diff options
Diffstat (limited to 'kernel/drivers/watchdog/moxart_wdt.c')
| -rw-r--r-- | kernel/drivers/watchdog/moxart_wdt.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/kernel/drivers/watchdog/moxart_wdt.c b/kernel/drivers/watchdog/moxart_wdt.c new file mode 100644 index 000000000..2789da2c0 --- /dev/null +++ b/kernel/drivers/watchdog/moxart_wdt.c @@ -0,0 +1,187 @@ +/* + * MOXA ART SoCs watchdog driver. + * + * Copyright (C) 2013 Jonas Jensen + * + * Jonas Jensen <jonas.jensen@gmail.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/err.h> +#include <linux/kernel.h> +#include <linux/notifier.h> +#include <linux/platform_device.h> +#include <linux/reboot.h> +#include <linux/watchdog.h> +#include <linux/moduleparam.h> + +#define REG_COUNT 0x4 +#define REG_MODE 0x8 +#define REG_ENABLE 0xC + +struct moxart_wdt_dev { + struct watchdog_device dev; + void __iomem *base; + unsigned int clock_frequency; + struct notifier_block restart_handler; +}; + +static int heartbeat; + +static int moxart_restart_handle(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + struct moxart_wdt_dev *moxart_wdt = container_of(this, + struct moxart_wdt_dev, + restart_handler); + writel(1, moxart_wdt->base + REG_COUNT); + writel(0x5ab9, moxart_wdt->base + REG_MODE); + writel(0x03, moxart_wdt->base + REG_ENABLE); + + return NOTIFY_DONE; +} + +static int moxart_wdt_stop(struct watchdog_device *wdt_dev) +{ + struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); + + writel(0, moxart_wdt->base + REG_ENABLE); + + return 0; +} + +static int moxart_wdt_start(struct watchdog_device *wdt_dev) +{ + struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev); + + writel(moxart_wdt->clock_frequency * wdt_dev->timeout, + moxart_wdt->base + REG_COUNT); + writel(0x5ab9, moxart_wdt->base + REG_MODE); + writel(0x03, moxart_wdt->base + REG_ENABLE); + + return 0; +} + +static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int timeout) +{ + wdt_dev->timeout = timeout; + + return 0; +} + +static const struct watchdog_info moxart_wdt_info = { + .identity = "moxart-wdt", + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, +}; + +static const struct watchdog_ops moxart_wdt_ops = { + .owner = THIS_MODULE, + .start = moxart_wdt_start, + .stop = moxart_wdt_stop, + .set_timeout = moxart_wdt_set_timeout, +}; + +static int moxart_wdt_probe(struct platform_device *pdev) +{ + struct moxart_wdt_dev *moxart_wdt; + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node; + struct resource *res; + struct clk *clk; + int err; + unsigned int max_timeout; + bool nowayout = WATCHDOG_NOWAYOUT; + + moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL); + if (!moxart_wdt) + return -ENOMEM; + + platform_set_drvdata(pdev, moxart_wdt); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + moxart_wdt->base = devm_ioremap_resource(dev, res); + if (IS_ERR(moxart_wdt->base)) + return PTR_ERR(moxart_wdt->base); + + clk = of_clk_get(node, 0); + if (IS_ERR(clk)) { + pr_err("%s: of_clk_get failed\n", __func__); + return PTR_ERR(clk); + } + + moxart_wdt->clock_frequency = clk_get_rate(clk); + if (moxart_wdt->clock_frequency == 0) { + pr_err("%s: incorrect clock frequency\n", __func__); + return -EINVAL; + } + + max_timeout = UINT_MAX / moxart_wdt->clock_frequency; + + moxart_wdt->dev.info = &moxart_wdt_info; + moxart_wdt->dev.ops = &moxart_wdt_ops; + moxart_wdt->dev.timeout = max_timeout; + moxart_wdt->dev.min_timeout = 1; + moxart_wdt->dev.max_timeout = max_timeout; + moxart_wdt->dev.parent = dev; + + watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev); + watchdog_set_nowayout(&moxart_wdt->dev, nowayout); + + watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt); + + err = watchdog_register_device(&moxart_wdt->dev); + if (err) + return err; + + moxart_wdt->restart_handler.notifier_call = moxart_restart_handle; + moxart_wdt->restart_handler.priority = 128; + err = register_restart_handler(&moxart_wdt->restart_handler); + if (err) + dev_err(dev, "cannot register restart notifier (err=%d)\n", + err); + + dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n", + moxart_wdt->dev.timeout, nowayout); + + return 0; +} + +static int moxart_wdt_remove(struct platform_device *pdev) +{ + struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev); + + unregister_restart_handler(&moxart_wdt->restart_handler); + moxart_wdt_stop(&moxart_wdt->dev); + + return 0; +} + +static const struct of_device_id moxart_watchdog_match[] = { + { .compatible = "moxa,moxart-watchdog" }, + { }, +}; + +static struct platform_driver moxart_wdt_driver = { + .probe = moxart_wdt_probe, + .remove = moxart_wdt_remove, + .driver = { + .name = "moxart-watchdog", + .of_match_table = moxart_watchdog_match, + }, +}; +module_platform_driver(moxart_wdt_driver); + +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds"); + +MODULE_DESCRIPTION("MOXART watchdog driver"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>"); |