On Tue, Feb 20, 2018 at 06:23:47PM -0800, José Roberto de Souza wrote: > 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 BTW since HSW/BDW don't have the mutex we should really be disabling PSR around aux ch usage on those platforms. Not sure how big of a locking inversion exercise it would be to make that happen though. > > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> > Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx> > --- > 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@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
