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Subject[PATCH 1/5] coresight: Correct buffer lost increment
Date
Many conditions may cause synchronisation to be lost when updating
the perf ring buffer but the end result is still the same: synchronisation
is lost. As such there is no need to increment the lost count for each
condition, just once will suffice.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
drivers/hwtracing/coresight/coresight-etb10.c | 10 +++++++---
drivers/hwtracing/coresight/coresight-tmc-etf.c | 8 ++++++--
2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index d5b96423e1a5..d9c233135d6d 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -353,6 +353,7 @@ static void etb_update_buffer(struct coresight_device *csdev,
struct perf_output_handle *handle,
void *sink_config)
{
+ bool lost = false;
int i, cur;
u8 *buf_ptr;
u32 read_ptr, write_ptr, capacity;
@@ -384,7 +385,7 @@ static void etb_update_buffer(struct coresight_device *csdev,
(unsigned long)write_ptr);

write_ptr &= ~(ETB_FRAME_SIZE_WORDS - 1);
- perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+ lost = true;
}

/*
@@ -395,7 +396,7 @@ static void etb_update_buffer(struct coresight_device *csdev,
*/
status = readl_relaxed(drvdata->base + ETB_STATUS_REG);
if (status & ETB_STATUS_RAM_FULL) {
- perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+ lost = true;
to_read = capacity;
read_ptr = write_ptr;
} else {
@@ -428,9 +429,12 @@ static void etb_update_buffer(struct coresight_device *csdev,
if (read_ptr > (drvdata->buffer_depth - 1))
read_ptr -= drvdata->buffer_depth;
/* let the decoder know we've skipped ahead */
- perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+ lost = true;
}

+ if (lost)
+ perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+
/* finally tell HW where we want to start reading from */
writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index e3b9fb82eb8d..2e0fb5b9372c 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -369,6 +369,7 @@ static void tmc_update_etf_buffer(struct coresight_device *csdev,
struct perf_output_handle *handle,
void *sink_config)
{
+ bool lost = false;
int i, cur;
u32 *buf_ptr;
u32 read_ptr, write_ptr;
@@ -397,7 +398,7 @@ static void tmc_update_etf_buffer(struct coresight_device *csdev,
*/
status = readl_relaxed(drvdata->base + TMC_STS);
if (status & TMC_STS_FULL) {
- perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+ lost = true;
to_read = drvdata->size;
} else {
to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->size);
@@ -442,9 +443,12 @@ static void tmc_update_etf_buffer(struct coresight_device *csdev,
read_ptr -= drvdata->size;
/* Tell the HW */
writel_relaxed(read_ptr, drvdata->base + TMC_RRP);
- perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+ lost = true;
}

+ if (lost)
+ perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+
cur = buf->cur;
offset = buf->offset;

--
2.7.4
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