drm/dp: Add definitions for TPS4 bits and macros to check the support

DP 1.4 spec adds a TPS4 training pattern sequence required for
HBR3. This patch adds the corresponding bit definitions in
MAX_DOWNSPREAD register and TRAINING_PATTERN_SET and
inline functions to check if this bit is set and for selecting
a proper TRAINING_PATTERN_MASK that changed to 0x7 on
DP spec 1.4

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1516660991-20697-2-git-send-email-manasi.d.navare@intel.com

include/drm/drm_dp_helper.h

@@ -75,6 +75,7 @@
 #define DP_MAX_DOWNSPREAD                   0x003
 # define DP_MAX_DOWNSPREAD_0_5		    (1 << 0)
 # define DP_NO_AUX_HANDSHAKE_LINK_TRAINING  (1 << 6)
+# define DP_TPS4_SUPPORTED                  (1 << 7)
 
 #define DP_NORP                             0x004
 
@@ -345,7 +346,9 @@
 # define DP_TRAINING_PATTERN_1		    1
 # define DP_TRAINING_PATTERN_2		    2
 # define DP_TRAINING_PATTERN_3		    3	    /* 1.2 */
+# define DP_TRAINING_PATTERN_4              7       /* 1.4 */
 # define DP_TRAINING_PATTERN_MASK	    0x3
+# define DP_TRAINING_PATTERN_MASK_1_4	    0xf
 
 /* DPCD 1.1 only. For DPCD >= 1.2 see per-lane DP_LINK_QUAL_LANEn_SET */
 # define DP_LINK_QUAL_PATTERN_11_DISABLE    (0 << 2)
@@ -971,6 +974,20 @@ drm_dp_tps3_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 		dpcd[DP_MAX_LANE_COUNT] & DP_TPS3_SUPPORTED;
 }
 
+static inline bool
+drm_dp_tps4_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+{
+	return dpcd[DP_DPCD_REV] >= 0x14 &&
+		dpcd[DP_MAX_DOWNSPREAD] & DP_TPS4_SUPPORTED;
+}
+
+static inline u8
+drm_dp_training_pattern_mask(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+{
+	return (dpcd[DP_DPCD_REV] >= 0x14) ? DP_TRAINING_PATTERN_MASK_1_4 :
+		DP_TRAINING_PATTERN_MASK;
+}
+
 static inline bool
 drm_dp_is_branch(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 {