soundwire: add BRA properties by bardliao · Pull Request #5710 · thesofproject/linux

bardliao · 2026-03-25T05:44:18Z

Add mipi-sdw-bra-mode-max-data-per-frame and mipi-sdw-bra-mode-block-alignment properties support

Copilot

Pull request overview

Adds support for new MIPI SoundWire DisCo/BRA device properties so BPT/BRA transfers can respect per-device constraints (max payload per frame and block alignment).

Changes:

Extend struct sdw_slave_prop with bra_block_alignment and bra_max_data_per_frame, and parse them from firmware properties.
Thread BRA constraints into Cadence BPT/BRA buffer-size calculations and Intel ACE2x BPT stream setup.
Update SDW_BPT_MSG_MAX_BYTES definition/comment to reference the DisCo spec limit.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
include/linux/soundwire/sdw.h	Adds BRA properties to slave props; changes `SDW_BPT_MSG_MAX_BYTES` definition/comment.
drivers/soundwire/mipi_disco.c	Reads the new BRA properties from device properties.
drivers/soundwire/intel_ace2x.c	Uses new props to select max bytes/frame and pass alignment into buffer sizing.
drivers/soundwire/cadence_master.h	Updates `sdw_cdns_bpt_find_buffer_sizes()` signature to accept alignment.
drivers/soundwire/cadence_master.c	Applies block-alignment when computing actual bytes/frame in BPT/BRA sizing.

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Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

drivers/soundwire/cadence_master.c:2181

When bra_block_alignment is set, the later clamp if (data_bytes < actual_bpt_bytes) actual_bpt_bytes = data_bytes; can re-introduce a per-frame payload length that is not a multiple of bra_block_alignment (e.g., a single short transfer or the last partial frame). This contradicts the new block-alignment requirement and can lead to invalid BRA frames on devices that enforce the alignment. Consider enforcing that data_bytes/remainder is a multiple of bra_block_alignment (return -EINVAL otherwise), or redesigning the sizing logic to keep an aligned actual_bpt_bytes and handle padding/trimming appropriately (read vs write).

	*data_per_frame = actual_bpt_bytes;

	if (data_bytes < actual_bpt_bytes)
		actual_bpt_bytes = data_bytes;

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Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

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Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

drivers/soundwire/cadence_master.c:2181

*data_per_frame is set before actual_bpt_bytes may be reduced to data_bytes, so callers can observe a data_per_frame larger than the size actually used to compute num_frames/buffer sizes. With bra_block_alignment this also means the later actual_bpt_bytes = data_bytes path can bypass the alignment constraint for small transfers. Consider applying the min(data_bytes, ...) step (and any alignment enforcement/handling for the last frame) before assigning *data_per_frame so the returned frame size is consistent with subsequent calculations.

	*data_per_frame = actual_bpt_bytes;

	if (data_bytes < actual_bpt_bytes)
		actual_bpt_bytes = data_bytes;

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

bardliao · 2026-05-26T00:19:34Z

+	device_property_read_u32(dev, "mipi-sdw-bra-mode-max-data-per-frame",
+				 &prop->bra_max_data_per_frame);


We don't check the DisCo table value here. We will check it when it is used instated.

The header[0] bit definitions are: Header[0] bits 7 – 6: BRA_HeaderType Header[0] bits 5 – 2: BRA_DeviceAddress[3:0] Header[0] bit 1 BRA_Opcode 1 => Write, 0 => Read Header[0] bit 0 BRA_NumBytes[8] And the header[1] indicates the BRA_NumBytes[7:0]. The existing code doesn't handle BRA_NumBytes[8] therefore the maximum BRA number of a frame is limited to 255. Fixes: fe8a9cf ("soundwire: pass sdw_bpt_section to cdns BPT helpers") Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

Add a property to struct sdw_slave_prop equivalent to the Disco property "mipi-sdw-bra-mode-block-alignment". The SoundWire Disco specification defines this as: "The data payload size for this BRA Mode shall be an integer multiple of the value of this Property." Change-Id: I27ab84b0ed0f236a5eae58600400a4c386132480 Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> Co-developed-by: Bard Liao <yung-chuan.liao@linux.intel.com> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

The data pre frame size should be a multiple of bra_block_alignment. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

Get the mipi-sdw-bra-mode-max-data-per-frame property which indicates the maximum data payload size (in bytes per frame excluding header, CRC, and footer) for the BRA Mode. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

The optional property indicates the maximum data payload size for the BRA mode. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

bardliao requested review from charleskeepax, Copilot, plbossart, rfvirgil and ujfalusi March 25, 2026 05:44

Copilot started reviewing on behalf of bardliao March 25, 2026 05:45 View session

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Comment thread include/linux/soundwire/sdw.h Outdated

Comment thread include/linux/soundwire/sdw.h Outdated

Comment thread drivers/soundwire/cadence_master.c

bardliao force-pushed the bra-properties branch from bc527d5 to f013d39 Compare March 25, 2026 07:11

bardliao requested a review from shumingfan as a code owner March 25, 2026 07:11

bardliao requested a review from Copilot April 8, 2026 12:08

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Comment thread drivers/soundwire/intel_ace2x.c Outdated

Copilot AI review requested due to automatic review settings April 8, 2026 12:26

Copilot started reviewing on behalf of bardliao April 8, 2026 12:29 View session

bardliao force-pushed the bra-properties branch from 30e8399 to fe9569b Compare April 8, 2026 12:29

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Comment thread drivers/soundwire/cadence_master.h

bardliao requested a review from Copilot May 25, 2026 11:20

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Comment thread include/linux/soundwire/sdw.h

Comment thread drivers/soundwire/cadence_master.c Outdated

bardliao force-pushed the bra-properties branch from fe9569b to ad8a024 Compare May 25, 2026 14:35

bardliao requested a review from Copilot May 25, 2026 14:36

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bardliao force-pushed the bra-properties branch from ad8a024 to 2da3fc0 Compare May 26, 2026 02:52

shumingfan approved these changes May 26, 2026

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ujfalusi reviewed Jun 2, 2026

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Comment thread drivers/soundwire/cadence_master.c

Comment thread drivers/soundwire/cadence_master.c

bardliao and others added 4 commits June 2, 2026 21:03

soundwire: intel: handle Peripheral bra_block_alignment

de46408

The data pre frame size should be a multiple of bra_block_alignment. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

soundwire: intel_ace2x: handle the max_data_per_frame property

c8ee28a

The optional property indicates the maximum data payload size for the BRA mode. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

bardliao force-pushed the bra-properties branch from 2da3fc0 to c8ee28a Compare June 2, 2026 13:12

ujfalusi approved these changes Jun 2, 2026

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soundwire: add BRA properties#5710

soundwire: add BRA properties#5710
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		device_property_read_u32(dev, "mipi-sdw-bra-mode-max-data-per-frame",
		&prop->bra_max_data_per_frame);

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