/* * Mediatek Watchdog Driver * * Copyright (C) 2014 Matthias Brugger * * Matthias Brugger * * 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. * * 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. * * Based on sunxi_wdt.c */ #include #include #include #include #include #include #include #include #include #include #include #include #include #define WDT_MAX_TIMEOUT 31 #define WDT_MIN_TIMEOUT 1 #define WDT_LENGTH_TIMEOUT(n) ((n) << 5) #define WDT_LENGTH 0x04 #define WDT_LENGTH_KEY 0x8 #define WDT_RST 0x08 #define WDT_RST_RELOAD 0x1971 #define WDT_MODE 0x00 #define WDT_MODE_EN (1 << 0) #define WDT_MODE_EXT_POL_LOW (0 << 1) #define WDT_MODE_EXT_POL_HIGH (1 << 1) #define WDT_MODE_EXRST_EN (1 << 2) #define WDT_MODE_IRQ_EN (1 << 3) #define WDT_MODE_AUTO_START (1 << 4) #define WDT_MODE_DUAL_EN (1 << 6) #define WDT_MODE_KEY 0x22000000 #define WDT_SWRST 0x14 #define WDT_SWRST_KEY 0x1209 #define DRV_NAME "mtk-wdt" #define DRV_VERSION "1.0" static bool nowayout = WATCHDOG_NOWAYOUT; static unsigned int timeout = WDT_MAX_TIMEOUT; struct mtk_wdt_dev { struct watchdog_device wdt_dev; void __iomem *wdt_base; struct notifier_block restart_handler; }; static int mtk_reset_handler(struct notifier_block *this, unsigned long mode, void *cmd) { struct mtk_wdt_dev *mtk_wdt; void __iomem *wdt_base; mtk_wdt = container_of(this, struct mtk_wdt_dev, restart_handler); wdt_base = mtk_wdt->wdt_base; while (1) { writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST); mdelay(5); } return NOTIFY_DONE; } static int mtk_wdt_ping(struct watchdog_device *wdt_dev) { struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = mtk_wdt->wdt_base; iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST); return 0; } static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev, unsigned int timeout) { struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = mtk_wdt->wdt_base; u32 reg; wdt_dev->timeout = timeout; /* * One bit is the value of 512 ticks * The clock has 32 KHz */ reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY; iowrite32(reg, wdt_base + WDT_LENGTH); mtk_wdt_ping(wdt_dev); return 0; } static int mtk_wdt_stop(struct watchdog_device *wdt_dev) { struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = mtk_wdt->wdt_base; u32 reg; reg = readl(wdt_base + WDT_MODE); reg &= ~WDT_MODE_EN; iowrite32(reg, wdt_base + WDT_MODE); return 0; } static int mtk_wdt_start(struct watchdog_device *wdt_dev) { u32 reg; struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); void __iomem *wdt_base = mtk_wdt->wdt_base; u32 ret; ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout); if (ret < 0) return ret; reg = ioread32(wdt_base + WDT_MODE); reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN); reg |= (WDT_MODE_EN | WDT_MODE_KEY); iowrite32(reg, wdt_base + WDT_MODE); return 0; } static const struct watchdog_info mtk_wdt_info = { .identity = DRV_NAME, .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static const struct watchdog_ops mtk_wdt_ops = { .owner = THIS_MODULE, .start = mtk_wdt_start, .stop = mtk_wdt_stop, .ping = mtk_wdt_ping, .set_timeout = mtk_wdt_set_timeout, }; static int mtk_wdt_probe(struct platform_device *pdev) { struct mtk_wdt_dev *mtk_wdt; struct resource *res; int err; mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL); if (!mtk_wdt) return -ENOMEM; platform_set_drvdata(pdev, mtk_wdt); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(mtk_wdt->wdt_base)) return PTR_ERR(mtk_wdt->wdt_base); mtk_wdt->wdt_dev.info = &mtk_wdt_info; mtk_wdt->wdt_dev.ops = &mtk_wdt_ops; mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; mtk_wdt->wdt_dev.parent = &pdev->dev; watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev); watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout); watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); mtk_wdt_stop(&mtk_wdt->wdt_dev); err = watchdog_register_device(&mtk_wdt->wdt_dev); if (unlikely(err)) return err; mtk_wdt->restart_handler.notifier_call = mtk_reset_handler; mtk_wdt->restart_handler.priority = 128; err = register_restart_handler(&mtk_wdt->restart_handler); if (err) dev_warn(&pdev->dev, "cannot register restart handler (err=%d)\n", err); dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n", mtk_wdt->wdt_dev.timeout, nowayout); return 0; } static int mtk_wdt_remove(struct platform_device *pdev) { struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev); unregister_restart_handler(&mtk_wdt->restart_handler); watchdog_unregister_device(&mtk_wdt->wdt_dev); return 0; } static const struct of_device_id mtk_wdt_dt_ids[] = { { .compatible = "mediatek,mt6589-wdt" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids); static struct platform_driver mtk_wdt_driver = { .probe = mtk_wdt_probe, .remove = mtk_wdt_remove, .driver = { .name = DRV_NAME, .of_match_table = mtk_wdt_dt_ids, }, }; module_platform_driver(mtk_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("Matthias Brugger "); MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver"); MODULE_VERSION(DRV_VERSION);