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Subject[PATCH 16/16] coresight: etm4x: Fix number of resources check for ETM 4.3 and above
Date
From: Mike Leach <mike.leach@linaro.org>

The initialisation code checks TRCIDR4 to determine the number of resource
selectors available on the system. Since ETM v 4.3, the value 0 has a
different meaning. This patch takes into account this change.

Cc: stable@vger.kernel.org
Signed-off-by: Mike Leach <mike.leach@linaro.org>
[Removed '.' in patch title, added stable]
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
drivers/hwtracing/coresight/coresight-etm4x.c | 8 +++++++-
drivers/hwtracing/coresight/coresight-etm4x.h | 3 +++
2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index b29ad4f7fac2..f5ab13aaecea 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -742,8 +742,14 @@ static void etm4_init_arch_data(void *info)
* The number of resource pairs conveyed by the HW starts at 0, i.e a
* value of 0x0 indicate 1 resource pair, 0x1 indicate two and so on.
* As such add 1 to the value of NUMRSPAIR for a better representation.
+ *
+ * For ETM v4.3 and later, 0x0 means 0, and no pairs are available -
+ * the default TRUE and FALSE resource selectors are omitted.
+ * Otherwise for values 0x1 and above the number is N + 1 as per v4.2.
*/
- drvdata->nr_resource = BMVAL(etmidr4, 16, 19) + 1;
+ drvdata->nr_resource = BMVAL(etmidr4, 16, 19);
+ if ((drvdata->arch < ETM4X_ARCH_4V3) || (drvdata->nr_resource > 0))
+ drvdata->nr_resource += 1;
/*
* NUMSSCC, bits[23:20] the number of single-shot
* comparator control for tracing. Read any status regs as these
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 5259f96fd28a..eefc7371c6c4 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -200,6 +200,9 @@
/* NS MON (EL3) mode never implemented */
#define ETM_EXLEVEL_NS_VICTLR_MASK GENMASK(22, 20)

+/* Interpretation of resource numbers change at ETM v4.3 architecture */
+#define ETM4X_ARCH_4V3 0x43
+
/**
* struct etmv4_config - configuration information related to an ETMv4
* @mode: Controls various modes supported by this ETM.
--
2.25.1
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