linux-kernel - [PATCH v4 3/5] watchdog: iTCO_wdt: Add PMC specific noreboot update api

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Message-Id: <e36dcfd637dd0fff2c3133cea0a541bdd3712418.1491002056.git.sathyanarayanan.kuppuswamy@linux.intel.com>
Date:   Fri, 31 Mar 2017 16:27:50 -0700
From:   Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
To:     andy@...radead.org, qipeng.zha@...el.com, dvhart@...radead.org,
        linux@...ck-us.net
Cc:     wim@...ana.be, sathyaosid@...il.com, david.e.box@...ux.intel.com,
        rajneesh.bhardwaj@...el.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-watchdog@...r.kernel.org
Subject: [PATCH v4 3/5] watchdog: iTCO_wdt: Add PMC specific noreboot update api

In some SOCs, setting noreboot bit needs modification to
PMC GC registers. But not all PMC drivers allow other drivers
to memory map their GC region. This could create mem request
conflict in watchdog driver. So this patch adds facility to allow
PMC drivers to pass noreboot update function to watchdog
drivers via platform data.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
Acked-by: Guenter Roeck <linux@...ck-us.net>
---
 drivers/watchdog/iTCO_wdt.c            | 28 +++++++++++++++++++---------
 include/linux/platform_data/itco_wdt.h |  1 +
 2 files changed, 20 insertions(+), 9 deletions(-)

Changes since v3:
 * Rebased on top of latest.

Changes since v2: 
 * Removed use of PMC API's directly in watchdog driver.
 * Added update_noreboot_flag to handle no IPC PMC compatibility
   issue mentioned by Guenter.

diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 3d0abc0..7c34259 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -100,6 +100,8 @@ struct iTCO_wdt_private {
 	 */
 	struct resource *gcs_pmc_res;
 	unsigned long __iomem *gcs_pmc;
+	/* pmc specific api to update noreboot flag */
+	int (*update_noreboot_flag)(bool status);
 	/* the lock for io operations */
 	spinlock_t io_lock;
 	/* the PCI-device */
@@ -176,9 +178,13 @@ static void iTCO_wdt_set_NO_REBOOT_bit(struct iTCO_wdt_private *p)
 
 	/* Set the NO_REBOOT bit: this disables reboots */
 	if (p->iTCO_version >= 2) {
-		val32 = readl(p->gcs_pmc);
-		val32 |= no_reboot_bit(p);
-		writel(val32, p->gcs_pmc);
+		if (p->update_noreboot_flag)
+			p->update_noreboot_flag(1);
+		else {
+			val32 = readl(p->gcs_pmc);
+			val32 |= no_reboot_bit(p);
+			writel(val32, p->gcs_pmc);
+		}
 	} else if (p->iTCO_version == 1) {
 		pci_read_config_dword(p->pci_dev, 0xd4, &val32);
 		val32 |= no_reboot_bit(p);
@@ -193,11 +199,14 @@ static int iTCO_wdt_unset_NO_REBOOT_bit(struct iTCO_wdt_private *p)
 
 	/* Unset the NO_REBOOT bit: this enables reboots */
 	if (p->iTCO_version >= 2) {
-		val32 = readl(p->gcs_pmc);
-		val32 &= ~enable_bit;
-		writel(val32, p->gcs_pmc);
-
-		val32 = readl(p->gcs_pmc);
+		if (p->update_noreboot_flag)
+			return p->update_noreboot_flag(0);
+		else {
+			val32 = readl(p->gcs_pmc);
+			val32 &= ~enable_bit;
+			writel(val32, p->gcs_pmc);
+			val32 = readl(p->gcs_pmc);
+		}
 	} else if (p->iTCO_version == 1) {
 		pci_read_config_dword(p->pci_dev, 0xd4, &val32);
 		val32 &= ~enable_bit;
@@ -426,13 +435,14 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	p->iTCO_version = pdata->version;
+	p->update_noreboot_flag = pdata->update_noreboot_flag;
 	p->pci_dev = to_pci_dev(dev->parent);
 
 	/*
 	 * Get the Memory-Mapped GCS or PMC register, we need it for the
 	 * NO_REBOOT flag (TCO v2 and v3).
 	 */
-	if (p->iTCO_version >= 2) {
+	if (p->iTCO_version >= 2 && !p->update_noreboot_flag) {
 		p->gcs_pmc_res = platform_get_resource(pdev,
 						       IORESOURCE_MEM,
 						       ICH_RES_MEM_GCS_PMC);
diff --git a/include/linux/platform_data/itco_wdt.h b/include/linux/platform_data/itco_wdt.h
index f16542c..ea1efb7 100644
--- a/include/linux/platform_data/itco_wdt.h
+++ b/include/linux/platform_data/itco_wdt.h
@@ -14,6 +14,7 @@
 struct itco_wdt_platform_data {
 	char name[32];
 	unsigned int version;
+	int (*update_noreboot_flag)(bool status);
 };
 
 #endif /* _ITCO_WDT_H_ */
-- 
2.7.4