drm/i915: Move the SPLL enabling into hsw_crt_pre_enable

The call to intel_ddi_pll_enable in haswell_crtc_mode_set is the only
function that still touches the hardware state from the crtc mode_set
callback on hsw. Since the SPLL isn't ever shared we can easily take
it out into the hsw crt encoder functions.

Temporarily we'll loose a bit of WARN_ON coverage with this, but once
the WRPLLs are switched over that will be restored. For the SPLL
selection add a WARN in the hsw fdi link training code.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[imre: rebased on patchset version w/o pch/crt/fdi refactoring]
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 5a045d3..d312cf89 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -137,6 +137,18 @@
 	pipe_config->adjusted_mode.flags |= intel_crt_get_flags(encoder);
 }
 
+static void hsw_crt_pre_enable(struct intel_encoder *encoder)
+{
+	struct drm_device *dev = encoder->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	WARN(I915_READ(SPLL_CTL) & SPLL_PLL_ENABLE, "SPLL already enabled\n");
+	I915_WRITE(SPLL_CTL,
+		   SPLL_PLL_ENABLE | SPLL_PLL_FREQ_1350MHz | SPLL_PLL_SSC);
+	POSTING_READ(SPLL_CTL);
+	udelay(20);
+}
+
 /* Note: The caller is required to filter out dpms modes not supported by the
  * platform. */
 static void intel_crt_set_dpms(struct intel_encoder *encoder, int mode)
@@ -860,6 +872,7 @@
 	if (HAS_DDI(dev)) {
 		crt->base.get_config = hsw_crt_get_config;
 		crt->base.get_hw_state = intel_ddi_get_hw_state;
+		crt->base.pre_enable = hsw_crt_pre_enable;
 	} else {
 		crt->base.get_config = intel_crt_get_config;
 		crt->base.get_hw_state = intel_crt_get_hw_state;