Re: [PATCH v2] drm/i915/tgl: Implement TGL DisplayPort training sequence

Souza, Jose
2019-08-21T20:22:38Z

On Tue, 2019-08-20 at 16:07 -0700, Manasi Navare wrote:
> On Tue, Aug 20, 2019 at 03:01:38PM -0700, José Roberto de Souza
> wrote:
> > On TGL some registers moved from DDI to transcoder and the
> > DisplayPort training sequence has a separate BSpec page.
> >
> > I started adding 'ifs' to the original intel_ddi_pre_enable_dp()
> > but
> > it was becoming really hard to follow, so a new and cleaner
> > function
> > for TGL was added with comments of all steps. It's similar to ICL,
> > but
> > different enough to deserve a new function
> >
> > The rest of DisplayPort enable and the whole disable sequences
> > remained the same.
> >
> > v2: FEC and DSC should be enabled on sink side before start link
> > training(Maarten reported and Manasi confirmed the DSC part)
> >
> > BSpec: 49190
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> > Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> > ---
> > drivers/gpu/drm/i915/display/intel_ddi.c | 138
> > ++++++++++++++++++++++-
> > drivers/gpu/drm/i915/display/intel_dp.c | 8 +-
> > 2 files changed, 138 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> > b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index 8eb2b3ec01ed..1c1534e2d833 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -1761,7 +1761,14 @@ void intel_ddi_set_vc_payload_alloc(const
> > struct intel_crtc_state *crtc_state,
> > I915_WRITE(TRANS_DDI_FUNC_CTL(cpu_transcoder), temp);
> > }
> >
> > -void intel_ddi_enable_transcoder_func(const struct
> > intel_crtc_state *crtc_state)
> > +/*
> > + * Returns the TRANS_DDI_FUNC_CTL value based on CRTC state.
> > + *
> > + * Only intended to be used by intel_ddi_enable_transcoder_func()
> > and
> > + * intel_ddi_config_transcoder_func().
> > + */
> > +static u32
> > +intel_ddi_transcoder_func_reg_val_get(const struct
> > intel_crtc_state *crtc_state)
> > {
> > struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> > struct intel_encoder *encoder =
> > intel_ddi_get_crtc_encoder(crtc);
> > @@ -1845,6 +1852,33 @@ void intel_ddi_enable_transcoder_func(const
> > struct intel_crtc_state *crtc_state)
> > temp |= DDI_PORT_WIDTH(crtc_state->lane_count);
> > }
> >
> > + return temp;
> > +}
> > +
> > +void intel_ddi_enable_transcoder_func(const struct
> > intel_crtc_state *crtc_state)
> > +{
> > + struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> > + struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> > + enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> > + u32 temp;
> > +
> > + temp = intel_ddi_transcoder_func_reg_val_get(crtc_state);
> > + I915_WRITE(TRANS_DDI_FUNC_CTL(cpu_transcoder), temp);
> > +}
> > +
> > +/*
> > + * Same as intel_ddi_enable_transcoder_func() but it do not set
> > the enable bit
> > + */
> > +static void
> > +intel_ddi_config_transcoder_func(const struct intel_crtc_state
> > *crtc_state)
> > +{
> > + struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
> > + struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> > + enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> > + u32 temp;
> > +
> > + temp = intel_ddi_transcoder_func_reg_val_get(crtc_state);
> > + temp &= ~TRANS_DDI_FUNC_ENABLE;
> > I915_WRITE(TRANS_DDI_FUNC_CTL(cpu_transcoder), temp);
> > }
> >
> > @@ -3160,9 +3194,93 @@ static void
> > intel_ddi_disable_fec_state(struct intel_encoder *encoder,
> > POSTING_READ(DP_TP_CTL(port));
> > }
> >
> > -static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
> > - const struct intel_crtc_state
> > *crtc_state,
> > - const struct drm_connector_state
> > *conn_state)
> > +static void tgl_ddi_pre_enable_dp(struct intel_encoder *encoder,
> > + const struct intel_crtc_state
> > *crtc_state,
> > + const struct drm_connector_state
> > *conn_state)
> > +{
> > + struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
> > + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > + enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
> > + struct intel_digital_port *dig_port = enc_to_dig_port(&encoder-
> > >base);
> > + bool is_mst = intel_crtc_has_type(crtc_state,
> > INTEL_OUTPUT_DP_MST);
> > + int level = intel_ddi_dp_level(intel_dp);
> > +
> > + intel_dp_set_link_params(intel_dp, crtc_state->port_clock,
> > + crtc_state->lane_count, is_mst);
> > +
> > + /* 1.a got on intel_atomic_commit_tail() */
>
> I think if this comment is kept in the code, better elaborate on what
> 1 is
>
> > +
> > + /* 2. */
> > + intel_edp_panel_on(intel_dp);
> > +
> > + /*
> > + * 1.b, 3. and 4. is done by before this functions by
> > + * haswell_crtc_enable()->intel_encoders_pre_pll_enable() and
> > + * haswell_crtc_enable()->intel_enable_shared_dpll()
> > + */
>
> Currently there is only gen11_dsi_pre_pll_enable pre_pll_enable hook,
> is there a
> separate gen12 hook for port clock programming in step 4?

No separated, it uses the same one for all platforms that supports DDI:
intel_ddi_pre_pll_enable()

>
> > +
> > + /* 5. */
> > + if (!intel_phy_is_tc(dev_priv, phy) ||
> > + dig_port->tc_mode != TC_PORT_TBT_ALT)
> > + intel_display_power_get(dev_priv,
> > + dig_port->ddi_io_power_domain);
> > +
> > + /* 6. */
> > + icl_program_mg_dp_mode(dig_port);
> > +
> > + /*
> > + * 7.a - Steps in this function that should only be executed
> > over MST
> > + * master as MST encoders will only be executed on MST master
> > as MST
> > + * encoder have have it's own pre_enable() hook
> > + */
> > + intel_ddi_enable_pipe_clock(crtc_state);
> > +
> > + /* 7.b */
> > + intel_ddi_config_transcoder_func(crtc_state);
> > +
> > + /* 7.d */
> > + icl_disable_phy_clock_gating(dig_port);
> > +
> > + /* 7.e */
> > + icl_ddi_vswing_sequence(encoder, crtc_state->port_clock, level,
> > + encoder->type);
> > +
> > + /* 7.f */
> > + if (intel_phy_is_combo(dev_priv, phy)) {
> > + bool lane_reversal =
> > + dig_port->saved_port_bits &
> > DDI_BUF_PORT_REVERSAL;
> > +
> > + intel_combo_phy_power_up_lanes(dev_priv, phy, false,
> > + crtc_state->lane_count,
> > + lane_reversal);
> > + }
> > +
> > + /* 7.g */
> > + intel_ddi_init_dp_buf_reg(encoder);
> > +
> > + if (!is_mst)
> > + intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
> > +
> > + intel_dp_sink_set_decompression_state(intel_dp, crtc_state,
> > true);
> > + /*
> > + * DDI FEC: "anticipates enabling FEC encoding sets the
> > FEC_READY bit
> > + * in the FEC_CONFIGURATION register to 1 before initiating
> > link
> > + * training
> > + */
> > + intel_dp_sink_set_fec_ready(intel_dp, crtc_state);
> > + /* 7.c, 7.h, 7.i, 7.j */
> > + intel_dp_start_link_train(intel_dp);
> > +
> > + /* 7.k */
> > + intel_dp_stop_link_train(intel_dp);
>
> intel_ddi_enable_fec(encoder, crtc_state); call before dsc_enable
> call is missing

Ouch, thanks.
Will fix that.

>
> Manasi
>
> > +
> > + /* 7.l */
> > + intel_dsc_enable(encoder, crtc_state);
> > +}
> > +
> > +static void hsw_ddi_pre_enable_dp(struct intel_encoder *encoder,
> > + const struct intel_crtc_state
> > *crtc_state,
> > + const struct drm_connector_state
> > *conn_state)
> > {
> > struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
> > struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > @@ -3228,6 +3346,18 @@ static void intel_ddi_pre_enable_dp(struct
> > intel_encoder *encoder,
> > intel_dsc_enable(encoder, crtc_state);
> > }
> >
> > +static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
> > + const struct intel_crtc_state
> > *crtc_state,
> > + const struct drm_connector_state
> > *conn_state)
> > +{
> > + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> > +
> > + if (INTEL_GEN(dev_priv) >= 12)
> > + tgl_ddi_pre_enable_dp(encoder, crtc_state, conn_state);
> > + else
> > + hsw_ddi_pre_enable_dp(encoder, crtc_state, conn_state);
> > +}
> > +
> > static void intel_ddi_pre_enable_hdmi(struct intel_encoder
> > *encoder,
> > const struct intel_crtc_state
> > *crtc_state,
> > const struct drm_connector_state
> > *conn_state)
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 5c45a3bb102d..1a59c50f7e0a 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -3950,13 +3950,13 @@ void intel_dp_set_idle_link_train(struct
> > intel_dp *intel_dp)
> > I915_WRITE(DP_TP_CTL(port), val);
> >
> > /*
> > - * On PORT_A we can have only eDP in SST mode. There the only
> > reason
> > - * we need to set idle transmission mode is to work around a HW
> > issue
> > - * where we enable the pipe while not in idle link-training
> > mode.
> > + * Until TGL on PORT_A we can have only eDP in SST mode. There
> > the only
> > + * reason we need to set idle transmission mode is to work
> > around a HW
> > + * issue where we enable the pipe while not in idle link-
> > training mode.
> > * In this case there is requirement to wait for a minimum
> > number of
> > * idle patterns to be sent.
> > */
> > - if (port == PORT_A)
> > + if (port == PORT_A && INTEL_GEN(dev_priv) < 12)
> > return;
> >
> > if (intel_de_wait_for_set(dev_priv, DP_TP_STATUS(port),
> > --
> > 2.22.1
> >