diff options
Diffstat (limited to 'drivers/watchdog/mtk_wdt.c')
| -rw-r--r-- | drivers/watchdog/mtk_wdt.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c new file mode 100644 index 000000000000..a87f6df6e85f --- /dev/null +++ b/drivers/watchdog/mtk_wdt.c @@ -0,0 +1,251 @@ +/* + * Mediatek Watchdog Driver + * + * Copyright (C) 2014 Matthias Brugger + * + * Matthias Brugger <matthias.bgg@gmail.com> + * + * 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 <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/platform_device.h> +#include <linux/types.h> +#include <linux/watchdog.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/delay.h> + +#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 <matthias.bgg@gmail.com>"); +MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver"); +MODULE_VERSION(DRV_VERSION); |