[PATCH v3 2/3] drm/i915/bios: Add function to check if edp data override is needed

[Suraj Kandpal <suraj.kandpal@intel.com>]

Add a function that helps identify if the rate provided needs to
be overridden. For this we need a function that compares the rate
provided and bitmask of rates provided in VBT.

--v2
-Rename functions [Jani]
-Return the mask instead of parsing it in function [Jani]
-Move the declaration in header [Jani]

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_bios.c | 29 +++++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_bios.h |  2 ++
 2 files changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 8337ebe0f2c8..7adb7c4b0432 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -2480,6 +2480,25 @@ static int parse_bdb_216_dp_max_link_rate(const int vbt_max_link_rate)
 	}
 }
 
+static u32 edp_rate_override_mask(int rate)
+{
+	switch (rate) {
+	case 2000000: return BDB_263_VBT_EDP_LINK_RATE_20;
+	case 1350000: return BDB_263_VBT_EDP_LINK_RATE_13_5;
+	case 1000000: return BDB_263_VBT_EDP_LINK_RATE_10;
+	case 810000: return BDB_263_VBT_EDP_LINK_RATE_8_1;
+	case 675000: return BDB_263_VBT_EDP_LINK_RATE_6_75;
+	case 540000: return BDB_263_VBT_EDP_LINK_RATE_5_4;
+	case 432000: return BDB_263_VBT_EDP_LINK_RATE_4_32;
+	case 324000: return BDB_263_VBT_EDP_LINK_RATE_3_24;
+	case 270000: return BDB_263_VBT_EDP_LINK_RATE_2_7;
+	case 243000: return BDB_263_VBT_EDP_LINK_RATE_2_43;
+	case 216000: return BDB_263_VBT_EDP_LINK_RATE_2_16;
+	case 162000: return BDB_263_VBT_EDP_LINK_RATE_1_62;
+	default: return 0;
+	}
+}
+
 int intel_bios_dp_max_link_rate(const struct intel_bios_encoder_data *devdata)
 {
 	if (!devdata || devdata->display->vbt.version < 216)
@@ -2499,6 +2518,16 @@ int intel_bios_dp_max_lane_count(const struct intel_bios_encoder_data *devdata)
 	return devdata->child.dp_max_lane_count + 1;
 }
 
+bool
+intel_bios_encoder_supports_edp_rate(const struct intel_bios_encoder_data *devdata,
+				     int rate)
+{
+	if (!devdata || devdata->display->vbt.version < 263)
+		return false;
+
+	return devdata->child.edp_data_rate_override & edp_rate_override_mask(rate);
+}
+
 static void sanitize_device_type(struct intel_bios_encoder_data *devdata,
 				 enum port port)
 {
diff --git a/drivers/gpu/drm/i915/display/intel_bios.h b/drivers/gpu/drm/i915/display/intel_bios.h
index 6cd7a011b8c4..a4abaa89a682 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.h
+++ b/drivers/gpu/drm/i915/display/intel_bios.h
@@ -251,6 +251,8 @@ bool intel_bios_encoder_supports_dvi(const struct intel_bios_encoder_data *devda
 bool intel_bios_encoder_supports_hdmi(const struct intel_bios_encoder_data *devdata);
 bool intel_bios_encoder_supports_dp(const struct intel_bios_encoder_data *devdata);
 bool intel_bios_encoder_supports_edp(const struct intel_bios_encoder_data *devdata);
+bool intel_bios_encoder_supports_edp_rate(const struct intel_bios_encoder_data *devdata,
+					  int rate);
 bool intel_bios_encoder_supports_typec_usb(const struct intel_bios_encoder_data *devdata);
 bool intel_bios_encoder_supports_tbt(const struct intel_bios_encoder_data *devdata);
 bool intel_bios_encoder_supports_dsi(const struct intel_bios_encoder_data *devdata);
-- 
2.34.1