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.

Signed-off-by: Madhav Chauhan <madhav.chau...@intel.com>
---
 drivers/gpu/drm/i915/intel_dsi.c | 79 ++++++++++++++++++++++++----------------
 1 file changed, 48 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index fc0ef49..6b68864 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 */
@@ -515,7 +532,8 @@ 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 +542,7 @@ 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 +728,6 @@ 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 +816,8 @@ 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 +829,7 @@ 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

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