drm/i915/icl: WaForwardProgressSoftReset

Avoids a hang during soft reset.

v2: Rebased on top of the WA refactoring
v3: Added References (Mika)
v4:
  - Rebased
  - C, not lisp (Chris)
  - Which steppings affected by this are not clear.
    For the moment, apply unconditionally as per the
    BSpec (Mika)
  - Add reference to another HSD also related

References: HSDES#1405476379
References: HSDES#2006612137
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1525814984-20039-14-git-send-email-oscar.mateo@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -9897,6 +9897,11 @@ enum skl_power_gate {
 /* Media decoder 2 MOCS registers */
 #define GEN11_MFX2_MOCS(i)	_MMIO(0x10000 + (i) * 4)
 
+#define GEN10_SCRATCH_LNCF2		_MMIO(0xb0a0)
+#define   PMFLUSHDONE_LNICRSDROP	(1 << 20)
+#define   PMFLUSH_GAPL3UNBLOCK		(1 << 21)
+#define   PMFLUSHDONE_LNEBLK		(1 << 22)
+
 /* gamt regs */
 #define GEN8_L3_LRA_1_GPGPU _MMIO(0x4dd4)
 #define   GEN8_L3_LRA_1_GPGPU_DEFAULT_VALUE_BDW  0x67F1427F /* max/min for LRA1/2 */

drivers/gpu/drm/i915/intel_workarounds.c

@@ -761,6 +761,13 @@ static void icl_gt_workarounds_apply(struct drm_i915_private *dev_priv)
 		I915_WRITE(INF_UNIT_LEVEL_CLKGATE,
 			   I915_READ(INF_UNIT_LEVEL_CLKGATE) |
 			   CGPSF_CLKGATE_DIS);
+
+	/* WaForwardProgressSoftReset:icl */
+	I915_WRITE(GEN10_SCRATCH_LNCF2,
+		   I915_READ(GEN10_SCRATCH_LNCF2) |
+		   PMFLUSHDONE_LNICRSDROP |
+		   PMFLUSH_GAPL3UNBLOCK |
+		   PMFLUSHDONE_LNEBLK);
 }
 
 void intel_gt_workarounds_apply(struct drm_i915_private *dev_priv)