linux-kernel - [PATCH] watchdog: iTCO: Drop driver-internal locking

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Message-ID: <20250517160936.3231017-1-linux@roeck-us.net>
Date: Sat, 17 May 2025 09:09:36 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc: linux-watchdog@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH] watchdog: iTCO: Drop driver-internal locking

The locking code in the iTCO watchdog driver has been carried along from
before the watchdog core existed. The watchdog core protects calls into
drivers since commit f4e9c82f64b5 ("watchdog: Add Locking support"),
making driver-internal locking unnecessary. Drop it.

Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/watchdog/iTCO_wdt.c | 24 ------------------------
 1 file changed, 24 deletions(-)

diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 7672582fa407..30a8d72d84fa 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -58,7 +58,6 @@
 #include <linux/platform_device.h>	/* For platform_driver framework */
 #include <linux/pci.h>			/* For pci functions */
 #include <linux/ioport.h>		/* For io-port access */
-#include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
 #include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
 #include <linux/io.h>			/* For inb/outb/... */
 #include <linux/platform_data/itco_wdt.h>
@@ -102,8 +101,6 @@ struct iTCO_wdt_private {
 	 * or memory-mapped PMC register bit 4 (TCO version 3).
 	 */
 	unsigned long __iomem *gcs_pmc;
-	/* the lock for io operations */
-	spinlock_t io_lock;
 	/* the PCI-device */
 	struct pci_dev *pci_dev;
 	/* whether or not the watchdog has been suspended */
@@ -286,13 +283,10 @@ static int iTCO_wdt_start(struct watchdog_device *wd_dev)
 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
 	unsigned int val;
 
-	spin_lock(&p->io_lock);
-
 	iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
 
 	/* disable chipset's NO_REBOOT bit */
 	if (p->update_no_reboot_bit(p->no_reboot_priv, false)) {
-		spin_unlock(&p->io_lock);
 		dev_err(wd_dev->parent, "failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
 		return -EIO;
 	}
@@ -309,7 +303,6 @@ static int iTCO_wdt_start(struct watchdog_device *wd_dev)
 	val &= 0xf7ff;
 	outw(val, TCO1_CNT(p));
 	val = inw(TCO1_CNT(p));
-	spin_unlock(&p->io_lock);
 
 	if (val & 0x0800)
 		return -1;
@@ -321,8 +314,6 @@ static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
 	unsigned int val;
 
-	spin_lock(&p->io_lock);
-
 	iTCO_vendor_pre_stop(p->smi_res);
 
 	/* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
@@ -334,8 +325,6 @@ static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
 	p->update_no_reboot_bit(p->no_reboot_priv, true);
 
-	spin_unlock(&p->io_lock);
-
 	if ((val & 0x0800) == 0)
 		return -1;
 	return 0;
@@ -345,8 +334,6 @@ static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
 {
 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
 
-	spin_lock(&p->io_lock);
-
 	/* Reload the timer by writing to the TCO Timer Counter register */
 	if (p->iTCO_version >= 2) {
 		outw(0x01, TCO_RLD(p));
@@ -358,7 +345,6 @@ static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
 		outb(0x01, TCO_RLD(p));
 	}
 
-	spin_unlock(&p->io_lock);
 	return 0;
 }
 
@@ -385,24 +371,20 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
 
 	/* Write new heartbeat to watchdog */
 	if (p->iTCO_version >= 2) {
-		spin_lock(&p->io_lock);
 		val16 = inw(TCOv2_TMR(p));
 		val16 &= 0xfc00;
 		val16 |= tmrval;
 		outw(val16, TCOv2_TMR(p));
 		val16 = inw(TCOv2_TMR(p));
-		spin_unlock(&p->io_lock);
 
 		if ((val16 & 0x3ff) != tmrval)
 			return -EINVAL;
 	} else if (p->iTCO_version == 1) {
-		spin_lock(&p->io_lock);
 		val8 = inb(TCOv1_TMR(p));
 		val8 &= 0xc0;
 		val8 |= (tmrval & 0xff);
 		outb(val8, TCOv1_TMR(p));
 		val8 = inb(TCOv1_TMR(p));
-		spin_unlock(&p->io_lock);
 
 		if ((val8 & 0x3f) != tmrval)
 			return -EINVAL;
@@ -421,19 +403,15 @@ static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
 
 	/* read the TCO Timer */
 	if (p->iTCO_version >= 2) {
-		spin_lock(&p->io_lock);
 		val16 = inw(TCO_RLD(p));
 		val16 &= 0x3ff;
-		spin_unlock(&p->io_lock);
 
 		time_left = ticks_to_seconds(p, val16);
 	} else if (p->iTCO_version == 1) {
-		spin_lock(&p->io_lock);
 		val8 = inb(TCO_RLD(p));
 		val8 &= 0x3f;
 		if (!(inw(TCO1_STS(p)) & 0x0008))
 			val8 += (inb(TCOv1_TMR(p)) & 0x3f);
-		spin_unlock(&p->io_lock);
 
 		time_left = ticks_to_seconds(p, val8);
 	}
@@ -493,8 +471,6 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
 	if (!p)
 		return -ENOMEM;
 
-	spin_lock_init(&p->io_lock);
-
 	p->tco_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_TCO);
 	if (!p->tco_res)
 		return -ENODEV;
-- 
2.45.2