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drivers/watchdog/meson_wdt.c
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81f7e3824 Initial Release, ... |
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/* * Meson Watchdog Driver * * Copyright (c) 2014 Carlo Caione * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/clk.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/init.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/types.h> #include <linux/watchdog.h> #define DRV_NAME "meson_wdt" #define MESON_WDT_TC 0x00 #define MESON_WDT_DC_RESET (3 << 24) #define MESON_WDT_RESET 0x04 #define MESON_WDT_TIMEOUT 30 #define MESON_WDT_MIN_TIMEOUT 1 #define MESON_SEC_TO_TC(s, c) ((s) * (c)) static bool nowayout = WATCHDOG_NOWAYOUT; static unsigned int timeout = MESON_WDT_TIMEOUT; struct meson_wdt_data { unsigned int enable; unsigned int terminal_count_mask; unsigned int count_unit; }; static struct meson_wdt_data meson6_wdt_data = { .enable = BIT(22), .terminal_count_mask = 0x3fffff, .count_unit = 100000, /* 10 us */ }; static struct meson_wdt_data meson8b_wdt_data = { .enable = BIT(19), .terminal_count_mask = 0xffff, .count_unit = 7812, /* 128 us */ }; struct meson_wdt_dev { struct watchdog_device wdt_dev; void __iomem *wdt_base; const struct meson_wdt_data *data; }; static int meson_wdt_restart(struct watchdog_device *wdt_dev, unsigned long action, void *data) { struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); u32 tc_reboot = MESON_WDT_DC_RESET; tc_reboot |= meson_wdt->data->enable; while (1) { writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC); mdelay(5); } return 0; } static int meson_wdt_ping(struct watchdog_device *wdt_dev) { struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); writel(0, meson_wdt->wdt_base + MESON_WDT_RESET); return 0; } static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev, unsigned int timeout) { struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); u32 reg; reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); reg &= ~meson_wdt->data->terminal_count_mask; reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit); writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); } static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev, unsigned int timeout) { wdt_dev->timeout = timeout; meson_wdt_change_timeout(wdt_dev, timeout); meson_wdt_ping(wdt_dev); return 0; } static int meson_wdt_stop(struct watchdog_device *wdt_dev) { struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); u32 reg; reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); reg &= ~meson_wdt->data->enable; writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); return 0; } static int meson_wdt_start(struct watchdog_device *wdt_dev) { struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev); u32 reg; meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout); meson_wdt_ping(wdt_dev); reg = readl(meson_wdt->wdt_base + MESON_WDT_TC); reg |= meson_wdt->data->enable; writel(reg, meson_wdt->wdt_base + MESON_WDT_TC); return 0; } static const struct watchdog_info meson_wdt_info = { .identity = DRV_NAME, .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static const struct watchdog_ops meson_wdt_ops = { .owner = THIS_MODULE, .start = meson_wdt_start, .stop = meson_wdt_stop, .ping = meson_wdt_ping, .set_timeout = meson_wdt_set_timeout, .restart = meson_wdt_restart, }; static const struct of_device_id meson_wdt_dt_ids[] = { { .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data }, { .compatible = "amlogic,meson8-wdt", .data = &meson6_wdt_data }, { .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data }, { .compatible = "amlogic,meson8m2-wdt", .data = &meson8b_wdt_data }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); static int meson_wdt_probe(struct platform_device *pdev) { struct resource *res; struct meson_wdt_dev *meson_wdt; const struct of_device_id *of_id; int err; meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL); if (!meson_wdt) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(meson_wdt->wdt_base)) return PTR_ERR(meson_wdt->wdt_base); of_id = of_match_device(meson_wdt_dt_ids, &pdev->dev); if (!of_id) { dev_err(&pdev->dev, "Unable to initialize WDT data "); return -ENODEV; } meson_wdt->data = of_id->data; meson_wdt->wdt_dev.parent = &pdev->dev; meson_wdt->wdt_dev.info = &meson_wdt_info; meson_wdt->wdt_dev.ops = &meson_wdt_ops; meson_wdt->wdt_dev.max_timeout = meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit; meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT; meson_wdt->wdt_dev.timeout = min_t(unsigned int, MESON_WDT_TIMEOUT, meson_wdt->wdt_dev.max_timeout); watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt); watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev); watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout); watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128); meson_wdt_stop(&meson_wdt->wdt_dev); watchdog_stop_on_reboot(&meson_wdt->wdt_dev); err = devm_watchdog_register_device(&pdev->dev, &meson_wdt->wdt_dev); if (err) return err; dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", meson_wdt->wdt_dev.timeout, nowayout); return 0; } static struct platform_driver meson_wdt_driver = { .probe = meson_wdt_probe, .driver = { .name = DRV_NAME, .of_match_table = meson_wdt_dt_ids, }, }; module_platform_driver(meson_wdt_driver); module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Carlo Caione <carlo@caione.org>"); MODULE_DESCRIPTION("Meson Watchdog Timer Driver"); |