[PATCH v2 3/3] soundwire: qcom: program MM_SYNC for multi-master

[Srinivas Kandagatla]

The primary and dependent frame generators must lock to a single
SWR_CLK for the shared bus to run. Program SWRM_V3_MM_SYNC_CONFIG
on both sides at init, and re-apply on resume as the register does
not survive a clock stop.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxxxxxxxx>
---
 drivers/soundwire/qcom.c | 56 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index 767147a6635d..92e1644623c5 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -46,6 +46,18 @@
 #define SWRM_V3_COMP_PARAMS_RD_FIFO_DEPTH			GENMASK(23, 18)
 
 #define SWRM_COMP_MASTER_ID					0x104
+
+#define SWRM_V3_MM_SYNC_CONFIG					0x108
+#define SWRM_V3_MM_SYNC_CONNECTED_MASTER_MASK			GENMASK(15, 0)
+#define SWRM_V3_MM_SYNC_IS_DEPENDENT_MASTER			BIT(16)
+#define SWRM_V3_MM_SYNC_MASK_CONTROL_BITS			BIT(17)
+
+#define SWRM_V3_COMP_FEATURE_CFG				0x10
+#define  SWRM_V3_COMP_FEATURE_CFG_BASE				0x00E
+#define  SWRM_V3_COMP_FEATURE_CFG_FORCE_MODE_EN			BIT(9)
+#define  SWRM_V3_COMP_FEATURE_CFG_CLK_PIN_AVAIL			BIT(10)
+#define  SWRM_V3_COMP_FEATURE_CFG_CLK_STOP_EXEC_ON_CMD_IGNORE	BIT(12)
+
 #define SWRM_V1_3_INTERRUPT_STATUS				0x200
 #define SWRM_V2_0_INTERRUPT_STATUS				0x5000
 #define SWRM_INTERRUPT_STATUS_RMSK				GENMASK(16, 0)
@@ -892,6 +904,43 @@ static bool swrm_wait_for_frame_gen_enabled(struct qcom_swrm_ctrl *ctrl)
 	return false;
 }
 
+static void qcom_swrm_program_mm_sync(struct qcom_swrm_ctrl *ctrl)
+{
+	struct qcom_swrm_ctrl *peer = ctrl->peer_ctrl;
+	u32 conn_mask;
+
+	/*
+	 * peer_ctrl is only ever set on qcom,soundwire-v3.1.0 IPs (the
+	 * multi-master binding requires that compatible), so the V3-only
+	 * MM_SYNC / COMP_FEATURE_CFG registers written below are safe to
+	 * touch here.
+	 */
+	if (!peer || peer->bus.controller_id < 1)
+		return;
+
+	conn_mask = BIT(peer->bus.controller_id - 1) &
+		    SWRM_V3_MM_SYNC_CONNECTED_MASTER_MASK;
+
+	if (ctrl->is_primary) {
+		ctrl->reg_write(ctrl, SWRM_V3_MM_SYNC_CONFIG, conn_mask);
+		ctrl->reg_write(ctrl, SWRM_V3_COMP_FEATURE_CFG,
+				SWRM_V3_COMP_FEATURE_CFG_BASE |
+				SWRM_V3_COMP_FEATURE_CFG_FORCE_MODE_EN |
+				SWRM_V3_COMP_FEATURE_CFG_CLK_PIN_AVAIL |
+				SWRM_V3_COMP_FEATURE_CFG_CLK_STOP_EXEC_ON_CMD_IGNORE);
+		return;
+	}
+
+	ctrl->reg_write(ctrl, SWRM_V3_MM_SYNC_CONFIG,
+			SWRM_V3_MM_SYNC_IS_DEPENDENT_MASTER |
+			SWRM_V3_MM_SYNC_MASK_CONTROL_BITS | conn_mask);
+
+	ctrl->reg_write(ctrl, SWRM_V3_COMP_FEATURE_CFG,
+			SWRM_V3_COMP_FEATURE_CFG_BASE |
+			SWRM_V3_COMP_FEATURE_CFG_FORCE_MODE_EN |
+			SWRM_V3_COMP_FEATURE_CFG_CLK_STOP_EXEC_ON_CMD_IGNORE);
+}
+
 static int qcom_swrm_init(struct qcom_swrm_ctrl *ctrl)
 {
 	u32 val;
@@ -920,6 +969,8 @@ static int qcom_swrm_init(struct qcom_swrm_ctrl *ctrl)
 	u32p_replace_bits(&val, SWRM_DEF_CMD_NO_PINGS, SWRM_MCP_CFG_MAX_NUM_OF_CMD_NO_PINGS_BMSK);
 	ctrl->reg_write(ctrl, SWRM_MCP_CFG_ADDR, val);
 
+	qcom_swrm_program_mm_sync(ctrl);
+
 	if (ctrl->version == SWRM_VERSION_1_7_0) {
 		ctrl->reg_write(ctrl, SWRM_LINK_MANAGER_EE, SWRM_EE_CPU);
 		ctrl->reg_write(ctrl, SWRM_MCP_BUS_CTRL,
@@ -1935,6 +1986,11 @@ static int __maybe_unused swrm_runtime_resume(struct device *dev)
 	} else {
 		reset_control_reset(ctrl->audio_cgcr);
 
+		qcom_swrm_program_mm_sync(ctrl);
+		/* dependent has no PM-runtime of its own */
+		if (ctrl->is_primary && ctrl->peer_ctrl)
+			qcom_swrm_program_mm_sync(ctrl->peer_ctrl);
+
 		if (ctrl->version == SWRM_VERSION_1_7_0) {
 			ctrl->reg_write(ctrl, SWRM_LINK_MANAGER_EE, SWRM_EE_CPU);
 			ctrl->reg_write(ctrl, SWRM_MCP_BUS_CTRL,
-- 
2.53.0