When PSR/PSR2/GTC is enabled hardware can do AUX transactions by it self, so lets use the mutex register that is available in gen9+ to avoid concurrent access by hardware and driver.
Reference: https://01.org/sites/default/files/documentation/intel-gfx-prm-osrc-skl-vol12-display.pdf Page 198 - AUX programming sequence Cc: Rodrigo Vivi <rodrigo.v...@intel.com> Cc: Jani Nikula <jani.nik...@linux.intel.com> Signed-off-by: José Roberto de Souza <jose.so...@intel.com> --- drivers/gpu/drm/i915/i915_reg.h | 9 ++++++++ drivers/gpu/drm/i915/intel_dp.c | 50 ++++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_drv.h | 1 + 3 files changed, 60 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 1412abcb27d4..a62e3c1badab 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -5318,6 +5318,7 @@ enum { #define _DPA_AUX_CH_DATA3 (dev_priv->info.display_mmio_offset + 0x6401c) #define _DPA_AUX_CH_DATA4 (dev_priv->info.display_mmio_offset + 0x64020) #define _DPA_AUX_CH_DATA5 (dev_priv->info.display_mmio_offset + 0x64024) +#define _DPA_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6402C) #define _DPB_AUX_CH_CTL (dev_priv->info.display_mmio_offset + 0x64110) #define _DPB_AUX_CH_DATA1 (dev_priv->info.display_mmio_offset + 0x64114) @@ -5325,6 +5326,7 @@ enum { #define _DPB_AUX_CH_DATA3 (dev_priv->info.display_mmio_offset + 0x6411c) #define _DPB_AUX_CH_DATA4 (dev_priv->info.display_mmio_offset + 0x64120) #define _DPB_AUX_CH_DATA5 (dev_priv->info.display_mmio_offset + 0x64124) +#define _DPB_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6412C) #define _DPC_AUX_CH_CTL (dev_priv->info.display_mmio_offset + 0x64210) #define _DPC_AUX_CH_DATA1 (dev_priv->info.display_mmio_offset + 0x64214) @@ -5332,6 +5334,7 @@ enum { #define _DPC_AUX_CH_DATA3 (dev_priv->info.display_mmio_offset + 0x6421c) #define _DPC_AUX_CH_DATA4 (dev_priv->info.display_mmio_offset + 0x64220) #define _DPC_AUX_CH_DATA5 (dev_priv->info.display_mmio_offset + 0x64224) +#define _DPC_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6422C) #define _DPD_AUX_CH_CTL (dev_priv->info.display_mmio_offset + 0x64310) #define _DPD_AUX_CH_DATA1 (dev_priv->info.display_mmio_offset + 0x64314) @@ -5339,6 +5342,7 @@ enum { #define _DPD_AUX_CH_DATA3 (dev_priv->info.display_mmio_offset + 0x6431c) #define _DPD_AUX_CH_DATA4 (dev_priv->info.display_mmio_offset + 0x64320) #define _DPD_AUX_CH_DATA5 (dev_priv->info.display_mmio_offset + 0x64324) +#define _DPD_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6432C) #define _DPF_AUX_CH_CTL (dev_priv->info.display_mmio_offset + 0x64510) #define _DPF_AUX_CH_DATA1 (dev_priv->info.display_mmio_offset + 0x64514) @@ -5346,6 +5350,7 @@ enum { #define _DPF_AUX_CH_DATA3 (dev_priv->info.display_mmio_offset + 0x6451c) #define _DPF_AUX_CH_DATA4 (dev_priv->info.display_mmio_offset + 0x64520) #define _DPF_AUX_CH_DATA5 (dev_priv->info.display_mmio_offset + 0x64524) +#define _DPF_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6452C) #define DP_AUX_CH_CTL(port) _MMIO_PORT(port, _DPA_AUX_CH_CTL, _DPB_AUX_CH_CTL) #define DP_AUX_CH_DATA(port, i) _MMIO(_PORT(port, _DPA_AUX_CH_DATA1, _DPB_AUX_CH_DATA1) + (i) * 4) /* 5 registers */ @@ -5378,6 +5383,10 @@ enum { #define DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(c) (((c) - 1) << 5) #define DP_AUX_CH_CTL_SYNC_PULSE_SKL(c) ((c) - 1) +#define DP_AUX_CH_MUTEX(port) _MMIO_PORT(port, _DPA_AUX_CH_MUTEX, _DPB_AUX_CH_MUTEX) +#define DP_AUX_CH_MUTEX_ENABLE (1 << 31) +#define DP_AUX_CH_MUTEX_STATUS (1 << 30) + /* * Computing GMCH M and N values for the Display Port link * diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index f20b25f98e5a..af07563bafba 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1081,6 +1081,45 @@ static uint32_t intel_dp_get_aux_send_ctl(struct intel_dp *intel_dp, aux_clock_divider); } +static bool intel_dp_aux_ch_trylock(struct intel_dp *intel_dp) +{ + struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp); + struct drm_i915_private *dev_priv = + to_i915(intel_dig_port->base.base.dev); + + if (INTEL_GEN(dev_priv) < 9) + return true; + + I915_WRITE(intel_dp->aux_ch_mutex_reg, DP_AUX_CH_MUTEX_ENABLE); + + /* Spec says that mutex is acquired when status bit is read as unset, + * if set it should be read again after 500usec. Here waiting for + * 2msec or 4 tries before give up. + */ + if (__intel_wait_for_register(dev_priv, intel_dp->aux_ch_mutex_reg, + DP_AUX_CH_MUTEX_STATUS, 0, 500, 2, + NULL)) { + DRM_WARN("dp_aux_ch port locked for too long"); + return false; + } + + return true; +} + +static void intel_dp_aux_ch_unlock(struct intel_dp *intel_dp) +{ + struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp); + struct drm_i915_private *dev_priv = + to_i915(intel_dig_port->base.base.dev); + + if (INTEL_GEN(dev_priv) < 9) + return; + + /* setting the status bit releases the mutex + keep mutex enabled */ + I915_WRITE(intel_dp->aux_ch_mutex_reg, DP_AUX_CH_MUTEX_ENABLE | + DP_AUX_CH_MUTEX_STATUS); +} + static int intel_dp_aux_ch(struct intel_dp *intel_dp, const uint8_t *send, int send_bytes, @@ -1115,6 +1154,11 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, intel_dp_check_edp(intel_dp); + if (!intel_dp_aux_ch_trylock(intel_dp)) { + ret = -EBUSY; + goto out_locked; + } + /* Try to wait for any previous AUX channel activity */ for (try = 0; try < 3; try++) { status = I915_READ_NOTRACE(ch_ctl); @@ -1244,6 +1288,8 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, ret = recv_bytes; out: + intel_dp_aux_ch_unlock(intel_dp); +out_locked: pm_qos_update_request(&dev_priv->pm_qos, PM_QOS_DEFAULT_VALUE); if (vdd) @@ -1496,6 +1542,10 @@ static void intel_aux_reg_init(struct intel_dp *intel_dp) intel_dp->aux_ch_ctl_reg = intel_aux_ctl_reg(dev_priv, port); for (i = 0; i < ARRAY_SIZE(intel_dp->aux_ch_data_reg); i++) intel_dp->aux_ch_data_reg[i] = intel_aux_data_reg(dev_priv, port, i); + if (INTEL_INFO(dev_priv)->gen >= 9) { + intel_dp->aux_ch_mutex_reg = DP_AUX_CH_MUTEX(port); + I915_WRITE(intel_dp->aux_ch_mutex_reg, DP_AUX_CH_MUTEX_ENABLE); + } } static void diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 50874f4035cf..0c88657d6066 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -1043,6 +1043,7 @@ struct intel_dp { i915_reg_t output_reg; i915_reg_t aux_ch_ctl_reg; i915_reg_t aux_ch_data_reg[5]; + i915_reg_t aux_ch_mutex_reg; uint32_t DP; int link_rate; uint8_t lane_count; -- 2.16.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
