drm/i915/display: implement wa_18038517565

Disable FBC compressor clock gating before enabling FBC and
clear it after disabling FBC.

v2: update the DG2 registers for this wa

v3: use local variable and single line reg definition (Jani)

Bspec: 74212, 72197, 69741, 65555
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://lore.kernel.org/r/20250330172616.718188-1-vinod.govindapillai@intel.com

Author: vgovind2

drivers/gpu/drm/i915/display/intel_fbc.c

@@ -520,6 +520,20 @@ static void ilk_fbc_activate(struct intel_fbc *fbc)
 		       DPFC_CTL_EN | g4x_dpfc_ctl(fbc));
 }
 
+static void fbc_compressor_clkgate_disable_wa(struct intel_fbc *fbc,
+					      bool disable)
+{
+	struct intel_display *display = fbc->display;
+
+	if (display->platform.dg2)
+		intel_de_rmw(display, GEN9_CLKGATE_DIS_4, DG2_DPFC_GATING_DIS,
+			     disable ? DG2_DPFC_GATING_DIS : 0);
+	else if (DISPLAY_VER(display) >= 14)
+		intel_de_rmw(display, MTL_PIPE_CLKGATE_DIS2(fbc->id),
+			     MTL_DPFC_GATING_DIS,
+			     disable ? MTL_DPFC_GATING_DIS : 0);
+}
+
 static void ilk_fbc_deactivate(struct intel_fbc *fbc)
 {
 	struct intel_display *display = fbc->display;
@@ -533,6 +547,10 @@ static void ilk_fbc_deactivate(struct intel_fbc *fbc)
 	if (dpfc_ctl & DPFC_CTL_EN) {
 		dpfc_ctl &= ~DPFC_CTL_EN;
 		intel_de_write(display, ILK_DPFC_CONTROL(fbc->id), dpfc_ctl);
+
+		/* wa_18038517565 Enable DPFC clock gating after FBC disable */
+		if (display->platform.dg2 || DISPLAY_VER(display) >= 14)
+			fbc_compressor_clkgate_disable_wa(fbc, false);
 	}
 }
 
@@ -922,6 +940,10 @@ static void intel_fbc_program_workarounds(struct intel_fbc *fbc)
 	if (DISPLAY_VER(display) >= 11 && !display->platform.dg2)
 		intel_de_rmw(display, ILK_DPFC_CHICKEN(fbc->id),
 			     0, DPFC_CHICKEN_FORCE_SLB_INVALIDATION);
+
+	/* wa_18038517565 Disable DPFC clock gating before FBC enable */
+	if (display->platform.dg2 || DISPLAY_VER(display) >= 14)
+		fbc_compressor_clkgate_disable_wa(fbc, true);
 }
 
 static void __intel_fbc_cleanup_cfb(struct intel_fbc *fbc)

drivers/gpu/drm/i915/i915_reg.h

@@ -1077,6 +1077,7 @@
 
 #define GEN9_CLKGATE_DIS_4		_MMIO(0x4653C)
 #define   BXT_GMBUS_GATING_DIS		(1 << 14)
+#define   DG2_DPFC_GATING_DIS		REG_BIT(31)
 
 #define GEN9_CLKGATE_DIS_5		_MMIO(0x46540)
 #define   DPCE_GATING_DIS		REG_BIT(17)
@@ -4242,6 +4243,11 @@ enum skl_power_gate {
 #define MTL_CLKGATE_DIS_TRANS(dev_priv, trans)			_MMIO_TRANS2(dev_priv, trans, _MTL_CLKGATE_DIS_TRANS_A)
 #define  MTL_CLKGATE_DIS_TRANS_DMASC_GATING_DIS		REG_BIT(7)
 
+#define _MTL_PIPE_CLKGATE_DIS2_A		0x60114
+#define _MTL_PIPE_CLKGATE_DIS2_B		0x61114
+#define MTL_PIPE_CLKGATE_DIS2(pipe)		_MMIO_PIPE(pipe, _MTL_PIPE_CLKGATE_DIS2_A, _MTL_PIPE_CLKGATE_DIS2_B)
+#define   MTL_DPFC_GATING_DIS			REG_BIT(6)
+
 #define MTL_MEM_SS_INFO_GLOBAL			_MMIO(0x45700)
 #define   MTL_N_OF_ENABLED_QGV_POINTS_MASK	REG_GENMASK(11, 8)
 #define   MTL_N_OF_POPULATED_CH_MASK		REG_GENMASK(7, 4)