[PATCH 2/2] drm/dp: Add definitions for TPS4 bits and macros to check the support

Manasi Navare
2018-01-22T22:43:11Z

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>
---
include/drm/drm_dp_helper.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index c80fa92..c239e6e 100644
--- a/include/drm/drm_dp_helper.h
+++ b/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)
@@ -989,6 +992,20 @@ drm_dp_tps3_supported(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
}

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])
{
return dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT;
--
2.7.4