*** Please do not send review to this patch here, it was sent separated https://lists.freedesktop.org/archives/intel-gfx/2018-February/156921.html it is only included here to avoid concurrency access when reading sink PSR status and errors registers *** 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. Older gen handling will be done separated. Reference: https://01.org/sites/default/files/documentation/intel-gfx-prm-osrc-skl-vol12-display.pdf Page 198 - AUX programming sequence 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 | 67 ++++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_drv.h | 1 + 3 files changed, 77 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index eea5b2c537d4..f36e839b4b4f 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -5385,6 +5385,15 @@ 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 _DPA_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6402C) +#define _DPB_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6412C) +#define _DPC_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6422C) +#define _DPD_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6432C) +#define _DPF_AUX_CH_MUTEX (dev_priv->info.display_mmio_offset + 0x6452C) +#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 2c3eb90b9499..7be2fec51651 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); + i915_reg_t ch_mutex; + + if (!intel_dp->aux_ch_mutex_reg) + return true; + + ch_mutex = intel_dp->aux_ch_mutex_reg(intel_dp); + I915_WRITE(ch_mutex, DP_AUX_CH_MUTEX_ENABLE); + + /* Spec says that mutex is acquired when status bit is read as unset, + * here waiting for 2msec or 4 tries before give up. + */ + if (intel_wait_for_register(dev_priv, ch_mutex, DP_AUX_CH_MUTEX_STATUS, + 0, 2)) { + 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_dp->aux_ch_mutex_reg) + return; + + /* setting the status bit releases the mutex + keep mutex enabled */ + I915_WRITE(intel_dp->aux_ch_mutex_reg(intel_dp), + 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, @@ -1119,6 +1158,11 @@ 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); @@ -1248,6 +1292,8 @@ 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) @@ -1504,6 +1550,24 @@ static i915_reg_t skl_aux_data_reg(struct intel_dp *intel_dp, int index) } } +static i915_reg_t skl_aux_mutex_reg(struct intel_dp *intel_dp) +{ + struct drm_i915_private *dev_priv = to_i915(intel_dp_to_dev(intel_dp)); + enum aux_ch aux_ch = intel_dp->aux_ch; + + switch (aux_ch) { + case AUX_CH_A: + case AUX_CH_B: + case AUX_CH_C: + case AUX_CH_D: + case AUX_CH_F: + return DP_AUX_CH_MUTEX(aux_ch); + default: + MISSING_CASE(aux_ch); + return DP_AUX_CH_MUTEX(AUX_CH_A); + } +} + static void intel_dp_aux_fini(struct intel_dp *intel_dp) { @@ -1544,6 +1608,9 @@ intel_dp_aux_init(struct intel_dp *intel_dp) else intel_dp->get_aux_send_ctl = g4x_get_aux_send_ctl; + if (INTEL_GEN(dev_priv) >= 9) + intel_dp->aux_ch_mutex_reg = skl_aux_mutex_reg; + drm_dp_aux_init(&intel_dp->aux); /* Failure to allocate our preferred name is not critical */ diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h index 8f38e584d375..267cc6c5a89f 100644 --- a/drivers/gpu/drm/i915/intel_drv.h +++ b/drivers/gpu/drm/i915/intel_drv.h @@ -1128,6 +1128,7 @@ struct intel_dp { i915_reg_t (*aux_ch_ctl_reg)(struct intel_dp *dp); i915_reg_t (*aux_ch_data_reg)(struct intel_dp *dp, int index); + i915_reg_t (*aux_ch_mutex_reg)(struct intel_dp *dp); /* This is called before a link training is starterd */ void (*prepare_link_retrain)(struct intel_dp *intel_dp); -- 2.16.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
