drm/i915/dg2: Add dbuf programming

DG2 extends our DDB to four DBuf slices; pipes A+B only have access to
the first two slices, whereas pipes C+D only have access to the second
two.

Confusingly, our bspec decided to switch from 1-based numbering
of dbuf slices (S1, S2) to 0-based numbering (S0, S1, S2, S3) in
Display13.  At the moment we're using the 0-based number scheme for the
DBUF_CTL_S() register addressing, but the 1-based number scheme in the
actual slice assignment tables.  We may want to consider switching the
assignment over to 0-based numbering too at some point...

Bspec: 49255
Bspec: 50057
Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721223043.834562-16-matthew.d.roper@intel.com

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

@@ -392,6 +392,10 @@ intel_display_power_put_all_in_set(struct drm_i915_private *i915,
 	intel_display_power_put_mask_in_set(i915, power_domain_set, power_domain_set->mask);
 }
 
+/*
+ * FIXME: We should probably switch this to a 0-based scheme to be consistent
+ * with how we now name/number DBUF_CTL instances.
+ */
 enum dbuf_slice {
 	DBUF_S1,
 	DBUF_S2,

drivers/gpu/drm/i915/intel_pm.c

@@ -4584,6 +4584,117 @@ static const struct dbuf_slice_conf_entry tgl_allowed_dbufs[] =
 	{}
 };
 
+static const struct dbuf_slice_conf_entry dg2_allowed_dbufs[] = {
+	{
+		.active_pipes = BIT(PIPE_A),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1) | BIT(DBUF_S2),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_B),
+		.dbuf_mask = {
+			[PIPE_B] = BIT(DBUF_S1) | BIT(DBUF_S2),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_A) | BIT(PIPE_B),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1),
+			[PIPE_B] = BIT(DBUF_S2),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_C),
+		.dbuf_mask = {
+			[PIPE_C] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_A) | BIT(PIPE_C),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1) | BIT(DBUF_S2),
+			[PIPE_C] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_B) | BIT(PIPE_C),
+		.dbuf_mask = {
+			[PIPE_B] = BIT(DBUF_S1) | BIT(DBUF_S2),
+			[PIPE_C] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_A) | BIT(PIPE_B) | BIT(PIPE_C),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1),
+			[PIPE_B] = BIT(DBUF_S2),
+			[PIPE_C] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_D] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_A) | BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1) | BIT(DBUF_S2),
+			[PIPE_D] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_B) | BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_B] = BIT(DBUF_S1) | BIT(DBUF_S2),
+			[PIPE_D] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_A) | BIT(PIPE_B) | BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1),
+			[PIPE_B] = BIT(DBUF_S2),
+			[PIPE_D] = BIT(DBUF_S3) | BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_C) | BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_C] = BIT(DBUF_S3),
+			[PIPE_D] = BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_A) | BIT(PIPE_C) | BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1) | BIT(DBUF_S2),
+			[PIPE_C] = BIT(DBUF_S3),
+			[PIPE_D] = BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_B) | BIT(PIPE_C) | BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_B] = BIT(DBUF_S1) | BIT(DBUF_S2),
+			[PIPE_C] = BIT(DBUF_S3),
+			[PIPE_D] = BIT(DBUF_S4),
+		},
+	},
+	{
+		.active_pipes = BIT(PIPE_A) | BIT(PIPE_B) | BIT(PIPE_C) | BIT(PIPE_D),
+		.dbuf_mask = {
+			[PIPE_A] = BIT(DBUF_S1),
+			[PIPE_B] = BIT(DBUF_S2),
+			[PIPE_C] = BIT(DBUF_S3),
+			[PIPE_D] = BIT(DBUF_S4),
+		},
+	},
+	{}
+};
+
 static const struct dbuf_slice_conf_entry adlp_allowed_dbufs[] = {
 	{
 		.active_pipes = BIT(PIPE_A),
@@ -4759,12 +4870,19 @@ static u32 adlp_compute_dbuf_slices(enum pipe pipe, u32 active_pipes)
 	return compute_dbuf_slices(pipe, active_pipes, adlp_allowed_dbufs);
 }
 
+static u32 dg2_compute_dbuf_slices(enum pipe pipe, u32 active_pipes)
+{
+	return compute_dbuf_slices(pipe, active_pipes, dg2_allowed_dbufs);
+}
+
 static u8 skl_compute_dbuf_slices(struct intel_crtc *crtc, u8 active_pipes)
 {
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
 	enum pipe pipe = crtc->pipe;
 
-	if (IS_ALDERLAKE_P(dev_priv))
+	if (IS_DG2(dev_priv))
+		return dg2_compute_dbuf_slices(pipe, active_pipes);
+	else if (IS_ALDERLAKE_P(dev_priv))
 		return adlp_compute_dbuf_slices(pipe, active_pipes);
 	else if (DISPLAY_VER(dev_priv) == 12)
 		return tgl_compute_dbuf_slices(pipe, active_pipes);