[PATCH v8 08/29] drm/msm/dp: replace power_on with active_stream_mask

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

From: Abhinav Kumar <quic_abhinavk@quicinc.com>

The power_on boolean cannot represent DP MST, where multiple streams
share a single link and its associated resources.

Replace power_on with active_stream_mask, a bitmask of the streams that
have been successfully enabled, and use it to track the lifetime of the
shared link. Link initialization is performed when enabling the first
stream, while link teardown is deferred until the last stream is
disabled.

A per-stream bit rather than a count is needed because two callers ask
whether one specific stream is up: msm_dp_display_disable() uses it to
stay idempotent, and msm_dp_display_disable_helper() uses it to tell
whether that stream ever made it through .atomic_enable().

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_audio.c   |  2 +-
 drivers/gpu/drm/msm/dp/dp_display.c | 56 ++++++++++++++++++++-----------------
 drivers/gpu/drm/msm/dp/dp_display.h |  2 +-
 3 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_audio.c b/drivers/gpu/drm/msm/dp/dp_audio.c
index df222943ae57f..05972a302e542 100644
--- a/drivers/gpu/drm/msm/dp/dp_audio.c
+++ b/drivers/gpu/drm/msm/dp/dp_audio.c
@@ -284,7 +284,7 @@ int msm_dp_audio_prepare(struct drm_bridge *bridge,
 	 * such cases check for connection status and bail out if not
 	 * connected.
 	 */
-	if (!msm_dp_display->power_on)
+	if (!msm_dp_display->active_stream_mask)
 		goto end;
 
 	audio = msm_dp_audio_get_data(msm_dp_display);
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index e046184a30f50..169990c10b367 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -652,16 +652,16 @@ static int msm_dp_display_prepare_link(struct msm_dp_display_private *dp)
 	if (dp->link->sink_count == 0)
 		return -ENOTCONN;
 
-	if (!msm_dp_display->power_on) {
+	if (!msm_dp_display->active_stream_mask) {
 		msm_dp_display_host_phy_init(dp);
 		force_link_train = true;
-	}
 
-	rc = msm_dp_ctrl_on_link(dp->ctrl, dp->panel);
-	if (rc) {
-		DRM_ERROR("Failed link training (rc=%d)\n", rc);
-		// TODO: schedule drm_connector_set_link_status_property()
-		return rc;
+		rc = msm_dp_ctrl_on_link(dp->ctrl, dp->panel);
+		if (rc) {
+			DRM_ERROR("Failed link training (rc=%d)\n", rc);
+			// TODO: schedule drm_connector_set_link_status_property()
+			return rc;
+		}
 	}
 
 	return msm_dp_ctrl_prepare_stream_on(dp->ctrl, dp->panel, force_link_train);
@@ -671,21 +671,19 @@ static int msm_dp_display_enable(struct msm_dp_display_private *dp,
 				 struct msm_dp_panel *msm_dp_panel,
 				 const struct msm_dp_mst_slot_info *slots)
 {
-	int rc = 0;
+	int rc;
 	struct msm_dp *msm_dp_display = &dp->msm_dp_display;
 
 	drm_dbg_dp(dp->drm_dev, "sink_count=%d\n", dp->link->sink_count);
-	if (msm_dp_display->power_on) {
-		drm_dbg_dp(dp->drm_dev, "Link already setup, return\n");
-		return 0;
-	}
 
 	rc = msm_dp_ctrl_on_stream(dp->ctrl, msm_dp_panel, msm_dp_display->mst_active,
 				   slots);
-	if (!rc)
-		msm_dp_display->power_on = true;
+	if (rc)
+		return rc;
 
-	return rc;
+	msm_dp_display->active_stream_mask |= BIT(msm_dp_panel->stream_id);
+
+	return 0;
 }
 
 static int msm_dp_display_post_enable(struct msm_dp *msm_dp_display)
@@ -732,9 +730,11 @@ static int msm_dp_display_disable(struct msm_dp_display_private *dp,
 {
 	struct msm_dp *msm_dp_display = &dp->msm_dp_display;
 
-	if (!msm_dp_display->power_on)
+	if (!(msm_dp_display->active_stream_mask & BIT(msm_dp_panel->stream_id)))
 		return 0;
 
+	msm_dp_display->active_stream_mask &= ~BIT(msm_dp_panel->stream_id);
+
 	msm_dp_panel_disable_vsc_sdp(msm_dp_panel);
 
 	msm_dp_ctrl_off_pixel_clk(dp->ctrl, msm_dp_panel->stream_id);
@@ -851,10 +851,10 @@ void msm_dp_snapshot(struct msm_disp_state *disp_state, struct msm_dp *dp)
 	 * if we are reading registers we need the link clocks to be on
 	 * however till DP cable is connected this will not happen as we
 	 * do not know the resolution to power up with. Hence check the
-	 * power_on status before dumping DP registers to avoid crash due
+	 * active stream state before dumping DP registers to avoid crash due
 	 * to unclocked access
 	 */
-	if (!dp->power_on)
+	if (!dp->active_stream_mask)
 		return;
 
 	msm_disp_snapshot_add_block(disp_state, msm_dp_display->ahb_len,
@@ -1514,16 +1514,17 @@ void msm_dp_display_atomic_disable(struct msm_dp *dp)
 
 	/*
 	 * If .atomic_enable() bailed out - link training failure is the common
-	 * case - the mainlink was never brought up and ->power_on stayed false.
-	 * Driving the PUSH_IDLE pattern into a controller that was never
-	 * enabled times out, and .atomic_post_disable() then drops the
-	 * controller's runtime-PM reference without tearing the PHY back down,
-	 * because msm_dp_display_disable() returns early on !power_on.  On
+	 * case - the mainlink was never brought up and the stream was never
+	 * marked active in ->active_stream_mask.  Driving the PUSH_IDLE pattern
+	 * into a controller that was never enabled times out, and
+	 * .atomic_post_disable() then drops the controller's runtime-PM
+	 * reference without tearing the PHY back down, because
+	 * msm_dp_display_disable() returns early for an inactive stream.  On
 	 * glymur (Snapdragon X2 Elite) that combination is answered by a
 	 * TrustZone-level SOCCP/ADSP force-stop and a silent SoC reset.
 	 * There is nothing to push idle, so leave it alone.
 	 */
-	if (!dp->power_on)
+	if (!dp->active_stream_mask)
 		return;
 
 	msm_dp_ctrl_push_vcpf(msm_dp_display->ctrl, msm_dp_display->panel);
@@ -1535,6 +1536,11 @@ static void msm_dp_display_unprepare(struct msm_dp_display_private *dp)
 {
 	struct msm_dp *msm_dp_display = &dp->msm_dp_display;
 
+	if (msm_dp_display->active_stream_mask) {
+		drm_dbg_dp(dp->drm_dev, "stream still active, return\n");
+		return;
+	}
+
 	/* dongle is still connected but sinks are disconnected */
 	if (dp->link->sink_count == 0)
 		msm_dp_link_psm_config(dp->link, &dp->panel->link_info, true);
@@ -1547,8 +1553,6 @@ static void msm_dp_display_unprepare(struct msm_dp_display_private *dp)
 	else
 		msm_dp_display_host_phy_exit(dp);
 
-	msm_dp_display->power_on = false;
-
 	pm_runtime_put_sync(&msm_dp_display->pdev->dev);
 
 	drm_dbg_dp(dp->drm_dev, "type=%d Done\n", msm_dp_display->connector_type);
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index 472429d092009..b163954deafcd 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -18,7 +18,7 @@ struct msm_dp {
 	struct drm_bridge *next_bridge;
 	struct drm_bridge *bridge;
 	bool audio_enabled;
-	bool power_on;
+	u32 active_stream_mask;
 	bool mst_active;
 	unsigned int connector_type;
 	bool is_edp;

-- 
2.43.0