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ASoC: SOF: Intel: hda-stream: Always use at least two BDLE for transfers

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The HDA specification states that the SDnLVI (Last Valid Index) must be at
least 1 (two BDLE entry).

Update the debug prints as well to provide better information.

While the LVI=0 worked so far without issues, it is better to align with
the specification to avoid unforeseen issues with FW loading.

Notes:
- The LVI > 0 rules is valid and honored for audio use cases
- LVI == 0 is used with software controlled (SPIB) transfers only for
  firmware and library loading, which is permitted by the hardware
- This is not spelled out in the specification and it is better to avoid
  cases

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://patch.msgid.link/20241107121532.3241-1-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Peter Ujfalusi 2024-11-07 14:15:32 +02:00 committed by Mark Brown
parent 8121de3346
commit 1b1f491dac
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GPG Key ID: 24D68B725D5487D0
1 changed files with 29 additions and 3 deletions
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32
sound/soc/sof/intel/hda-stream.c
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@ -119,13 +119,39 @@ int hda_dsp_stream_setup_bdl(struct snd_sof_dev *sdev,
int remain, ioc;
period_bytes = hstream->period_bytes;
dev_dbg(sdev->dev, "period_bytes:0x%x\n", period_bytes);
if (!period_bytes)
dev_dbg(sdev->dev, "period_bytes: %#x, bufsize: %#x\n", period_bytes,
hstream->bufsize);
if (!period_bytes) {
unsigned int chunk_size;
chunk_size = snd_sgbuf_get_chunk_size(dmab, 0, hstream->bufsize);
period_bytes = hstream->bufsize;
/*
* HDA spec demands that the LVI value must be at least one
* before the DMA operation can begin. This means that there
* must be at least two BDLE present for the transfer.
*
* If the buffer is not a single continuous area then the
* hda_setup_bdle() will create multiple BDLEs for each segment.
* If the memory is a single continuous area, force it to be
* split into two 'periods', otherwise the transfer will be
* split to multiple BDLE for each chunk in hda_setup_bdle()
*
* Note: period_bytes == 0 can only happen for firmware or
* library loading. The data size is 4K aligned, which ensures
* that the second chunk's start address will be 128-byte
* aligned.
*/
if (chunk_size == hstream->bufsize)
period_bytes /= 2;
}
periods = hstream->bufsize / period_bytes;
dev_dbg(sdev->dev, "periods:%d\n", periods);
dev_dbg(sdev->dev, "periods: %d\n", periods);
remain = hstream->bufsize % period_bytes;
if (remain)