From mboxrd@z Thu Jan 1 00:00:00 1970 From: suzuki.poulose@arm.com (Suzuki K Poulose) Date: Wed, 11 Jul 2018 15:16:36 +0100 Subject: [PATCH 3/6] coresight: tmc-etr: Relax collection of trace from sysfs mode In-Reply-To: <1531318599-8840-1-git-send-email-suzuki.poulose@arm.com> References: <1531318599-8840-1-git-send-email-suzuki.poulose@arm.com> Message-ID: <1531318599-8840-4-git-send-email-suzuki.poulose@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 Signed-off-by: Suzuki K Poulose --- 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 edbfeaa..e54c8a4 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1168,19 +1168,17 @@ 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); -- 2.7.4