drm/i915/icl: WaDisCtxReload

Revert to the legacy implementation to avoid a system hang.

v2: Correct the address for GAMW_ECO_DEV_RW_IA_REG
v3: Renamed to Wa_220166154
v4: Rebased on top of the WA refactoring
v5: Added References (Mika)
v6:
  - Rebased
  - C, not lisp (Chris)

References: HSDES#220166154
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1525814984-20039-9-git-send-email-oscar.mateo@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -8273,6 +8273,9 @@ enum {
 #define   GEN11_LSN_UNSLCVC_GAFS_HALF_CL2_MAXALLOC	(1 << 9)
 #define   GEN11_LSN_UNSLCVC_GAFS_HALF_SF_MAXALLOC	(1 << 7)
 
+#define GAMW_ECO_DEV_RW_IA_REG			_MMIO(0x4080)
+#define   GAMW_ECO_DEV_CTX_RELOAD_DISABLE	(1 << 7)
+
 /* IVYBRIDGE DPF */
 #define GEN7_L3CDERRST1(slice)		_MMIO(0xB008 + (slice) * 0x200) /* L3CD Error Status 1 */
 #define   GEN7_L3CDERRST1_ROW_MASK	(0x7ff<<14)

drivers/gpu/drm/i915/intel_workarounds.c

@@ -733,6 +733,12 @@ static void icl_gt_workarounds_apply(struct drm_i915_private *dev_priv)
 	I915_WRITE(GEN11_LSN_UNSLCVC, I915_READ(GEN11_LSN_UNSLCVC) |
 				      GEN11_LSN_UNSLCVC_GAFS_HALF_SF_MAXALLOC |
 				      GEN11_LSN_UNSLCVC_GAFS_HALF_CL2_MAXALLOC);
+
+	/* Wa_220166154:icl
+	 * Formerly known as WaDisCtxReload
+	 */
+	I915_WRITE(GAMW_ECO_DEV_RW_IA_REG, I915_READ(GAMW_ECO_DEV_RW_IA_REG) |
+					   GAMW_ECO_DEV_CTX_RELOAD_DISABLE);
 }
 
 void intel_gt_workarounds_apply(struct drm_i915_private *dev_priv)