Adds a function to check the link status across all lanes for Displayport. This is functionality required to establish more fine-grained control over the Displayport interface, both for operational reliability and compliance testing.
Signed-off-by: Todd Previte <tprev...@gmail.com> --- drivers/gpu/drm/i915/intel_dp.c | 61 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 64c9803..c865c32 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -38,6 +38,22 @@ #define DP_LINK_CHECK_TIMEOUT (10 * 1000) +typedef enum { + LINK_TRAINING_STATUS_OK = 0, + LINK_TRAINING_CR_FAILED, + LINK_TRAINING_CR_COMPLETE, + LINK_TRAINING_CE_FAILED, + LINK_TRAINING_CE_COMPLETE, + LINK_TRAINING_STATUS_READ_FAILED +} IntelDPLinkTrainingStatus; + +typedef enum { + DP_LINK_TRAINING_STATE_IDLE = 0, + DP_LINK_TRAINING_STATE_CLOCK_REC, + DP_LINK_TRAINING_STATE_CHANNEL_EQ, + DP_LINK_TRAINING_STATE_ADJUST +} DPLinkTrainingState; + struct dp_link_dpll { int link_bw; struct dpll dpll; @@ -2356,6 +2372,51 @@ intel_dp_set_signal_levels(struct intel_dp *intel_dp, uint32_t *DP) *DP = (*DP & ~mask) | signal_levels; } +bool +intel_dp_verify_link_status(DPLinkTrainingState state, + uint8_t lane_count, + uint8_t *link_status) +{ + uint32_t status = 0; + bool link_ok = false; + uint8_t ls[5]; + + switch (state) { + case DP_LINK_TRAINING_STATE_CLOCK_REC: + status = (link_status[0] & DP_LANE_CR_DONE) + + ((link_status[0] >> 4) & DP_LANE_CR_DONE) + + (link_status[1] & DP_LANE_CR_DONE) + + ((link_status[1] >> 4) & DP_LANE_CR_DONE); + // Valid CR status = sum of bits == lane count + link_ok = status == lane_count ? true : false; + break; + case DP_LINK_TRAINING_STATE_CHANNEL_EQ: + ls[0] = ((link_status[0] & DP_LANE_CHANNEL_EQ_DONE) >> 1) + + ((link_status[0] & DP_LANE_SYMBOL_LOCKED) >> 2); + ls[1] = (((link_status[0] >> 4) & DP_LANE_CHANNEL_EQ_DONE) >> 1) + + (((link_status[0] >> 4) & DP_LANE_SYMBOL_LOCKED) >> 2); + ls[2] = ((link_status[1] & DP_LANE_CHANNEL_EQ_DONE) >> 1) + + ((link_status[1] & DP_LANE_SYMBOL_LOCKED) >> 2); + ls[3] = (((link_status[1] >> 4) & DP_LANE_CHANNEL_EQ_DONE) >> 1) + + (((link_status[1] >> 4) & DP_LANE_SYMBOL_LOCKED) >> 2); + ls[4] = link_status[2] & DP_INTERLANE_ALIGN_DONE; + // Combine lane status - must equal active lane count + status = ls[0] + ls[1] + ls[2] + ls[3]; + // CE status is all lanes + lane alignment (ls[4]) + link_ok = (status == lane_count) && ls[4] ? true : false; + break; + default: + // Invalid state for checking link status + break; + } + + if (!link_ok) { + // FIXME: Log failure here, detailed error status output + } + + return link_ok; +} + uint32_t intel_dp_set_training_pattern(uint8_t training_pattern, struct intel_dp *intel_dp) -- 1.8.3.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx