From b741173fd1a1d6d3f264046a93307db9f808e623 Mon Sep 17 00:00:00 2001
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Wed, 8 Dec 2021 01:29:00 +0300
Subject: drm/msm/dsi: move DSI host powerup to modeset time
Git-commit: 7d8e9a90509f1bd1d193a0c93cb8d1dbad9049fb
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

The DSI subsystem does not fully fall into the pre-enable/enable system
of callbacks, since typically DSI device bridge drivers expect to be
able to communicate with DSI devices at the pre-enable() callback. The
reason is that for some DSI hosts enabling the video stream would
prevent other drivers from sending DSI commands. For example see the
panel-bridge driver, which does drm_panel_prepare() from the
pre_enable() callback (which would be called before our pre_enable()
callback, resulting in panel preparation failures as the link is not yet
ready).

Therewere several attempts to solve this issue, but currently the best
approach is to power up the DSI link from the mode_set() callback,
allowing next bridge/panel to use DSI transfers in the pre_enable()
time. Follow this approach.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Link: https://lore.kernel.org/r/20211207222901.988484-2-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/msm/dsi/dsi_manager.c | 43 +++++++++++++++++++--------
 1 file changed, 31 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
index 1dbbfca163d9..0c1b7dde377c 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c
@@ -315,13 +315,12 @@ dsi_mgr_connector_best_encoder(struct drm_connector *connector)
 	return msm_dsi_get_encoder(msm_dsi);
 }
 
-static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
+static void dsi_mgr_bridge_power_on(struct drm_bridge *bridge)
 {
 	int id = dsi_mgr_bridge_get_id(bridge);
 	struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
 	struct msm_dsi *msm_dsi1 = dsi_mgr_get_dsi(DSI_1);
 	struct mipi_dsi_host *host = msm_dsi->host;
-	struct drm_panel *panel = msm_dsi->panel;
 	struct msm_dsi_phy_shared_timings phy_shared_timings[DSI_MAX];
 	bool is_bonded_dsi = IS_BONDED_DSI();
 	int ret;
@@ -362,6 +361,34 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
 	if (is_bonded_dsi && msm_dsi1)
 		msm_dsi_host_enable_irq(msm_dsi1->host);
 
+	return;
+
+host1_on_fail:
+	msm_dsi_host_power_off(host);
+host_on_fail:
+	dsi_mgr_phy_disable(id);
+phy_en_fail:
+	return;
+}
+
+static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
+{
+	int id = dsi_mgr_bridge_get_id(bridge);
+	struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
+	struct msm_dsi *msm_dsi1 = dsi_mgr_get_dsi(DSI_1);
+	struct mipi_dsi_host *host = msm_dsi->host;
+	struct drm_panel *panel = msm_dsi->panel;
+	bool is_bonded_dsi = IS_BONDED_DSI();
+	int ret;
+
+	DBG("id=%d", id);
+	if (!msm_dsi_device_connected(msm_dsi))
+		return;
+
+	/* Do nothing with the host if it is slave-DSI in case of bonded DSI */
+	if (is_bonded_dsi && !IS_MASTER_DSI_LINK(id))
+		return;
+
 	/* Always call panel functions once, because even for dual panels,
 	 * there is only one drm_panel instance.
 	 */
@@ -396,17 +423,7 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
 	if (panel)
 		drm_panel_unprepare(panel);
 panel_prep_fail:
-	msm_dsi_host_disable_irq(host);
-	if (is_bonded_dsi && msm_dsi1)
-		msm_dsi_host_disable_irq(msm_dsi1->host);
 
-	if (is_bonded_dsi && msm_dsi1)
-		msm_dsi_host_power_off(msm_dsi1->host);
-host1_on_fail:
-	msm_dsi_host_power_off(host);
-host_on_fail:
-	dsi_mgr_phy_disable(id);
-phy_en_fail:
 	return;
 }
 
@@ -552,6 +569,8 @@ static void dsi_mgr_bridge_mode_set(struct drm_bridge *bridge,
 	msm_dsi_host_set_display_mode(host, adjusted_mode);
 	if (is_bonded_dsi && other_dsi)
 		msm_dsi_host_set_display_mode(other_dsi->host, adjusted_mode);
+
+	dsi_mgr_bridge_power_on(bridge);
 }
 
 static const struct drm_connector_funcs dsi_mgr_connector_funcs = {
-- 
2.38.1