drm/i915: Parametrize FBC_TAG registers

Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -2011,7 +2011,7 @@ enum skl_disp_power_wells {
 #define   FBC_CTL_CPU_FENCE	(1<<1)
 #define   FBC_CTL_PLANE(plane)	((plane)<<0)
 #define FBC_FENCE_OFF		0x03218 /* BSpec typo has 321Bh */
-#define FBC_TAG			0x03300
+#define FBC_TAG(i)		(0x03300 + (i) * 4)
 
 #define FBC_STATUS2		0x43214
 #define  FBC_COMPRESSION_MASK	0x7ff

drivers/gpu/drm/i915/intel_fbc.c

@@ -101,7 +101,7 @@ static void i8xx_fbc_enable(struct intel_crtc *crtc)
 
 	/* Clear old tags */
 	for (i = 0; i < (FBC_LL_SIZE / 32) + 1; i++)
-		I915_WRITE(FBC_TAG + (i * 4), 0);
+		I915_WRITE(FBC_TAG(i), 0);
 
 	if (IS_GEN4(dev_priv)) {
 		u32 fbc_ctl2;