[PATCH v2 1/2] coresight: etm4x: Fix timestamp bit field handling

[Leo Yan]

Timestamps in the trace data appear as all zeros on recent kernels,
although the feature works correctly on old kernels (e.g., v6.12).

Since commit c382ee674c8b ("arm64/sysreg/tools: Move TRFCR definitions
to sysreg"), the TRFCR_ELx_TS_{VIRTUAL|GUEST_PHYSICAL|PHYSICAL} macros
were updated to remove the bit shift. As a result, the driver no longer
shifts bits when operates the timestamp field.

Fix this by using the FIELD_PREP() and FIELD_GET() helpers.

Reported-by: Tamas Zsoldos <tamas.zsoldos at arm.com>
Fixes: c382ee674c8b ("arm64/sysreg/tools: Move TRFCR definitions to sysreg")
Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c  | 2 +-
 drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 6a5898355a83..acb4a58e4bb9 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1237,7 +1237,7 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata)
 	 * tracing at the kernel EL and EL0, forcing to use the
 	 * virtual time as the timestamp.
 	 */
-	trfcr = (TRFCR_EL1_TS_VIRTUAL |
+	trfcr = (FIELD_PREP(TRFCR_EL1_TS_MASK, TRFCR_EL1_TS_VIRTUAL) |
 		 TRFCR_EL1_ExTRE |
 		 TRFCR_EL1_E0TRE);
 
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index 49d5fb87a74b..ab251865b893 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -2320,11 +2320,11 @@ static ssize_t ts_source_show(struct device *dev,
 		goto out;
 	}
 
-	switch (drvdata->trfcr & TRFCR_EL1_TS_MASK) {
+	val = FIELD_GET(TRFCR_EL1_TS_MASK, drvdata->trfcr);
+	switch (val) {
 	case TRFCR_EL1_TS_VIRTUAL:
 	case TRFCR_EL1_TS_GUEST_PHYSICAL:
 	case TRFCR_EL1_TS_PHYSICAL:
-		val = FIELD_GET(TRFCR_EL1_TS_MASK, drvdata->trfcr);
 		break;
 	default:
 		val = -1;
-- 
2.34.1