[PATCH 04/17] dt-bindings: arm: coresight: Add support to skip trace unit power up

Mathieu Poirier mathieu.poirier at linaro.org
Thu Jul 16 13:57:33 EDT 2020


From: Tingwei Zhang <tingwei at codeaurora.org>

Add "qcom,skip-power-up" property to identify systems which can
skip powering up of trace unit since they share the same power
domain as their CPU core. This is required to identify such
systems with hardware errata which stops the CPU watchdog counter
when the power up bit is set (TRCPDCR.PU).

Signed-off-by: Tingwei Zhang <tingwei at codeaurora.org>
Co-developed-by: Sai Prakash Ranjan <saiprakash.ranjan at codeaurora.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan at codeaurora.org>
Reviewed-by: Rob Herring <robh at kernel.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier at linaro.org>
---
 Documentation/devicetree/bindings/arm/coresight.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
index 846f6daae71b..e4b2eda0b53b 100644
--- a/Documentation/devicetree/bindings/arm/coresight.txt
+++ b/Documentation/devicetree/bindings/arm/coresight.txt
@@ -108,6 +108,13 @@ its hardware characteristcs.
 	* arm,cp14: must be present if the system accesses ETM/PTM management
 	  registers via co-processor 14.
 
+	* qcom,skip-power-up: boolean. Indicates that an implementation can
+	  skip powering up the trace unit. TRCPDCR.PU does not have to be set
+	  on Qualcomm Technologies Inc. systems since ETMs are in the same power
+	  domain as their CPU cores. This property is required to identify such
+	  systems with hardware errata where the CPU watchdog counter is stopped
+	  when TRCPDCR.PU is set.
+
 * Optional property for TMC:
 
 	* arm,buffer-size: size of contiguous buffer space for TMC ETR
-- 
2.25.1




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