[PATCH 5/5] soundwire: intel_ace2x: handle the max_data_per_frame property

[Bard Liao]

The optional property indicates the maximum data payload size for the
BRA mode.

Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
---
 drivers/soundwire/intel_ace2x.c | 18 ++++++++++++++++--
 include/linux/soundwire/sdw.h   |  8 ++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/soundwire/intel_ace2x.c b/drivers/soundwire/intel_ace2x.c
index 2fc5589bbd72..ad83811037d2 100644
--- a/drivers/soundwire/intel_ace2x.c
+++ b/drivers/soundwire/intel_ace2x.c
@@ -57,6 +57,7 @@ static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *
 	struct sdw_port_config *pconfig;
 	unsigned int pdi0_buf_size_pre_frame;
 	unsigned int pdi1_buf_size_pre_frame;
+	unsigned int max_data_per_frame;
 	unsigned int pdi0_buffer_size_;
 	unsigned int pdi1_buffer_size_;
 	unsigned int pdi0_buffer_size;
@@ -168,11 +169,24 @@ static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *
 	pdi0_buffer_size = 0;
 	pdi1_buffer_size = 0;
 	num_frames = 0;
+
+	if (slave->prop.bra_max_data_per_frame) {
+		max_data_per_frame = slave->prop.bra_max_data_per_frame;
+		if (max_data_per_frame > SDW_BRA_MAX_BYTES_PER_FRAME) {
+			dev_warn(&slave->dev,
+				 "BRA max_data_per_frame %u exceeds limit %u, clamping\n",
+				 max_data_per_frame, SDW_BRA_MAX_BYTES_PER_FRAME);
+			max_data_per_frame = SDW_BRA_MAX_BYTES_PER_FRAME;
+		}
+	} else {
+		max_data_per_frame = SDW_BRA_MAX_BYTES_PER_FRAME;
+	}
+
 	/* Add up pdi buffer size and frame numbers of each BPT sections */
 	for (i = 0; i < msg->sections; i++) {
 		ret = sdw_cdns_bpt_find_buffer_sizes(command, cdns->bus.params.row,
 						     cdns->bus.params.col,
-						     msg->sec[i].len, SDW_BPT_MSG_MAX_BYTES,
+						     msg->sec[i].len, max_data_per_frame,
 						     slave->prop.bra_block_alignment,
 						     &data_per_frame, &pdi0_buffer_size_,
 						     &pdi1_buffer_size_, &num_frames_);
@@ -197,7 +211,7 @@ static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *
 		/* Get buffer size of a full frame */
 		ret = sdw_cdns_bpt_find_buffer_sizes(command, cdns->bus.params.row,
 						     cdns->bus.params.col,
-						     data_per_frame, SDW_BPT_MSG_MAX_BYTES,
+						     data_per_frame, max_data_per_frame,
 						     slave->prop.bra_block_alignment,
 						     &data_per_frame, &pdi0_buf_size_pre_frame,
 						     &pdi1_buf_size_pre_frame, &fake_num_frames);
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index 89009a2c321d..769a8ba5b5c6 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -843,6 +843,14 @@ struct sdw_defer {
  */
 #define SDW_BPT_MSG_MAX_BYTES  (1024 * 1024)
 
+/*
+ * According to mipi SoundWire DisCo Specification_v2-1,
+ * this maximum value shall not exceed 470.
+ * Note that the largest number of bytes accessible by a single BRA operation is limited to 470
+ * bytes when using lane 0, but goes up to 502 bytes when using one of the optional extra lanes.
+ */
+#define SDW_BRA_MAX_BYTES_PER_FRAME  470
+
 struct sdw_bpt_msg;
 
 /**
-- 
2.43.0