[PATCH] soundwire: qcom: allow multi-link on newer devices

[Krzysztof Kozlowski]

Newer Qualcomm SoCs like X1E80100 might come with four speakers spread
over two Soundwire controllers, thus they need a multi-link Soundwire
stream runtime.

Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>

---

This is an entirely different approach than my previous try here:
https://lore.kernel.org/all/20231025144601.268645-1-krzysztof.kozlowski@xxxxxxxxxx/
---
 drivers/soundwire/qcom.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index 412b8e663a0a..57943724f0eb 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -920,6 +920,18 @@ static int qcom_swrm_init(struct qcom_swrm_ctrl *ctrl)
 	return 0;
 }
 
+static int qcom_swrm_read_prop(struct sdw_bus *bus)
+{
+	struct qcom_swrm_ctrl *ctrl = to_qcom_sdw(bus);
+
+	if (ctrl->version >= SWRM_VERSION_2_0_0) {
+		bus->multi_link = true;
+		bus->hw_sync_min_links = 3;
+	}
+
+	return 0;
+}
+
 static enum sdw_command_response qcom_swrm_xfer_msg(struct sdw_bus *bus,
 						    struct sdw_msg *msg)
 {
@@ -1078,6 +1090,7 @@ static const struct sdw_master_port_ops qcom_swrm_port_ops = {
 };
 
 static const struct sdw_master_ops qcom_swrm_ops = {
+	.read_prop = qcom_swrm_read_prop,
 	.xfer_msg = qcom_swrm_xfer_msg,
 	.pre_bank_switch = qcom_swrm_pre_bank_switch,
 	.post_bank_switch = qcom_swrm_post_bank_switch,
@@ -1196,6 +1209,15 @@ static int qcom_swrm_stream_alloc_ports(struct qcom_swrm_ctrl *ctrl,
 
 	mutex_lock(&ctrl->port_lock);
 	list_for_each_entry(m_rt, &stream->master_list, stream_node) {
+		/*
+		 * For streams with multiple masters:
+		 * Allocate ports only for devices connected to this master.
+		 * Such devices will have ports allocated by their own master
+		 * and its qcom_swrm_stream_alloc_ports() call.
+		 */
+		if (ctrl->bus.id != m_rt->bus->id)
+			continue;
+
 		if (m_rt->direction == SDW_DATA_DIR_RX) {
 			maxport = ctrl->num_dout_ports;
 			port_mask = &ctrl->dout_port_mask;
-- 
2.34.1