[PATCH 12/17] coresight etr: Relax collection of trace from sysfs mode

[Suzuki K Poulose]

Since the ETR now uses mode specific buffers, we can reliably
provide the trace data captured in sysfs mode, even when the ETR
is operating in PERF mode.

Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c 
b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index ef7498f05b34..31353fc34b53 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1231,19 +1231,17 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
                goto out;
        }
 
-       /* Don't interfere if operated from Perf */
-       if (drvdata->mode == CS_MODE_PERF) {
-               ret = -EINVAL;
-               goto out;
-       }
-
-       /* If sysfs_buf is NULL the trace data has been read already */
+       /*
+        * We can safely allow reads even if the ETR is operating in PERF mode,
+        * since the sysfs session is captured in mode specific data.
+        * If drvdata::sysfs_data is NULL the trace data has been read already.
+        */
        if (!drvdata->sysfs_buf) {
                ret = -EINVAL;
                goto out;
        }
 
-       /* Disable the TMC if we are trying to read from a running session */
+       /* Disable the TMC if we are trying to read from a running session. */
        if (drvdata->mode == CS_MODE_SYSFS)
                tmc_etr_disable_hw(drvdata);
 
-- 
2.13.6