[Intel-gfx] [PATCH] drm/i915: Small joiner RAM buffer size is platform-specific

[Matt Roper]

According to the bspec, GLK/CNL have a smaller small joiner RAM buffer
than ICL+.  This feels like something that could easily change again on
future platforms, so let's just add a function to return the proper
per-platform buffer size.  That may also slightly simplify the upcoming
bigjoiner enabling.

Since we have to change intel_dp_dsc_get_output_bpp()'s signature to
pass the dev_priv down for the platform check, let's take the
opportunity to also make that function static since it isn't used
outside the intel_dp file.

Bspec: 20388
Bspec: 49259
Cc: Manasi Navare <manasi.d.navare at intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 29 ++++++++++++++++++-------
 drivers/gpu/drm/i915/display/intel_dp.h |  2 --
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 829559f97440..e38db7278cf2 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -68,9 +68,6 @@
 
 #define DP_DPRX_ESI_LEN 14
 
-/* DP DSC small joiner has 2 FIFOs each of 640 x 6 bytes */
-#define DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER	61440
-
 /* DP DSC throughput values used for slice count calculations KPixels/s */
 #define DP_DSC_PEAK_PIXEL_RATE			2720000
 #define DP_DSC_MAX_ENC_THROUGHPUT_0		340000
@@ -164,6 +161,10 @@ static void vlv_steal_power_sequencer(struct drm_i915_private *dev_priv,
 				      enum pipe pipe);
 static void intel_dp_unset_edid(struct intel_dp *intel_dp);
 
+static u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private *i915,
+				       int link_clock, u8 lane_count,
+				       int mode_clock, int mode_hdisplay);
+
 /* update sink rates from dpcd */
 static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
 {
@@ -541,7 +542,8 @@ intel_dp_mode_valid(struct drm_connector *connector,
 								true);
 		} else if (drm_dp_sink_supports_fec(intel_dp->fec_capable)) {
 			dsc_max_output_bpp =
-				intel_dp_dsc_get_output_bpp(max_link_clock,
+				intel_dp_dsc_get_output_bpp(dev_priv,
+							    max_link_clock,
 							    max_lanes,
 							    target_clock,
 							    mode->hdisplay) >> 4;
@@ -1968,7 +1970,8 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 		u8 dsc_dp_slice_count;
 
 		dsc_max_output_bpp =
-			intel_dp_dsc_get_output_bpp(pipe_config->port_clock,
+			intel_dp_dsc_get_output_bpp(dev_priv,
+						    pipe_config->port_clock,
 						    pipe_config->lane_count,
 						    adjusted_mode->crtc_clock,
 						    adjusted_mode->crtc_hdisplay);
@@ -4373,8 +4376,18 @@ intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
 		DP_DPRX_ESI_LEN;
 }
 
-u16 intel_dp_dsc_get_output_bpp(int link_clock, u8 lane_count,
-				int mode_clock, int mode_hdisplay)
+static int
+small_joiner_ram_size_bits(struct drm_i915_private *i915)
+{
+	if (INTEL_GEN(i915) >= 11)
+		return 7680 * 8;
+	else
+		return 6144 * 8;
+}
+
+static u16 intel_dp_dsc_get_output_bpp(struct drm_i915_private *i915,
+				       int link_clock, u8 lane_count,
+				       int mode_clock, int mode_hdisplay)
 {
 	u16 bits_per_pixel, max_bpp_small_joiner_ram;
 	int i;
@@ -4390,7 +4403,7 @@ u16 intel_dp_dsc_get_output_bpp(int link_clock, u8 lane_count,
 		mode_clock;
 
 	/* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
-	max_bpp_small_joiner_ram = DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER /
+	max_bpp_small_joiner_ram = small_joiner_ram_size_bits(i915) /
 		mode_hdisplay;
 
 	/*
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index e01d1f89409d..1bcbf44b0b4e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -103,8 +103,6 @@ bool intel_dp_source_supports_hbr2(struct intel_dp *intel_dp);
 bool intel_dp_source_supports_hbr3(struct intel_dp *intel_dp);
 bool
 intel_dp_get_link_status(struct intel_dp *intel_dp, u8 *link_status);
-u16 intel_dp_dsc_get_output_bpp(int link_clock, u8 lane_count,
-				int mode_clock, int mode_hdisplay);
 u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp, int mode_clock,
 				int mode_hdisplay);
 
-- 
2.21.0