[PATCH v5 4/4] drivers: watchdog: ast2500 and ast2600 support bootstatus

[Peter Yin]

Add WDIOF_EXTERN1 and WDIOF_CARDRESET bootstatus in ast2600

Regarding the AST2600 specification, the WDTn Timeout Status Register
(WDT10) has bit 1 reserved. Bit 1 of the status register indicates
on ast2500 if the boot was from the second boot source.
It does not indicate that the most recent reset was triggered by
the watchdog. The code should just be changed to set WDIOF_CARDRESET
if bit 0 of the status register is set.

Include SCU register to veriy WDIOF_EXTERN1 in ast2600 SCU74 or
ast2500 SCU3C when bit1 is set.

Signed-off-by: Peter Yin <peteryin.openbmc@xxxxxxxxx>
---
 drivers/watchdog/aspeed_wdt.c | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index b4773a6aaf8c..c3c8098c035d 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -11,10 +11,12 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/kstrtox.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/watchdog.h>
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
@@ -82,6 +84,13 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
 #define WDT_RESET_MASK1		0x1c
 #define WDT_RESET_MASK2		0x20
 
+/*
+ * Ast2600 SCU74 bit1 is External reset flag
+ * Ast2500 SCU3C bit1 is External reset flag
+ */
+#define AST2500_SYSTEM_RESET_EVENT	0x3C
+#define AST2600_SYSTEM_RESET_EVENT	0x74
+#define   EXTERN_RESET_FLAG		BIT(1)
 /*
  * WDT_RESET_WIDTH controls the characteristics of the external pulse (if
  * enabled), specifically:
@@ -330,6 +339,11 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
+	struct regmap *scu_base = syscon_regmap_lookup_by_phandle(dev->of_node,
+							     "aspeed,scu");
+	if (IS_ERR(scu_base))
+		return PTR_ERR(scu_base);
+
 	wdt->wdd.info = &aspeed_wdt_info;
 
 	if (wdt->cfg->irq_mask) {
@@ -459,14 +473,26 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	}
 
 	status = readl(wdt->base + WDT_TIMEOUT_STATUS);
-	if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) {
+	if (status & WDT_TIMEOUT_STATUS_EVENT)
 		wdt->wdd.bootstatus = WDIOF_CARDRESET;
 
-		if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
-		    of_device_is_compatible(np, "aspeed,ast2500-wdt"))
-			wdt->wdd.groups = bswitch_groups;
+	if (of_device_is_compatible(np, "aspeed,ast2600-wdt")) {
+		ret = regmap_read(scu_base,
+				  AST2600_SYSTEM_RESET_EVENT,
+				  &status);
+	} else {
+		ret = regmap_read(scu_base,
+				  AST2500_SYSTEM_RESET_EVENT,
+				  &status);
+		wdt->wdd.groups = bswitch_groups;
 	}
 
+	/*
+	 * Reset cause by Extern Reset
+	 */
+	if (status & EXTERN_RESET_FLAG && !ret)
+		wdt->wdd.bootstatus |= WDIOF_EXTERN1;
+
 	dev_set_drvdata(dev, wdt);
 
 	return devm_watchdog_register_device(dev, &wdt->wdd);
-- 
2.25.1