From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: linux-arm-kernel@lists.infradead.org
Cc: suzuki.poulose@arm.com, alexander.shishkin@linux.intel.com,
coresight@lists.linaro.org, acme@kernel.org,
peterz@infradead.org, mingo@redhat.com, leo.yan@linaro.org,
mike.leach@linaro.org
Subject: [PATCH V2 3/6] coresight: tmc-etf: Properly set AUX buffer head in snapshot mode
Date: Tue, 14 May 2019 13:40:15 -0600 [thread overview]
Message-ID: <20190514194018.23420-4-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20190514194018.23420-1-mathieu.poirier@linaro.org>
Unify amongst sink drivers how the AUX ring buffer head is communicated
to user space. That way the same algorithm in cs_etm_find_snapshot()
can be used to determine where the latest data is and how much of it
to access.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
drivers/hwtracing/coresight/coresight-tmc-etf.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 2527b5d3b65e..d026bd04a6af 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -542,11 +542,15 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
}
}
- /* In snapshot mode we have to update the head */
- if (buf->snapshot) {
- handle->head = (cur * PAGE_SIZE) + offset;
- to_read = buf->nr_pages << PAGE_SHIFT;
- }
+ /*
+ * In snapshot mode we simply increment the head by the number of byte
+ * that were written. User space function cs_etm_find_snapshot() will
+ * figure out how many bytes to get from the AUX buffer based on the
+ * position of the head.
+ */
+ if (buf->snapshot)
+ handle->head += to_read;
+
CS_LOCK(drvdata->base);
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
--
2.17.1
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next prev parent reply other threads:[~2019-05-14 19:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-14 19:40 [PATCH V2 0/6] coresight: Fix snapshot mode Mathieu Poirier
2019-05-14 19:40 ` [PATCH V2 1/6] coresight: etb10: Properly set AUX buffer head in " Mathieu Poirier
2019-05-15 9:45 ` Suzuki K Poulose
2019-05-15 14:28 ` Mathieu Poirier
2019-05-16 9:41 ` Suzuki K Poulose
2019-05-14 19:40 ` [PATCH V2 2/6] coresight: tmc-etr: " Mathieu Poirier
2019-05-14 19:40 ` Mathieu Poirier [this message]
2019-05-14 19:40 ` [PATCH V2 4/6] coresight: tmc-etf: Fix snapshot mode update function Mathieu Poirier
2019-05-14 19:40 ` [PATCH V2 5/6] coresight: perf: Don't set the truncated flag in snapshot mode Mathieu Poirier
2019-05-16 15:22 ` Suzuki K Poulose
2019-05-14 19:40 ` [PATCH V2 6/6] perf tools: Properly set the value of 'old' and 'head' " Mathieu Poirier
2019-05-16 15:00 ` Leo Yan
2019-05-20 19:53 ` Mathieu Poirier
2019-05-21 1:54 ` Leo Yan
2019-05-16 15:09 ` [PATCH V2 0/6] coresight: Fix " Leo Yan
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