linux-kernel - [PATCH 1/2] watchdog: aspeed: Add pre-timeout interrupt support

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Message-Id: <20221021151559.781983-2-eajames@linux.ibm.com>
Date:   Fri, 21 Oct 2022 10:15:58 -0500
From:   Eddie James <eajames@...ux.ibm.com>
To:     linux-watchdog@...r.kernel.org
Cc:     linux-aspeed@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        wim@...ux-watchdog.org, linux@...ck-us.net, andrew@...id.au,
        joel@....id.au, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, devicetree@...r.kernel.org,
        Eddie James <eajames@...ux.ibm.com>
Subject: [PATCH 1/2] watchdog: aspeed: Add pre-timeout interrupt support

Enable the pre-timeout interrupt if requested by device property.

Signed-off-by: Eddie James <eajames@...ux.ibm.com>
---
 drivers/watchdog/aspeed_wdt.c | 53 +++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index 0cff2adfbfc9..8e12181a827e 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -5,11 +5,14 @@
  * Joel Stanley <joel@....id.au>
  */
 
+#include <linux/bits.h>
 #include <linux/delay.h>
+#include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 
@@ -26,20 +29,32 @@ struct aspeed_wdt {
 
 struct aspeed_wdt_config {
 	u32 ext_pulse_width_mask;
+	u32 irq_shift;
+	u32 irq_mask;
 };
 
 static const struct aspeed_wdt_config ast2400_config = {
 	.ext_pulse_width_mask = 0xff,
+	.irq_shift = 0,
+	.irq_mask = 0,
 };
 
 static const struct aspeed_wdt_config ast2500_config = {
 	.ext_pulse_width_mask = 0xfffff,
+	.irq_shift = 12,
+	.irq_mask = GENMASK(31, 12),
+};
+
+static const struct aspeed_wdt_config ast2600_config = {
+	.ext_pulse_width_mask = 0xfffff,
+	.irq_shift = 0,
+	.irq_mask = GENMASK(31, 10),
 };
 
 static const struct of_device_id aspeed_wdt_of_table[] = {
 	{ .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
 	{ .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
-	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2500_config },
+	{ .compatible = "aspeed,ast2600-wdt", .data = &ast2600_config },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
@@ -58,6 +73,7 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
 #define   WDT_CTRL_RESET_SYSTEM		BIT(1)
 #define   WDT_CTRL_ENABLE		BIT(0)
 #define WDT_TIMEOUT_STATUS	0x10
+#define   WDT_TIMEOUT_STATUS_IRQ		BIT(2)
 #define   WDT_TIMEOUT_STATUS_BOOT_SECONDARY	BIT(1)
 #define WDT_CLEAR_TIMEOUT_STATUS	0x14
 #define   WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION	BIT(0)
@@ -243,6 +259,17 @@ static const struct watchdog_info aspeed_wdt_info = {
 	.identity	= KBUILD_MODNAME,
 };
 
+static irqreturn_t aspeed_wdt_irq(int irq, void *arg)
+{
+	struct aspeed_wdt *wdt = arg;
+	u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
+
+	if (status & WDT_TIMEOUT_STATUS_IRQ)
+		panic("Watchdog pre-timeout IRQ");
+
+	return IRQ_NONE;
+}
+
 static int aspeed_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -253,6 +280,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	const char *reset_type;
 	u32 duration;
 	u32 status;
+	u32 timeout = 0;
 	int ret;
 
 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
@@ -291,6 +319,27 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	if (of_device_is_compatible(np, "aspeed,ast2400-wdt"))
 		wdt->ctrl = WDT_CTRL_1MHZ_CLK;
 
+	if (config->irq_mask) {
+		if (!of_property_read_u32(np, "aspeed,pre-timeout-irq-us", &timeout) && timeout) {
+			int irq =  platform_get_irq(pdev, 0);
+
+			if (irq < 0) {
+				dev_warn(dev, "Couldn't find IRQ: %d\n", irq);
+				timeout = 0;
+			} else {
+				ret = devm_request_irq(dev, irq, aspeed_wdt_irq, IRQF_SHARED,
+						       dev_name(dev), wdt);
+				if (ret) {
+					dev_warn(dev, "Couldn't request IRQ:%d\n", ret);
+					timeout = 0;
+				} else {
+					wdt->ctrl |= ((timeout << config->irq_shift) &
+						      config->irq_mask) | WDT_CTRL_WDT_INTR;
+				}
+			}
+		}
+	}
+
 	/*
 	 * Control reset on a per-device basis to ensure the
 	 * host is not affected by a BMC reboot
@@ -308,7 +357,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 		else if (!strcmp(reset_type, "system"))
 			wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
 				     WDT_CTRL_RESET_SYSTEM;
-		else if (strcmp(reset_type, "none"))
+		else if (strcmp(reset_type, "none") && !timeout)
 			return -EINVAL;
 	}
 	if (of_property_read_bool(np, "aspeed,external-signal"))
-- 
2.31.1