mbox series

[v2,0/5] Add support to read the restart reason from IMEM

Message ID 20250416-wdt_reset_reason-v2-0-c65bba312914@oss.qualcomm.com
Headers show
Series Add support to read the restart reason from IMEM | expand

Message

Kathiravan Thirumoorthy April 16, 2025, 8:29 a.m. UTC 
In Qualcomm IPQ SoC, if the system is rebooted due to the watchdog
timeout, there is no way to identify it. Current approach of checking
the EXPIRED_STATUS in WDT_STS is not working.

To achieve this, if the system is rebooted due to watchdog timeout, the
information is captured in the IMEM by the bootloader (along with other
reason codes as well).

This series attempts to address this by adding the support to read the
IMEM and populate the information via bootstatus sysfs file. As of now,
we are handling only the non secure watchdog timeout reason.

Konrad, I sticked with syscon API to access the IMEM instead of exposing
it as mmio-sram to align with what is available in the mainline. Do let
me know if the current approach is still not correct / feasible.

Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com>
---
Changes in v2:
- Dropped the RFC tag
- Reworked the driver changes to use the syscon API
- Link to v1: 20250408-wdt_reset_reason-v1-0-e6ec30c2c926@oss.qualcomm.com

---
Kathiravan Thirumoorthy (5):
      dt-bindings: sram: qcom,imem: Document IPQ5424 compatible
      arm64: dts: qcom: ipq5424: Add the IMEM node
      dt-bindings: watchdog: separate out the IPQ5424 compatilble
      arm64: dts: qcom: ipq5424: drop the fallback WDT compatible
      watchdog: qcom: add support to read the restart reason from IMEM

 .../devicetree/bindings/sram/qcom,imem.yaml        |  1 +
 .../devicetree/bindings/watchdog/qcom-wdt.yaml     |  7 +++-
 arch/arm64/boot/dts/qcom/ipq5424.dtsi              | 11 ++++-
 drivers/watchdog/qcom-wdt.c                        | 47 +++++++++++++++++++++-
 4 files changed, 61 insertions(+), 5 deletions(-)
---
base-commit: 7702d0130dc002bab2c3571ddb6ff68f82d99aea
change-id: 20250408-wdt_reset_reason-e12921963fa6

Best regards,

Comments

Konrad Dybcio April 16, 2025, 2:52 p.m. UTC | #1 
On 4/16/25 10:29 AM, Kathiravan Thirumoorthy wrote:
> Add the IMEM node to the device tree to extract debugging information
> like system restart reason, which is populated via IMEM. Define the
> IMEM region to enable this functionality.
> 
> As described, overall IMEM region is 112KB but only initial 4KB is
> accessible by all masters in the SoC.
> 
> Signed-off-by: Kathiravan Thirumoorthy <kathiravan.thirumoorthy@oss.qualcomm.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad