drm/i915/psr: set CHICKEN_TRANS for psr2

As per bpsec, CHICKEN_TRANS_EDP bit 12 ,15 must be programmed in
psr2 enable sequence.
bit 12 : Program Transcoder EDP VSC DIP header with a valid setting for
        PSR2 and Set CHICKEN_TRANS_EDP(0x420cc) bit 12 for programmable
        header packet.
bit 15 : Set CHICKEN_TRANS_EDP(0x420cc) bit 15 if Y coordinate is supported

v2: (Rodrigo)
- move CHICKEN_TRANS_EDP bit set logic right after setup_vsc

v3:(Rodrigo)
- initialize chicken_trans to CHICKEN_TRANS_BIT12 instead of 0

v4:(chris wilson)
- use BIT(12), remove CHICKEN_TRANS_BIT12
- remove unnecessary comments
- update commit message

v5:
- rename bit 12 PSR2_VSC_ENABLE_PROG_HEADER
- rename bit 15 PSR2_ADD_VERTICAL_LINE_COUNT

v6:(Rodrigo)
- remove TRANS_EDP=3, use cpu_transcoder

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jim Bride <jim.bride@linux.intel.com>
Signed-off-by: vathsala nagaraju <vathsala.nagaraju@intel.com>
Signed-off-by: Patil Deepti <deepti.patil@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1484247691-20930-1-git-send-email-vathsala.nagaraju@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -6449,6 +6449,12 @@ enum {
 #define  BDW_DPRS_MASK_VBLANK_SRD	(1 << 0)
 #define CHICKEN_PIPESL_1(pipe) _MMIO_PIPE(pipe, _CHICKEN_PIPESL_1_A, _CHICKEN_PIPESL_1_B)
 
+#define CHICKEN_TRANS_A         0x420c0
+#define CHICKEN_TRANS_B         0x420c4
+#define CHICKEN_TRANS(trans) _MMIO_TRANS(trans, CHICKEN_TRANS_A, CHICKEN_TRANS_B)
+#define PSR2_VSC_ENABLE_PROG_HEADER    (1<<12)
+#define PSR2_ADD_VERTICAL_LINE_COUNT   (1<<15)
+
 #define DISP_ARB_CTL	_MMIO(0x45000)
 #define  DISP_FBC_MEMORY_WAKE		(1<<31)
 #define  DISP_TILE_SURFACE_SWIZZLING	(1<<13)

drivers/gpu/drm/i915/intel_psr.c

@@ -480,6 +480,9 @@ void intel_psr_enable(struct intel_dp *intel_dp)
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	struct drm_device *dev = intel_dig_port->base.base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct intel_crtc *crtc = to_intel_crtc(intel_dig_port->base.base.crtc);
+	enum transcoder cpu_transcoder = crtc->config->cpu_transcoder;
+	u32 chicken;
 
 	if (!HAS_PSR(dev_priv)) {
 		DRM_DEBUG_KMS("PSR not supported on this platform\n");
@@ -505,6 +508,10 @@ void intel_psr_enable(struct intel_dp *intel_dp)
 	if (HAS_DDI(dev_priv)) {
 		if (dev_priv->psr.psr2_support) {
 			skl_psr_setup_su_vsc(intel_dp);
+			chicken = PSR2_VSC_ENABLE_PROG_HEADER;
+			if (dev_priv->psr.y_cord_support)
+				chicken |= PSR2_ADD_VERTICAL_LINE_COUNT;
+			I915_WRITE(CHICKEN_TRANS(cpu_transcoder), chicken);
 		} else {
 			/* set up vsc header for psr1 */
 			hsw_psr_setup_vsc(intel_dp);