diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-etb10.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-etb10.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index 4ee4c80a4354..0764647b92bc 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -374,7 +374,30 @@ static void *etb_alloc_buffer(struct coresight_device *csdev, int nr_pages, bool overwrite) { int node, cpu = event->cpu; + u32 capacity; struct cs_buffers *buf; + struct etb_drvdata *drvdata; + + /* + * In snapsot mode the size of the perf ring buffer needs to be equal + * to the size of the device's internal memory if we want to reuse the + * generic AUX buffer management mechanic. + * + * For example (assuming 4096 byte page size): + * + * # cat /sys/bus/coresight/devices/20010000.etb/mgmt/rdp + * 0x2000 + * # perf record -e cs_etm/@20010000.etf/ -S -m,8 --per-thread $APP + * + */ + drvdata = dev_get_drvdata(csdev->dev.parent); + capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS; + + if (overwrite && + ((nr_pages << PAGE_SHIFT) != capacity)) { + dev_err(&csdev->dev, "Ring buffer not equal to device buffer"); + return NULL; + } if (cpu == -1) cpu = smp_processor_id(); |