drm/i915/bdw: Implement edp PSR workarounds

This implements a workaround for PSR dealing with some vblank issue.

WaPsrDPAMaskVBlankInSRD && WaPsrDPRSUnmaskVBlankInSRD

v2: forgot to git add bogus whitespace fix

v3: Update with workaround names.
Use for_each_pipe() and CHICKEN_PIPESL_1(pipe) macro (Ville)

Cc: Art Runyan <arthur.j.runyan@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Jesse Barnes <jbarnes@virtuosugeek.org>
[danvet: Kill redundant IS_BDW check and remove the copious amount of
uneeded lines added.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -4113,8 +4113,14 @@
 # define CHICKEN3_DGMG_DONE_FIX_DISABLE		(1 << 2)
 
 #define CHICKEN_PAR1_1		0x42080
+#define  DPA_MASK_VBLANK_SRD	(1 << 15)
 #define  FORCE_ARB_IDLE_PLANES	(1 << 14)
 
+#define _CHICKEN_PIPESL_1_A	0x420b0
+#define _CHICKEN_PIPESL_1_B	0x420b4
+#define  DPRS_MASK_VBLANK_SRD	(1 << 0)
+#define CHICKEN_PIPESL_1(pipe) _PIPE(pipe, _CHICKEN_PIPESL_1_A, _CHICKEN_PIPESL_1_B)
+
 #define DISP_ARB_CTL	0x45000
 #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)
 #define  DISP_FBC_WM_DIS		(1<<15)

drivers/gpu/drm/i915/intel_pm.c

@@ -5277,6 +5277,7 @@ static void lpt_suspend_hw(struct drm_device *dev)
 static void gen8_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum pipe i;
 
 	I915_WRITE(WM3_LP_ILK, 0);
 	I915_WRITE(WM2_LP_ILK, 0);
@@ -5287,6 +5288,17 @@ static void gen8_init_clock_gating(struct drm_device *dev)
 
 	/* WaSwitchSolVfFArbitrationPriority */
 	I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) | HSW_ECOCHK_ARB_PRIO_SOL);
+
+	/* WaPsrDPAMaskVBlankInSRD */
+	I915_WRITE(CHICKEN_PAR1_1,
+		   I915_READ(CHICKEN_PAR1_1) | DPA_MASK_VBLANK_SRD);
+
+	/* WaPsrDPRSUnmaskVBlankInSRD */
+	for_each_pipe(i) {
+		I915_WRITE(CHICKEN_PIPESL_1(i),
+			   I915_READ(CHICKEN_PIPESL_1(i) |
+				     DPRS_MASK_VBLANK_SRD));
+	}
 }
 
 static void haswell_init_clock_gating(struct drm_device *dev)