drm/i915: move i9xx dpll enabling into crtc enable function

Now that we have the proper pipe config to track this, we don't need
to write any registers any more.

Note that for platforms without DPLL_MD (pre-gen4) which store the
pixel mutliplier in the DPLL register I've decided to keep the
seemingly "redundant" write: The comment right below saying "do this
trice for luck" doesn't instill confidence ...

v2: Drop a few now unnecessary local variables and switch the enable
function to take a struct intel_crtc * to simply arguments.

v3: Rebase on top of the newly-colored BUG_ON.

v4: Amend commit message to alliviate Imre's comment about the
redudant DPLL write for the pixel mutliplier.

Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -1331,32 +1331,48 @@ static void vlv_enable_pll(struct drm_i915_private *dev_priv, enum pipe pipe)
 	udelay(150); /* wait for warmup */
 }
 
-static void i9xx_enable_pll(struct drm_i915_private *dev_priv, enum pipe pipe)
+static void i9xx_enable_pll(struct intel_crtc *crtc)
 {
-	int reg;
-	u32 val;
+	struct drm_device *dev = crtc->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int reg = DPLL(crtc->pipe);
+	u32 dpll = crtc->config.dpll_hw_state.dpll;
 
-	assert_pipe_disabled(dev_priv, pipe);
+	assert_pipe_disabled(dev_priv, crtc->pipe);
 
 	/* No really, not for ILK+ */
 	BUG_ON(dev_priv->info->gen >= 5);
 
 	/* PLL is protected by panel, make sure we can write it */
-	if (IS_MOBILE(dev_priv->dev) && !IS_I830(dev_priv->dev))
-		assert_panel_unlocked(dev_priv, pipe);
+	if (IS_MOBILE(dev) && !IS_I830(dev))
+		assert_panel_unlocked(dev_priv, crtc->pipe);
 
-	reg = DPLL(pipe);
-	val = I915_READ(reg);
-	val |= DPLL_VCO_ENABLE;
+	I915_WRITE(reg, dpll);
+
+	/* Wait for the clocks to stabilize. */
+	POSTING_READ(reg);
+	udelay(150);
+
+	if (INTEL_INFO(dev)->gen >= 4) {
+		I915_WRITE(DPLL_MD(crtc->pipe),
+			   crtc->config.dpll_hw_state.dpll_md);
+	} else {
+		/* The pixel multiplier can only be updated once the
+		 * DPLL is enabled and the clocks are stable.
+		 *
+		 * So write it again.
+		 */
+		I915_WRITE(reg, dpll);
+	}
 
 	/* We do this three times for luck */
-	I915_WRITE(reg, val);
+	I915_WRITE(reg, dpll);
 	POSTING_READ(reg);
 	udelay(150); /* wait for warmup */
-	I915_WRITE(reg, val);
+	I915_WRITE(reg, dpll);
 	POSTING_READ(reg);
 	udelay(150); /* wait for warmup */
-	I915_WRITE(reg, val);
+	I915_WRITE(reg, dpll);
 	POSTING_READ(reg);
 	udelay(150); /* wait for warmup */
 }
@@ -3646,7 +3662,11 @@ static void i9xx_crtc_enable(struct drm_crtc *crtc)
 	intel_crtc->active = true;
 	intel_update_watermarks(dev);
 
-	i9xx_enable_pll(dev_priv, pipe);
+	for_each_encoder_on_crtc(dev, crtc, encoder)
+		if (encoder->pre_pll_enable)
+			encoder->pre_pll_enable(encoder);
+
+	i9xx_enable_pll(intel_crtc);
 
 	for_each_encoder_on_crtc(dev, crtc, encoder)
 		if (encoder->pre_enable)
@@ -4488,8 +4508,6 @@ static void i9xx_update_pll(struct intel_crtc *crtc,
 {
 	struct drm_device *dev = crtc->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_encoder *encoder;
-	int pipe = crtc->pipe;
 	u32 dpll;
 	bool is_sdvo;
 	struct dpll *clock = &crtc->config.dpll;
@@ -4553,37 +4571,14 @@ static void i9xx_update_pll(struct intel_crtc *crtc,
 	dpll |= DPLL_VCO_ENABLE;
 	crtc->config.dpll_hw_state.dpll = dpll;
 
-	I915_WRITE(DPLL(pipe), dpll & ~DPLL_VCO_ENABLE);
-	POSTING_READ(DPLL(pipe));
-	udelay(150);
-
-	for_each_encoder_on_crtc(dev, &crtc->base, encoder)
-		if (encoder->pre_pll_enable)
-			encoder->pre_pll_enable(encoder);
-
-	if (crtc->config.has_dp_encoder)
-		intel_dp_set_m_n(crtc);
-
-	I915_WRITE(DPLL(pipe), dpll);
-
-	/* Wait for the clocks to stabilize. */
-	POSTING_READ(DPLL(pipe));
-	udelay(150);
-
 	if (INTEL_INFO(dev)->gen >= 4) {
 		u32 dpll_md = (crtc->config.pixel_multiplier - 1)
 			<< DPLL_MD_UDI_MULTIPLIER_SHIFT;
 		crtc->config.dpll_hw_state.dpll_md = dpll_md;
-
-		I915_WRITE(DPLL_MD(pipe), dpll_md);
-	} else {
-		/* The pixel multiplier can only be updated once the
-		 * DPLL is enabled and the clocks are stable.
-		 *
-		 * So write it again.
-		 */
-		I915_WRITE(DPLL(pipe), dpll);
 	}
+
+	if (crtc->config.has_dp_encoder)
+		intel_dp_set_m_n(crtc);
 }
 
 static void i8xx_update_pll(struct intel_crtc *crtc,
@@ -4592,8 +4587,6 @@ static void i8xx_update_pll(struct intel_crtc *crtc,
 {
 	struct drm_device *dev = crtc->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_encoder *encoder;
-	int pipe = crtc->pipe;
 	u32 dpll;
 	struct dpll *clock = &crtc->config.dpll;
 
@@ -4620,27 +4613,6 @@ static void i8xx_update_pll(struct intel_crtc *crtc,
 
 	dpll |= DPLL_VCO_ENABLE;
 	crtc->config.dpll_hw_state.dpll = dpll;
-
-	I915_WRITE(DPLL(pipe), dpll & ~DPLL_VCO_ENABLE);
-	POSTING_READ(DPLL(pipe));
-	udelay(150);
-
-	for_each_encoder_on_crtc(dev, &crtc->base, encoder)
-		if (encoder->pre_pll_enable)
-			encoder->pre_pll_enable(encoder);
-
-	I915_WRITE(DPLL(pipe), dpll);
-
-	/* Wait for the clocks to stabilize. */
-	POSTING_READ(DPLL(pipe));
-	udelay(150);
-
-	/* The pixel multiplier can only be updated once the
-	 * DPLL is enabled and the clocks are stable.
-	 *
-	 * So write it again.
-	 */
-	I915_WRITE(DPLL(pipe), dpll);
 }
 
 static void intel_set_pipe_timings(struct intel_crtc *intel_crtc)