[RFC] soundwire: add runtime BPT support#5604
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Pull request overview
This PR implements runtime BPT (Bulk Point-to-Point) stream support for SoundWire, enabling firmware downloads while audio streams are active. The changes calculate available columns in SoundWire frames and allocate them to BPT streams on a first-come, first-served basis, with a reservation of 2 columns for audio streams when possible.
Key changes:
- Modified bandwidth calculation to exclude BPT streams and use remaining available bandwidth
- Added
bpt_hstopfield to track BPT stream column allocation - Updated frame column allocation logic to dynamically reserve space for audio streams
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.
| File | Description |
|---|---|
| include/linux/soundwire/sdw.h | Added bpt_hstop field to track BPT stream column boundaries |
| drivers/soundwire/stream.c | Excluded BPT streams from bandwidth calculations during prepare/deprepare |
| drivers/soundwire/intel_ace2x.c | Updated to use bpt_hstop instead of total columns for BPT buffer calculations |
| drivers/soundwire/generic_bandwidth_allocation.c | Implemented dynamic column allocation logic with BPT stream filtering and reservation |
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| return ret; | ||
| } | ||
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| if (stream->type == SDW_STREAM_BPT) { |
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| * Use the maximum freq to get maximum bandwidth and no need to try another freq | ||
| * if BPT stream is running | ||
| */ | ||
| if (!is_clock_scaling_supported(bus) || bus->bpt_stream_refcount) | ||
| clk_values = 1; |
We should get as much as bandwidth for the BPT stream. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
The DP0 (BPT) params are computed in sdw_compute_dp0_port_params(). We should exclude the BPT stream when calculating the audio streams. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
We just need to conunt the audio stream bandwidth and BRA stream will use the remaining bandwidth. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
colume The existing code assumes the column number will not change, but it could change if curr_dr_freq changes. Calculate the new column number before checking the bandwidth to make the checking be more accurate. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
To allow BPT and audio stream work simultaneously, we need to record the hstop of the BPT stream. And use column bpt_hstop + 1 to the last column for audio streams. No function changed since bus->bpt_hstop is set to bus->params.col - 1 for now. Will update bus->audio_stream_hstart in the follow up commit. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Update bus->bpt_hstop to record the hstop of the BPT stream. And return -EAGAIN when there is no bandwidth for the BPT stream. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
When a BRA stream is running, we should subtract the columns that is used by the BRA stream in bandwidth calculation. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Now the SoundWire BPT stream and the audio stream can share the SoundWire bus bandwidth. However, it is still not allowed to have more than 1 BPT stream running simultaneously. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
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| if (bus->bpt_stream_refcount) | ||
| available_col = total_col - bus->bpt_hstop - 1; | ||
| else | ||
| available_col = total_col - 1; |
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| restore_params: | ||
| memcpy(&bus->params, ¶ms, sizeof(params)); | ||
| bus->bpt_hstop = prev_bpt_hstop; | ||
| return ret; |
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The driver may want to use BPT stream to download the firmware while an audio stream is running. This series calculates the available columns in a SoundWire frame and use them for the BPT stream. The streams are on on a first-come, first-served basis but will reserve 2 columns for the audio stream if possible. That should apply to most cases.