[PATCH v2 1/2] watchdog: aspeed: Enable pre-timeout interrupt

[Eddie James <eajames@linux.ibm.com>]

Enable the core pre-timeout interrupt on AST2500 and AST2600.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/watchdog/aspeed_wdt.c | 104 ++++++++++++++++++++++++++++------
 1 file changed, 88 insertions(+), 16 deletions(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index 0cff2adfbfc9..86b5331bc491 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -5,11 +5,14 @@
  * Joel Stanley <joel@jms.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>
 
@@ -18,28 +21,41 @@ module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
+struct aspeed_wdt_config {
+	u32 ext_pulse_width_mask;
+	u32 irq_shift;
+	u32 irq_mask;
+};
+
 struct aspeed_wdt {
 	struct watchdog_device	wdd;
 	void __iomem		*base;
 	u32			ctrl;
-};
-
-struct aspeed_wdt_config {
-	u32 ext_pulse_width_mask;
+	const struct aspeed_wdt_config *cfg;
 };
 
 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 +74,7 @@ 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)
@@ -160,6 +177,26 @@ static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
 	return 0;
 }
 
+static int aspeed_wdt_set_pretimeout(struct watchdog_device *wdd,
+				     unsigned int pretimeout)
+{
+	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+	u32 actual = pretimeout * WDT_RATE_1MHZ;
+	u32 s = wdt->cfg->irq_shift;
+	u32 m = wdt->cfg->irq_mask;
+
+	wdd->pretimeout = pretimeout;
+	wdt->ctrl &= ~m;
+	if (pretimeout)
+		wdt->ctrl |= ((actual << s) & m) | WDT_CTRL_WDT_INTR;
+	else
+		wdt->ctrl &= ~WDT_CTRL_WDT_INTR;
+
+	writel(wdt->ctrl, wdt->base + WDT_CTRL);
+
+	return 0;
+}
+
 static int aspeed_wdt_restart(struct watchdog_device *wdd,
 			      unsigned long action, void *data)
 {
@@ -232,6 +269,7 @@ static const struct watchdog_ops aspeed_wdt_ops = {
 	.stop		= aspeed_wdt_stop,
 	.ping		= aspeed_wdt_ping,
 	.set_timeout	= aspeed_wdt_set_timeout,
+	.set_pretimeout = aspeed_wdt_set_pretimeout,
 	.restart	= aspeed_wdt_restart,
 	.owner		= THIS_MODULE,
 };
@@ -243,10 +281,29 @@ static const struct watchdog_info aspeed_wdt_info = {
 	.identity	= KBUILD_MODNAME,
 };
 
+static const struct watchdog_info aspeed_wdt_pretimeout_info = {
+	.options	= WDIOF_KEEPALIVEPING
+			| WDIOF_PRETIMEOUT
+			| WDIOF_MAGICCLOSE
+			| WDIOF_SETTIMEOUT,
+	.identity	= KBUILD_MODNAME,
+};
+
+static irqreturn_t aspeed_wdt_irq(int irq, void *arg)
+{
+	struct watchdog_device *wdd = arg;
+	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
+	u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
+
+	if (status & WDT_TIMEOUT_STATUS_IRQ)
+		watchdog_notify_pretimeout(wdd);
+
+	return IRQ_HANDLED;
+}
+
 static int aspeed_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	const struct aspeed_wdt_config *config;
 	const struct of_device_id *ofdid;
 	struct aspeed_wdt *wdt;
 	struct device_node *np;
@@ -259,11 +316,33 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	if (!wdt)
 		return -ENOMEM;
 
+	np = dev->of_node;
+
+	ofdid = of_match_node(aspeed_wdt_of_table, np);
+	if (!ofdid)
+		return -EINVAL;
+	wdt->cfg = ofdid->data;
+
 	wdt->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
 	wdt->wdd.info = &aspeed_wdt_info;
+
+	if (wdt->cfg->irq_mask) {
+		int irq = platform_get_irq_optional(pdev, 0);
+
+		if (irq > 0) {
+			ret = devm_request_irq(dev, irq, aspeed_wdt_irq,
+					       IRQF_SHARED, dev_name(dev),
+					       wdt);
+			if (ret)
+				return ret;
+
+			wdt->wdd.info = &aspeed_wdt_pretimeout_info;
+		}
+	}
+
 	wdt->wdd.ops = &aspeed_wdt_ops;
 	wdt->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
 	wdt->wdd.parent = dev;
@@ -273,13 +352,6 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 
 	watchdog_set_nowayout(&wdt->wdd, nowayout);
 
-	np = dev->of_node;
-
-	ofdid = of_match_node(aspeed_wdt_of_table, np);
-	if (!ofdid)
-		return -EINVAL;
-	config = ofdid->data;
-
 	/*
 	 * On clock rates:
 	 *  - ast2400 wdt can run at PCLK, or 1MHz
@@ -331,7 +403,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 		(of_device_is_compatible(np, "aspeed,ast2600-wdt"))) {
 		u32 reg = readl(wdt->base + WDT_RESET_WIDTH);
 
-		reg &= config->ext_pulse_width_mask;
+		reg &= wdt->cfg->ext_pulse_width_mask;
 		if (of_property_read_bool(np, "aspeed,ext-active-high"))
 			reg |= WDT_ACTIVE_HIGH_MAGIC;
 		else
@@ -339,7 +411,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 
 		writel(reg, wdt->base + WDT_RESET_WIDTH);
 
-		reg &= config->ext_pulse_width_mask;
+		reg &= wdt->cfg->ext_pulse_width_mask;
 		if (of_property_read_bool(np, "aspeed,ext-push-pull"))
 			reg |= WDT_PUSH_PULL_MAGIC;
 		else
@@ -349,7 +421,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	}
 
 	if (!of_property_read_u32(np, "aspeed,ext-pulse-duration", &duration)) {
-		u32 max_duration = config->ext_pulse_width_mask + 1;
+		u32 max_duration = wdt->cfg->ext_pulse_width_mask + 1;
 
 		if (duration == 0 || duration > max_duration) {
 			dev_err(dev, "Invalid pulse duration: %uus\n",
-- 
2.31.1