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From:   huaqian.li@siemens.com
To:     wim@linux-watchdog.org, linux@roeck-us.net, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org
Cc:     huaqianlee@gmail.com, nm@ti.com, vigneshr@ti.com,
        kristo@kernel.org, linux-watchdog@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, jan.kiszka@siemens.com,
        baocheng.su@siemens.com, Li Hua Qian <huaqian.li@siemens.com>
Subject: [PATCH v3 1/3] dt-bindings: watchdog: ti,rti-wdt: Add support for WDIOF_CARDRESET
Date:   Thu, 13 Jul 2023 17:51:25 +0800
Message-Id: <20230713095127.1230109-2-huaqian.li@siemens.com>
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From: Li Hua Qian <huaqian.li@siemens.com>

TI RTI (Real Time Interrupt) Watchdog doesn't support to record the
watchdog cause. Add a reserved memory to know the last reboot was caused
by the watchdog card. In the reserved memory, some specific info will be
saved to indicate whether the watchdog reset was triggered in last
boot.

Signed-off-by: Li Hua Qian <huaqian.li@siemens.com>
---
 .../devicetree/bindings/watchdog/ti,rti-wdt.yaml     | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
index fc553211e42d..8c16fd3929ec 100644
--- a/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
+++ b/Documentation/devicetree/bindings/watchdog/ti,rti-wdt.yaml
@@ -34,6 +34,18 @@ properties:
   power-domains:
     maxItems: 1
 
+  memory-region:
+    maxItems: 1
+    description:
+      Contains the watchdog reserved memory. It is optional.
+      In the reserved memory, the specified values, which are
+      PON_REASON_SOF_NUM(0xBBBBCCCC), PON_REASON_MAGIC_NUM(0xDDDDDDDD),
+      and PON_REASON_EOF_NUM(0xCCCCBBBB), are pre-stored at the first
+      3 * 4 bytes to tell that last boot was caused by watchdog reset.
+      Once the PON reason is captured by driver(rti_wdt.c), the driver
+      is supposed to wipe the whole memory region.
+
+
 required:
   - compatible
   - reg
-- 
2.34.1