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ASoC: SOF: trace: Use proper DMA direction for the trace data buffer

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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>
This commit is contained in:
Peter Ujfalusi 2022-03-10 11:16:49 -06:00 committed by Mark Brown
parent 7e4bfcf10a
commit d8b502a7c3
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GPG Key ID: 24D68B725D5487D0
1 changed files with 10 additions and 2 deletions
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12
sound/soc/sof/trace.c
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@ -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);