soundwire: introduce BPT section

Currently we send a BRA message with a start address with continuous
registers in a BPT stream. However, a codec may need to write different
register sections shortly. Introduce a register section in struct
sdw_btp_msg which contain register start address, length, and buffer.
This commit uses only 1 section for each BPT message. And we need to add
up all BPT section length and check if it reach maximum BPT bytes.
No function changes.

Signed-off-by: Bard Liao <[e-mail]>
Reviewed-by: Ranjani Sridharan <[e-mail]>
Tested-by: Shuming Fan <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/soundwire/bus.c

···
 
 int sdw_bpt_send_async(struct sdw_bus *bus, struct sdw_slave *slave, struct sdw_bpt_msg *msg)
 {
-	if (msg->len > SDW_BPT_MSG_MAX_BYTES) {
-		dev_err(bus->dev, "Invalid BPT message length %d\n", msg->len);
+	int len = 0;
+	int i;
+
+	for (i = 0; i < msg->sections; i++)
+		len += msg->sec[i].len;
+
+	if (len > SDW_BPT_MSG_MAX_BYTES) {
+		dev_err(bus->dev, "Invalid BPT message length %d\n", len);
 		return -EINVAL;
 	}
 

drivers/soundwire/bus.h

···
 };
 
 /**
- * struct sdw_btp_msg - Message structure
+ * struct sdw_btp_section - Message section structure
  * @addr: Start Register address accessed in the Slave
  * @len: number of bytes to transfer. More than 64Kb can be transferred
  * but a practical limit of SDW_BPT_MSG_MAX_BYTES is enforced.
- * @dev_num: Slave device number
- * @flags: transfer flags, indicate if xfer is read or write
- * @buf: message data buffer (filled by host for write, filled
+ * @buf: section data buffer (filled by host for write, filled
  * by Peripheral hardware for reads)
  */
-struct sdw_bpt_msg {
+struct sdw_bpt_section {
 	u32 addr;
 	u32 len;
+	u8 *buf;
+};
+
+/**
+ * struct sdw_btp_msg - Message structure
+ * @sec: Pointer to array of sections
+ * @sections: Number of sections in the array
+ * @dev_num: Slave device number
+ * @flags: transfer flags, indicate if xfer is read or write
+ */
+struct sdw_bpt_msg {
+	struct sdw_bpt_section *sec;
+	int sections;
 	u8 dev_num;
 	u8 flags;
-	u8 *buf;
 };
 
 #define SDW_DOUBLE_RATE_FACTOR		2

drivers/soundwire/debugfs.c

···
 static int do_bpt_sequence(struct sdw_slave *slave, bool write, u8 *buffer)
 {
 	struct sdw_bpt_msg msg = {0};
+	struct sdw_bpt_section *sec;
 
-	msg.addr = start_addr;
-	msg.len = num_bytes;
+	sec = kcalloc(1, sizeof(*sec), GFP_KERNEL);
+	if (!sec)
+		return -ENOMEM;
+	msg.sections = 1;
+
+	sec[0].addr = start_addr;
+	sec[0].len = num_bytes;
+
+	msg.sec = sec;
 	msg.dev_num = slave->dev_num;
 	if (write)
 		msg.flags = SDW_MSG_FLAG_WRITE;
 	else
 		msg.flags = SDW_MSG_FLAG_READ;
-	msg.buf = buffer;
+	sec[0].buf = buffer;
 
 	return sdw_bpt_send_sync(slave->bus, slave, &msg);
 }

drivers/soundwire/intel_ace2x.c

···
 		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);
+					     msg->sec[0].len, SDW_BPT_MSG_MAX_BYTES,
+					     &data_per_frame, &pdi0_buffer_size, &pdi1_buffer_size,
+					     &num_frames);
 	if (ret < 0)
 		goto deprepare_stream;
 
···
 	}
 
 	dev_dbg(cdns->dev, "Message len %d transferred in %d frames (%d per frame)\n",
-		msg->len, num_frames, data_per_frame);
+		msg->sec[0].len, num_frames, data_per_frame);
 	dev_dbg(cdns->dev, "sizes pdi0 %d pdi1 %d tx_bandwidth %d rx_bandwidth %d\n",
 		pdi0_buffer_size, pdi1_buffer_size, tx_dma_bandwidth, rx_dma_bandwidth);
 
···
 	}
 
 	if (!command) {
-		ret = sdw_cdns_prepare_write_dma_buffer(msg->dev_num, msg->addr, msg->buf,
-							msg->len, data_per_frame,
+		ret = sdw_cdns_prepare_write_dma_buffer(msg->dev_num, msg->sec[0].addr,
+							msg->sec[0].buf,
+							msg->sec[0].len, data_per_frame,
 							sdw->bpt_ctx.dmab_tx_bdl.area,
 							pdi0_buffer_size, &tx_total_bytes);
 	} else {
-		ret = sdw_cdns_prepare_read_dma_buffer(msg->dev_num, msg->addr,	msg->len,
+		ret = sdw_cdns_prepare_read_dma_buffer(msg->dev_num, msg->sec[0].addr,
+						       msg->sec[0].len,
 						       data_per_frame,
 						       sdw->bpt_ctx.dmab_tx_bdl.area,
 						       pdi0_buffer_size, &tx_total_bytes,
···
 	struct sdw_cdns *cdns = &sdw->cdns;
 	int ret;
 
-	if (msg->len < INTEL_BPT_MSG_BYTE_MIN) {
+	if (msg->sec[0].len < INTEL_BPT_MSG_BYTE_MIN) {
 		dev_err(cdns->dev, "BPT message length %d is less than the minimum bytes %d\n",
-			msg->len, INTEL_BPT_MSG_BYTE_MIN);
+			msg->sec[0].len, INTEL_BPT_MSG_BYTE_MIN);
 		return -EINVAL;
 	}
 
···
 	} else {
 		ret = sdw_cdns_check_read_response(cdns->dev, sdw->bpt_ctx.dmab_rx_bdl.area,
 						   sdw->bpt_ctx.pdi1_buffer_size,
-						   msg->buf, msg->len, sdw->bpt_ctx.num_frames,
+						   msg->sec[0].buf, msg->sec[0].len,
+						   sdw->bpt_ctx.num_frames,
 						   sdw->bpt_ctx.data_per_frame);
 		if (ret < 0)
 			dev_err(cdns->dev, "%s: BPT Read failed %d\n", __func__, ret);