diff options
Diffstat (limited to 'drivers/watchdog/meson_wdt.c')
| -rw-r--r-- | drivers/watchdog/meson_wdt.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/drivers/watchdog/meson_wdt.c b/drivers/watchdog/meson_wdt.c new file mode 100644 index 000000000..1f4155ee3 --- /dev/null +++ b/drivers/watchdog/meson_wdt.c @@ -0,0 +1,235 @@ +/* + * 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/notifier.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reboot.h> +#include <linux/types.h> +#include <linux/watchdog.h> + +#define DRV_NAME "meson_wdt" + +#define MESON_WDT_TC 0x00 +#define MESON_WDT_TC_EN BIT(22) +#define MESON_WDT_TC_TM_MASK 0x3fffff +#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_WDT_MAX_TIMEOUT (MESON_WDT_TC_TM_MASK / 100000) + +#define MESON_SEC_TO_TC(s) ((s) * 100000) + +static bool nowayout = WATCHDOG_NOWAYOUT; +static unsigned int timeout = MESON_WDT_TIMEOUT; + +struct meson_wdt_dev { + struct watchdog_device wdt_dev; + void __iomem *wdt_base; + struct notifier_block restart_handler; +}; + +static int meson_restart_handle(struct notifier_block *this, unsigned long mode, + void *cmd) +{ + u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN; + struct meson_wdt_dev *meson_wdt = container_of(this, + struct meson_wdt_dev, + restart_handler); + + while (1) { + writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC); + mdelay(5); + } + + return NOTIFY_DONE; +} + +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_TC_TM_MASK; + reg |= MESON_SEC_TO_TC(timeout); + 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_TC_EN; + 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_TC_EN; + 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, +}; + +static int meson_wdt_probe(struct platform_device *pdev) +{ + struct resource *res; + struct meson_wdt_dev *meson_wdt; + 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); + + 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.timeout = MESON_WDT_TIMEOUT; + meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT; + meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_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); + + meson_wdt_stop(&meson_wdt->wdt_dev); + + err = watchdog_register_device(&meson_wdt->wdt_dev); + if (err) + return err; + + platform_set_drvdata(pdev, meson_wdt); + + meson_wdt->restart_handler.notifier_call = meson_restart_handle; + meson_wdt->restart_handler.priority = 128; + err = register_restart_handler(&meson_wdt->restart_handler); + if (err) + dev_err(&pdev->dev, + "cannot register restart handler (err=%d)\n", err); + + dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", + meson_wdt->wdt_dev.timeout, nowayout); + + return 0; +} + +static int meson_wdt_remove(struct platform_device *pdev) +{ + struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); + + unregister_restart_handler(&meson_wdt->restart_handler); + + watchdog_unregister_device(&meson_wdt->wdt_dev); + + return 0; +} + +static void meson_wdt_shutdown(struct platform_device *pdev) +{ + struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev); + + meson_wdt_stop(&meson_wdt->wdt_dev); +} + +static const struct of_device_id meson_wdt_dt_ids[] = { + { .compatible = "amlogic,meson6-wdt" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids); + +static struct platform_driver meson_wdt_driver = { + .probe = meson_wdt_probe, + .remove = meson_wdt_remove, + .shutdown = meson_wdt_shutdown, + .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"); |