soundwire/ASoC: add fake BRA frame to align Intel DMA buffer size

drivers/soundwire/cadence_master.c

@@ -2098,6 +2098,36 @@ static unsigned int sdw_cdns_read_pdi1_buffer_size(unsigned int actual_data_size
 	return total * 2;
 }
 
+int sdw_cdns_bpt_find_bandwidth(int command, /* 0: write, 1: read */
+				int row, int col, int frame_rate,
+				unsigned int *tx_dma_bandwidth,
+				unsigned int *rx_dma_bandwidth)
+{
+	unsigned int bpt_bits = row * (col - 1);
+	unsigned int bpt_bytes = bpt_bits >> 3;
+	unsigned int pdi0_buffer_size;
+	unsigned int pdi1_buffer_size;
+	unsigned int data_per_frame;
+
+	data_per_frame = sdw_cdns_bra_actual_data_size(bpt_bytes);
+	if (!data_per_frame)
+		return -EINVAL;
+
+	if (command == 0) {
+		pdi0_buffer_size = sdw_cdns_write_pdi0_buffer_size(data_per_frame);
+		pdi1_buffer_size = SDW_CDNS_WRITE_PDI1_BUFFER_SIZE;
+	} else {
+		pdi0_buffer_size = SDW_CDNS_READ_PDI0_BUFFER_SIZE;
+		pdi1_buffer_size = sdw_cdns_read_pdi1_buffer_size(data_per_frame);
+	}
+
+	*tx_dma_bandwidth = pdi0_buffer_size * 8 * frame_rate;
+	*rx_dma_bandwidth = pdi1_buffer_size * 8 * frame_rate;
+
+	return 0;
+}
+EXPORT_SYMBOL(sdw_cdns_bpt_find_bandwidth);
+
 int sdw_cdns_bpt_find_buffer_sizes(int command, /* 0: write, 1: read */
 				   int row, int col, unsigned int data_bytes,
 				   unsigned int requested_bytes_per_frame,
@@ -2118,9 +2148,6 @@ int sdw_cdns_bpt_find_buffer_sizes(int command, /* 0: write, 1: read */
 	if (!actual_bpt_bytes)
 		return -EINVAL;
 
-	if (data_bytes < actual_bpt_bytes)
-		actual_bpt_bytes = data_bytes;
-
 	/*
 	 * the caller may want to set the number of bytes per frame,
 	 * allow when possible
@@ -2130,6 +2157,9 @@ int sdw_cdns_bpt_find_buffer_sizes(int command, /* 0: write, 1: read */
 
 	*data_per_frame = actual_bpt_bytes;
 
+	if (data_bytes < actual_bpt_bytes)
+		actual_bpt_bytes = data_bytes;
+
 	if (command == 0) {
 		/*
 		 * for writes we need to send all the data_bytes per frame,
@@ -2367,7 +2397,7 @@ EXPORT_SYMBOL(sdw_cdns_prepare_write_dma_buffer);
 
 int sdw_cdns_prepare_read_dma_buffer(u8 dev_num, u32 start_register, int data_size,
 				     int data_per_frame, u8 *dma_buffer, int dma_buffer_size,
-				     int *dma_buffer_total_bytes)
+				     int *dma_buffer_total_bytes, unsigned int fake_size)
 {
 	int total_dma_data_written = 0;
 	u8 *p_dma_buffer = dma_buffer;
@@ -2419,6 +2449,43 @@ int sdw_cdns_prepare_read_dma_buffer(u8 dev_num, u32 start_register, int data_si
 		if (ret < 0)
 			return ret;
 
+		counter++;
+
+		p_dma_buffer += dma_data_written;
+		dma_buffer_size -= dma_data_written;
+		total_dma_data_written += dma_data_written;
+	}
+
+	/* Add fake frame */
+	header[0] &= ~GENMASK(7, 6);	/* Set inactive flag in BPT/BRA frame heade */
+	while (fake_size >= data_per_frame) {
+		header[1] = data_per_frame;
+		ret = sdw_cdns_prepare_read_pd0_buffer(header, SDW_CDNS_BRA_HDR, p_dma_buffer,
+						       dma_buffer_size, &dma_data_written,
+						       counter);
+		if (ret < 0)
+			return ret;
+
+		counter++;
+
+		fake_size -= data_per_frame;
+		p_dma_buffer += dma_data_written;
+		dma_buffer_size -= dma_data_written;
+		total_dma_data_written += dma_data_written;
+	}
+
+	if (fake_size) {
+		header[1] = fake_size;
+		ret = sdw_cdns_prepare_read_pd0_buffer(header, SDW_CDNS_BRA_HDR, p_dma_buffer,
+						       dma_buffer_size, &dma_data_written,
+						       counter);
+		if (ret < 0)
+			return ret;
+
+		counter++;
+
+		p_dma_buffer += dma_data_written;
+		dma_buffer_size -= dma_data_written;
 		total_dma_data_written += dma_data_written;
 	}
 
@@ -2499,14 +2566,14 @@ int sdw_cdns_check_write_response(struct device *dev, u8 *dma_buffer,
 		ret = check_frame_start(header, counter);
 		if (ret < 0) {
 			dev_err(dev, "%s: bad frame %d/%d start header %x\n",
-				__func__, i, num_frames, header);
+				__func__, i + 1, num_frames, header);
 			return ret;
 		}
 
 		ret = check_frame_end(footer);
 		if (ret < 0) {
 			dev_err(dev, "%s: bad frame %d/%d end footer %x\n",
-				__func__, i, num_frames, footer);
+				__func__, i + 1, num_frames, footer);
 			return ret;
 		}
 
@@ -2577,7 +2644,7 @@ int sdw_cdns_check_read_response(struct device *dev, u8 *dma_buffer, int dma_buf
 		ret = check_frame_start(header, counter);
 		if (ret < 0) {
 			dev_err(dev, "%s: bad frame %d/%d start header %x\n",
-				__func__, i, num_frames, header);
+				__func__, i + 1, num_frames, header);
 			return ret;
 		}
 
@@ -2592,7 +2659,7 @@ int sdw_cdns_check_read_response(struct device *dev, u8 *dma_buffer, int dma_buf
 
 		if (crc != expected_crc) {
 			dev_err(dev, "%s: bad frame %d/%d crc %#x expected %#x\n",
-				__func__, i, num_frames, crc, expected_crc);
+				__func__, i + 1, num_frames, crc, expected_crc);
 			return -EIO;
 		}
 
@@ -2603,7 +2670,7 @@ int sdw_cdns_check_read_response(struct device *dev, u8 *dma_buffer, int dma_buf
 		ret = check_frame_end(footer);
 		if (ret < 0) {
 			dev_err(dev, "%s: bad frame %d/%d end footer %x\n",
-				__func__, i, num_frames, footer);
+				__func__, i + 1, num_frames, footer);
 			return ret;
 		}
 

drivers/soundwire/cadence_master.h

@@ -209,6 +209,11 @@ void sdw_cdns_config_update(struct sdw_cdns *cdns);
 int sdw_cdns_config_update_set_wait(struct sdw_cdns *cdns);
 
 /* SoundWire BPT/BRA helpers to format data */
+int sdw_cdns_bpt_find_bandwidth(int command, /* 0: write, 1: read */
+				int row, int col, int frame_rate,
+				unsigned int *tx_dma_bandwidth,
+				unsigned int *rx_dma_bandwidth);
+
 int sdw_cdns_bpt_find_buffer_sizes(int command, /* 0: write, 1: read */
 				   int row, int col, unsigned int data_bytes,
 				   unsigned int requested_bytes_per_frame,
@@ -221,7 +226,7 @@ int sdw_cdns_prepare_write_dma_buffer(u8 dev_num, u32 start_register, u8 *data,
 
 int sdw_cdns_prepare_read_dma_buffer(u8 dev_num, u32 start_register, int data_size,
 				     int data_per_frame, u8 *dma_buffer, int dma_buffer_size,
-				     int *dma_buffer_total_bytes);
+				     int *dma_buffer_total_bytes, unsigned int fake_size);
 
 int sdw_cdns_check_write_response(struct device *dev, u8 *dma_buffer,
 				  int dma_buffer_size, int num_frames);

drivers/soundwire/generic_bandwidth_allocation.c

@@ -125,6 +125,9 @@ static void sdw_compute_dp0_port_params(struct sdw_bus *bus)
 	struct sdw_master_runtime *m_rt;
 
 	list_for_each_entry(m_rt, &bus->m_rt_list, bus_node) {
+		/* DP0 is for BPT only */
+		if (m_rt->stream->type != SDW_STREAM_BPT)
+			continue;
 		sdw_compute_dp0_master_ports(m_rt);
 		sdw_compute_dp0_slave_ports(m_rt);
 	}

drivers/soundwire/intel_ace2x.c

@@ -44,6 +44,8 @@ static int sdw_slave_bpt_stream_add(struct sdw_slave *slave, struct sdw_stream_r
 	return ret;
 }
 
+#define READ_PDI1_MIN_SIZE	12
+
 static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *slave,
 				       struct sdw_bpt_msg *msg)
 {
@@ -53,15 +55,23 @@ static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *
 	struct sdw_stream_runtime *stream;
 	struct sdw_stream_config sconfig;
 	struct sdw_port_config *pconfig;
+	unsigned int pdi0_buf_size_pre_frame;
+	unsigned int pdi1_buf_size_pre_frame;
 	unsigned int pdi0_buffer_size;
 	unsigned int tx_dma_bandwidth;
 	unsigned int pdi1_buffer_size;
 	unsigned int rx_dma_bandwidth;
+	unsigned int fake_num_frames;
 	unsigned int data_per_frame;
 	unsigned int tx_total_bytes;
 	struct sdw_cdns_pdi *pdi0;
 	struct sdw_cdns_pdi *pdi1;
+	unsigned int rx_alignment;
+	unsigned int tx_alignment;
 	unsigned int num_frames;
+	unsigned int fake_size;
+	unsigned int tx_pad;
+	unsigned int rx_pad;
 	int command;
 	int ret1;
 	int ret;
@@ -138,6 +148,13 @@ static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *
 
 	command = (msg->flags & SDW_MSG_FLAG_WRITE) ? 0 : 1;
 
+	ret = sdw_cdns_bpt_find_bandwidth(command, cdns->bus.params.row,
+					  cdns->bus.params.col,
+					  prop->default_frame_rate,
+					  &tx_dma_bandwidth, &rx_dma_bandwidth);
+	if (ret < 0)
+		goto deprepare_stream;
+
 	ret = sdw_cdns_bpt_find_buffer_sizes(command, cdns->bus.params.row, cdns->bus.params.col,
 					     msg->len, SDW_BPT_MSG_MAX_BYTES, &data_per_frame,
 					     &pdi0_buffer_size, &pdi1_buffer_size, &num_frames);
@@ -148,10 +165,44 @@ static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *
 	sdw->bpt_ctx.pdi1_buffer_size = pdi1_buffer_size;
 	sdw->bpt_ctx.num_frames = num_frames;
 	sdw->bpt_ctx.data_per_frame = data_per_frame;
-	tx_dma_bandwidth = div_u64((u64)pdi0_buffer_size * 8 * (u64)prop->default_frame_rate,
-				   num_frames);
-	rx_dma_bandwidth = div_u64((u64)pdi1_buffer_size * 8 * (u64)prop->default_frame_rate,
-				   num_frames);
+
+	rx_alignment = hda_sdw_bpt_get_buf_size_alignment(rx_dma_bandwidth);
+	tx_alignment = hda_sdw_bpt_get_buf_size_alignment(tx_dma_bandwidth);
+
+	if (command) { /* read */
+		/* 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, &pdi0_buf_size_pre_frame,
+						     &pdi1_buf_size_pre_frame, &fake_num_frames);
+		if (ret < 0)
+			goto deprepare_stream;
+
+		/* find fake pdi1 buffer size */
+		rx_pad = rx_alignment - (pdi1_buffer_size % rx_alignment);
+		while (rx_pad <= READ_PDI1_MIN_SIZE) {
+			rx_pad += rx_alignment;
+		}
+		pdi1_buffer_size += rx_pad;
+		/* It is fine if we request more than enough byte to read */
+		fake_num_frames = DIV_ROUND_UP(rx_pad, pdi1_buf_size_pre_frame);
+		fake_size = fake_num_frames * data_per_frame;
+
+		/* find fake pdi0 buffer size */
+		pdi0_buffer_size += (fake_num_frames * pdi0_buf_size_pre_frame);
+		tx_pad = tx_alignment - (pdi0_buffer_size % tx_alignment);
+		pdi0_buffer_size += tx_pad;
+	} else { /* write */
+		/*
+		 * For the write command, the rx data block is 4, and the rx buffer size of a frame
+		 * is 8. So the rx buffer size (pdi0_buffer_size) is always a mutiple of rx
+		 * alignment.
+		 */
+		tx_pad = tx_alignment - (pdi0_buffer_size % tx_alignment);
+		pdi0_buffer_size += tx_pad;
+
+	}
 
 	dev_dbg(cdns->dev, "Message len %d transferred in %d frames (%d per frame)\n",
 		msg->len, num_frames, data_per_frame);
@@ -177,7 +228,7 @@ static int intel_ace2x_bpt_open_stream(struct sdw_intel *sdw, struct sdw_slave *
 		ret = sdw_cdns_prepare_read_dma_buffer(msg->dev_num, msg->addr,	msg->len,
 						       data_per_frame,
 						       sdw->bpt_ctx.dmab_tx_bdl.area,
-						       pdi0_buffer_size, &tx_total_bytes);
+						       pdi0_buffer_size, &tx_total_bytes, fake_size);
 	}
 
 	if (!ret)

include/sound/hda-sdw-bpt.h

@@ -30,6 +30,8 @@ int hda_sdw_bpt_wait(struct device *dev, struct hdac_ext_stream *bpt_tx_stream,
 int hda_sdw_bpt_close(struct device *dev, struct hdac_ext_stream *bpt_tx_stream,
 		      struct snd_dma_buffer *dmab_tx_bdl, struct hdac_ext_stream *bpt_rx_stream,
 		      struct snd_dma_buffer *dmab_rx_bdl);
+
+unsigned int hda_sdw_bpt_get_buf_size_alignment(unsigned int dma_bandwidth);
 #else
 static inline int hda_sdw_bpt_open(struct device *dev, int link_id,
 				   struct hdac_ext_stream **bpt_tx_stream,
@@ -64,6 +66,11 @@ static inline int hda_sdw_bpt_close(struct device *dev, struct hdac_ext_stream *
 	WARN_ONCE(1, "SoundWire BPT is disabled");
 	return -EOPNOTSUPP;
 }
+
+static inline unsigned int hda_sdw_bpt_get_buf_size_alignment(unsigned int dma_bandwidth)
+{
+	return 0;
+}
 #endif
 
 #endif /* __HDA_SDW_BPT_H */

sound/soc/sof/intel/hda-sdw-bpt.c

@@ -10,6 +10,7 @@
  * Hardware interface for SoundWire BPT support with HDA DMA
  */
 
+#include <linux/lcm.h>
 #include <sound/hdaudio_ext.h>
 #include <sound/hda-mlink.h>
 #include <sound/hda-sdw-bpt.h>
@@ -247,6 +248,18 @@ static int hda_sdw_bpt_dma_disable(struct device *dev, struct hdac_ext_stream *s
 	return ret;
 }
 
+#define FIFO_ALIGNMENT	64
+
+unsigned int hda_sdw_bpt_get_buf_size_alignment(unsigned int dma_bandwidth)
+{
+	unsigned int num_channels = DIV_ROUND_UP(dma_bandwidth, BPT_FREQUENCY * 32);
+	unsigned int data_block = num_channels * 4;
+	unsigned int alignment = lcm(data_block, FIFO_ALIGNMENT);
+
+	return alignment;
+}
+EXPORT_SYMBOL_NS(hda_sdw_bpt_get_buf_size_alignment, "SND_SOC_SOF_INTEL_HDA_SDW_BPT");
+
 int hda_sdw_bpt_open(struct device *dev, int link_id, struct hdac_ext_stream **bpt_tx_stream,
 		     struct snd_dma_buffer *dmab_tx_bdl, u32 bpt_tx_num_bytes,
 		     u32 tx_dma_bandwidth, struct hdac_ext_stream **bpt_rx_stream,