--- /dev/null
+/*
+ * 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);
projects / platform / kernel / linux-stable.git / commitdiff