drm/i915/xelpd: add XE_LPD display characteristics

Let's start preparing for upcoming platforms that will use an XE_LPD
design.

v2:
 - Use the now-preferred "XE_LPD" term to refer to this design
 - Utilize DISPLAY_VER() rather than a feature flag
 - Drop unused mbus_size field (Lucas)
v3:
 - Adjust for dbuf.{size,slice_mask} (Ville)
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com> (v2)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210506161930.309688-2-imre.deak@intel.com

drivers/gpu/drm/i915/display/intel_display_power.h

@@ -380,6 +380,8 @@ intel_display_power_put_all_in_set(struct drm_i915_private *i915,
 enum dbuf_slice {
 	DBUF_S1,
 	DBUF_S2,
+	DBUF_S3,
+	DBUF_S4,
 	I915_MAX_DBUF_SLICES
 };
 

drivers/gpu/drm/i915/i915_pci.c

@@ -939,6 +939,16 @@ static const struct intel_device_info adl_s_info = {
 	.dma_mask_size = 46,
 };
 
+#define XE_LPD_FEATURES \
+	.display.ver = 13,						\
+	.display.has_psr_hw_tracking = 0,				\
+	.abox_mask = GENMASK(1, 0),					\
+	.pipe_mask = BIT(PIPE_A) | BIT(PIPE_B) | BIT(PIPE_C) | BIT(PIPE_D), \
+	.cpu_transcoder_mask = BIT(TRANSCODER_A) | BIT(TRANSCODER_B) |	\
+		BIT(TRANSCODER_C) | BIT(TRANSCODER_D),			\
+	.dbuf.size = 4096,						\
+	.dbuf.slice_mask = BIT(DBUF_S1) | BIT(DBUF_S2) | BIT(DBUF_S3) | BIT(DBUF_S4)
+
 #undef GEN
 #undef PLATFORM