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