watchdog: sp805_wdt: convert to watchdog core

This patch converts existing sp805 watchdog driver to use already in place
common infrastructure present in watchdog core. With this lot of code goes away.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 82 insertions, 159 deletions

diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
index bbb170e50055..18d4bcfd1bfc 100644
--- a/drivers/watchdog/sp805_wdt.c
+++ b/drivers/watchdog/sp805_wdt.c
@@ -16,20 +16,17 @@
 #include <linux/amba/bus.h>
 #include <linux/bitops.h>
 #include <linux/clk.h>
-#include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/kernel.h>
 #include <linux/math64.h>
-#include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/pm.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
-#include <linux/uaccess.h>
 #include <linux/watchdog.h>
 
 /* default timeout in seconds */
@@ -56,6 +53,7 @@
 
 /**
  * struct sp805_wdt: sp805 wdt device structure
+ * @wdd: instance of struct watchdog_device
  * @lock: spin lock protecting dev structure and io access
  * @base: base address of wdt
  * @clk: clock structure of wdt
@@ -65,24 +63,24 @@
  * @timeout: current programmed timeout
  */
 struct sp805_wdt {
+        struct watchdog_device          wdd;
         spinlock_t                      lock;
         void __iomem                    *base;
         struct clk                      *clk;
         struct amba_device              *adev;
-        unsigned long                   status;
-        #define WDT_BUSY                0
-        #define WDT_CAN_BE_CLOSED       1
         unsigned int                    load_val;
         unsigned int                    timeout;
 };
 
-/* local variables */
-static struct sp805_wdt *wdt;
 static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+                "Set to 1 to keep watchdog running after device release");
 
 /* This routine finds load value that will reset system in required timout */
-static void wdt_setload(unsigned int timeout)
+static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
 {
+        struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
         u64 load, rate;
 
         rate = clk_get_rate(wdt->clk);
@@ -103,11 +101,14 @@ static void wdt_setload(unsigned int timeout)
         /* roundup timeout to closest positive integer value */
         wdt->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
         spin_unlock(&wdt->lock);
+
+        return 0;
 }
 
 /* returns number of seconds left for reset to occur */
-static u32 wdt_timeleft(void)
+static unsigned int wdt_timeleft(struct watchdog_device *wdd)
 {
+        struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
         u64 load, rate;
 
         rate = clk_get_rate(wdt->clk);
@@ -123,166 +124,88 @@ static u32 wdt_timeleft(void)
         return div_u64(load, rate);
 }
 
-/* enables watchdog timers reset */
-static void wdt_enable(void)
+static int wdt_config(struct watchdog_device *wdd, bool ping)
 {
+        struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
+        int ret;
+
+        if (!ping) {
+                ret = clk_enable(wdt->clk);
+                if (ret) {
+                        dev_err(&wdt->adev->dev, "clock enable fail");
+                        return ret;
+                }
+        }
+
         spin_lock(&wdt->lock);
 
         writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
         writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
-        writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
-        writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
-        writel_relaxed(LOCK, wdt->base + WDTLOCK);
-
-        /* Flush posted writes. */
-        readl_relaxed(wdt->base + WDTLOCK);
-        spin_unlock(&wdt->lock);
-}
 
-/* disables watchdog timers reset */
-static void wdt_disable(void)
-{
-        spin_lock(&wdt->lock);
+        if (!ping) {
+                writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
+                writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
+                                WDTCONTROL);
+        }
 
-        writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
-        writel_relaxed(0, wdt->base + WDTCONTROL);
         writel_relaxed(LOCK, wdt->base + WDTLOCK);
 
         /* Flush posted writes. */
         readl_relaxed(wdt->base + WDTLOCK);
         spin_unlock(&wdt->lock);
+
+        return 0;
 }
 
-static ssize_t sp805_wdt_write(struct file *file, const char *data,
-                size_t len, loff_t *ppos)
+static int wdt_ping(struct watchdog_device *wdd)
 {
-        if (len) {
-                if (!nowayout) {
-                        size_t i;
-
-                        clear_bit(WDT_CAN_BE_CLOSED, &wdt->status);
-
-                        for (i = 0; i != len; i++) {
-                                char c;
-
-                                if (get_user(c, data + i))
-                                        return -EFAULT;
-                                /* Check for Magic Close character */
-                                if (c == 'V') {
-                                        set_bit(WDT_CAN_BE_CLOSED,
-                                                        &wdt->status);
-                                        break;
-                                }
-                        }
-                }
-                wdt_enable();
-        }
-        return len;
+        return wdt_config(wdd, true);
 }
 
-static const struct watchdog_info ident = {
-        .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
-        .identity = MODULE_NAME,
-};
-
-static long sp805_wdt_ioctl(struct file *file, unsigned int cmd,
-                unsigned long arg)
+/* enables watchdog timers reset */
+static int wdt_enable(struct watchdog_device *wdd)
 {
-        int ret = -ENOTTY;
-        unsigned int timeout;
-
-        switch (cmd) {
-        case WDIOC_GETSUPPORT:
-                ret = copy_to_user((struct watchdog_info *)arg, &ident,
-                                sizeof(ident)) ? -EFAULT : 0;
-                break;
-
-        case WDIOC_GETSTATUS:
-                ret = put_user(0, (int *)arg);
-                break;
-
-        case WDIOC_KEEPALIVE:
-                wdt_enable();
-                ret = 0;
-                break;
-
-        case WDIOC_SETTIMEOUT:
-                ret = get_user(timeout, (unsigned int *)arg);
-                if (ret)
-                        break;
-
-                wdt_setload(timeout);
-
-                wdt_enable();
-                /* Fall through */
-
-        case WDIOC_GETTIMEOUT:
-                ret = put_user(wdt->timeout, (unsigned int *)arg);
-                break;
-        case WDIOC_GETTIMELEFT:
-                ret = put_user(wdt_timeleft(), (unsigned int *)arg);
-                break;
-        }
-        return ret;
+        return wdt_config(wdd, false);
 }
 
-static int sp805_wdt_open(struct inode *inode, struct file *file)
+/* disables watchdog timers reset */
+static int wdt_disable(struct watchdog_device *wdd)
 {
-        int ret = 0;
+        struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
 
-        if (test_and_set_bit(WDT_BUSY, &wdt->status))
-                return -EBUSY;
-
-        ret = clk_enable(wdt->clk);
-        if (ret) {
-                dev_err(&wdt->adev->dev, "clock enable fail");
-                goto err;
-        }
-
-        wdt_enable();
-
-        /* can not be closed, once enabled */
-        clear_bit(WDT_CAN_BE_CLOSED, &wdt->status);
-        return nonseekable_open(inode, file);
+        spin_lock(&wdt->lock);
 
-err:
-        clear_bit(WDT_BUSY, &wdt->status);
-        return ret;
-}
+        writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
+        writel_relaxed(0, wdt->base + WDTCONTROL);
+        writel_relaxed(LOCK, wdt->base + WDTLOCK);
 
-static int sp805_wdt_release(struct inode *inode, struct file *file)
-{
-        if (!test_bit(WDT_CAN_BE_CLOSED, &wdt->status)) {
-                clear_bit(WDT_BUSY, &wdt->status);
-                dev_warn(&wdt->adev->dev, "Device closed unexpectedly\n");
-                return 0;
-        }
+        /* Flush posted writes. */
+        readl_relaxed(wdt->base + WDTLOCK);
+        spin_unlock(&wdt->lock);
 
-        wdt_disable();
         clk_disable(wdt->clk);
-        clear_bit(WDT_BUSY, &wdt->status);
 
         return 0;
 }
 
-static const struct file_operations sp805_wdt_fops = {
-        .owner = THIS_MODULE,
-        .llseek = no_llseek,
-        .write = sp805_wdt_write,
-        .unlocked_ioctl = sp805_wdt_ioctl,
-        .open = sp805_wdt_open,
-        .release = sp805_wdt_release,
+static const struct watchdog_info wdt_info = {
+        .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+        .identity = MODULE_NAME,
 };
 
-static struct miscdevice sp805_wdt_miscdev = {
-        .minor = WATCHDOG_MINOR,
-        .name = "watchdog",
-        .fops = &sp805_wdt_fops,
+static const struct watchdog_ops wdt_ops = {
+        .owner          = THIS_MODULE,
+        .start          = wdt_enable,
+        .stop           = wdt_disable,
+        .ping           = wdt_ping,
+        .set_timeout    = wdt_setload,
+        .get_timeleft   = wdt_timeleft,
 };
 
 static int __devinit
 sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
 {
+        struct sp805_wdt *wdt;
         int ret = 0;
 
         if (!devm_request_mem_region(&adev->dev, adev->res.start,
@@ -315,19 +238,26 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
         }
 
         wdt->adev = adev;
+        wdt->wdd.info = &wdt_info;
+        wdt->wdd.ops = &wdt_ops;
+
         spin_lock_init(&wdt->lock);
-        wdt_setload(DEFAULT_TIMEOUT);
+        watchdog_set_nowayout(&wdt->wdd, nowayout);
+        watchdog_set_drvdata(&wdt->wdd, wdt);
+        wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
 
-        ret = misc_register(&sp805_wdt_miscdev);
-        if (ret < 0) {
-                dev_warn(&adev->dev, "cannot register misc device\n");
-                goto err_misc_register;
+        ret = watchdog_register_device(&wdt->wdd);
+        if (ret) {
+                dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
+                                ret);
+                goto err_register;
         }
+        amba_set_drvdata(adev, wdt);
 
         dev_info(&adev->dev, "registration successful\n");
         return 0;
 
-err_misc_register:
+err_register:
         clk_put(wdt->clk);
 err:
         dev_err(&adev->dev, "Probe Failed!!!\n");
@@ -336,7 +266,11 @@ err:
 
 static int __devexit sp805_wdt_remove(struct amba_device *adev)
 {
-        misc_deregister(&sp805_wdt_miscdev);
+        struct sp805_wdt *wdt = amba_get_drvdata(adev);
+
+        watchdog_unregister_device(&wdt->wdd);
+        amba_set_drvdata(adev, NULL);
+        watchdog_set_drvdata(&wdt->wdd, NULL);
         clk_put(wdt->clk);
 
         return 0;
@@ -345,28 +279,22 @@ static int __devexit sp805_wdt_remove(struct amba_device *adev)
 #ifdef CONFIG_PM
 static int sp805_wdt_suspend(struct device *dev)
 {
-        if (test_bit(WDT_BUSY, &wdt->status)) {
-                wdt_disable();
-                clk_disable(wdt->clk);
-        }
+        struct sp805_wdt *wdt = dev_get_drvdata(dev);
+
+        if (watchdog_active(&wdt->wdd))
+                return wdt_disable(&wdt->wdd);
 
         return 0;
 }
 
 static int sp805_wdt_resume(struct device *dev)
 {
-        int ret = 0;
+        struct sp805_wdt *wdt = dev_get_drvdata(dev);
 
-        if (test_bit(WDT_BUSY, &wdt->status)) {
-                ret = clk_enable(wdt->clk);
-                if (ret) {
-                        dev_err(dev, "clock enable fail");
-                        return ret;
-                }
-                wdt_enable();
-        }
+        if (watchdog_active(&wdt->wdd))
+                return wdt_enable(&wdt->wdd);
 
-        return ret;
+        return 0;
 }
 #endif /* CONFIG_PM */
 
@@ -395,11 +323,6 @@ static struct amba_driver sp805_wdt_driver = {
 
 module_amba_driver(sp805_wdt_driver);
 
-module_param(nowayout, bool, 0);
-MODULE_PARM_DESC(nowayout,
-                "Set to 1 to keep watchdog running after device release");
-
 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@st.com>");
 MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);