drm/i915: Reorganize the DSI enable/disable sequence

Basically ULPS handling during enable/disable has been moved to
pre_enable and post_disable phases. PLL and panel power disable
also has been moved to post_disable phase. The ULPS entry/exit
sequneces as suggested by HW team is as follows -

During enable time -
set DEVICE_READY --> Clear DEVICE_READY --> set DEVICE_READY

And during disable time to flush all FIFOs -
set ENTER_SLEEP --> EXIT_SLEEP --> ENTER_SLEEP

Also during disbale sequnece sub-encoder disable is moved to the end
after port is disabled.

v2: Based on comments from Ville
    - Detailed epxlaination in the commit messgae
    - Moved parameter changes out into another patch
    - Backlight enabling will be a new patch

v3: Updated as per Jani's comments
    - Removed the I915_WRITE_BITS as it is not needed
    - Moved panel_reset and send_otp_cmds hooks to dsi_pre_enable
    - Moved disable_panel_power hook to dsi_post_disable
    - Replace hardcoding with AFE_LATCHOUT

v4: Make intel_dsi_device_ready and intel_dsi_clear_device_ready static
Signed-off-by: NYogesh Mohan Marimuthu <yogesh.mohan.marimuthu@intel.com>
Signed-off-by: NShobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dsi.c

@@ -101,46 +101,57 @@ static void intel_dsi_pre_pll_enable(struct intel_encoder *encoder)
 	vlv_enable_dsi_pll(encoder);
 }
 
-static void intel_dsi_pre_enable(struct intel_encoder *encoder)
+static void intel_dsi_device_ready(struct intel_encoder *encoder)
 {
+	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
+	int pipe = intel_crtc->pipe;
+	u32 val;
+
 	DRM_DEBUG_KMS("\n");
-}
 
-static void intel_dsi_enable(struct intel_encoder *encoder)
+	val = I915_READ(MIPI_PORT_CTRL(pipe));
+	I915_WRITE(MIPI_PORT_CTRL(pipe), val | LP_OUTPUT_HOLD);
+	usleep_range(1000, 1500);
+	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY | ULPS_STATE_EXIT);
+	usleep_range(2000, 2500);
+	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY);
+	usleep_range(2000, 2500);
+	I915_WRITE(MIPI_DEVICE_READY(pipe), 0x00);
+	usleep_range(2000, 2500);
+	I915_WRITE(MIPI_DEVICE_READY(pipe), DEVICE_READY);
+	usleep_range(2000, 2500);
+}
+static void intel_dsi_pre_enable(struct intel_encoder *encoder)
 {
-	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
-	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
-	int pipe = intel_crtc->pipe;
-	u32 temp;
 
 	DRM_DEBUG_KMS("\n");
 
 	if (intel_dsi->dev.dev_ops->panel_reset)
 		intel_dsi->dev.dev_ops->panel_reset(&intel_dsi->dev);
 
-	temp = I915_READ(MIPI_DEVICE_READY(pipe));
-	if ((temp & DEVICE_READY) == 0) {
-		temp &= ~ULPS_STATE_MASK;
-		I915_WRITE(MIPI_DEVICE_READY(pipe), temp | DEVICE_READY);
-	} else if (temp & ULPS_STATE_MASK) {
-		temp &= ~ULPS_STATE_MASK;
-		I915_WRITE(MIPI_DEVICE_READY(pipe), temp | ULPS_STATE_EXIT);
-		/*
-		 * We need to ensure that there is a minimum of 1 ms time
-		 * available before clearing the UPLS exit state.
-		 */
-		msleep(2);
-		I915_WRITE(MIPI_DEVICE_READY(pipe), temp);
-	}
+	/* put device in ready state */
+	intel_dsi_device_ready(encoder);
 
 	if (intel_dsi->dev.dev_ops->send_otp_cmds)
 		intel_dsi->dev.dev_ops->send_otp_cmds(&intel_dsi->dev);
+}
+
+static void intel_dsi_enable(struct intel_encoder *encoder)
+{
+	struct drm_device *dev = encoder->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+	int pipe = intel_crtc->pipe;
+	u32 temp;
+
+	DRM_DEBUG_KMS("\n");
 
 	if (is_cmd_mode(intel_dsi))
 		I915_WRITE(MIPI_MAX_RETURN_PKT_SIZE(pipe), 8 * 4);
-
-	if (is_vid_mode(intel_dsi)) {
+	else {
 		msleep(20); /* XXX */
 		dpi_send_cmd(intel_dsi, TURN_ON);
 		msleep(100);
@@ -157,7 +168,8 @@ static void intel_dsi_enable(struct intel_encoder *encoder)
 
 static void intel_dsi_disable(struct intel_encoder *encoder)
 {
-	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
+	struct drm_device *dev = encoder->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
 	int pipe = intel_crtc->pipe;
@@ -165,8 +177,6 @@ static void intel_dsi_disable(struct intel_encoder *encoder)
 
 	DRM_DEBUG_KMS("\n");
 
-	intel_dsi->dev.dev_ops->disable(&intel_dsi->dev);
-
 	if (is_vid_mode(intel_dsi)) {
 		dpi_send_cmd(intel_dsi, SHUTDOWN);
 		msleep(10);
@@ -179,20 +189,54 @@ static void intel_dsi_disable(struct intel_encoder *encoder)
 		msleep(2);
 	}
 
-	temp = I915_READ(MIPI_DEVICE_READY(pipe));
-	if (temp & DEVICE_READY) {
-		temp &= ~DEVICE_READY;
-		temp &= ~ULPS_STATE_MASK;
-		I915_WRITE(MIPI_DEVICE_READY(pipe), temp);
-	}
+	/* if disable packets are sent before sending shutdown packet then in
+	 * some next enable sequence send turn on packet error is observed */
+	if (intel_dsi->dev.dev_ops->disable)
+		intel_dsi->dev.dev_ops->disable(&intel_dsi->dev);
 }
 
-static void intel_dsi_post_disable(struct intel_encoder *encoder)
+static void intel_dsi_clear_device_ready(struct intel_encoder *encoder)
 {
+	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
+	int pipe = intel_crtc->pipe;
+	u32 val;
+
 	DRM_DEBUG_KMS("\n");
 
+	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+	usleep_range(2000, 2500);
+
+	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_EXIT);
+	usleep_range(2000, 2500);
+
+	I915_WRITE(MIPI_DEVICE_READY(pipe), ULPS_STATE_ENTER);
+	usleep_range(2000, 2500);
+
+	val = I915_READ(MIPI_PORT_CTRL(pipe));
+	I915_WRITE(MIPI_PORT_CTRL(pipe), val & ~LP_OUTPUT_HOLD);
+	usleep_range(1000, 1500);
+
+	if (wait_for(((I915_READ(MIPI_PORT_CTRL(pipe)) & AFE_LATCHOUT)
+					== 0x00000), 30))
+		DRM_ERROR("DSI LP not going Low\n");
+
+	I915_WRITE(MIPI_DEVICE_READY(pipe), 0x00);
+	usleep_range(2000, 2500);
+
 	vlv_disable_dsi_pll(encoder);
 }
+static void intel_dsi_post_disable(struct intel_encoder *encoder)
+{
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+
+	DRM_DEBUG_KMS("\n");
+
+	intel_dsi_clear_device_ready(encoder);
+
+	if (intel_dsi->dev.dev_ops->disable_panel_power)
+		intel_dsi->dev.dev_ops->disable_panel_power(&intel_dsi->dev);
+}
 
 static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
 				   enum pipe *pipe)

drivers/gpu/drm/i915/intel_dsi.h

@@ -41,6 +41,8 @@ struct intel_dsi_dev_ops {
 
 	void (*panel_reset)(struct intel_dsi_device *dsi);
 
+	void (*disable_panel_power)(struct intel_dsi_device *dsi);
+
 	/* one time programmable commands if needed */
 	void (*send_otp_cmds)(struct intel_dsi_device *dsi);