Re: [Intel-gfx] [PATCH 04/13] drm/i915/mtl: C20 port clock calculation

[Radhakrishna Sripada <radhakrishna.sripada@intel.com>]

On Thu, Apr 20, 2023 at 03:40:41PM +0300, Mika Kahola wrote:
> Calculate port clock with C20 phy.
> 
> BSpec: 64568
> Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cx0_phy.c  | 45 +++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_cx0_phy.h  |  2 +
>  .../gpu/drm/i915/display/intel_cx0_phy_regs.h |  4 ++
>  drivers/gpu/drm/i915/display/intel_ddi.c      |  4 +-
>  drivers/gpu/drm/i915/display/intel_dpll.c     |  2 +
>  5 files changed, 55 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> index 144474540ef4..f7720acaf58c 100644
> --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> @@ -2274,6 +2274,51 @@ int intel_c10pll_calc_port_clock(struct intel_encoder *encoder,
>  	return tmpclk;
>  }
>  
> +int intel_c20pll_calc_port_clock(struct intel_encoder *encoder,
> +				 const struct intel_c20pll_state *pll_state)
> +{
> +	unsigned int frac, frac_en, frac_quot, frac_rem, frac_den;
> +	unsigned int multiplier, refclk = 38400;
> +	unsigned int tx_clk_div;
> +	unsigned int ref_clk_mpllb_div;
> +	unsigned int fb_clk_div4_en;
> +	unsigned int ref, vco;
> +	unsigned int tx_rate_mult;
> +	unsigned int tx_rate = REG_FIELD_GET(C20_PHY_TX_RATE, pll_state->tx[0]);
> +
> +	if (pll_state->tx[0] & C20_PHY_USE_MPLLB) {
This method of judging mplla vs mpllb seems more appropriate than the one used
during intel_c20pll_readout_hw_state in patch 02/13.

Update 2/13 mplla vs mpllb selection based on this logic.

Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
> +		tx_rate_mult = 1;
> +		frac_en = REG_FIELD_GET(C20_MPLLB_FRACEN, pll_state->mpllb[6]);
> +		frac_quot = pll_state->mpllb[8];
> +		frac_rem =  pll_state->mpllb[9];
> +		frac_den =  pll_state->mpllb[7];
> +		multiplier = REG_FIELD_GET(C20_MULTIPLIER_MASK, pll_state->mpllb[0]);
> +		tx_clk_div = REG_FIELD_GET(C20_MPLLB_TX_CLK_DIV_MASK, pll_state->mpllb[0]);
> +		ref_clk_mpllb_div = REG_FIELD_GET(C20_REF_CLK_MPLLB_DIV_MASK, pll_state->mpllb[6]);
> +		fb_clk_div4_en = 0;
> +	} else {
> +		tx_rate_mult = 2;
> +		frac_en = REG_FIELD_GET(C20_MPLLA_FRACEN, pll_state->mplla[6]);
> +		frac_quot = pll_state->mplla[8];
> +		frac_rem =  pll_state->mplla[9];
> +		frac_den =  pll_state->mplla[7];
> +		multiplier = REG_FIELD_GET(C20_MULTIPLIER_MASK, pll_state->mplla[0]);
> +		tx_clk_div = REG_FIELD_GET(C20_MPLLA_TX_CLK_DIV_MASK, pll_state->mplla[1]);
> +		ref_clk_mpllb_div = REG_FIELD_GET(C20_REF_CLK_MPLLB_DIV_MASK, pll_state->mplla[6]);
> +		fb_clk_div4_en = REG_FIELD_GET(C20_FB_CLK_DIV4_EN, pll_state->mplla[0]);
> +	}
> +
> +	if (frac_en)
> +		frac = frac_quot + DIV_ROUND_CLOSEST(frac_rem, frac_den);
> +	else
> +		frac = 0;
> +
> +	ref = DIV_ROUND_CLOSEST(refclk * (1 << (1 + fb_clk_div4_en)), 1 << ref_clk_mpllb_div);
> +	vco = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(ref, (multiplier << (17 - 2)) + frac) >> 17, 10);
> +
> +	return vco << tx_rate_mult >> tx_clk_div >> tx_rate;
> +}
> +
>  static void intel_program_port_clock_ctl(struct intel_encoder *encoder,
>  					 const struct intel_crtc_state *crtc_state,
>  					 bool lane_reversal)
> diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.h b/drivers/gpu/drm/i915/display/intel_cx0_phy.h
> index c643aae27bac..83bd3500091b 100644
> --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.h
> +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.h
> @@ -34,6 +34,8 @@ void intel_c20pll_readout_hw_state(struct intel_encoder *encoder,
>  				   struct intel_c20pll_state *pll_state);
>  void intel_c20pll_dump_hw_state(struct drm_i915_private *i915,
>  				const struct intel_c20pll_state *hw_state);
> +int intel_c20pll_calc_port_clock(struct intel_encoder *encoder,
> +				 const struct intel_c20pll_state *pll_state);
>  void intel_cx0_phy_set_signal_levels(struct intel_encoder *encoder,
>  				     const struct intel_crtc_state *crtc_state);
>  int intel_cx0_phy_check_hdmi_link_rate(struct intel_hdmi *hdmi, int clock);
> diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h b/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h
> index 6fcb1680fb54..a5e5bee24533 100644
> --- a/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h
> +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h
> @@ -195,17 +195,21 @@
>  #define PHY_C20_VDR_CUSTOM_WIDTH	0xD02
>  #define PHY_C20_A_TX_CNTX_CFG(idx)	(0xCF2E - (idx))
>  #define PHY_C20_B_TX_CNTX_CFG(idx)	(0xCF2A - (idx))
> +#define   C20_PHY_TX_RATE		REG_GENMASK(2, 0)
>  #define PHY_C20_A_CMN_CNTX_CFG(idx)	(0xCDAA - (idx))
>  #define PHY_C20_B_CMN_CNTX_CFG(idx)	(0xCDA5 - (idx))
>  #define PHY_C20_A_MPLLA_CNTX_CFG(idx)	(0xCCF0 - (idx))
>  #define PHY_C20_B_MPLLA_CNTX_CFG(idx)	(0xCCE5 - (idx))
>  #define   C20_MPLLA_FRACEN		REG_BIT(14)
> +#define   C20_FB_CLK_DIV4_EN		REG_BIT(13)
>  #define   C20_MPLLA_TX_CLK_DIV_MASK	REG_GENMASK(10, 8)
>  #define PHY_C20_A_MPLLB_CNTX_CFG(idx)	(0xCB5A - (idx))
>  #define PHY_C20_B_MPLLB_CNTX_CFG(idx)	(0xCB4E - (idx))
>  #define   C20_MPLLB_TX_CLK_DIV_MASK	REG_GENMASK(15, 13)
>  #define   C20_MPLLB_FRACEN		REG_BIT(13)
> +#define   C20_REF_CLK_MPLLB_DIV_MASK	REG_GENMASK(12, 10)
>  #define   C20_MULTIPLIER_MASK		REG_GENMASK(11, 0)
> +#define   C20_PHY_USE_MPLLB		REG_BIT(7)
>  
>  #define RAWLANEAONX_DIG_TX_MPLLB_CAL_DONE_BANK(idx) (0x303D + (idx))
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index d414dd8c26bf..8e6d6afca400 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3856,13 +3856,13 @@ static void mtl_ddi_get_config(struct intel_encoder *encoder,
>  	if (intel_is_c10phy(i915, phy)) {
>  		intel_c10pll_readout_hw_state(encoder, &crtc_state->cx0pll_state.c10);
>  		intel_c10pll_dump_hw_state(i915, &crtc_state->cx0pll_state.c10);
> +		crtc_state->port_clock = intel_c10pll_calc_port_clock(encoder, &crtc_state->cx0pll_state.c10);
>  	} else {
>  		intel_c20pll_readout_hw_state(encoder, &crtc_state->cx0pll_state.c20);
>  		intel_c20pll_dump_hw_state(i915, &crtc_state->cx0pll_state.c20);
> +		crtc_state->port_clock = intel_c20pll_calc_port_clock(encoder, &crtc_state->cx0pll_state.c20);
>  	}
>  
> -	crtc_state->port_clock = intel_c10pll_calc_port_clock(encoder, &crtc_state->cx0pll_state.c10);
> -
>  	intel_ddi_get_config(encoder, crtc_state);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_dpll.c b/drivers/gpu/drm/i915/display/intel_dpll.c
> index a9fbef0fa817..ca0f362a40e3 100644
> --- a/drivers/gpu/drm/i915/display/intel_dpll.c
> +++ b/drivers/gpu/drm/i915/display/intel_dpll.c
> @@ -1014,6 +1014,8 @@ static int mtl_crtc_compute_clock(struct intel_atomic_state *state,
>  	/* TODO: Do the readback via intel_compute_shared_dplls() */
>  	if (intel_is_c10phy(i915, phy))
>  		crtc_state->port_clock = intel_c10pll_calc_port_clock(encoder, &crtc_state->cx0pll_state.c10);
> +	else
> +		crtc_state->port_clock = intel_c20pll_calc_port_clock(encoder, &crtc_state->cx0pll_state.c20);
>  
>  	crtc_state->hw.adjusted_mode.crtc_clock = intel_crtc_dotclock(crtc_state);
>  
> -- 
> 2.34.1
>