[Intel-gfx] [PATCH 09/19] drm/i915: automatic FDI training support for Ivy Bridge

[Jesse Barnes]

Ivy Bridge supports auto-training on the CPU side, so add a separate
training function to handle it.

Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/i915_reg.h      |    2 +
 drivers/gpu/drm/i915/intel_display.c |   82 +++++++++++++++++++++++++++++++--
 2 files changed, 79 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index aba3fe5..03c99ed 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3116,6 +3116,8 @@
 #define  FDI_LINK_TRAIN_AUTO		(1<<10)
 #define  FDI_SCRAMBLING_ENABLE          (0<<7)
 #define  FDI_SCRAMBLING_DISABLE         (1<<7)
+/* Ivybridge */
+#define  FDI_AUTO_TRAIN_DONE		(1<<1)
 
 /* FDI_RX, FDI_X is hard-wired to Transcoder_X */
 #define _FDI_RXA_CTL             0xf000c
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index ab840a6..3396043 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2411,6 +2411,75 @@ static void ivb_manual_fdi_link_train(struct drm_crtc *crtc)
 	DRM_DEBUG_KMS("FDI train done.\n");
 }
 
+/* On Ivybridge we can use auto training */
+static void ivb_fdi_link_train(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	unsigned long start = jiffies_to_msecs(jiffies);
+	int pipe = intel_crtc->pipe;
+	u32 reg, temp, i, j;
+
+	/* Can't pair IVB & Ibex Peak */
+	BUG_ON(HAS_PCH_IBX(dev));
+
+	reg = FDI_TX_CTL(pipe);
+	temp = I915_READ(reg);
+	temp &= ~(7 << 19);
+	temp |= (intel_crtc->fdi_lanes - 1) << 19;
+	temp &= ~FDI_LINK_TRAIN_NONE;
+	I915_WRITE(reg, temp);
+
+	/* Enable auto training on TX and RX */
+	for (i = 0; i < ARRAY_SIZE(snb_b_fdi_train_param); i++) {
+		/* Try each vswing/pre-emphasis pair twice */
+		for (j = 0; j < 2; j++) {
+			reg = FDI_TX_CTL(pipe);
+			temp = I915_READ(reg);
+			temp |= FDI_AUTO_TRAINING;
+			temp &= ~FDI_LINK_TRAIN_VOL_EMP_MASK;
+			temp |= snb_b_fdi_train_param[i];
+			I915_WRITE(reg, temp | FDI_TX_ENABLE);
+
+			reg = FDI_RX_CTL(pipe);
+			temp = I915_READ(reg);
+			I915_WRITE(reg, temp | FDI_RX_ENABLE);
+			POSTING_READ(reg);
+
+			udelay(5);
+
+			reg = FDI_TX_CTL(pipe);
+			temp = I915_READ(reg);
+			if ((temp & FDI_AUTO_TRAIN_DONE) ||
+			    (I915_READ(reg) & FDI_AUTO_TRAIN_DONE)) {
+				DRM_DEBUG_KMS("FDI auto train complete in %d ms\n",
+					      jiffies_to_msecs(jiffies) - start);
+				goto done;
+			}
+
+			reg = FDI_TX_CTL(pipe);
+			temp = I915_READ(reg);
+			I915_WRITE(reg, temp & ~FDI_TX_ENABLE);
+
+			reg = FDI_RX_CTL(pipe);
+			temp = I915_READ(reg);
+			I915_WRITE(reg, temp & ~FDI_RX_ENABLE);
+			POSTING_READ(reg);
+			udelay(31); /* wait idle time before retrying */
+		}
+	}
+	DRM_ERROR("FDI auto train failed\n");
+	return;
+
+done:
+	reg = FDI_RX_CTL(pipe);
+	temp = I915_READ(reg);
+	temp |= FDI_FS_ERR_CORRECT_ENABLE | FDI_FE_ERR_CORRECT_ENABLE;
+	I915_WRITE(reg, temp);
+	POSTING_READ(reg);
+}
+
 static void ironlake_fdi_pll_enable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
@@ -2452,7 +2521,7 @@ static void ironlake_fdi_pll_enable(struct drm_crtc *crtc)
 	}
 }
 
-static void ironlake_fdi_disable(struct drm_crtc *crtc)
+static void ironlake_fdi_pll_disable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -2674,9 +2743,9 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc)
 	is_pch_port = intel_crtc_driving_pch(crtc);
 
 	if (is_pch_port)
-		ironlake_fdi_enable(crtc);
+		ironlake_fdi_pll_enable(crtc);
 	else
-		ironlake_fdi_disable(crtc);
+		ironlake_fdi_pll_disable(crtc);
 
 	/* Enable panel fitting for LVDS */
 	if (dev_priv->pch_pf_size &&
@@ -2729,7 +2798,7 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
 	I915_WRITE(PF_CTL(pipe), 0);
 	I915_WRITE(PF_WIN_SZ(pipe), 0);
 
-	ironlake_fdi_disable(crtc);
+	ironlake_fdi_pll_disable(crtc);
 
 	/* This is a horrible layering violation; we should be doing this in
 	 * the connector/encoder ->prepare instead, but we don't always have
@@ -7418,7 +7487,10 @@ static void intel_init_display(struct drm_device *dev)
 			dev_priv->display.fdi_link_train = gen6_fdi_link_train;
 		} else if (IS_IVYBRIDGE(dev)) {
 			/* FIXME: detect B0+ stepping and use auto training */
-			dev_priv->display.fdi_link_train = ivb_manual_fdi_link_train;
+			if (0)
+				dev_priv->display.fdi_link_train = ivb_fdi_link_train;
+			else
+				dev_priv->display.fdi_link_train = ivb_manual_fdi_link_train;
 		} else
 			dev_priv->display.update_wm = NULL;
 	} else if (IS_PINEVIEW(dev)) {
-- 
1.7.4.1