diff options
| author | Peter Ujfalusi <peter.ujfalusi@linux.intel.com> | 2022-03-10 11:16:49 -0600 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2022-03-11 13:40:55 +0000 |
| commit | d8b502a7c353a63269d5ac3cfa7e5a04308df6a1 (patch) | |
| tree | 74a7fef3e536a9be29f96700a1574a03d84ba883 | |
| parent | 7e4bfcf10a03981cb3056d723bb2f92eead5c0bb (diff) | |
| download | lwn-d8b502a7c353a63269d5ac3cfa7e5a04308df6a1.tar.gz lwn-d8b502a7c353a63269d5ac3cfa7e5a04308df6a1.zip | |
ASoC: SOF: trace: Use proper DMA direction for the trace data buffer
Buffers allocated with snd_dma_alloc_pages() will have DMA direction
DMA_BIDIRECTIONAL. The trace data memory is only used for one DMA
direction: DMA_FROM_DEVICE, DMA only writes there, never reads.
We also need to do a sync before accessing (reading with CPU) from the
trace data buffer to copy it to user space.
Note: snd_dma_buffer_sync() is also used for normal playback and capture
streams to make sure that the data is available for the DMA or CPU.
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220310171651.249385-4-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | sound/soc/sof/trace.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/sound/soc/sof/trace.c b/sound/soc/sof/trace.c index 104388c551cb..ea8e4506d02e 100644 --- a/sound/soc/sof/trace.c +++ b/sound/soc/sof/trace.c @@ -320,6 +320,13 @@ static ssize_t sof_dfsentry_trace_read(struct file *file, char __user *buffer, if (count > avail) count = avail; + /* + * make sure that all trace data is available for the CPU as the trace + * data buffer might be allocated from non consistent memory. + * Note: snd_dma_buffer_sync() is called for normal audio playback and + * capture streams also. + */ + snd_dma_buffer_sync(&sdev->dmatb, SNDRV_DMA_SYNC_CPU); /* copy available trace data to debugfs */ rem = copy_to_user(buffer, ((u8 *)(dfse->buf) + lpos), count); if (rem) @@ -464,8 +471,9 @@ int snd_sof_init_trace(struct snd_sof_dev *sdev) } /* allocate trace data buffer */ - ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV_SG, sdev->dev, - DMA_BUF_SIZE_FOR_TRACE, &sdev->dmatb); + ret = snd_dma_alloc_dir_pages(SNDRV_DMA_TYPE_DEV_SG, sdev->dev, + DMA_FROM_DEVICE, DMA_BUF_SIZE_FOR_TRACE, + &sdev->dmatb); if (ret < 0) { dev_err(sdev->dev, "error: can't alloc buffer for trace %d\n", ret); |