[RESEND PATCH v3 0/3] watchdog: f71808e_wdt: migrate to new kernel API

[RESEND PATCH v3 0/3] watchdog: f71808e_wdt: migrate to new kernel API

[Ahmad Fatoum]

This series migrates the driver to the new kernel watchdog API and
then to the driver model.

Main feedback from Guenther on v2 was that I need to split it up to
enable review. I have done so by removing the extra refactoring for
now and focused on the functional changes described above. The diff
is now much better readable.

I tested it on a f81866.

v3 -> RESEND:
  https://lore.kernel.org/linux-watchdog/cover.dedd9f1159389b0a438076ef5e5a46aded186463.1612457906.git-series.a.fatoum@pengutronix.de/#t
  Didn't generate any feedback over 2 months. Resending for exposure.

v2 -> v3:
  https://lore.kernel.org/linux-watchdog/20201020062112.6762-1-a.fatoum@pengutronix.de/
  - factored out identifier renaming again for easier review
  - reordered commits
  - removed refactoring that can go in later. Focusing now on kernel watchdog
    API and platform device/driver migration
  - removed platform_device_id and changed code to match by name

v1 -> v2:
  https://lore.kernel.org/linux-watchdog/20200611191750.28096-1-a.fatoum@pengutronix.de/
  - reworked to platform device/driver pair (Guenther)
  - squashed identifier renaming into the patches that touch
    the respective lines anyway
  - fixed checkpatch.pl nitpicks (Guenther)
  - fixed locally used variable declared without static (0-day)
  - fixed unneded line break due to old line limit (Guenther)
  - renamed struct fintek_wdog_data to struct fintek_wdt

Ahmad Fatoum (3):
  watchdog: f71808e_wdt: rename variant-independent identifiers appropriately
  watchdog: f71808e_wdt: migrate to new kernel watchdog API
  watchdog: f71808e_wdt: refactor to platform device/driver pair

 drivers/watchdog/Kconfig       |   1 +-
 drivers/watchdog/f71808e_wdt.c | 450 +++++++---------------------------
 2 files changed, 100 insertions(+), 351 deletions(-)

base-commit: 1048ba83fb1c00cd24172e23e8263972f6b5d9ac
-- 
git-series 0.9.1

[RESEND PATCH v3 1/3] watchdog: f71808e_wdt: rename variant-independent identifiers appropriately

[Ahmad Fatoum]

Code for the common parts of the driver either uses watchdog_ as
prefix for the watchdog API or f71808e_ for everything else.

The driver now supports 9 more variants besides the f71808e,
so let's rename the common parts to start with fintek_wdt_ instead.

This makes code browsing easier, because it's readily apparent
that functions are not variant-specific. Some watchdog_-prefixed
functions remain, but these will be dropped altogether with the move
to the kernel watchdog API in a later commit.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/watchdog/f71808e_wdt.c | 66 +++++++++++++++++------------------
 1 file changed, 33 insertions(+), 33 deletions(-)

diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
index f60beec1bbae..665bef272a33 100644
--- a/drivers/watchdog/f71808e_wdt.c
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -113,7 +113,7 @@ MODULE_PARM_DESC(start_withtimeout, "Start watchdog timer on module load with"
 enum chips { f71808fg, f71858fg, f71862fg, f71868, f71869, f71882fg, f71889fg,
 	     f81803, f81865, f81866};
 
-static const char *f71808e_names[] = {
+static const char *fintek_wdt_names[] = {
 	"f71808fg",
 	"f71858fg",
 	"f71862fg",
@@ -136,7 +136,7 @@ static inline int superio_enter(int base);
 static inline void superio_select(int base, int ld);
 static inline void superio_exit(int base);
 
-struct watchdog_data {
+struct fintek_wdt {
 	unsigned short	sioaddr;
 	enum chips	type;
 	unsigned long	opened;
@@ -152,7 +152,7 @@ struct watchdog_data {
 	char		caused_reboot;	/* last reboot was by the watchdog */
 };
 
-static struct watchdog_data watchdog = {
+static struct fintek_wdt watchdog = {
 	.lock = __MUTEX_INITIALIZER(watchdog.lock),
 };
 
@@ -218,7 +218,7 @@ static inline void superio_exit(int base)
 	release_region(base, 2);
 }
 
-static int watchdog_set_timeout(int timeout)
+static int fintek_wdt_set_timeout(int timeout)
 {
 	if (timeout <= 0
 	 || timeout >  max_timeout) {
@@ -242,7 +242,7 @@ static int watchdog_set_timeout(int timeout)
 	return 0;
 }
 
-static int watchdog_set_pulse_width(unsigned int pw)
+static int fintek_wdt_set_pulse_width(unsigned int pw)
 {
 	int err = 0;
 	unsigned int t1 = 25, t2 = 125, t3 = 5000;
@@ -276,7 +276,7 @@ static int watchdog_set_pulse_width(unsigned int pw)
 	return err;
 }
 
-static int watchdog_keepalive(void)
+static int fintek_wdt_keepalive(void)
 {
 	int err = 0;
 
@@ -306,13 +306,13 @@ static int watchdog_keepalive(void)
 	return err;
 }
 
-static int watchdog_start(void)
+static int fintek_wdt_start(void)
 {
 	int err;
 	u8 tmp;
 
 	/* Make sure we don't die as soon as the watchdog is enabled below */
-	err = watchdog_keepalive();
+	err = fintek_wdt_keepalive();
 	if (err)
 		return err;
 
@@ -433,7 +433,7 @@ static int watchdog_start(void)
 	return err;
 }
 
-static int watchdog_stop(void)
+static int fintek_wdt_stop(void)
 {
 	int err = 0;
 
@@ -465,7 +465,7 @@ static int watchdog_get_status(void)
 	return status;
 }
 
-static bool watchdog_is_running(void)
+static bool fintek_wdt_is_running(void)
 {
 	/*
 	 * if we fail to determine the watchdog's status assume it to be
@@ -499,7 +499,7 @@ static int watchdog_open(struct inode *inode, struct file *file)
 	if (test_and_set_bit(0, &watchdog.opened))
 		return -EBUSY;
 
-	err = watchdog_start();
+	err = fintek_wdt_start();
 	if (err) {
 		clear_bit(0, &watchdog.opened);
 		return err;
@@ -517,10 +517,10 @@ static int watchdog_release(struct inode *inode, struct file *file)
 	clear_bit(0, &watchdog.opened);
 
 	if (!watchdog.expect_close) {
-		watchdog_keepalive();
+		fintek_wdt_keepalive();
 		pr_crit("Unexpected close, not stopping watchdog!\n");
 	} else if (!nowayout) {
-		watchdog_stop();
+		fintek_wdt_stop();
 	}
 	return 0;
 }
@@ -561,7 +561,7 @@ static ssize_t watchdog_write(struct file *file, const char __user *buf,
 		}
 
 		/* someone wrote to us, we should restart timer */
-		watchdog_keepalive();
+		fintek_wdt_keepalive();
 	}
 	return count;
 }
@@ -608,24 +608,24 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
 			return -EFAULT;
 
 		if (new_options & WDIOS_DISABLECARD)
-			watchdog_stop();
+			fintek_wdt_stop();
 
 		if (new_options & WDIOS_ENABLECARD)
-			return watchdog_start();
+			return fintek_wdt_start();
 		fallthrough;
 
 	case WDIOC_KEEPALIVE:
-		watchdog_keepalive();
+		fintek_wdt_keepalive();
 		return 0;
 
 	case WDIOC_SETTIMEOUT:
 		if (get_user(new_timeout, uarg.i))
 			return -EFAULT;
 
-		if (watchdog_set_timeout(new_timeout))
+		if (fintek_wdt_set_timeout(new_timeout))
 			return -EINVAL;
 
-		watchdog_keepalive();
+		fintek_wdt_keepalive();
 		fallthrough;
 
 	case WDIOC_GETTIMEOUT:
@@ -641,7 +641,7 @@ static int watchdog_notify_sys(struct notifier_block *this, unsigned long code,
 	void *unused)
 {
 	if (code == SYS_DOWN || code == SYS_HALT)
-		watchdog_stop();
+		fintek_wdt_stop();
 	return NOTIFY_DONE;
 }
 
@@ -679,7 +679,7 @@ static int __init watchdog_init(int sioaddr)
 
 	snprintf(watchdog.ident.identity,
 		sizeof(watchdog.ident.identity), "%s watchdog",
-		f71808e_names[watchdog.type]);
+		fintek_wdt_names[watchdog.type]);
 
 	err = superio_enter(sioaddr);
 	if (err)
@@ -698,10 +698,10 @@ static int __init watchdog_init(int sioaddr)
 
 	superio_exit(sioaddr);
 
-	err = watchdog_set_timeout(timeout);
+	err = fintek_wdt_set_timeout(timeout);
 	if (err)
 		return err;
-	err = watchdog_set_pulse_width(pulse_width);
+	err = fintek_wdt_set_pulse_width(pulse_width);
 	if (err)
 		return err;
 
@@ -724,7 +724,7 @@ static int __init watchdog_init(int sioaddr)
 			goto exit_miscdev;
 		}
 
-		err = watchdog_start();
+		err = fintek_wdt_start();
 		if (err) {
 			pr_err("cannot start watchdog timer\n");
 			goto exit_miscdev;
@@ -772,7 +772,7 @@ static int __init watchdog_init(int sioaddr)
 	return err;
 }
 
-static int __init f71808e_find(int sioaddr)
+static int __init fintek_wdt_find(int sioaddr)
 {
 	u16 devid;
 	int err = superio_enter(sioaddr);
@@ -828,14 +828,14 @@ static int __init f71808e_find(int sioaddr)
 	}
 
 	pr_info("Found %s watchdog chip, revision %d\n",
-		f71808e_names[watchdog.type],
+		fintek_wdt_names[watchdog.type],
 		(int)superio_inb(sioaddr, SIO_REG_DEVREV));
 exit:
 	superio_exit(sioaddr);
 	return err;
 }
 
-static int __init f71808e_init(void)
+static int __init fintek_wdt_init(void)
 {
 	static const unsigned short addrs[] = { 0x2e, 0x4e };
 	int err = -ENODEV;
@@ -847,7 +847,7 @@ static int __init f71808e_init(void)
 	}
 
 	for (i = 0; i < ARRAY_SIZE(addrs); i++) {
-		err = f71808e_find(addrs[i]);
+		err = fintek_wdt_find(addrs[i]);
 		if (err == 0)
 			break;
 	}
@@ -857,11 +857,11 @@ static int __init f71808e_init(void)
 	return watchdog_init(addrs[i]);
 }
 
-static void __exit f71808e_exit(void)
+static void __exit fintek_wdt_exit(void)
 {
-	if (watchdog_is_running()) {
+	if (fintek_wdt_is_running()) {
 		pr_warn("Watchdog timer still running, stopping it\n");
-		watchdog_stop();
+		fintek_wdt_stop();
 	}
 	misc_deregister(&watchdog_miscdev);
 	unregister_reboot_notifier(&watchdog_notifier);
@@ -871,5 +871,5 @@ MODULE_DESCRIPTION("F71808E Watchdog Driver");
 MODULE_AUTHOR("Giel van Schijndel <me@mortis.eu>");
 MODULE_LICENSE("GPL");
 
-module_init(f71808e_init);
-module_exit(f71808e_exit);
+module_init(fintek_wdt_init);
+module_exit(fintek_wdt_exit);
-- 
git-series 0.9.1

[RESEND PATCH v3 2/3] watchdog: f71808e_wdt: migrate to new kernel watchdog API

[Ahmad Fatoum]

Migrating the driver lets us drop the watchdog misc device boilerplate
and reduces size by 285 lines. It also brings us support for new
functionality like CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED.

This incurs a slight backwards-compatibility break, because the new
kernel watchdog API doesn't support unloading modules for drivers
whose watchdog hardware is reported to be running.

This means following scenario will be no longer supported:
 - BIOS has enabled watchdog
 - Module is loaded and unloaded without opening watchdog
 - module_exit is expected to succeed and disable watchdog HW

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/watchdog/Kconfig       |   1 +-
 drivers/watchdog/f71808e_wdt.c | 390 ++++------------------------------
 2 files changed, 53 insertions(+), 338 deletions(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 7ff941e71b79..cbce0c176a7e 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1081,6 +1081,7 @@ config EBC_C384_WDT
 config F71808E_WDT
 	tristate "Fintek F718xx, F818xx Super I/O Watchdog"
 	depends on X86
+	select WATCHDOG_CORE
 	help
 	  This is the driver for the hardware watchdog on the Fintek F71808E,
 	  F71862FG, F71868, F71869, F71882FG, F71889FG, F81803, F81865, and
diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
index 665bef272a33..5496d2bb0089 100644
--- a/drivers/watchdog/f71808e_wdt.c
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -9,16 +9,10 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/err.h>
-#include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
-#include <linux/miscdevice.h>
 #include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/notifier.h>
-#include <linux/reboot.h>
-#include <linux/uaccess.h>
 #include <linux/watchdog.h>
 
 #define DRVNAME "f71808e_wdt"
@@ -137,24 +131,18 @@ static inline void superio_select(int base, int ld);
 static inline void superio_exit(int base);
 
 struct fintek_wdt {
+	struct watchdog_device wdd;
 	unsigned short	sioaddr;
 	enum chips	type;
-	unsigned long	opened;
-	struct mutex	lock;
-	char		expect_close;
 	struct watchdog_info ident;
 
-	unsigned short	timeout;
 	u8		timer_val;	/* content for the wd_time register */
 	char		minutes_mode;
 	u8		pulse_val;	/* pulse width flag */
 	char		pulse_mode;	/* enable pulse output mode? */
-	char		caused_reboot;	/* last reboot was by the watchdog */
 };
 
-static struct fintek_wdt watchdog = {
-	.lock = __MUTEX_INITIALIZER(watchdog.lock),
-};
+static struct fintek_wdt watchdog;
 
 /* Super I/O functions */
 static inline int superio_inb(int base, int reg)
@@ -218,17 +206,9 @@ static inline void superio_exit(int base)
 	release_region(base, 2);
 }
 
-static int fintek_wdt_set_timeout(int timeout)
+static int fintek_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
 {
-	if (timeout <= 0
-	 || timeout >  max_timeout) {
-		pr_err("watchdog timeout out of range\n");
-		return -EINVAL;
-	}
-
-	mutex_lock(&watchdog.lock);
-
-	watchdog.timeout = timeout;
+	wdd->timeout = timeout;
 	if (timeout > 0xff) {
 		watchdog.timer_val = DIV_ROUND_UP(timeout, 60);
 		watchdog.minutes_mode = true;
@@ -237,14 +217,11 @@ static int fintek_wdt_set_timeout(int timeout)
 		watchdog.minutes_mode = false;
 	}
 
-	mutex_unlock(&watchdog.lock);
-
 	return 0;
 }
 
 static int fintek_wdt_set_pulse_width(unsigned int pw)
 {
-	int err = 0;
 	unsigned int t1 = 25, t2 = 125, t3 = 5000;
 
 	if (watchdog.type == f71868) {
@@ -253,8 +230,6 @@ static int fintek_wdt_set_pulse_width(unsigned int pw)
 		t3 = 6000;
 	}
 
-	mutex_lock(&watchdog.lock);
-
 	if        (pw <=  1) {
 		watchdog.pulse_val = 0;
 	} else if (pw <= t1) {
@@ -265,25 +240,21 @@ static int fintek_wdt_set_pulse_width(unsigned int pw)
 		watchdog.pulse_val = 3;
 	} else {
 		pr_err("pulse width out of range\n");
-		err = -EINVAL;
-		goto exit_unlock;
+		return -EINVAL;
 	}
 
 	watchdog.pulse_mode = pw;
 
-exit_unlock:
-	mutex_unlock(&watchdog.lock);
-	return err;
+	return 0;
 }
 
-static int fintek_wdt_keepalive(void)
+static int fintek_wdt_keepalive(struct watchdog_device *wdd)
 {
-	int err = 0;
+	int err;
 
-	mutex_lock(&watchdog.lock);
 	err = superio_enter(watchdog.sioaddr);
 	if (err)
-		goto exit_unlock;
+		return err;
 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
 
 	if (watchdog.minutes_mode)
@@ -301,25 +272,22 @@ static int fintek_wdt_keepalive(void)
 
 	superio_exit(watchdog.sioaddr);
 
-exit_unlock:
-	mutex_unlock(&watchdog.lock);
-	return err;
+	return 0;
 }
 
-static int fintek_wdt_start(void)
+static int fintek_wdt_start(struct watchdog_device *wdd)
 {
 	int err;
 	u8 tmp;
 
 	/* Make sure we don't die as soon as the watchdog is enabled below */
-	err = fintek_wdt_keepalive();
+	err = fintek_wdt_keepalive(wdd);
 	if (err)
 		return err;
 
-	mutex_lock(&watchdog.lock);
 	err = superio_enter(watchdog.sioaddr);
 	if (err)
-		goto exit_unlock;
+		return err;
 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
 
 	/* Watchdog pin configuration */
@@ -407,6 +375,8 @@ static int fintek_wdt_start(void)
 	superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
 			F71808FG_FLAG_WD_EN);
 
+	set_bit(WDOG_HW_RUNNING, &wdd->status);
+
 	if (watchdog.pulse_mode) {
 		/* Select "pulse" output mode with given duration */
 		u8 wdt_conf = superio_inb(watchdog.sioaddr,
@@ -427,20 +397,17 @@ static int fintek_wdt_start(void)
 
 exit_superio:
 	superio_exit(watchdog.sioaddr);
-exit_unlock:
-	mutex_unlock(&watchdog.lock);
 
 	return err;
 }
 
-static int fintek_wdt_stop(void)
+static int fintek_wdt_stop(struct watchdog_device *wdd)
 {
-	int err = 0;
+	int err;
 
-	mutex_lock(&watchdog.lock);
 	err = superio_enter(watchdog.sioaddr);
 	if (err)
-		goto exit_unlock;
+		return err;
 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
 
 	superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
@@ -448,232 +415,31 @@ static int fintek_wdt_stop(void)
 
 	superio_exit(watchdog.sioaddr);
 
-exit_unlock:
-	mutex_unlock(&watchdog.lock);
-
-	return err;
-}
-
-static int watchdog_get_status(void)
-{
-	int status = 0;
-
-	mutex_lock(&watchdog.lock);
-	status = (watchdog.caused_reboot) ? WDIOF_CARDRESET : 0;
-	mutex_unlock(&watchdog.lock);
-
-	return status;
-}
-
-static bool fintek_wdt_is_running(void)
-{
-	/*
-	 * if we fail to determine the watchdog's status assume it to be
-	 * running to be on the safe side
-	 */
-	bool is_running = true;
-
-	mutex_lock(&watchdog.lock);
-	if (superio_enter(watchdog.sioaddr))
-		goto exit_unlock;
-	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
-
-	is_running = (superio_inb(watchdog.sioaddr, SIO_REG_ENABLE) & BIT(0))
-		&& (superio_inb(watchdog.sioaddr, F71808FG_REG_WDT_CONF)
-			& BIT(F71808FG_FLAG_WD_EN));
-
-	superio_exit(watchdog.sioaddr);
-
-exit_unlock:
-	mutex_unlock(&watchdog.lock);
-	return is_running;
-}
-
-/* /dev/watchdog api */
-
-static int watchdog_open(struct inode *inode, struct file *file)
-{
-	int err;
-
-	/* If the watchdog is alive we don't need to start it again */
-	if (test_and_set_bit(0, &watchdog.opened))
-		return -EBUSY;
-
-	err = fintek_wdt_start();
-	if (err) {
-		clear_bit(0, &watchdog.opened);
-		return err;
-	}
-
-	if (nowayout)
-		__module_get(THIS_MODULE);
-
-	watchdog.expect_close = 0;
-	return stream_open(inode, file);
-}
-
-static int watchdog_release(struct inode *inode, struct file *file)
-{
-	clear_bit(0, &watchdog.opened);
-
-	if (!watchdog.expect_close) {
-		fintek_wdt_keepalive();
-		pr_crit("Unexpected close, not stopping watchdog!\n");
-	} else if (!nowayout) {
-		fintek_wdt_stop();
-	}
 	return 0;
 }
 
-/*
- *      watchdog_write:
- *      @file: file handle to the watchdog
- *      @buf: buffer to write
- *      @count: count of bytes
- *      @ppos: pointer to the position to write. No seeks allowed
- *
- *      A write to a watchdog device is defined as a keepalive signal. Any
- *      write of data will do, as we we don't define content meaning.
- */
-
-static ssize_t watchdog_write(struct file *file, const char __user *buf,
-			    size_t count, loff_t *ppos)
+static bool fintek_wdt_is_running(u8 wdt_conf)
 {
-	if (count) {
-		if (!nowayout) {
-			size_t i;
-
-			/* In case it was set long ago */
-			bool expect_close = false;
-
-			for (i = 0; i != count; i++) {
-				char c;
-				if (get_user(c, buf + i))
-					return -EFAULT;
-				if (c == 'V')
-					expect_close = true;
-			}
-
-			/* Properly order writes across fork()ed processes */
-			mutex_lock(&watchdog.lock);
-			watchdog.expect_close = expect_close;
-			mutex_unlock(&watchdog.lock);
-		}
-
-		/* someone wrote to us, we should restart timer */
-		fintek_wdt_keepalive();
-	}
-	return count;
+	return (superio_inb(watchdog.sioaddr, SIO_REG_ENABLE) & BIT(0))
+		&& (wdt_conf & BIT(F71808FG_FLAG_WD_EN));
 }
 
-/*
- *      watchdog_ioctl:
- *      @inode: inode of the device
- *      @file: file handle to the device
- *      @cmd: watchdog command
- *      @arg: argument pointer
- *
- *      The watchdog API defines a common set of functions for all watchdogs
- *      according to their available features.
- */
-static long watchdog_ioctl(struct file *file, unsigned int cmd,
-	unsigned long arg)
-{
-	int status;
-	int new_options;
-	int new_timeout;
-	union {
-		struct watchdog_info __user *ident;
-		int __user *i;
-	} uarg;
-
-	uarg.i = (int __user *)arg;
-
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		return copy_to_user(uarg.ident, &watchdog.ident,
-			sizeof(watchdog.ident)) ? -EFAULT : 0;
-
-	case WDIOC_GETSTATUS:
-		status = watchdog_get_status();
-		if (status < 0)
-			return status;
-		return put_user(status, uarg.i);
-
-	case WDIOC_GETBOOTSTATUS:
-		return put_user(0, uarg.i);
-
-	case WDIOC_SETOPTIONS:
-		if (get_user(new_options, uarg.i))
-			return -EFAULT;
-
-		if (new_options & WDIOS_DISABLECARD)
-			fintek_wdt_stop();
-
-		if (new_options & WDIOS_ENABLECARD)
-			return fintek_wdt_start();
-		fallthrough;
-
-	case WDIOC_KEEPALIVE:
-		fintek_wdt_keepalive();
-		return 0;
-
-	case WDIOC_SETTIMEOUT:
-		if (get_user(new_timeout, uarg.i))
-			return -EFAULT;
-
-		if (fintek_wdt_set_timeout(new_timeout))
-			return -EINVAL;
-
-		fintek_wdt_keepalive();
-		fallthrough;
-
-	case WDIOC_GETTIMEOUT:
-		return put_user(watchdog.timeout, uarg.i);
-
-	default:
-		return -ENOTTY;
-
-	}
-}
-
-static int watchdog_notify_sys(struct notifier_block *this, unsigned long code,
-	void *unused)
-{
-	if (code == SYS_DOWN || code == SYS_HALT)
-		fintek_wdt_stop();
-	return NOTIFY_DONE;
-}
-
-static const struct file_operations watchdog_fops = {
-	.owner		= THIS_MODULE,
-	.llseek		= no_llseek,
-	.open		= watchdog_open,
-	.release	= watchdog_release,
-	.write		= watchdog_write,
-	.unlocked_ioctl	= watchdog_ioctl,
-	.compat_ioctl	= compat_ptr_ioctl,
-};
-
-static struct miscdevice watchdog_miscdev = {
-	.minor		= WATCHDOG_MINOR,
-	.name		= "watchdog",
-	.fops		= &watchdog_fops,
-};
-
-static struct notifier_block watchdog_notifier = {
-	.notifier_call = watchdog_notify_sys,
+static const struct watchdog_ops fintek_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = fintek_wdt_start,
+	.stop = fintek_wdt_stop,
+	.ping = fintek_wdt_keepalive,
+	.set_timeout = fintek_wdt_set_timeout,
 };
 
 static int __init watchdog_init(int sioaddr)
 {
+	struct watchdog_device *wdd;
 	int wdt_conf, err = 0;
 
-	/* No need to lock watchdog.lock here because no entry points
-	 * into the module have been registered yet.
-	 */
 	watchdog.sioaddr = sioaddr;
-	watchdog.ident.options = WDIOF_MAGICCLOSE
+	watchdog.ident.options = WDIOF_SETTIMEOUT
+				| WDIOF_MAGICCLOSE
 				| WDIOF_KEEPALIVEPING
 				| WDIOF_CARDRESET;
 
@@ -687,7 +453,6 @@ static int __init watchdog_init(int sioaddr)
 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
 
 	wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF);
-	watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS);
 
 	/*
 	 * We don't want WDTMOUT_STS to stick around till regular reboot.
@@ -696,80 +461,34 @@ static int __init watchdog_init(int sioaddr)
 	superio_outb(sioaddr, F71808FG_REG_WDT_CONF,
 		     wdt_conf | BIT(F71808FG_FLAG_WDTMOUT_STS));
 
-	superio_exit(sioaddr);
-
-	err = fintek_wdt_set_timeout(timeout);
-	if (err)
-		return err;
-	err = fintek_wdt_set_pulse_width(pulse_width);
-	if (err)
-		return err;
-
-	err = register_reboot_notifier(&watchdog_notifier);
-	if (err)
-		return err;
+	wdd = &watchdog.wdd;
 
-	err = misc_register(&watchdog_miscdev);
-	if (err) {
-		pr_err("cannot register miscdev on minor=%d\n",
-		       watchdog_miscdev.minor);
-		goto exit_reboot;
-	}
+	if (fintek_wdt_is_running(wdt_conf))
+		set_bit(WDOG_HW_RUNNING, &wdd->status);
 
-	if (start_withtimeout) {
-		if (start_withtimeout <= 0
-		 || start_withtimeout >  max_timeout) {
-			pr_err("starting timeout out of range\n");
-			err = -EINVAL;
-			goto exit_miscdev;
-		}
-
-		err = fintek_wdt_start();
-		if (err) {
-			pr_err("cannot start watchdog timer\n");
-			goto exit_miscdev;
-		}
-
-		mutex_lock(&watchdog.lock);
-		err = superio_enter(sioaddr);
-		if (err)
-			goto exit_unlock;
-		superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
-
-		if (start_withtimeout > 0xff) {
-			/* select minutes for timer units */
-			superio_set_bit(sioaddr, F71808FG_REG_WDT_CONF,
-				F71808FG_FLAG_WD_UNIT);
-			superio_outb(sioaddr, F71808FG_REG_WD_TIME,
-				DIV_ROUND_UP(start_withtimeout, 60));
-		} else {
-			/* select seconds for timer units */
-			superio_clear_bit(sioaddr, F71808FG_REG_WDT_CONF,
-				F71808FG_FLAG_WD_UNIT);
-			superio_outb(sioaddr, F71808FG_REG_WD_TIME,
-				start_withtimeout);
-		}
+	superio_exit(sioaddr);
 
-		superio_exit(sioaddr);
-		mutex_unlock(&watchdog.lock);
+	wdd->info               = &watchdog.ident;
+	wdd->ops                = &fintek_wdt_ops;
+	wdd->min_timeout        = 1;
+	wdd->max_timeout        = max_timeout;
 
-		if (nowayout)
-			__module_get(THIS_MODULE);
+	watchdog_set_nowayout(wdd, nowayout);
+	watchdog_stop_on_unregister(wdd);
+	watchdog_stop_on_reboot(wdd);
+	watchdog_init_timeout(wdd, start_withtimeout, NULL);
 
-		pr_info("watchdog started with initial timeout of %u sec\n",
-			start_withtimeout);
-	}
+	if (wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS))
+		wdd->bootstatus = WDIOF_CARDRESET;
 
-	return 0;
-
-exit_unlock:
-	mutex_unlock(&watchdog.lock);
-exit_miscdev:
-	misc_deregister(&watchdog_miscdev);
-exit_reboot:
-	unregister_reboot_notifier(&watchdog_notifier);
+	/*
+	 * WATCHDOG_HANDLE_BOOT_ENABLED can result in keepalive being directly
+	 * called without a set_timeout before, so it needs to be done here once
+	 */
+	fintek_wdt_set_timeout(wdd, timeout);
+	fintek_wdt_set_pulse_width(pulse_width);
 
-	return err;
+	return watchdog_register_device(wdd);
 }
 
 static int __init fintek_wdt_find(int sioaddr)
@@ -859,12 +578,7 @@ static int __init fintek_wdt_init(void)
 
 static void __exit fintek_wdt_exit(void)
 {
-	if (fintek_wdt_is_running()) {
-		pr_warn("Watchdog timer still running, stopping it\n");
-		fintek_wdt_stop();
-	}
-	misc_deregister(&watchdog_miscdev);
-	unregister_reboot_notifier(&watchdog_notifier);
+	watchdog_unregister_device(&watchdog.wdd);
 }
 
 MODULE_DESCRIPTION("F71808E Watchdog Driver");
-- 
git-series 0.9.1

Re: [RESEND PATCH v3 2/3] watchdog: f71808e_wdt: migrate to new kernel watchdog API

[Guenter Roeck]

On 4/13/21 3:46 AM, Ahmad Fatoum wrote:
> Migrating the driver lets us drop the watchdog misc device boilerplate
> and reduces size by 285 lines. It also brings us support for new
> functionality like CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED.
> 
> This incurs a slight backwards-compatibility break, because the new
> kernel watchdog API doesn't support unloading modules for drivers
> whose watchdog hardware is reported to be running.
> 
> This means following scenario will be no longer supported:
>  - BIOS has enabled watchdog
>  - Module is loaded and unloaded without opening watchdog
>  - module_exit is expected to succeed and disable watchdog HW
> 

Couple of quick comments below.

> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  drivers/watchdog/Kconfig       |   1 +-
>  drivers/watchdog/f71808e_wdt.c | 390 ++++------------------------------
>  2 files changed, 53 insertions(+), 338 deletions(-)
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 7ff941e71b79..cbce0c176a7e 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1081,6 +1081,7 @@ config EBC_C384_WDT
>  config F71808E_WDT
>  	tristate "Fintek F718xx, F818xx Super I/O Watchdog"
>  	depends on X86
> +	select WATCHDOG_CORE
>  	help
>  	  This is the driver for the hardware watchdog on the Fintek F71808E,
>  	  F71862FG, F71868, F71869, F71882FG, F71889FG, F81803, F81865, and
> diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
> index 665bef272a33..5496d2bb0089 100644
> --- a/drivers/watchdog/f71808e_wdt.c
> +++ b/drivers/watchdog/f71808e_wdt.c
> @@ -9,16 +9,10 @@
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
>  #include <linux/err.h>
> -#include <linux/fs.h>
>  #include <linux/init.h>
>  #include <linux/io.h>
>  #include <linux/ioport.h>
> -#include <linux/miscdevice.h>
>  #include <linux/module.h>
> -#include <linux/mutex.h>
> -#include <linux/notifier.h>
> -#include <linux/reboot.h>
> -#include <linux/uaccess.h>
>  #include <linux/watchdog.h>
>  
>  #define DRVNAME "f71808e_wdt"
> @@ -137,24 +131,18 @@ static inline void superio_select(int base, int ld);
>  static inline void superio_exit(int base);
>  
>  struct fintek_wdt {
> +	struct watchdog_device wdd;
>  	unsigned short	sioaddr;
>  	enum chips	type;
> -	unsigned long	opened;
> -	struct mutex	lock;
> -	char		expect_close;
>  	struct watchdog_info ident;
>  
> -	unsigned short	timeout;
>  	u8		timer_val;	/* content for the wd_time register */
>  	char		minutes_mode;
>  	u8		pulse_val;	/* pulse width flag */
>  	char		pulse_mode;	/* enable pulse output mode? */
> -	char		caused_reboot;	/* last reboot was by the watchdog */
>  };
>  
> -static struct fintek_wdt watchdog = {
> -	.lock = __MUTEX_INITIALIZER(watchdog.lock),
> -};
> +static struct fintek_wdt watchdog;

This should really be allocated, and "watchdog" is a terrible variable name
even if static, especially given the previous patch.

>  
>  /* Super I/O functions */
>  static inline int superio_inb(int base, int reg)
> @@ -218,17 +206,9 @@ static inline void superio_exit(int base)
>  	release_region(base, 2);
>  }
>  
> -static int fintek_wdt_set_timeout(int timeout)
> +static int fintek_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
>  {
> -	if (timeout <= 0
> -	 || timeout >  max_timeout) {
> -		pr_err("watchdog timeout out of range\n");
> -		return -EINVAL;
> -	}
> -
> -	mutex_lock(&watchdog.lock);
> -
> -	watchdog.timeout = timeout;
> +	wdd->timeout = timeout;

This needs to save the actual timeout, which differs from the
configured one if larger than 255.

>  	if (timeout > 0xff) {
>  		watchdog.timer_val = DIV_ROUND_UP(timeout, 60);
>  		watchdog.minutes_mode = true;
> @@ -237,14 +217,11 @@ static int fintek_wdt_set_timeout(int timeout)
>  		watchdog.minutes_mode = false;
>  	}
>  
> -	mutex_unlock(&watchdog.lock);
> -
>  	return 0;
>  }
>  
>  static int fintek_wdt_set_pulse_width(unsigned int pw)
>  {
> -	int err = 0;
>  	unsigned int t1 = 25, t2 = 125, t3 = 5000;
>  
>  	if (watchdog.type == f71868) {
> @@ -253,8 +230,6 @@ static int fintek_wdt_set_pulse_width(unsigned int pw)
>  		t3 = 6000;
>  	}
>  
> -	mutex_lock(&watchdog.lock);
> -
>  	if        (pw <=  1) {
>  		watchdog.pulse_val = 0;
>  	} else if (pw <= t1) {
> @@ -265,25 +240,21 @@ static int fintek_wdt_set_pulse_width(unsigned int pw)
>  		watchdog.pulse_val = 3;
>  	} else {
>  		pr_err("pulse width out of range\n");
> -		err = -EINVAL;
> -		goto exit_unlock;
> +		return -EINVAL;
>  	}
>  
>  	watchdog.pulse_mode = pw;
>  
> -exit_unlock:
> -	mutex_unlock(&watchdog.lock);
> -	return err;
> +	return 0;
>  }
>  
> -static int fintek_wdt_keepalive(void)
> +static int fintek_wdt_keepalive(struct watchdog_device *wdd)
>  {
> -	int err = 0;
> +	int err;
>  
> -	mutex_lock(&watchdog.lock);
>  	err = superio_enter(watchdog.sioaddr);
>  	if (err)
> -		goto exit_unlock;
> +		return err;
>  	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
>  
>  	if (watchdog.minutes_mode)
> @@ -301,25 +272,22 @@ static int fintek_wdt_keepalive(void)
>  
>  	superio_exit(watchdog.sioaddr);
>  
> -exit_unlock:
> -	mutex_unlock(&watchdog.lock);
> -	return err;
> +	return 0;
>  }
>  
> -static int fintek_wdt_start(void)
> +static int fintek_wdt_start(struct watchdog_device *wdd)
>  {
>  	int err;
>  	u8 tmp;
>  
>  	/* Make sure we don't die as soon as the watchdog is enabled below */
> -	err = fintek_wdt_keepalive();
> +	err = fintek_wdt_keepalive(wdd);
>  	if (err)
>  		return err;
>  
> -	mutex_lock(&watchdog.lock);
>  	err = superio_enter(watchdog.sioaddr);
>  	if (err)
> -		goto exit_unlock;
> +		return err;
>  	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
>  
>  	/* Watchdog pin configuration */
> @@ -407,6 +375,8 @@ static int fintek_wdt_start(void)
>  	superio_set_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
>  			F71808FG_FLAG_WD_EN);
>  
> +	set_bit(WDOG_HW_RUNNING, &wdd->status);
> +

This is wrong unless the watchdog can not be stopped.
With the bit set, the core will continue pinging the satchdog even
after it was stopped. The bit should be set only if the watchdog
can not be stopped once started, which I think is not the case here.

>  	if (watchdog.pulse_mode) {
>  		/* Select "pulse" output mode with given duration */
>  		u8 wdt_conf = superio_inb(watchdog.sioaddr,
> @@ -427,20 +397,17 @@ static int fintek_wdt_start(void)
>  
>  exit_superio:
>  	superio_exit(watchdog.sioaddr);
> -exit_unlock:
> -	mutex_unlock(&watchdog.lock);
>  
>  	return err;
>  }
>  
> -static int fintek_wdt_stop(void)
> +static int fintek_wdt_stop(struct watchdog_device *wdd)
>  {
> -	int err = 0;
> +	int err;
>  
> -	mutex_lock(&watchdog.lock);
>  	err = superio_enter(watchdog.sioaddr);
>  	if (err)
> -		goto exit_unlock;
> +		return err;
>  	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
>  
>  	superio_clear_bit(watchdog.sioaddr, F71808FG_REG_WDT_CONF,
> @@ -448,232 +415,31 @@ static int fintek_wdt_stop(void)
>  
>  	superio_exit(watchdog.sioaddr);
>  
> -exit_unlock:
> -	mutex_unlock(&watchdog.lock);
> -
> -	return err;
> -}
> -
> -static int watchdog_get_status(void)
> -{
> -	int status = 0;
> -
> -	mutex_lock(&watchdog.lock);
> -	status = (watchdog.caused_reboot) ? WDIOF_CARDRESET : 0;
> -	mutex_unlock(&watchdog.lock);
> -
> -	return status;
> -}
> -
> -static bool fintek_wdt_is_running(void)
> -{
> -	/*
> -	 * if we fail to determine the watchdog's status assume it to be
> -	 * running to be on the safe side
> -	 */
> -	bool is_running = true;
> -
> -	mutex_lock(&watchdog.lock);
> -	if (superio_enter(watchdog.sioaddr))
> -		goto exit_unlock;
> -	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
> -
> -	is_running = (superio_inb(watchdog.sioaddr, SIO_REG_ENABLE) & BIT(0))
> -		&& (superio_inb(watchdog.sioaddr, F71808FG_REG_WDT_CONF)
> -			& BIT(F71808FG_FLAG_WD_EN));
> -
> -	superio_exit(watchdog.sioaddr);
> -
> -exit_unlock:
> -	mutex_unlock(&watchdog.lock);
> -	return is_running;
> -}
> -
> -/* /dev/watchdog api */
> -
> -static int watchdog_open(struct inode *inode, struct file *file)
> -{
> -	int err;
> -
> -	/* If the watchdog is alive we don't need to start it again */
> -	if (test_and_set_bit(0, &watchdog.opened))
> -		return -EBUSY;
> -
> -	err = fintek_wdt_start();
> -	if (err) {
> -		clear_bit(0, &watchdog.opened);
> -		return err;
> -	}
> -
> -	if (nowayout)
> -		__module_get(THIS_MODULE);
> -
> -	watchdog.expect_close = 0;
> -	return stream_open(inode, file);
> -}
> -
> -static int watchdog_release(struct inode *inode, struct file *file)
> -{
> -	clear_bit(0, &watchdog.opened);
> -
> -	if (!watchdog.expect_close) {
> -		fintek_wdt_keepalive();
> -		pr_crit("Unexpected close, not stopping watchdog!\n");
> -	} else if (!nowayout) {
> -		fintek_wdt_stop();
> -	}
>  	return 0;
>  }
>  
> -/*
> - *      watchdog_write:
> - *      @file: file handle to the watchdog
> - *      @buf: buffer to write
> - *      @count: count of bytes
> - *      @ppos: pointer to the position to write. No seeks allowed
> - *
> - *      A write to a watchdog device is defined as a keepalive signal. Any
> - *      write of data will do, as we we don't define content meaning.
> - */
> -
> -static ssize_t watchdog_write(struct file *file, const char __user *buf,
> -			    size_t count, loff_t *ppos)
> +static bool fintek_wdt_is_running(u8 wdt_conf)
>  {
> -	if (count) {
> -		if (!nowayout) {
> -			size_t i;
> -
> -			/* In case it was set long ago */
> -			bool expect_close = false;
> -
> -			for (i = 0; i != count; i++) {
> -				char c;
> -				if (get_user(c, buf + i))
> -					return -EFAULT;
> -				if (c == 'V')
> -					expect_close = true;
> -			}
> -
> -			/* Properly order writes across fork()ed processes */
> -			mutex_lock(&watchdog.lock);
> -			watchdog.expect_close = expect_close;
> -			mutex_unlock(&watchdog.lock);
> -		}
> -
> -		/* someone wrote to us, we should restart timer */
> -		fintek_wdt_keepalive();
> -	}
> -	return count;
> +	return (superio_inb(watchdog.sioaddr, SIO_REG_ENABLE) & BIT(0))
> +		&& (wdt_conf & BIT(F71808FG_FLAG_WD_EN));
>  }
>  
> -/*
> - *      watchdog_ioctl:
> - *      @inode: inode of the device
> - *      @file: file handle to the device
> - *      @cmd: watchdog command
> - *      @arg: argument pointer
> - *
> - *      The watchdog API defines a common set of functions for all watchdogs
> - *      according to their available features.
> - */
> -static long watchdog_ioctl(struct file *file, unsigned int cmd,
> -	unsigned long arg)
> -{
> -	int status;
> -	int new_options;
> -	int new_timeout;
> -	union {
> -		struct watchdog_info __user *ident;
> -		int __user *i;
> -	} uarg;
> -
> -	uarg.i = (int __user *)arg;
> -
> -	switch (cmd) {
> -	case WDIOC_GETSUPPORT:
> -		return copy_to_user(uarg.ident, &watchdog.ident,
> -			sizeof(watchdog.ident)) ? -EFAULT : 0;
> -
> -	case WDIOC_GETSTATUS:
> -		status = watchdog_get_status();
> -		if (status < 0)
> -			return status;
> -		return put_user(status, uarg.i);
> -
> -	case WDIOC_GETBOOTSTATUS:
> -		return put_user(0, uarg.i);
> -
> -	case WDIOC_SETOPTIONS:
> -		if (get_user(new_options, uarg.i))
> -			return -EFAULT;
> -
> -		if (new_options & WDIOS_DISABLECARD)
> -			fintek_wdt_stop();
> -
> -		if (new_options & WDIOS_ENABLECARD)
> -			return fintek_wdt_start();
> -		fallthrough;
> -
> -	case WDIOC_KEEPALIVE:
> -		fintek_wdt_keepalive();
> -		return 0;
> -
> -	case WDIOC_SETTIMEOUT:
> -		if (get_user(new_timeout, uarg.i))
> -			return -EFAULT;
> -
> -		if (fintek_wdt_set_timeout(new_timeout))
> -			return -EINVAL;
> -
> -		fintek_wdt_keepalive();
> -		fallthrough;
> -
> -	case WDIOC_GETTIMEOUT:
> -		return put_user(watchdog.timeout, uarg.i);
> -
> -	default:
> -		return -ENOTTY;
> -
> -	}
> -}
> -
> -static int watchdog_notify_sys(struct notifier_block *this, unsigned long code,
> -	void *unused)
> -{
> -	if (code == SYS_DOWN || code == SYS_HALT)
> -		fintek_wdt_stop();
> -	return NOTIFY_DONE;
> -}
> -
> -static const struct file_operations watchdog_fops = {
> -	.owner		= THIS_MODULE,
> -	.llseek		= no_llseek,
> -	.open		= watchdog_open,
> -	.release	= watchdog_release,
> -	.write		= watchdog_write,
> -	.unlocked_ioctl	= watchdog_ioctl,
> -	.compat_ioctl	= compat_ptr_ioctl,
> -};
> -
> -static struct miscdevice watchdog_miscdev = {
> -	.minor		= WATCHDOG_MINOR,
> -	.name		= "watchdog",
> -	.fops		= &watchdog_fops,
> -};
> -
> -static struct notifier_block watchdog_notifier = {
> -	.notifier_call = watchdog_notify_sys,
> +static const struct watchdog_ops fintek_wdt_ops = {
> +	.owner = THIS_MODULE,
> +	.start = fintek_wdt_start,
> +	.stop = fintek_wdt_stop,
> +	.ping = fintek_wdt_keepalive,
> +	.set_timeout = fintek_wdt_set_timeout,
>  };
>  
>  static int __init watchdog_init(int sioaddr)
>  {
> +	struct watchdog_device *wdd;
>  	int wdt_conf, err = 0;
>  
> -	/* No need to lock watchdog.lock here because no entry points
> -	 * into the module have been registered yet.
> -	 */
>  	watchdog.sioaddr = sioaddr;
> -	watchdog.ident.options = WDIOF_MAGICCLOSE
> +	watchdog.ident.options = WDIOF_SETTIMEOUT
> +				| WDIOF_MAGICCLOSE
>  				| WDIOF_KEEPALIVEPING
>  				| WDIOF_CARDRESET;
>  
> @@ -687,7 +453,6 @@ static int __init watchdog_init(int sioaddr)
>  	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
>  
>  	wdt_conf = superio_inb(sioaddr, F71808FG_REG_WDT_CONF);
> -	watchdog.caused_reboot = wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS);
>  
>  	/*
>  	 * We don't want WDTMOUT_STS to stick around till regular reboot.
> @@ -696,80 +461,34 @@ static int __init watchdog_init(int sioaddr)
>  	superio_outb(sioaddr, F71808FG_REG_WDT_CONF,
>  		     wdt_conf | BIT(F71808FG_FLAG_WDTMOUT_STS));
>  
> -	superio_exit(sioaddr);
> -
> -	err = fintek_wdt_set_timeout(timeout);
> -	if (err)
> -		return err;
> -	err = fintek_wdt_set_pulse_width(pulse_width);
> -	if (err)
> -		return err;
> -
> -	err = register_reboot_notifier(&watchdog_notifier);
> -	if (err)
> -		return err;
> +	wdd = &watchdog.wdd;
>  
> -	err = misc_register(&watchdog_miscdev);
> -	if (err) {
> -		pr_err("cannot register miscdev on minor=%d\n",
> -		       watchdog_miscdev.minor);
> -		goto exit_reboot;
> -	}
> +	if (fintek_wdt_is_running(wdt_conf))
> +		set_bit(WDOG_HW_RUNNING, &wdd->status);
>  
> -	if (start_withtimeout) {
> -		if (start_withtimeout <= 0
> -		 || start_withtimeout >  max_timeout) {
> -			pr_err("starting timeout out of range\n");
> -			err = -EINVAL;
> -			goto exit_miscdev;
> -		}
> -
> -		err = fintek_wdt_start();
> -		if (err) {
> -			pr_err("cannot start watchdog timer\n");
> -			goto exit_miscdev;
> -		}
> -
> -		mutex_lock(&watchdog.lock);
> -		err = superio_enter(sioaddr);
> -		if (err)
> -			goto exit_unlock;
> -		superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
> -
> -		if (start_withtimeout > 0xff) {
> -			/* select minutes for timer units */
> -			superio_set_bit(sioaddr, F71808FG_REG_WDT_CONF,
> -				F71808FG_FLAG_WD_UNIT);
> -			superio_outb(sioaddr, F71808FG_REG_WD_TIME,
> -				DIV_ROUND_UP(start_withtimeout, 60));
> -		} else {
> -			/* select seconds for timer units */
> -			superio_clear_bit(sioaddr, F71808FG_REG_WDT_CONF,
> -				F71808FG_FLAG_WD_UNIT);
> -			superio_outb(sioaddr, F71808FG_REG_WD_TIME,
> -				start_withtimeout);
> -		}
> +	superio_exit(sioaddr);
>  
> -		superio_exit(sioaddr);
> -		mutex_unlock(&watchdog.lock);
> +	wdd->info               = &watchdog.ident;
> +	wdd->ops                = &fintek_wdt_ops;
> +	wdd->min_timeout        = 1;
> +	wdd->max_timeout        = max_timeout;
>  
> -		if (nowayout)
> -			__module_get(THIS_MODULE);
> +	watchdog_set_nowayout(wdd, nowayout);
> +	watchdog_stop_on_unregister(wdd);
> +	watchdog_stop_on_reboot(wdd);
> +	watchdog_init_timeout(wdd, start_withtimeout, NULL);
>  
> -		pr_info("watchdog started with initial timeout of %u sec\n",
> -			start_withtimeout);
> -	}
> +	if (wdt_conf & BIT(F71808FG_FLAG_WDTMOUT_STS))
> +		wdd->bootstatus = WDIOF_CARDRESET;
>  
> -	return 0;
> -
> -exit_unlock:
> -	mutex_unlock(&watchdog.lock);
> -exit_miscdev:
> -	misc_deregister(&watchdog_miscdev);
> -exit_reboot:
> -	unregister_reboot_notifier(&watchdog_notifier);
> +	/*
> +	 * WATCHDOG_HANDLE_BOOT_ENABLED can result in keepalive being directly
> +	 * called without a set_timeout before, so it needs to be done here once
> +	 */
> +	fintek_wdt_set_timeout(wdd, timeout);
> +	fintek_wdt_set_pulse_width(pulse_width);
>  
> -	return err;
> +	return watchdog_register_device(wdd);
>  }
>  
>  static int __init fintek_wdt_find(int sioaddr)
> @@ -859,12 +578,7 @@ static int __init fintek_wdt_init(void)
>  
>  static void __exit fintek_wdt_exit(void)
>  {
> -	if (fintek_wdt_is_running()) {
> -		pr_warn("Watchdog timer still running, stopping it\n");
> -		fintek_wdt_stop();
> -	}
> -	misc_deregister(&watchdog_miscdev);
> -	unregister_reboot_notifier(&watchdog_notifier);
> +	watchdog_unregister_device(&watchdog.wdd);
>  }
>  
>  MODULE_DESCRIPTION("F71808E Watchdog Driver");
> 

Re: [RESEND PATCH v3 2/3] watchdog: f71808e_wdt: migrate to new kernel watchdog API

[Ahmad Fatoum]

Hello Guenter,

On 03.05.21 16:31, Guenter Roeck wrote:
>> -static struct fintek_wdt watchdog = {
>> -	.lock = __MUTEX_INITIALIZER(watchdog.lock),
>> -};
>> +static struct fintek_wdt watchdog;
> 
> This should really be allocated, and "watchdog" is a terrible variable name
> even if static, especially given the previous patch.

I can add a follow up patch to change this. I maintained the old
state of things here to make review easier.

> 
>>  
>>  /* Super I/O functions */
>>  static inline int superio_inb(int base, int reg)
>> @@ -218,17 +206,9 @@ static inline void superio_exit(int base)
>>  	release_region(base, 2);
>>  }
>>  
>> -static int fintek_wdt_set_timeout(int timeout)
>> +static int fintek_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
>>  {
>> -	if (timeout <= 0
>> -	 || timeout >  max_timeout) {
>> -		pr_err("watchdog timeout out of range\n");
>> -		return -EINVAL;
>> -	}
>> -
>> -	mutex_lock(&watchdog.lock);
>> -
>> -	watchdog.timeout = timeout;
>> +	wdd->timeout = timeout;
> 
> This needs to save the actual timeout, which differs from the
> configured one if larger than 255.

Oh, makes sense. Will changes with v4.

Thanks,
Ahmad

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [RESEND PATCH v3 2/3] watchdog: f71808e_wdt: migrate to new kernel watchdog API

[Guenter Roeck]

On Mon, May 03, 2021 at 04:39:25PM +0200, Ahmad Fatoum wrote:
> Hello Guenter,
> 
> On 03.05.21 16:31, Guenter Roeck wrote:
> >> -static struct fintek_wdt watchdog = {
> >> -	.lock = __MUTEX_INITIALIZER(watchdog.lock),
> >> -};
> >> +static struct fintek_wdt watchdog;
> > 
> > This should really be allocated, and "watchdog" is a terrible variable name
> > even if static, especially given the previous patch.
> 
> I can add a follow up patch to change this. I maintained the old
> state of things here to make review easier.
> 
Odd argument. You changed all the function names (unnecessarily,
if you ask me) in the first patch of the series because they were
too generic in your opinion. That by itself added a lot of unnecessary
complexity to the review. And pretty much everything else changed
in this patch anyway.

Guenter

Re: [RESEND PATCH v3 2/3] watchdog: f71808e_wdt: migrate to new kernel watchdog API

[Ahmad Fatoum]

Hello Guenter,

On 03.05.21 17:28, Guenter Roeck wrote:
> On Mon, May 03, 2021 at 04:39:25PM +0200, Ahmad Fatoum wrote:
>> Hello Guenter,
>>
>> On 03.05.21 16:31, Guenter Roeck wrote:
>>>> -static struct fintek_wdt watchdog = {
>>>> -	.lock = __MUTEX_INITIALIZER(watchdog.lock),
>>>> -};
>>>> +static struct fintek_wdt watchdog;
>>>
>>> This should really be allocated, and "watchdog" is a terrible variable name
>>> even if static, especially given the previous patch.
>>
>> I can add a follow up patch to change this. I maintained the old
>> state of things here to make review easier.
>>
> Odd argument. You changed all the function names (unnecessarily,
> if you ask me) in the first patch of the series because they were
> too generic in your opinion.

I find it surprising to have a function called watchdog_set_timeout
defined locally in a driver.

But yes, the first patch was more useful in v2, where new functions
were added for pinmuxing each variant. Having f71808e_ for generic
code and f8186fg_ for a variant would not help code comprehension.

> That by itself added a lot of unnecessary complexity to the review.

This was not my intention. I figured having a separate patch that just
does the rename should make review of follow-up commits easier, not harder...

> And pretty much everything else changed
> in this patch anyway.

Feedback on v2 was that I change too much and that this made review harder.
I thus left name changes in a separate patch and limited changes in follow-up
commit to signatures where appropriate.

Thanks,
Ahmad

> 
> Guenter
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

[RESEND PATCH v3 3/3] watchdog: f71808e_wdt: refactor to platform device/driver pair

[Ahmad Fatoum]

Driver so far wasn't ported to the driver model and registered
the watchdog device out of the init after probing the I/O ports
for a watchdog with correct vendor and device revision.

Keep the device detection part at init time, but move watchdog
registration to a platform driver probe function.

Suggested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/watchdog/f71808e_wdt.c | 42 +++++++++++++++++++++++++++++++----
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
index 5496d2bb0089..e96f2c274b80 100644
--- a/drivers/watchdog/f71808e_wdt.c
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -13,6 +13,7 @@
 #include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/module.h>
+#include <linux/platform_device.h>
 #include <linux/watchdog.h>
 
 #define DRVNAME "f71808e_wdt"
@@ -432,10 +433,18 @@ static const struct watchdog_ops fintek_wdt_ops = {
 	.set_timeout = fintek_wdt_set_timeout,
 };
 
-static int __init watchdog_init(int sioaddr)
+static int fintek_wdt_probe(struct platform_device *pdev)
 {
 	struct watchdog_device *wdd;
 	int wdt_conf, err = 0;
+	struct resource *res;
+	int sioaddr;
+
+	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (!res)
+		return -ENXIO;
+
+	sioaddr = res->start;
 
 	watchdog.sioaddr = sioaddr;
 	watchdog.ident.options = WDIOF_SETTIMEOUT
@@ -468,6 +477,7 @@ static int __init watchdog_init(int sioaddr)
 
 	superio_exit(sioaddr);
 
+	wdd->parent		= &pdev->dev;
 	wdd->info               = &watchdog.ident;
 	wdd->ops                = &fintek_wdt_ops;
 	wdd->min_timeout        = 1;
@@ -488,7 +498,7 @@ static int __init watchdog_init(int sioaddr)
 	fintek_wdt_set_timeout(wdd, timeout);
 	fintek_wdt_set_pulse_width(pulse_width);
 
-	return watchdog_register_device(wdd);
+	return devm_watchdog_register_device(&pdev->dev, wdd);
 }
 
 static int __init fintek_wdt_find(int sioaddr)
@@ -554,9 +564,19 @@ static int __init fintek_wdt_find(int sioaddr)
 	return err;
 }
 
+static struct platform_driver fintek_wdt_driver = {
+	.probe          = fintek_wdt_probe,
+	.driver         = {
+		.name   = DRVNAME,
+	},
+};
+
+static struct platform_device *fintek_wdt_pdev;
+
 static int __init fintek_wdt_init(void)
 {
 	static const unsigned short addrs[] = { 0x2e, 0x4e };
+	struct resource wdt_res = {};
 	int err = -ENODEV;
 	int i;
 
@@ -573,12 +593,26 @@ static int __init fintek_wdt_init(void)
 	if (i == ARRAY_SIZE(addrs))
 		return err;
 
-	return watchdog_init(addrs[i]);
+	platform_driver_register(&fintek_wdt_driver);
+
+	wdt_res.name = "superio port";
+	wdt_res.flags = IORESOURCE_IO;
+	wdt_res.start = addrs[i];
+	wdt_res.end   = addrs[i] + 1;
+
+	fintek_wdt_pdev = platform_device_register_simple(DRVNAME, -1, &wdt_res, 1);
+	if (IS_ERR(fintek_wdt_pdev)) {
+		platform_driver_unregister(&fintek_wdt_driver);
+		return PTR_ERR(fintek_wdt_pdev);
+	}
+
+	return 0;
 }
 
 static void __exit fintek_wdt_exit(void)
 {
-	watchdog_unregister_device(&watchdog.wdd);
+	platform_device_unregister(fintek_wdt_pdev);
+	platform_driver_unregister(&fintek_wdt_driver);
 }
 
 MODULE_DESCRIPTION("F71808E Watchdog Driver");
-- 
git-series 0.9.1

Re: [RESEND PATCH v3 0/3] watchdog: f71808e_wdt: migrate to new kernel API

[Marc Kleine-Budde]

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On 13.04.2021 12:46:43, Ahmad Fatoum wrote:
> This series migrates the driver to the new kernel watchdog API and
> then to the driver model.
> 
> Main feedback from Guenther on v2 was that I need to split it up to
> enable review. I have done so by removing the extra refactoring for
> now and focused on the functional changes described above. The diff
> is now much better readable.
> 
> I tested it on a f81866.

Is there a chance to get this series applied and mainline? Is there
anything that's blocking it?

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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Re: [RESEND PATCH v3 0/3] watchdog: f71808e_wdt: migrate to new kernel API

[Guenter Roeck]

On 5/3/21 6:09 AM, Marc Kleine-Budde wrote:
> On 13.04.2021 12:46:43, Ahmad Fatoum wrote:
>> This series migrates the driver to the new kernel watchdog API and
>> then to the driver model.
>>
>> Main feedback from Guenther on v2 was that I need to split it up to
>> enable review. I have done so by removing the extra refactoring for
>> now and focused on the functional changes described above. The diff
>> is now much better readable.
>>
>> I tested it on a f81866.
> 
> Is there a chance to get this series applied and mainline? Is there
> anything that's blocking it?
> 

Yes, time to review. Sorry, I am way backlogged with code reviews.

Guenter

Re: [RESEND PATCH v3 0/3] watchdog: f71808e_wdt: migrate to new kernel API

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1171 bytes --]

On 03.05.2021 06:33:21, Guenter Roeck wrote:
> On 5/3/21 6:09 AM, Marc Kleine-Budde wrote:
> > On 13.04.2021 12:46:43, Ahmad Fatoum wrote:
> >> This series migrates the driver to the new kernel watchdog API and
> >> then to the driver model.
> >>
> >> Main feedback from Guenther on v2 was that I need to split it up to
> >> enable review. I have done so by removing the extra refactoring for
> >> now and focused on the functional changes described above. The diff
> >> is now much better readable.
> >>
> >> I tested it on a f81866.
> > 
> > Is there a chance to get this series applied and mainline? Is there
> > anything that's blocking it?
> > 
> 
> Yes, time to review. Sorry, I am way backlogged with code reviews.

That sounds familiar to me :/

But on the other hand I have a co-worker that's interested in watchdogs
:) He'll try to do some reviews.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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