drm/i915/mcr: Hold forcewake and MCR lock over PPAT setup

PPAT setup involves a series of multicast writes.  This can be optimized
slightly be acquiring forcewake and the steering lock just once for the
entire sequence.

v2:
 - We should use FW_REG_WRITE instead of FW_REG_READ.  (Bala)

Suggested-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221130155852.19601-1-matthew.d.roper@intel.com

drivers/gpu/drm/i915/gt/intel_gtt.c

@@ -481,14 +481,25 @@ static void tgl_setup_private_ppat(struct intel_uncore *uncore)
 
 static void xehp_setup_private_ppat(struct intel_gt *gt)
 {
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(0), GEN8_PPAT_WB);
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(1), GEN8_PPAT_WC);
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(2), GEN8_PPAT_WT);
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(3), GEN8_PPAT_UC);
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(4), GEN8_PPAT_WB);
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(5), GEN8_PPAT_WB);
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(6), GEN8_PPAT_WB);
-	intel_gt_mcr_multicast_write(gt, XEHP_PAT_INDEX(7), GEN8_PPAT_WB);
+	enum forcewake_domains fw;
+	unsigned long flags;
+
+	fw = intel_uncore_forcewake_for_reg(gt->uncore, _MMIO(XEHP_PAT_INDEX(0).reg),
+					    FW_REG_WRITE);
+	intel_uncore_forcewake_get(gt->uncore, fw);
+
+	intel_gt_mcr_lock(gt, &flags);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(0), GEN8_PPAT_WB);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(1), GEN8_PPAT_WC);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(2), GEN8_PPAT_WT);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(3), GEN8_PPAT_UC);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(4), GEN8_PPAT_WB);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(5), GEN8_PPAT_WB);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(6), GEN8_PPAT_WB);
+	intel_gt_mcr_multicast_write_fw(gt, XEHP_PAT_INDEX(7), GEN8_PPAT_WB);
+	intel_gt_mcr_unlock(gt, flags);
+
+	intel_uncore_forcewake_put(gt->uncore, fw);
 }
 
 static void icl_setup_private_ppat(struct intel_uncore *uncore)