CNTR_CTRL_PRESCALE_MIN 2 #define CNTR_CTRL_PRESCALE_SHIFT 8 #define CNTR_COUNT_LOW(id) (CNTR_CTRL(id) + 0x4) #define CNTR_COUNT_HIGH(id) (CNTR_CTRL(id) + 0x8) #define WATCHDOG_TIMEOUT 120 static unsigned int timeout; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); 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) ")"); struct armada_37xx_watchdog { struct watchdog_device wdt; struct regmap *cpu_misc; void __iomem *reg; u64 timeout; /* in clock ticks */ unsigned long clk_rate; struct clk *clk; }; static u64 get_counter_value(struct armada_37xx_watchdog *dev, int id) { u64 val; /* * when low is read, high is latched into flip-flops so that it can be * read consistently without using software debouncing */ val = readl(dev->reg + CNTR_COUNT_LOW(id)); val |= ((u64)readl(dev->reg + CNTR_COUNT_HIGH(id))) << 32; return val; } static void set_counter_value(struct armada_37xx_watchdog *dev, int id, u64 val) { writel(val & 0xffffffff, dev->reg + CNTR_COUNT_LOW(id)); writel(val >> 32, dev->reg + CNTR_COUNT_HIGH(id)); } static void counter_enable(struct armada_37xx_watchdog *dev, int id) { u32 reg; reg = readl(dev->reg + CNTR_CTRL(id)); reg |= CNTR_CTRL_ENABLE; writel(reg, dev->reg + CNTR_CTRL(id)); } static void counter_disable(struct armada_37xx_watchdog *dev, int id) { u32 reg; reg = readl(dev->reg + CNTR_CTRL(id)); reg &= ~CNTR_CTRL_ENABLE; writel(reg, dev->reg + CNTR_CTRL(id)); } static void init_counter(struct armada_37xx_watchdog *dev, int id, u32 mode, u32 trig_src) { u32 reg; reg = readl(dev->reg + CNTR_CTRL(id)); reg &= ~(CNTR_CTRL_MODE_MASK | CNTR_CTRL_PRESCALE_MASK | CNTR_CTRL_TRIG_SRC_MASK); /* set mode */ reg |= mode & CNTR_CTRL_MODE_MASK; /* set prescaler to the min value */ reg |= CNTR_CTRL_PRESCALE_MIN << CNTR_CTRL_PRESCALE_SHIFT; /* set trigger source */ reg |= trig_src & CNTR_CTRL_TRIG_SRC_MASK; writel(reg, dev->reg + CNTR_CTRL(id)); } static int armada_37xx_wdt_ping(struct watchdog_device *wdt) { struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); /* counter 1 is retriggered by forcing end count on counter 0 */ counter_disable(dev, CNTR_ID_RETRIGGER); counter_enable(dev, CNTR_ID_RETRIGGER); return 0; } static unsigned int armada_37xx_wdt_get_timeleft(struct watchdog_device *wdt) { struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); u64 res; res = get_counter_value(dev, CNTR_ID_WDOG) * CNTR_CTRL_PRESCALE_MIN; do_div(res, dev->clk_rate); return res; } static int armada_37xx_wdt_set_timeout(struct watchdog_device *wdt, unsigned int timeout) { struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); wdt->timeout = timeout; /* * Compute the timeout in clock rate. We use smallest possible * prescaler, which divides the clock rate by 2 * (CNTR_CTRL_PRESCALE_MIN). */ dev->timeout = (u64)dev->clk_rate * timeout; do_div(dev->timeout, CNTR_CTRL_PRESCALE_MIN); set_counter_value(dev, CNTR_ID_WDOG, dev->timeout); return 0; } static bool armada_37xx_wdt_is_running(struct armada_37xx_watchdog *dev) { u32 reg; regmap_read(dev->cpu_misc, WDT_TIMER_SELECT, ®); if ((reg & WDT_TIMER_SELECT_MASK) != WDT_TIMER_SELECT_VAL) return false; reg = readl(dev->reg + CNTR_CTRL(CNTR_ID_WDOG)); return !!(reg & CNTR_CTRL_ACTIVE); } static int armada_37xx_wdt_start(struct watchdog_device *wdt) { struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); /* select counter 1 as watchdog counter */ regmap_write(dev->cpu_misc, WDT_TIMER_SELECT, WDT_TIMER_SELECT_VAL); /* init counter 0 as retrigger counter for counter 1 */ init_counter(dev, CNTR_ID_RETRIGGER, CNTR_CTRL_MODE_ONESHOT, 0); set_counter_value(dev, CNTR_ID_RETRIGGER, 0); /* init counter 1 to be retriggerable by counter 0 end count */ init_counter(dev, CNTR_ID_WDOG, CNTR_CTRL_MODE_HWSIG, CNTR_CTRL_TRIG_SRC_PREV_CNTR); set_counter_value(dev, CNTR_ID_WDOG, dev->timeout); /* enable counter 1 */ counter_enable(dev, CNTR_ID_WDOG); /* start counter 1 by forcing immediate end count on counter 0 */ counter_enable(dev, CNTR_ID_RETRIGGER); return 0; } static int armada_37xx_wdt_stop(struct watchdog_device *wdt) { struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt); counter_disable(dev, CNTR_ID_WDOG); counter_disable(dev, CNTR_ID_RETRIGGER); regmap_write(dev->cpu_misc, WDT_TIMER_SELECT, 0); return 0; } static const struct watchdog_info armada_37xx_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "Armada 37xx Watchdog", }; static const struct watchdog_ops armada_37xx_wdt_ops = { .owner = THIS_MODULE, .start = armada_37xx_wdt_start, .stop = armada_37xx_wdt_stop, .ping = armada_37xx_wdt_ping, .set_timeout = armada_37xx_wdt_set_timeout, .get_timeleft = armada_37xx_wdt_get_timeleft, }; static int armada_37xx_wdt_probe(struct platform_device *pdev) { struct armada_37xx_watchdog *dev; struct regmap *regmap; int ret; dev = devm_kzalloc(&pdev->dev, sizeof(struct armada_37xx_watchdog), GFP_KERNEL); if (!dev) return -ENOMEM; dev->wdt.info = &armada_37xx_wdt_info; dev->wdt.ops = &armada_37xx_wdt_ops; regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "marvell,system-controller"); if (IS_ERR(regmap)) return PTR_ERR(regmap); dev->cpu_misc = regmap; dev->reg = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(dev->reg)) return PTR_ERR(dev->reg); /* init clock */ dev->clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(dev->clk)) return PTR_ERR(dev->clk); dev->clk_rate = clk_get_rate(dev->clk); if (!dev->clk_rate) return -EINVAL; /* * Since the timeout in seconds is given as 32 bit unsigned int, and * the counters hold 64 bit values, even after multiplication by clock * rate the counter can hold timeout of UINT_MAX seconds. */ dev->wdt.min_timeout = 1; dev->wdt.max_timeout = UINT_MAX; dev->wdt.parent = &pdev->dev; /* default value, possibly override by module parameter or dtb */ dev->wdt.timeout = WATCHDOG_TIMEOUT; watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev); platform_set_drvdata(pdev, &dev->wdt); watchdog_set_drvdata(&dev->wdt, dev); armada_37xx_wdt_set_timeout(&dev->wdt, dev->wdt.timeout); if (armada_37xx_wdt_is_running(dev)) set_bit(WDOG_HW_RUNNING, &dev->wdt.status); watchdog_set_nowayout(&dev->wdt, nowayout); watchdog_stop_on_reboot(&dev->wdt); ret = devm_watchdog_register_device(&pdev->dev, &dev->wdt); if (ret) return ret; dev_info(&pdev->dev, "Initial timeout %d sec%s\n", dev->wdt.timeout, nowayout ? ", nowayout" : ""); return 0; } static int __maybe_unused armada_37xx_wdt_suspend(struct device *dev) { struct watchdog_device *wdt = dev_get_drvdata(dev); return armada_37xx_wdt_stop(wdt); } static int __maybe_unused armada_37xx_wdt_resume(struct device *dev) { struct watchdog_device *wdt = dev_get_drvdata(dev); if (watchdog_active(wdt)) return armada_37xx_wdt_start(wdt); return 0; } static const struct dev_pm_ops armada_37xx_wdt_dev_pm_ops = { SET_SYSTEM_SLEEP_PM_OPS(armada_37xx_wdt_suspend, armada_37xx_wdt_resume) }; #ifdef CONFIG_OF static const struct of_device_id armada_37xx_wdt_match[] = { { .compatible = "marvell,armada-3700-wdt", }, {}, }; MODULE_DEVICE_TABLE(of, armada_37xx_wdt_match); #endif static struct platform_driver armada_37xx_wdt_driver = { .probe = armada_37xx_wdt_probe, .driver = { .name = "armada_37xx_wdt", .of_match_table = of_match_ptr(armada_37xx_wdt_match), .pm = &armada_37xx_wdt_dev_pm_ops, }, }; module_platform_driver(armada_37xx_wdt_driver); MODULE_AUTHOR("Marek Behun "); MODULE_DESCRIPTION("Armada 37xx CPU Watchdog"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:armada_37xx_wdt");