[Intel-gfx] [PATCH 2/3] drm/i915/display: Convert link bitrate to corresponding PLL clock

[Sripada, Radhakrishna]

Hi Mika,

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Mika
> Kahola
> Sent: Monday, December 4, 2023 3:59 AM
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH 2/3] drm/i915/display: Convert link bitrate to
> corresponding PLL clock
> 
> Compute clock during PLL readout. This prevents warn when only c20 phy
> is connected during modprobe. The intel_c20pll_calc_port_clock()
> function returns link bitrate which in DP2.0 and HDMI cases does not match
> with the clock rate. Hence, conversion function is needed to convert
> link bitrate to corresponding PLL clock rate.
> 
> while at it, update clock on C10 pll state as well.
> 
> Signed-off-by: Clint Taylor <Clinton.A.Taylor at intel.com>
> Signed-off-by: Mika Kahola <mika.kahola at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cx0_phy.c | 38 ++++++++++++++++++--
>  drivers/gpu/drm/i915/display/intel_cx0_phy.h |  1 +
>  drivers/gpu/drm/i915/display/intel_ddi.c     |  2 +-
>  3 files changed, 37 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> index 2e6412fc2258..02efe2786c6a 100644
> --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> @@ -1871,6 +1871,7 @@ static int intel_c10pll_calc_state(struct
> intel_crtc_state *crtc_state,
>  }
> 
>  static void intel_c10pll_readout_hw_state(struct intel_encoder *encoder,
> +					  struct intel_crtc_state *crtc_state,
>  					  struct intel_c10pll_state *pll_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> @@ -1894,6 +1895,7 @@ static void intel_c10pll_readout_hw_state(struct
> intel_encoder *encoder,
> 
>  	pll_state->cmn = intel_cx0_read(i915, encoder->port, lane,
> PHY_C10_VDR_CMN(0));
>  	pll_state->tx = intel_cx0_read(i915, encoder->port, lane,
> PHY_C10_VDR_TX(0));
> +	pll_state->clock = crtc_state->port_clock;
> 
>  	intel_cx0_phy_transaction_end(encoder, wakeref);
>  }
> @@ -2445,12 +2447,33 @@ static void intel_program_port_clock_ctl(struct
> intel_encoder *encoder,
>  		     XELPDP_SSC_ENABLE_PLLB, val);
>  }
> 
> +static int intel_link_bitrate_to_clock(struct intel_encoder *encoder,
> +				       struct intel_crtc_state *crtc_state,
> +				       int link_bit_rate)
> +{
> +	const struct intel_c20pll_state * const *tables;
> +	int i;
> +
> +	tables = intel_c20_pll_tables_get(crtc_state, encoder);
This will produce incorrect result. intel_c20_pll_tables_get depends on
intel_crtc_has_{dp_encoder,hdmi..} which depends crtc_state->output_types
to determine edp/dp/hdmi table which is not initialized until later in
mtl_ddi_init_config under intel_ddi_get_config -> intel_ddi_read_func_ctl

We might be needing a separate sanitization of initial pll state to be done after
intel_ddi_get_config. Or a special case to handle initial modeset.

--Radhakrishna Sripada
> +	if (!tables)
> +		return -EINVAL;
> +
> +	for (i = 0; tables[i]; i++) {
> +		if (link_bit_rate == tables[i]->link_bit_rate)
> +			return tables[i]->clock;
> +	}
> +
> +	return -EINVAL;
> +}
> +
>  static void intel_c20pll_readout_hw_state(struct intel_encoder *encoder,
> +					  struct intel_crtc_state *crtc_state,
>  					  struct intel_c20pll_state *pll_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
>  	bool cntx;
>  	intel_wakeref_t wakeref;
> +	int clock;
>  	int i;
> 
>  	wakeref = intel_cx0_phy_transaction_begin(encoder);
> @@ -2500,6 +2523,13 @@ static void intel_c20pll_readout_hw_state(struct
> intel_encoder *encoder,
>  		}
>  	}
> 
> +	pll_state->link_bit_rate = intel_c20pll_calc_port_clock(encoder,
> pll_state);
> +	clock = intel_link_bitrate_to_clock(encoder, crtc_state,
> +					    pll_state->link_bit_rate);
> +
> +	if (clock >= 0)
> +		pll_state->clock = clock;
> +
>  	intel_cx0_phy_transaction_end(encoder, wakeref);
>  }
> 
> @@ -3053,15 +3083,16 @@ static void intel_c10pll_state_verify(const struct
> intel_crtc_state *state,
>  }
> 
>  void intel_cx0pll_readout_hw_state(struct intel_encoder *encoder,
> +				   struct intel_crtc_state *crtc_state,
>  				   struct intel_cx0pll_state *pll_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
>  	enum phy phy = intel_port_to_phy(i915, encoder->port);
> 
>  	if (intel_is_c10phy(i915, phy))
> -		intel_c10pll_readout_hw_state(encoder, &pll_state->c10);
> +		intel_c10pll_readout_hw_state(encoder, crtc_state, &pll_state-
> >c10);
>  	else
> -		intel_c20pll_readout_hw_state(encoder, &pll_state->c20);
> +		intel_c20pll_readout_hw_state(encoder, crtc_state, &pll_state-
> >c20);
>  }
> 
>  int intel_cx0pll_calc_port_clock(struct intel_encoder *encoder,
> @@ -3145,7 +3176,8 @@ void intel_cx0pll_state_verify(struct
> intel_atomic_state *state,
>  	if (intel_tc_port_in_tbt_alt_mode(enc_to_dig_port(encoder)))
>  		return;
> 
> -	intel_cx0pll_readout_hw_state(encoder, &mpll_hw_state);
> +	intel_cx0pll_readout_hw_state(encoder, (struct
> intel_crtc_state*)new_crtc_state,
> +				      &mpll_hw_state);
> 
>  	if (intel_is_c10phy(i915, phy))
>  		intel_c10pll_state_verify(new_crtc_state, crtc, encoder,
> &mpll_hw_state.c10);
> diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.h
> b/drivers/gpu/drm/i915/display/intel_cx0_phy.h
> index c6682677253a..eac7354e9a4e 100644
> --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.h
> +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.h
> @@ -32,6 +32,7 @@ intel_mtl_port_pll_type(struct intel_encoder *encoder,
> 
>  int intel_cx0pll_calc_state(struct intel_crtc_state *crtc_state, struct
> intel_encoder *encoder);
>  void intel_cx0pll_readout_hw_state(struct intel_encoder *encoder,
> +				   struct intel_crtc_state *crtc_state,
>  				   struct intel_cx0pll_state *pll_state);
>  int intel_cx0pll_calc_port_clock(struct intel_encoder *encoder,
>  				 const struct intel_cx0pll_state *pll_state);
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 38f28c480b38..508d3363e89f 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3953,7 +3953,7 @@ static void mtl_ddi_get_config(struct intel_encoder
> *encoder,
>  	if (intel_tc_port_in_tbt_alt_mode(dig_port)) {
>  		crtc_state->port_clock =
> intel_mtl_tbt_calc_port_clock(encoder);
>  	} else {
> -		intel_cx0pll_readout_hw_state(encoder, &crtc_state-
> >cx0pll_state);
> +		intel_cx0pll_readout_hw_state(encoder, crtc_state, &crtc_state-
> >cx0pll_state);
>  		crtc_state->port_clock = intel_cx0pll_calc_port_clock(encoder,
> &crtc_state->cx0pll_state);
>  	}
> 
> --
> 2.34.1