drm/i915/vbt: Add eDP Data rate overrride field in VBT

Add edp_data_rate_override field VBT which gives us a mask
of rates which needs to be skipped in favour of
subsequent higher rate.

--v2
-Rename vbt field [Jani]
-Fix comment to 263+ [Jani]
-Use BIT_U32 [Jani]
-Fix the bits assignment in vbt [Jani]

--v3
-Add a mask which represents all link rates [Ankit]

Bspec: 20124
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://lore.kernel.org/r/20250821042653.269227-2-suraj.kandpal@intel.com
(cherry picked from commit 4d33c77)
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: surajk8

drivers/gpu/drm/i915/display/intel_bios.c

@@ -2747,8 +2747,10 @@ static int child_device_expected_size(u16 version)
 {
 	BUILD_BUG_ON(sizeof(struct child_device_config) < 40);
 
-	if (version > 256)
+	if (version > 263)
 		return -ENOENT;
+	else if (version >= 263)
+		return 44;
 	else if (version >= 256)
 		return 40;
 	else if (version >= 216)

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

@@ -437,6 +437,22 @@ enum vbt_gmbus_ddi {
 #define BDB_230_VBT_DP_MAX_LINK_RATE_UHBR13P5	6
 #define BDB_230_VBT_DP_MAX_LINK_RATE_UHBR20	7
 
+/* EDP link rate 263+ */
+#define BDB_263_VBT_EDP_LINK_RATE_1_62		BIT_U32(0)
+#define BDB_263_VBT_EDP_LINK_RATE_2_16		BIT_U32(1)
+#define BDB_263_VBT_EDP_LINK_RATE_2_43		BIT_U32(2)
+#define BDB_263_VBT_EDP_LINK_RATE_2_7		BIT_U32(3)
+#define BDB_263_VBT_EDP_LINK_RATE_3_24		BIT_U32(4)
+#define BDB_263_VBT_EDP_LINK_RATE_4_32		BIT_U32(5)
+#define BDB_263_VBT_EDP_LINK_RATE_5_4		BIT_U32(6)
+#define BDB_263_VBT_EDP_LINK_RATE_6_75		BIT_U32(7)
+#define BDB_263_VBT_EDP_LINK_RATE_8_1		BIT_U32(8)
+#define BDB_263_VBT_EDP_LINK_RATE_10		BIT_U32(9)
+#define BDB_263_VBT_EDP_LINK_RATE_13_5		BIT_U32(10)
+#define BDB_263_VBT_EDP_LINK_RATE_20		BIT_U32(11)
+#define BDB_263_VBT_EDP_NUM_RATES		12
+#define BDB_263_VBT_EDP_RATES_MASK		GENMASK(BDB_263_VBT_EDP_NUM_RATES - 1, 0)
+
 /*
  * The child device config, aka the display device data structure, provides a
  * description of a port and its configuration on the platform.
@@ -547,6 +563,8 @@ struct child_device_config {
 	u8 dp_max_link_rate:3;					/* 216+ */
 	u8 dp_max_link_rate_reserved:5;				/* 216+ */
 	u8 efp_index;						/* 256+ */
+	u32 edp_data_rate_override:12;				/* 263+ */
+	u32 edp_data_rate_override_reserved:20;			/* 263+ */
 } __packed;
 
 struct bdb_general_definitions {