/* Copyright (c) 2014, The Linux Foundation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and * only version 2 as published by the Free Software Foundation. * * 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. * */ #include <linux/clk.h> #include <linux/delay.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/reboot.h> #include <linux/watchdog.h> #define WDT_RST 0x0 #define WDT_EN 0x8 #define WDT_BITE_TIME 0x24 struct qcom_wdt { struct watchdog_device wdd; struct clk *clk; unsigned long rate; struct notifier_block restart_nb; void __iomem *base; }; static inline struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd) { return container_of(wdd, struct qcom_wdt, wdd); } static int qcom_wdt_start(struct watchdog_device *wdd) { struct qcom_wdt *wdt = to_qcom_wdt(wdd); writel(0, wdt->base + WDT_EN); writel(1, wdt->base + WDT_RST); writel(wdd->timeout * wdt->rate, wdt->base + WDT_BITE_TIME); writel(1, wdt->base + WDT_EN); return 0; } static int qcom_wdt_stop(struct watchdog_device *wdd) { struct qcom_wdt *wdt = to_qcom_wdt(wdd); writel(0, wdt->base + WDT_EN); return 0; } static int qcom_wdt_ping(struct watchdog_device *wdd) { struct qcom_wdt *wdt = to_qcom_wdt(wdd); writel(1, wdt->base + WDT_RST); return 0; } static int qcom_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { wdd->timeout = timeout; return qcom_wdt_start(wdd); } static const struct watchdog_ops qcom_wdt_ops = { .start = qcom_wdt_start, .stop = qcom_wdt_stop, .ping = qcom_wdt_ping, .set_timeout = qcom_wdt_set_timeout, .owner = THIS_MODULE, }; static const struct watchdog_info qcom_wdt_info = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, .identity = KBUILD_MODNAME, }; static int qcom_wdt_restart(struct notifier_block *nb, unsigned long action, void *data) { struct qcom_wdt *wdt = container_of(nb, struct qcom_wdt, restart_nb); u32 timeout; /* * Trigger watchdog bite: * Setup BITE_TIME to be 128ms, and enable WDT. */ timeout = 128 * wdt->rate / 1000; writel(0, wdt->base + WDT_EN); writel(1, wdt->base + WDT_RST); writel(timeout, wdt->base + WDT_BITE_TIME); writel(1, wdt->base + WDT_EN); /* * Actually make sure the above sequence hits hardware before sleeping. */ wmb(); msleep(150); return NOTIFY_DONE; } static int qcom_wdt_probe(struct platform_device *pdev) { struct qcom_wdt *wdt; struct resource *res; int ret; wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); wdt->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(wdt->base)) return PTR_ERR(wdt->base); wdt->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(wdt->clk)) { dev_err(&pdev->dev, "failed to get input clock\n"); return PTR_ERR(wdt->clk); } ret = clk_prepare_enable(wdt->clk); if (ret) { dev_err(&pdev->dev, "failed to setup clock\n"); return ret; } /* * We use the clock rate to calculate the max timeout, so ensure it's * not zero to avoid a divide-by-zero exception. * * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such * that it would bite before a second elapses it's usefulness is * limited. Bail if this is the case. */ wdt->rate = clk_get_rate(wdt->clk); if (wdt->rate == 0 || wdt->rate > 0x10000000U) { dev_err(&pdev->dev, "invalid clock rate\n"); ret = -EINVAL; goto err_clk_unprepare; } wdt->wdd.dev = &pdev->dev; wdt->wdd.info = &qcom_wdt_info; wdt->wdd.ops = &qcom_wdt_ops; wdt->wdd.min_timeout = 1; wdt->wdd.max_timeout = 0x10000000U / wdt->rate; /* * If 'timeout-sec' unspecified in devicetree, assume a 30 second * default, unless the max timeout is less than 30 seconds, then use * the max instead. */ wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U); watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev); ret = watchdog_register_device(&wdt->wdd); if (ret) { dev_err(&pdev->dev, "failed to register watchdog\n"); goto err_clk_unprepare; } /* * WDT restart notifier has priority 0 (use as a last resort) */ wdt->restart_nb.notifier_call = qcom_wdt_restart; ret = register_restart_handler(&wdt->restart_nb); if (ret) dev_err(&pdev->dev, "failed to setup restart handler\n"); platform_set_drvdata(pdev, wdt); return 0; err_clk_unprepare: clk_disable_unprepare(wdt->clk); return ret; } static int qcom_wdt_remove(struct platform_device *pdev) { struct qcom_wdt *wdt = platform_get_drvdata(pdev); unregister_restart_handler(&wdt->restart_nb); watchdog_unregister_device(&wdt->wdd); clk_disable_unprepare(wdt->clk); return 0; } static const struct of_device_id qcom_wdt_of_table[] = { { .compatible = "qcom,kpss-wdt-msm8960", }, { .compatible = "qcom,kpss-wdt-apq8064", }, { .compatible = "qcom,kpss-wdt-ipq8064", }, { }, }; MODULE_DEVICE_TABLE(of, qcom_wdt_of_table); static struct platform_driver qcom_watchdog_driver = { .probe = qcom_wdt_probe, .remove = qcom_wdt_remove, .driver = { .name = KBUILD_MODNAME, .of_match_table = qcom_wdt_of_table, }, }; module_platform_driver(qcom_watchdog_driver); MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver"); MODULE_LICENSE("GPL v2");