// SPDX-License-Identifier: GPL-2.0+ /* * ST's LPC Watchdog * * Copyright (C) 2014 STMicroelectronics -- All Rights Reserved * * Author: David Paris <david.paris@st.com> for STMicroelectronics * Lee Jones <lee.jones@linaro.org> for STMicroelectronics */ #include <linux/clk.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/mfd/syscon.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/watchdog.h> #include <dt-bindings/mfd/st-lpc.h> /* Low Power Alarm */ #define LPC_LPA_LSB_OFF 0x410 #define LPC_LPA_START_OFF 0x418 /* LPC as WDT */ #define LPC_WDT_OFF 0x510 static struct watchdog_device st_wdog_dev; struct st_wdog_syscfg { unsigned int reset_type_reg; unsigned int reset_type_mask; unsigned int enable_reg; unsigned int enable_mask; }; struct st_wdog { void __iomem *base; struct device *dev; struct regmap *regmap; const struct st_wdog_syscfg *syscfg; struct clk *clk; unsigned long clkrate; bool warm_reset; }; static struct st_wdog_syscfg stih407_syscfg = { .enable_reg = 0x204, .enable_mask = BIT(19), }; static const struct of_device_id st_wdog_match[] = { { .compatible = "st,stih407-lpc", .data = &stih407_syscfg, }, {}, }; MODULE_DEVICE_TABLE(of, st_wdog_match); static void st_wdog_setup(struct st_wdog *st_wdog, bool enable) { /* Type of watchdog reset - 0: Cold 1: Warm */ if (st_wdog->syscfg->reset_type_reg) regmap_update_bits(st_wdog->regmap, st_wdog->syscfg->reset_type_reg, st_wdog->syscfg->reset_type_mask, st_wdog->warm_reset); /* Mask/unmask watchdog reset */ regmap_update_bits(st_wdog->regmap, st_wdog->syscfg->enable_reg, st_wdog->syscfg->enable_mask, enable ? 0 : st_wdog->syscfg->enable_mask); } static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout) { unsigned long clkrate = st_wdog->clkrate; writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF); writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF); } static int st_wdog_start(struct watchdog_device *wdd) { struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); writel_relaxed(1, st_wdog->base + LPC_WDT_OFF); return 0; } static int st_wdog_stop(struct watchdog_device *wdd) { struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); writel_relaxed(0, st_wdog->base + LPC_WDT_OFF); return 0; } static int st_wdog_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); wdd->timeout = timeout; st_wdog_load_timer(st_wdog, timeout); return 0; } static int st_wdog_keepalive(struct watchdog_device *wdd) { struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); st_wdog_load_timer(st_wdog, wdd->timeout); return 0; } static const struct watchdog_info st_wdog_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "ST LPC WDT", }; static const struct watchdog_ops st_wdog_ops = { .owner = THIS_MODULE, .start = st_wdog_start, .stop = st_wdog_stop, .ping = st_wdog_keepalive, .set_timeout = st_wdog_set_timeout, }; static struct watchdog_device st_wdog_dev = { .info = &st_wdog_info, .ops = &st_wdog_ops, }; static void st_clk_disable_unprepare(void *data) { clk_disable_unprepare(data); } static int st_wdog_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; struct st_wdog *st_wdog; struct regmap *regmap; struct clk *clk; void __iomem *base; uint32_t mode; int ret; ret = of_property_read_u32(np, "st,lpc-mode", &mode); if (ret) { dev_err(dev, "An LPC mode must be provided\n"); return -EINVAL; } /* LPC can either run as a Clocksource or in RTC or WDT mode */ if (mode != ST_LPC_MODE_WDT) return -ENODEV; st_wdog = devm_kzalloc(dev, sizeof(*st_wdog), GFP_KERNEL); if (!st_wdog) return -ENOMEM; st_wdog->syscfg = (struct st_wdog_syscfg *)device_get_match_data(dev); base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(base)) return PTR_ERR(base); regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg"); if (IS_ERR(regmap)) { dev_err(dev, "No syscfg phandle specified\n"); return PTR_ERR(regmap); } clk = devm_clk_get(dev, NULL); if (IS_ERR(clk)) { dev_err(dev, "Unable to request clock\n"); return PTR_ERR(clk); } st_wdog->dev = dev; st_wdog->base = base; st_wdog->clk = clk; st_wdog->regmap = regmap; st_wdog->warm_reset = of_property_read_bool(np, "st,warm_reset"); st_wdog->clkrate = clk_get_rate(st_wdog->clk); if (!st_wdog->clkrate) { dev_err(dev, "Unable to fetch clock rate\n"); return -EINVAL; } st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate; st_wdog_dev.parent = dev; ret = clk_prepare_enable(clk); if (ret) { dev_err(dev, "Unable to enable clock\n"); return ret; } ret = devm_add_action_or_reset(dev, st_clk_disable_unprepare, clk); if (ret) return ret; watchdog_set_drvdata(&st_wdog_dev, st_wdog); watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT); /* Init Watchdog timeout with value in DT */ ret = watchdog_init_timeout(&st_wdog_dev, 0, dev); if (ret) return ret; ret = devm_watchdog_register_device(dev, &st_wdog_dev); if (ret) return ret; st_wdog_setup(st_wdog, true); dev_info(dev, "LPC Watchdog driver registered, reset type is %s", st_wdog->warm_reset ? "warm" : "cold"); return ret; } static void st_wdog_remove(struct platform_device *pdev) { struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev); st_wdog_setup(st_wdog, false); } static int st_wdog_suspend(struct device *dev) { struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev); if (watchdog_active(&st_wdog_dev)) st_wdog_stop(&st_wdog_dev); st_wdog_setup(st_wdog, false); clk_disable(st_wdog->clk); return 0; } static int st_wdog_resume(struct device *dev) { struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev); int ret; ret = clk_enable(st_wdog->clk); if (ret) { dev_err(dev, "Unable to re-enable clock\n"); watchdog_unregister_device(&st_wdog_dev); clk_unprepare(st_wdog->clk); return ret; } st_wdog_setup(st_wdog, true); if (watchdog_active(&st_wdog_dev)) { st_wdog_load_timer(st_wdog, st_wdog_dev.timeout); st_wdog_start(&st_wdog_dev); } return 0; } static DEFINE_SIMPLE_DEV_PM_OPS(st_wdog_pm_ops, st_wdog_suspend, st_wdog_resume); static struct platform_driver st_wdog_driver = { .driver = { .name = "st-lpc-wdt", .pm = pm_sleep_ptr(&st_wdog_pm_ops), .of_match_table = st_wdog_match, }, .probe = st_wdog_probe, .remove_new = st_wdog_remove, }; module_platform_driver(st_wdog_driver); MODULE_AUTHOR("David Paris <david.paris@st.com>"); MODULE_DESCRIPTION("ST LPC Watchdog Driver"); MODULE_LICENSE("GPL");