Subject: [PATCH] drm/i915/glk: Enable cold boot for GLK DSI

From: Madhav Chauhan <[email-masked]>
Date: Mon, 8 May 2017 17:54:44 +0530

As per BSEPC, if device ready bit is '0' in enable IO sequence
then its a cold boot/reset scenario eg: S3/S4 resume. In these
conditions we need to program certain registers and prepare port
from the middle of DSI enable sequence otherwise feature like S3/S4
doesn't work.

V2: Do not assume that on enable when power has not been lost,
all the registers contain the correct information already.
Program DSI registers for normal boot scenario from
glk_dsi_device_ready() (Jani N).

Signed-off-by: Madhav Chauhan <[email-masked]>
---
 drivers/gpu/drm/i915/intel_dsi.c | 82 +++++++++++++++++++++++++---------------
 1 file changed, 51 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index fc0ef49..5582859 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -346,12 +346,17 @@ static bool intel_dsi_compute_config(struct intel_encoder *encoder,
 	return true;
 }
 
-static void glk_dsi_device_ready(struct intel_encoder *encoder)
+static void intel_dsi_prepare(struct intel_encoder *intel_encoder,
+			      struct intel_crtc_state *pipe_config);
+
+static void glk_dsi_device_ready(struct intel_encoder *encoder,
+				 struct intel_crtc_state *pipe_config)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
 	enum port port;
 	u32 tmp, val;
+	bool cold_boot = false;
 
 	/* Set the MIPI mode
 	 * If MIPI_Mode is off, then writing to LP_Wake bit is not reflecting.
@@ -370,7 +375,10 @@ static void glk_dsi_device_ready(struct intel_encoder *encoder)
 	/* Program LP Wake */
 	for_each_dsi_port(port, intel_dsi->ports) {
 		tmp = I915_READ(MIPI_CTRL(port));
-		tmp |= GLK_LP_WAKE;
+		if (!(I915_READ(MIPI_DEVICE_READY(port)) & DEVICE_READY))
+			tmp &= ~GLK_LP_WAKE;
+		else
+			tmp |= GLK_LP_WAKE;
 		I915_WRITE(MIPI_CTRL(port), tmp);
 	}
 
@@ -382,6 +390,15 @@ static void glk_dsi_device_ready(struct intel_encoder *encoder)
 			DRM_ERROR("MIPIO port is powergated\n");
 	}
 
+	/* Check if cold boot scenario */
+	for_each_dsi_port(port, intel_dsi->ports) {
+		cold_boot |= !(I915_READ(MIPI_DEVICE_READY(port)) &
+							DEVICE_READY);
+	}
+
+	if (cold_boot)
+		intel_dsi_prepare(encoder, pipe_config);
+
 	/* Wait for MIPI PHY status bit to set */
 	for_each_dsi_port(port, intel_dsi->ports) {
 		if (intel_wait_for_register(dev_priv,
@@ -402,34 +419,34 @@ static void glk_dsi_device_ready(struct intel_encoder *encoder)
 			val |= DEVICE_READY;
 			I915_WRITE(MIPI_DEVICE_READY(port), val);
 			usleep_range(10, 15);
-		}
-
-		/* Enter ULPS */
-		val = I915_READ(MIPI_DEVICE_READY(port));
-		val &= ~ULPS_STATE_MASK;
-		val |= (ULPS_STATE_ENTER | DEVICE_READY);
-		I915_WRITE(MIPI_DEVICE_READY(port), val);
+		} else {
+			/* Enter ULPS */
+			val = I915_READ(MIPI_DEVICE_READY(port));
+			val &= ~ULPS_STATE_MASK;
+			val |= (ULPS_STATE_ENTER | DEVICE_READY);
+			I915_WRITE(MIPI_DEVICE_READY(port), val);
 
-		/* Wait for ULPS active */
-		if (intel_wait_for_register(dev_priv,
+			/* Wait for ULPS active */
+			if (intel_wait_for_register(dev_priv,
 				MIPI_CTRL(port), GLK_ULPS_NOT_ACTIVE, 0, 20))
-			DRM_ERROR("ULPS not active\n");
+				DRM_ERROR("ULPS not active\n");
 
-		/* Exit ULPS */
-		val = I915_READ(MIPI_DEVICE_READY(port));
-		val &= ~ULPS_STATE_MASK;
-		val |= (ULPS_STATE_EXIT | DEVICE_READY);
-		I915_WRITE(MIPI_DEVICE_READY(port), val);
+			/* Exit ULPS */
+			val = I915_READ(MIPI_DEVICE_READY(port));
+			val &= ~ULPS_STATE_MASK;
+			val |= (ULPS_STATE_EXIT | DEVICE_READY);
+			I915_WRITE(MIPI_DEVICE_READY(port), val);
 
-		/* Enter Normal Mode */
-		val = I915_READ(MIPI_DEVICE_READY(port));
-		val &= ~ULPS_STATE_MASK;
-		val |= (ULPS_STATE_NORMAL_OPERATION | DEVICE_READY);
-		I915_WRITE(MIPI_DEVICE_READY(port), val);
+			/* Enter Normal Mode */
+			val = I915_READ(MIPI_DEVICE_READY(port));
+			val &= ~ULPS_STATE_MASK;
+			val |= (ULPS_STATE_NORMAL_OPERATION | DEVICE_READY);
+			I915_WRITE(MIPI_DEVICE_READY(port), val);
 
-		tmp = I915_READ(MIPI_CTRL(port));
-		tmp &= ~GLK_LP_WAKE;
-		I915_WRITE(MIPI_CTRL(port), tmp);
+			tmp = I915_READ(MIPI_CTRL(port));
+			tmp &= ~GLK_LP_WAKE;
+			I915_WRITE(MIPI_CTRL(port), tmp);
+		}
 	}
 
 	/* Wait for Stop state */
@@ -447,6 +464,9 @@ static void glk_dsi_device_ready(struct intel_encoder *encoder)
 				AFE_LATCHOUT, 20))
 			DRM_ERROR("D-PHY not entering LP-11 state\n");
 	}
+
+	if (!cold_boot)
+		intel_dsi_prepare(encoder, pipe_config);
 }
 
 static void bxt_dsi_device_ready(struct intel_encoder *encoder)
@@ -515,7 +535,8 @@ static void vlv_dsi_device_ready(struct intel_encoder *encoder)
 	}
 }
 
-static void intel_dsi_device_ready(struct intel_encoder *encoder)
+static void intel_dsi_device_ready(struct intel_encoder *encoder,
+				   struct intel_crtc_state *pipe_config)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 
@@ -524,7 +545,7 @@ static void intel_dsi_device_ready(struct intel_encoder *encoder)
 	else if (IS_BROXTON(dev_priv))
 		bxt_dsi_device_ready(encoder);
 	else if (IS_GEMINILAKE(dev_priv))
-		glk_dsi_device_ready(encoder);
+		glk_dsi_device_ready(encoder, pipe_config);
 }
 
 static void glk_dsi_enter_low_power_mode(struct intel_encoder *encoder)
@@ -710,8 +731,6 @@ static void intel_dsi_port_disable(struct intel_encoder *encoder)
 	}
 }
 
-static void intel_dsi_prepare(struct intel_encoder *intel_encoder,
-			      struct intel_crtc_state *pipe_config);
 static void intel_dsi_unprepare(struct intel_encoder *encoder);
 
 static void intel_dsi_msleep(struct intel_dsi *intel_dsi, int msec)
@@ -800,7 +819,8 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder,
 		I915_WRITE(DSPCLK_GATE_D, val);
 	}
 
-	intel_dsi_prepare(encoder, pipe_config);
+	if (!IS_GEMINILAKE(dev_priv))
+		intel_dsi_prepare(encoder, pipe_config);
 
 	/* Power on, try both CRC pmic gpio and VBT */
 	if (intel_dsi->gpio_panel)
@@ -812,7 +832,7 @@ static void intel_dsi_pre_enable(struct intel_encoder *encoder,
 	intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_DEASSERT_RESET);
 
 	/* Put device in ready state (LP-11) */
-	intel_dsi_device_ready(encoder);
+	intel_dsi_device_ready(encoder, pipe_config);
 
 	/* Send initialization commands in LP mode */
 	intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_INIT_OTP);
-- 
1.9.1