Date:   Sun, 24 Dec 2017 13:04:14 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Wim Van Sebroeck <wim@...ana.be>
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        Zoltán Böszörményi 
        <zboszor@...hu>, Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 09/12] watchdog: sp5100_tco: Convert to use watchdog subsystem

Convert to watchdog subsystem. As part of that rework, use devm functions
where possible, and replace almost all static variables with a dynamically
allocated data structure.

Cc: Zoltán Böszörményi <zboszor@...hu>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/watchdog/sp5100_tco.c | 358 ++++++++++++------------------------------
 1 file changed, 102 insertions(+), 256 deletions(-)

diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index 1123fad38fdf..bb6c4608c1c0 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -24,37 +24,31 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <linux/types.h>
-#include <linux/miscdevice.h>
-#include <linux/watchdog.h>
-#include <linux/init.h>
-#include <linux/fs.h>
 #include <linux/pci.h>
-#include <linux/ioport.h>
 #include <linux/platform_device.h>
-#include <linux/uaccess.h>
-#include <linux/io.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
 
 #include "sp5100_tco.h"
 
-/* Module and version information */
-#define TCO_VERSION "0.05"
-#define TCO_MODULE_NAME "SP5100 TCO timer"
-#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
+#define TCO_DRIVER_NAME	"sp5100-tco"
 
 /* internal variables */
-static u32 tcobase_phys;
-static u32 tco_wdt_fired;
-static void __iomem *tcobase;
-static DEFINE_SPINLOCK(tco_lock);	/* Guards the hardware */
-static unsigned long timer_alive;
-static char tco_expect_close;
-static struct pci_dev *sp5100_tco_pci;
+
+struct sp5100_tco {
+	struct watchdog_device wdd;
+	void __iomem *tcobase;
+};
 
 /* the watchdog platform device */
 static struct platform_device *sp5100_tco_platform_device;
+/* the associated PCI device */
+static struct pci_dev *sp5100_tco_pci;
 
 /* module parameters */
 
@@ -79,55 +73,52 @@ static bool tco_has_sp5100_reg_layout(struct pci_dev *dev)
 	       dev->revision < 0x40;
 }
 
-static void tco_timer_start(void)
+static int tco_timer_start(struct watchdog_device *wdd)
 {
+	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
 	u32 val;
-	unsigned long flags;
 
-	spin_lock_irqsave(&tco_lock, flags);
-	val = readl(SP5100_WDT_CONTROL(tcobase));
+	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
 	val |= SP5100_WDT_START_STOP_BIT;
-	writel(val, SP5100_WDT_CONTROL(tcobase));
-	spin_unlock_irqrestore(&tco_lock, flags);
+	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
+
+	return 0;
 }
 
-static void tco_timer_stop(void)
+static int tco_timer_stop(struct watchdog_device *wdd)
 {
+	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
 	u32 val;
-	unsigned long flags;
 
-	spin_lock_irqsave(&tco_lock, flags);
-	val = readl(SP5100_WDT_CONTROL(tcobase));
+	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
 	val &= ~SP5100_WDT_START_STOP_BIT;
-	writel(val, SP5100_WDT_CONTROL(tcobase));
-	spin_unlock_irqrestore(&tco_lock, flags);
+	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
+
+	return 0;
 }
 
-static void tco_timer_keepalive(void)
+static int tco_timer_ping(struct watchdog_device *wdd)
 {
+	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
 	u32 val;
-	unsigned long flags;
 
-	spin_lock_irqsave(&tco_lock, flags);
-	val = readl(SP5100_WDT_CONTROL(tcobase));
+	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
 	val |= SP5100_WDT_TRIGGER_BIT;
-	writel(val, SP5100_WDT_CONTROL(tcobase));
-	spin_unlock_irqrestore(&tco_lock, flags);
+	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
+
+	return 0;
 }
 
-static int tco_timer_set_heartbeat(int t)
+static int tco_timer_set_timeout(struct watchdog_device *wdd,
+				 unsigned int t)
 {
-	unsigned long flags;
-
-	if (t < 0 || t > 0xffff)
-		return -EINVAL;
+	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
 
 	/* Write new heartbeat to watchdog */
-	spin_lock_irqsave(&tco_lock, flags);
-	writel(t, SP5100_WDT_COUNT(tcobase));
-	spin_unlock_irqrestore(&tco_lock, flags);
+	writel(t, SP5100_WDT_COUNT(tco->tcobase));
+
+	wdd->timeout = t;
 
-	heartbeat = t;
 	return 0;
 }
 
@@ -182,137 +173,7 @@ static void tco_timer_enable(void)
 	}
 }
 
-/*
- *	/dev/watchdog handling
- */
-
-static int sp5100_tco_open(struct inode *inode, struct file *file)
-{
-	/* /dev/watchdog can only be opened once */
-	if (test_and_set_bit(0, &timer_alive))
-		return -EBUSY;
-
-	/* Reload and activate timer */
-	tco_timer_start();
-	tco_timer_keepalive();
-	return nonseekable_open(inode, file);
-}
-
-static int sp5100_tco_release(struct inode *inode, struct file *file)
-{
-	/* Shut off the timer. */
-	if (tco_expect_close == 42) {
-		tco_timer_stop();
-	} else {
-		pr_crit("Unexpected close, not stopping watchdog!\n");
-		tco_timer_keepalive();
-	}
-	clear_bit(0, &timer_alive);
-	tco_expect_close = 0;
-	return 0;
-}
-
-static ssize_t sp5100_tco_write(struct file *file, const char __user *data,
-				size_t len, loff_t *ppos)
-{
-	/* See if we got the magic character 'V' and reload the timer */
-	if (len) {
-		if (!nowayout) {
-			size_t i;
-
-			/* note: just in case someone wrote the magic character
-			 * five months ago... */
-			tco_expect_close = 0;
-
-			/* scan to see whether or not we got the magic character
-			 */
-			for (i = 0; i != len; i++) {
-				char c;
-				if (get_user(c, data + i))
-					return -EFAULT;
-				if (c == 'V')
-					tco_expect_close = 42;
-			}
-		}
-
-		/* someone wrote to us, we should reload the timer */
-		tco_timer_keepalive();
-	}
-	return len;
-}
-
-static long sp5100_tco_ioctl(struct file *file, unsigned int cmd,
-			     unsigned long arg)
-{
-	int new_options, retval = -EINVAL;
-	int new_heartbeat;
-	void __user *argp = (void __user *)arg;
-	int __user *p = argp;
-	static const struct watchdog_info ident = {
-		.options =		WDIOF_SETTIMEOUT |
-					WDIOF_KEEPALIVEPING |
-					WDIOF_MAGICCLOSE,
-		.firmware_version =	0,
-		.identity =		TCO_MODULE_NAME,
-	};
-
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		return copy_to_user(argp, &ident,
-			sizeof(ident)) ? -EFAULT : 0;
-	case WDIOC_GETSTATUS:
-	case WDIOC_GETBOOTSTATUS:
-		return put_user(0, p);
-	case WDIOC_SETOPTIONS:
-		if (get_user(new_options, p))
-			return -EFAULT;
-		if (new_options & WDIOS_DISABLECARD) {
-			tco_timer_stop();
-			retval = 0;
-		}
-		if (new_options & WDIOS_ENABLECARD) {
-			tco_timer_start();
-			tco_timer_keepalive();
-			retval = 0;
-		}
-		return retval;
-	case WDIOC_KEEPALIVE:
-		tco_timer_keepalive();
-		return 0;
-	case WDIOC_SETTIMEOUT:
-		if (get_user(new_heartbeat, p))
-			return -EFAULT;
-		if (tco_timer_set_heartbeat(new_heartbeat))
-			return -EINVAL;
-		tco_timer_keepalive();
-		/* Fall through */
-	case WDIOC_GETTIMEOUT:
-		return put_user(heartbeat, p);
-	default:
-		return -ENOTTY;
-	}
-}
-
-/*
- * Kernel Interfaces
- */
-
-static const struct file_operations sp5100_tco_fops = {
-	.owner =		THIS_MODULE,
-	.llseek =		no_llseek,
-	.write =		sp5100_tco_write,
-	.unlocked_ioctl =	sp5100_tco_ioctl,
-	.open =			sp5100_tco_open,
-	.release =		sp5100_tco_release,
-};
-
-static struct miscdevice sp5100_tco_miscdev = {
-	.minor =	WATCHDOG_MINOR,
-	.name =		"watchdog",
-	.fops =		&sp5100_tco_fops,
-};
-
-static u8 sp5100_tco_read_pm_reg32(u8 index)
+static u32 sp5100_tco_read_pm_reg32(u8 index)
 {
 	u32 val = 0;
 	int i;
@@ -323,14 +184,13 @@ static u8 sp5100_tco_read_pm_reg32(u8 index)
 	return val;
 }
 
-/*
- * Init & exit routines
- */
-static int sp5100_tco_setupdevice(struct device *dev)
+static int sp5100_tco_setupdevice(struct device *dev,
+				  struct watchdog_device *wdd)
 {
-	const char *dev_name = NULL;
-	u32 val;
+	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
+	const char *dev_name;
 	u8 base_addr;
+	u32 val;
 	int ret;
 
 	/*
@@ -361,8 +221,8 @@ static int sp5100_tco_setupdevice(struct device *dev)
 	dev_dbg(dev, "Got 0x%04x from indirect I/O\n", val);
 
 	/* Check MMIO address conflict */
-	if (!request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE,
-					  dev_name)) {
+	if (!devm_request_mem_region(dev, val, SP5100_WDT_MEM_MAP_SIZE,
+				     dev_name)) {
 		dev_dbg(dev, "MMIO address 0x%04x already in use\n", val);
 		/*
 		 * Secondly, Find the watchdog timer MMIO address
@@ -391,8 +251,8 @@ static int sp5100_tco_setupdevice(struct device *dev)
 		/* Add the Watchdog Timer offset to base address. */
 		val += SB800_PM_WDT_MMIO_OFFSET;
 		/* Check MMIO address conflict */
-		if (!request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE,
-						  dev_name)) {
+		if (!devm_request_mem_region(dev, val, SP5100_WDT_MEM_MAP_SIZE,
+					     dev_name)) {
 			dev_dbg(dev, "MMIO address 0x%04x already in use\n",
 				val);
 			ret = -EBUSY;
@@ -401,13 +261,11 @@ static int sp5100_tco_setupdevice(struct device *dev)
 		dev_dbg(dev, "Got 0x%04x from SBResource_MMIO register\n", val);
 	}
 
-	tcobase_phys = val;
-
-	tcobase = ioremap(val, SP5100_WDT_MEM_MAP_SIZE);
-	if (!tcobase) {
+	tco->tcobase = devm_ioremap(dev, val, SP5100_WDT_MEM_MAP_SIZE);
+	if (!tco->tcobase) {
 		dev_err(dev, "failed to get tcobase address\n");
 		ret = -ENOMEM;
-		goto unreg_mem_region;
+		goto unreg_region;
 	}
 
 	dev_info(dev, "Using 0x%04x for watchdog MMIO address\n", val);
@@ -416,107 +274,95 @@ static int sp5100_tco_setupdevice(struct device *dev)
 	tco_timer_enable();
 
 	/* Check that the watchdog action is set to reset the system */
-	val = readl(SP5100_WDT_CONTROL(tcobase));
+	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
 	/*
 	 * Save WatchDogFired status, because WatchDogFired flag is
 	 * cleared here.
 	 */
-	tco_wdt_fired = val & SP5100_WDT_FIRED;
+	if (val & SP5100_WDT_FIRED)
+		wdd->bootstatus = WDIOF_CARDRESET;
 	val &= ~SP5100_WDT_ACTION_RESET;
-	writel(val, SP5100_WDT_CONTROL(tcobase));
+	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
 
 	/* Set a reasonable heartbeat before we stop the timer */
-	tco_timer_set_heartbeat(heartbeat);
+	tco_timer_set_timeout(wdd, wdd->timeout);
 
 	/*
 	 * Stop the TCO before we change anything so we don't race with
 	 * a zeroed timer.
 	 */
-	tco_timer_stop();
+	tco_timer_stop(wdd);
 
 	release_region(SP5100_IO_PM_INDEX_REG, SP5100_PM_IOPORTS_SIZE);
 
 	return 0;
 
-unreg_mem_region:
-	release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
 unreg_region:
 	release_region(SP5100_IO_PM_INDEX_REG, SP5100_PM_IOPORTS_SIZE);
 	return ret;
 }
 
+static struct watchdog_info sp5100_tco_wdt_info = {
+	.identity = "SP5100 TCO timer",
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops sp5100_tco_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = tco_timer_start,
+	.stop = tco_timer_stop,
+	.ping = tco_timer_ping,
+	.set_timeout = tco_timer_set_timeout,
+};
+
 static int sp5100_tco_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct watchdog_device *wdd;
+	struct sp5100_tco *tco;
 	int ret;
 
-	/*
-	 * Check whether or not the hardware watchdog is there. If found, then
-	 * set it up.
-	 */
-	ret = sp5100_tco_setupdevice(dev);
+	tco = devm_kzalloc(dev, sizeof(*tco), GFP_KERNEL);
+	if (!tco)
+		return -ENOMEM;
+
+	wdd = &tco->wdd;
+	wdd->parent = dev;
+	wdd->info = &sp5100_tco_wdt_info;
+	wdd->ops = &sp5100_tco_wdt_ops;
+	wdd->timeout = WATCHDOG_HEARTBEAT;
+	wdd->min_timeout = 1;
+	wdd->max_timeout = 0xffff;
+
+	if (watchdog_init_timeout(wdd, heartbeat, NULL))
+		dev_info(dev, "timeout value invalid, using %d\n",
+			 wdd->timeout);
+	watchdog_set_nowayout(wdd, nowayout);
+	watchdog_stop_on_reboot(wdd);
+	watchdog_stop_on_unregister(wdd);
+	watchdog_set_drvdata(wdd, tco);
+
+	ret = sp5100_tco_setupdevice(dev, wdd);
 	if (ret)
 		return ret;
 
-	/* Check to see if last reboot was due to watchdog timeout */
-	dev_info(dev, "Last reboot was %striggered by watchdog.\n",
-		 tco_wdt_fired ? "" : "not ");
-
-	/*
-	 * Check that the heartbeat value is within it's range.
-	 * If not, reset to the default.
-	 */
-	if (tco_timer_set_heartbeat(heartbeat)) {
-		heartbeat = WATCHDOG_HEARTBEAT;
-		tco_timer_set_heartbeat(heartbeat);
-	}
-
-	ret = misc_register(&sp5100_tco_miscdev);
-	if (ret != 0) {
-		dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
-			WATCHDOG_MINOR, ret);
-		goto exit;
+	ret = devm_watchdog_register_device(dev, wdd);
+	if (ret) {
+		dev_err(dev, "cannot register watchdog device (err=%d)\n", ret);
+		return ret;
 	}
 
-	clear_bit(0, &timer_alive);
-
 	/* Show module parameters */
-	dev_info(dev, "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
-		 tcobase, heartbeat, nowayout);
+	dev_info(dev, "initialized. heartbeat=%d sec (nowayout=%d)\n",
+		 wdd->timeout, nowayout);
 
 	return 0;
-
-exit:
-	iounmap(tcobase);
-	release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
-	return ret;
-}
-
-static int sp5100_tco_remove(struct platform_device *pdev)
-{
-	/* Stop the timer before we leave */
-	if (!nowayout)
-		tco_timer_stop();
-
-	/* Deregister */
-	misc_deregister(&sp5100_tco_miscdev);
-	iounmap(tcobase);
-	release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
-
-	return 0;
-}
-
-static void sp5100_tco_shutdown(struct platform_device *pdev)
-{
-	tco_timer_stop();
 }
 
 static struct platform_driver sp5100_tco_driver = {
 	.probe		= sp5100_tco_probe,
-	.remove		= sp5100_tco_remove,
-	.shutdown	= sp5100_tco_shutdown,
 	.driver		= {
-		.name	= TCO_MODULE_NAME,
+		.name	= TCO_DRIVER_NAME,
 	},
 };
 
@@ -555,14 +401,14 @@ static int __init sp5100_tco_init(void)
 	if (!sp5100_tco_pci)
 		return -ENODEV;
 
-	pr_info("SP5100/SB800 TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
+	pr_info("SP5100/SB800 TCO WatchDog Timer Driver\n");
 
 	err = platform_driver_register(&sp5100_tco_driver);
 	if (err)
 		return err;
 
-	sp5100_tco_platform_device = platform_device_register_simple(
-					TCO_MODULE_NAME, -1, NULL, 0);
+	sp5100_tco_platform_device =
+		platform_device_register_simple(TCO_DRIVER_NAME, -1, NULL, 0);
 	if (IS_ERR(sp5100_tco_platform_device)) {
 		err = PTR_ERR(sp5100_tco_platform_device);
 		goto unreg_platform_driver;
-- 
2.7.4

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