diff options
Diffstat (limited to 'drivers/watchdog/imx2_wdt.c')
| -rw-r--r-- | drivers/watchdog/imx2_wdt.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c new file mode 100644 index 000000000000..ea25885781bb --- /dev/null +++ b/drivers/watchdog/imx2_wdt.c @@ -0,0 +1,358 @@ +/* + * Watchdog driver for IMX2 and later processors + * + * Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de> + * + * some parts adapted by similar drivers from Darius Augulis and Vladimir + * Zapolskiy, additional improvements by Wim Van Sebroeck. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * NOTE: MX1 has a slightly different Watchdog than MX2 and later: + * + * MX1: MX2+: + * ---- ----- + * Registers: 32-bit 16-bit + * Stopable timer: Yes No + * Need to enable clk: No Yes + * Halt on suspend: Manual Can be automatic + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> +#include <linux/clk.h> +#include <linux/fs.h> +#include <linux/io.h> +#include <linux/uaccess.h> +#include <linux/timer.h> +#include <linux/jiffies.h> +#include <mach/hardware.h> + +#define DRIVER_NAME "imx2-wdt" + +#define IMX2_WDT_WCR 0x00 /* Control Register */ +#define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */ +#define IMX2_WDT_WCR_WRE (1 << 3) /* -> WDOG Reset Enable */ +#define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */ + +#define IMX2_WDT_WSR 0x02 /* Service Register */ +#define IMX2_WDT_SEQ1 0x5555 /* -> service sequence 1 */ +#define IMX2_WDT_SEQ2 0xAAAA /* -> service sequence 2 */ + +#define IMX2_WDT_MAX_TIME 128 +#define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */ + +#define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8) + +#define IMX2_WDT_STATUS_OPEN 0 +#define IMX2_WDT_STATUS_STARTED 1 +#define IMX2_WDT_EXPECT_CLOSE 2 + +static struct { + struct clk *clk; + void __iomem *base; + unsigned timeout; + unsigned long status; + struct timer_list timer; /* Pings the watchdog when closed */ +} imx2_wdt; + +static struct miscdevice imx2_wdt_miscdev; + +static int nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + + +static unsigned timeout = IMX2_WDT_DEFAULT_TIME; +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" + __MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")"); + +static const struct watchdog_info imx2_wdt_info = { + .identity = "imx2+ watchdog", + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, +}; + +static inline void imx2_wdt_setup(void) +{ + u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR); + + /* Strip the old watchdog Time-Out value */ + val &= ~IMX2_WDT_WCR_WT; + /* Generate reset if WDOG times out */ + val &= ~IMX2_WDT_WCR_WRE; + /* Keep Watchdog Disabled */ + val &= ~IMX2_WDT_WCR_WDE; + /* Set the watchdog's Time-Out value */ + val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout); + + __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); + + /* enable the watchdog */ + val |= IMX2_WDT_WCR_WDE; + __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); +} + +static inline void imx2_wdt_ping(void) +{ + __raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR); + __raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR); +} + +static void imx2_wdt_timer_ping(unsigned long arg) +{ + /* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */ + imx2_wdt_ping(); + mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2); +} + +static void imx2_wdt_start(void) +{ + if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { + /* at our first start we enable clock and do initialisations */ + clk_enable(imx2_wdt.clk); + + imx2_wdt_setup(); + } else /* delete the timer that pings the watchdog after close */ + del_timer_sync(&imx2_wdt.timer); + + /* Watchdog is enabled - time to reload the timeout value */ + imx2_wdt_ping(); +} + +static void imx2_wdt_stop(void) +{ + /* we don't need a clk_disable, it cannot be disabled once started. + * We use a timer to ping the watchdog while /dev/watchdog is closed */ + imx2_wdt_timer_ping(0); +} + +static void imx2_wdt_set_timeout(int new_timeout) +{ + u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR); + + /* set the new timeout value in the WSR */ + val &= ~IMX2_WDT_WCR_WT; + val |= WDOG_SEC_TO_COUNT(new_timeout); + __raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR); +} + +static int imx2_wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status)) + return -EBUSY; + + imx2_wdt_start(); + return nonseekable_open(inode, file); +} + +static int imx2_wdt_close(struct inode *inode, struct file *file) +{ + if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout) + imx2_wdt_stop(); + else { + dev_crit(imx2_wdt_miscdev.parent, + "Unexpected close: Expect reboot!\n"); + imx2_wdt_ping(); + } + + clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); + clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status); + return 0; +} + +static long imx2_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + int new_value; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &imx2_wdt_info, + sizeof(struct watchdog_info)) ? -EFAULT : 0; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + + case WDIOC_KEEPALIVE: + imx2_wdt_ping(); + return 0; + + case WDIOC_SETTIMEOUT: + if (get_user(new_value, p)) + return -EFAULT; + if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME)) + return -EINVAL; + imx2_wdt_set_timeout(new_value); + imx2_wdt.timeout = new_value; + imx2_wdt_ping(); + + /* Fallthrough to return current value */ + case WDIOC_GETTIMEOUT: + return put_user(imx2_wdt.timeout, p); + + default: + return -ENOTTY; + } +} + +static ssize_t imx2_wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + size_t i; + char c; + + if (len == 0) /* Can we see this even ? */ + return 0; + + clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); + /* scan to see whether or not we got the magic character */ + for (i = 0; i != len; i++) { + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') + set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status); + } + + imx2_wdt_ping(); + return len; +} + +static const struct file_operations imx2_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .unlocked_ioctl = imx2_wdt_ioctl, + .open = imx2_wdt_open, + .release = imx2_wdt_close, + .write = imx2_wdt_write, +}; + +static struct miscdevice imx2_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &imx2_wdt_fops, +}; + +static int __init imx2_wdt_probe(struct platform_device *pdev) +{ + int ret; + int res_size; + struct resource *res; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "can't get device resources\n"); + return -ENODEV; + } + + res_size = resource_size(res); + if (!devm_request_mem_region(&pdev->dev, res->start, res_size, + res->name)) { + dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n", + res_size, res->start); + return -ENOMEM; + } + + imx2_wdt.base = devm_ioremap_nocache(&pdev->dev, res->start, res_size); + if (!imx2_wdt.base) { + dev_err(&pdev->dev, "ioremap failed\n"); + return -ENOMEM; + } + + imx2_wdt.clk = clk_get_sys("imx-wdt.0", NULL); + if (IS_ERR(imx2_wdt.clk)) { + dev_err(&pdev->dev, "can't get Watchdog clock\n"); + return PTR_ERR(imx2_wdt.clk); + } + + imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME); + if (imx2_wdt.timeout != timeout) + dev_warn(&pdev->dev, "Initial timeout out of range! " + "Clamped from %u to %u\n", timeout, imx2_wdt.timeout); + + setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0); + + imx2_wdt_miscdev.parent = &pdev->dev; + ret = misc_register(&imx2_wdt_miscdev); + if (ret) + goto fail; + + dev_info(&pdev->dev, + "IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n", + imx2_wdt.timeout, nowayout); + return 0; + +fail: + imx2_wdt_miscdev.parent = NULL; + clk_put(imx2_wdt.clk); + return ret; +} + +static int __exit imx2_wdt_remove(struct platform_device *pdev) +{ + misc_deregister(&imx2_wdt_miscdev); + + if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { + del_timer_sync(&imx2_wdt.timer); + + dev_crit(imx2_wdt_miscdev.parent, + "Device removed: Expect reboot!\n"); + } else + clk_put(imx2_wdt.clk); + + imx2_wdt_miscdev.parent = NULL; + return 0; +} + +static void imx2_wdt_shutdown(struct platform_device *pdev) +{ + if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) { + /* we are running, we need to delete the timer but will give + * max timeout before reboot will take place */ + del_timer_sync(&imx2_wdt.timer); + imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME); + imx2_wdt_ping(); + + dev_crit(imx2_wdt_miscdev.parent, + "Device shutdown: Expect reboot!\n"); + } +} + +static struct platform_driver imx2_wdt_driver = { + .probe = imx2_wdt_probe, + .remove = __exit_p(imx2_wdt_remove), + .shutdown = imx2_wdt_shutdown, + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + }, +}; + +static int __init imx2_wdt_init(void) +{ + return platform_driver_probe(&imx2_wdt_driver, imx2_wdt_probe); +} +module_init(imx2_wdt_init); + +static void __exit imx2_wdt_exit(void) +{ + platform_driver_unregister(&imx2_wdt_driver); +} +module_exit(imx2_wdt_exit); + +MODULE_AUTHOR("Wolfram Sang"); +MODULE_DESCRIPTION("Watchdog driver for IMX2 and later"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); +MODULE_ALIAS("platform:" DRIVER_NAME); |