Merge v6.12.43linux-rolling-lts

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 54 insertions, 4 deletions

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 84dca3695f86..e5e6d7f15918 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -644,6 +644,8 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
 	} else {
 		wdd->timeout = DW_WDT_DEFAULT_SECONDS;
 		watchdog_init_timeout(wdd, 0, dev);
+		/* Limit timeout value to hardware constraints. */
+		dw_wdt_set_timeout(wdd, wdd->timeout);
 	}
 
 	platform_set_drvdata(pdev, dw_wdt);
diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index f01ed38aba67..d5c91759dc00 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -601,7 +601,11 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
 	/* Check that the heartbeat value is within it's range;
 	   if not reset to the default */
 	if (iTCO_wdt_set_timeout(&p->wddev, heartbeat)) {
-		iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT);
+		ret = iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT);
+		if (ret != 0) {
+			dev_err(dev, "Failed to set watchdog timeout (%d)\n", WATCHDOG_TIMEOUT);
+			return ret;
+		}
 		dev_info(dev, "timeout value out of range, using %d\n",
 			WATCHDOG_TIMEOUT);
 	}
diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
index 5f23913ce3b4..6ce1bfb39064 100644
--- a/drivers/watchdog/sbsa_gwdt.c
+++ b/drivers/watchdog/sbsa_gwdt.c
@@ -75,11 +75,17 @@
 #define SBSA_GWDT_VERSION_MASK  0xF
 #define SBSA_GWDT_VERSION_SHIFT 16
 
+#define SBSA_GWDT_IMPL_MASK	0x7FF
+#define SBSA_GWDT_IMPL_SHIFT	0
+#define SBSA_GWDT_IMPL_MEDIATEK	0x426
+
 /**
  * struct sbsa_gwdt - Internal representation of the SBSA GWDT
  * @wdd:		kernel watchdog_device structure
  * @clk:		store the System Counter clock frequency, in Hz.
  * @version:            store the architecture version
+ * @need_ws0_race_workaround:
+ *			indicate whether to adjust wdd->timeout to avoid a race with WS0
  * @refresh_base:	Virtual address of the watchdog refresh frame
  * @control_base:	Virtual address of the watchdog control frame
  */
@@ -87,6 +93,7 @@ struct sbsa_gwdt {
 	struct watchdog_device	wdd;
 	u32			clk;
 	int			version;
+	bool			need_ws0_race_workaround;
 	void __iomem		*refresh_base;
 	void __iomem		*control_base;
 };
@@ -161,6 +168,31 @@ static int sbsa_gwdt_set_timeout(struct watchdog_device *wdd,
 		 */
 		sbsa_gwdt_reg_write(((u64)gwdt->clk / 2) * timeout, gwdt);
 
+	/*
+	 * Some watchdog hardware has a race condition where it will ignore
+	 * sbsa_gwdt_keepalive() if it is called at the exact moment that a
+	 * timeout occurs and WS0 is being asserted. Unfortunately, the default
+	 * behavior of the watchdog core is very likely to trigger this race
+	 * when action=0 because it programs WOR to be half of the desired
+	 * timeout, and watchdog_next_keepalive() chooses the exact same time to
+	 * send keepalive pings.
+	 *
+	 * This triggers a race where sbsa_gwdt_keepalive() can be called right
+	 * as WS0 is being asserted, and affected hardware will ignore that
+	 * write and continue to assert WS0. After another (timeout / 2)
+	 * seconds, the same race happens again. If the driver wins then the
+	 * explicit refresh will reset WS0 to false but if the hardware wins,
+	 * then WS1 is asserted and the system resets.
+	 *
+	 * Avoid the problem by scheduling keepalive heartbeats one second later
+	 * than the WOR timeout.
+	 *
+	 * This workaround might not be needed in a future revision of the
+	 * hardware.
+	 */
+	if (gwdt->need_ws0_race_workaround)
+		wdd->min_hw_heartbeat_ms = timeout * 500 + 1000;
+
 	return 0;
 }
 
@@ -202,12 +234,15 @@ static int sbsa_gwdt_keepalive(struct watchdog_device *wdd)
 static void sbsa_gwdt_get_version(struct watchdog_device *wdd)
 {
 	struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd);
-	int ver;
+	int iidr, ver, impl;
 
-	ver = readl(gwdt->control_base + SBSA_GWDT_W_IIDR);
-	ver = (ver >> SBSA_GWDT_VERSION_SHIFT) & SBSA_GWDT_VERSION_MASK;
+	iidr = readl(gwdt->control_base + SBSA_GWDT_W_IIDR);
+	ver = (iidr >> SBSA_GWDT_VERSION_SHIFT) & SBSA_GWDT_VERSION_MASK;
+	impl = (iidr >> SBSA_GWDT_IMPL_SHIFT) & SBSA_GWDT_IMPL_MASK;
 
 	gwdt->version = ver;
+	gwdt->need_ws0_race_workaround =
+		!action && (impl == SBSA_GWDT_IMPL_MEDIATEK);
 }
 
 static int sbsa_gwdt_start(struct watchdog_device *wdd)
@@ -299,6 +334,15 @@ static int sbsa_gwdt_probe(struct platform_device *pdev)
 	else
 		wdd->max_hw_heartbeat_ms = GENMASK_ULL(47, 0) / gwdt->clk * 1000;
 
+	if (gwdt->need_ws0_race_workaround) {
+		/*
+		 * A timeout of 3 seconds means that WOR will be set to 1.5
+		 * seconds and the heartbeat will be scheduled every 2.5
+		 * seconds.
+		 */
+		wdd->min_timeout = 3;
+	}
+
 	status = readl(cf_base + SBSA_GWDT_WCS);
 	if (status & SBSA_GWDT_WCS_WS1) {
 		dev_warn(dev, "System reset by WDT.\n");