Re: [PATCH v4 2/8] drm/i915: Use literal representation of cdclk tables

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Sep 10, 2019 at 08:42:46AM -0700, Matt Roper wrote:
> The bspec lays out legal cdclk frequencies, PLL ratios, and CD2X
> dividers in an easy-to-read table for most recent platforms.  We've been
> translating the data from that table into platform-specific code logic,
> but it's easy to overlook an area we need to update when adding new
> cdclk values or enabling new platforms.  Let's just add a form of the
> bspec table to the code and then adjust our functions to pull what they
> need directly out of the table.
> 
> v2: Fix comparison when finding best cdclk.
> 
> v3: Another logic fix for calc_cdclk.
> 
> v4:
>  - Use named initializers for cdclk tables. (Ville)
>  - Include refclk as a field in the table instead of adding all three
>    ratios for each entry. (Ville)
>  - Terminate tables with an empty entry to avoid needing to store the
>    table size. (Ville)
>  - Don't try so hard to return reasonable values from our lookup
>    functions if we get impossible inputs; just WARN and return 0.
>    (Ville)
>  - Keep a bxt_ prefix on the lookup functions since they're still only
>    used on bxt+ for now.  We can rename them later if we extend this
>    table-based approach back to older platforms.  (Ville)
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cdclk.c | 303 +++++++--------------
>  drivers/gpu/drm/i915/display/intel_cdclk.h |   7 +
>  drivers/gpu/drm/i915/i915_drv.h            |   3 +
>  3 files changed, 110 insertions(+), 203 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 01ed3262d91e..c8cf288b8e8e 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -1161,28 +1161,88 @@ static void skl_uninit_cdclk(struct drm_i915_private *dev_priv)
>  	skl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
>  }
>  
> -static int bxt_calc_cdclk(int min_cdclk)
> -{
> -	if (min_cdclk > 576000)
> -		return 624000;
> -	else if (min_cdclk > 384000)
> -		return 576000;
> -	else if (min_cdclk > 288000)
> -		return 384000;
> -	else if (min_cdclk > 144000)
> -		return 288000;
> -	else
> -		return 144000;
> +static const struct intel_cdclk_vals bxt_cdclk_table[] = {
> +	{ .refclk = 19200, .cdclk = 144000, .divider = 8, .ratio = 60 },
> +	{ .refclk = 19200, .cdclk = 288000, .divider = 4, .ratio = 60 },
> +	{ .refclk = 19200, .cdclk = 384000, .divider = 3, .ratio = 60 },
> +	{ .refclk = 19200, .cdclk = 576000, .divider = 2, .ratio = 60 },
> +	{ .refclk = 19200, .cdclk = 624000, .divider = 2, .ratio = 65 },
> +	{}
> +};

If only we had constexpr so we could do
BUILD_BUG_ON(ref*ratio == cdclk*div) without having to hand roll
it for every table entry. Oh well.

> +
> +static const struct intel_cdclk_vals glk_cdclk_table[] = {
> +	{ .refclk = 19200, .cdclk =  79200, .divider = 8, .ratio = 33 },
> +	{ .refclk = 19200, .cdclk = 158400, .divider = 4, .ratio = 33 },
> +	{ .refclk = 19200, .cdclk = 316800, .divider = 2, .ratio = 33 },
> +	{}
> +};
> +
> +static const struct intel_cdclk_vals cnl_cdclk_table[] = {
> +	{ .refclk = 19200, .cdclk = 168000, 4, 35 },
> +	{ .refclk = 19200, .cdclk = 336000, 2, 35 },
> +	{ .refclk = 19200, .cdclk = 528000, 2, 55 },
> +
> +	{ .refclk = 24000, .cdclk = 168000, 4, 35 },
> +	{ .refclk = 24000, .cdclk = 336000, 2, 35 },
> +	{ .refclk = 24000, .cdclk = 528000, 2, 55 },

The ratios looks wrong here. Also missing .divider= and .ratio=.

> +	{}
> +};
> +
> +static const struct intel_cdclk_vals icl_cdclk_table[] = {
> +	{ .refclk = 19200, .cdclk = 172800, .divider = 2, .ratio = 18 },
> +	{ .refclk = 19200, .cdclk = 192000, .divider = 2, .ratio = 20 },
> +	{ .refclk = 19200, .cdclk = 307200, .divider = 2, .ratio = 32 },
> +	{ .refclk = 19200, .cdclk = 326400, .divider = 4, .ratio = 68 },
> +	{ .refclk = 19200, .cdclk = 556800, .divider = 2, .ratio = 58 },
> +	{ .refclk = 19200, .cdclk = 652800, .divider = 2, .ratio = 68 },
> +
> +	{ .refclk = 24000, .cdclk = 180000, .divider = 2, .ratio = 15 },
> +	{ .refclk = 24000, .cdclk = 192000, .divider = 2, .ratio = 16 },
> +	{ .refclk = 24000, .cdclk = 312000, .divider = 2, .ratio = 26 },
> +	{ .refclk = 24000, .cdclk = 324000, .divider = 4, .ratio = 54 },
> +	{ .refclk = 24000, .cdclk = 552000, .divider = 2, .ratio = 46 },
> +	{ .refclk = 24000, .cdclk = 648000, .divider = 2, .ratio = 54 },
> +
> +	{ .refclk = 38400, .cdclk = 172800, .divider = 2, .ratio =  9 },
> +	{ .refclk = 38400, .cdclk = 192000, .divider = 2, .ratio = 10 },
> +	{ .refclk = 38400, .cdclk = 307200, .divider = 2, .ratio = 16 },
> +	{ .refclk = 38400, .cdclk = 326400, .divider = 4, .ratio = 34 },
> +	{ .refclk = 38400, .cdclk = 556800, .divider = 2, .ratio = 29 },
> +	{ .refclk = 38400, .cdclk = 652800, .divider = 2, .ratio = 34 },
> +	{}
> +};

Everything else seems to check out.

With the cnl tables fixed:
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> +
> +static int bxt_calc_cdclk(struct drm_i915_private *dev_priv, int min_cdclk)
> +{
> +	const struct intel_cdclk_vals *table = dev_priv->cdclk.table;
> +	int i;
> +
> +	for (i = 0; table[i].refclk; i++)
> +		if (table[i].refclk == dev_priv->cdclk.hw.ref &&
> +		    table[i].cdclk >= min_cdclk)
> +			return table[i].cdclk;
> +
> +	WARN(1, "Cannot satisfy minimum cdclk %d with refclk %u\n",
> +	     min_cdclk, dev_priv->cdclk.hw.ref);
> +	return 0;
>  }
>  
> -static int glk_calc_cdclk(int min_cdclk)
> +static int bxt_calc_cdclk_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
>  {
> -	if (min_cdclk > 158400)
> -		return 316800;
> -	else if (min_cdclk > 79200)
> -		return 158400;
> -	else
> -		return 79200;
> +	const struct intel_cdclk_vals *table = dev_priv->cdclk.table;
> +	int i;
> +
> +	if (cdclk == dev_priv->cdclk.hw.bypass)
> +		return 0;
> +
> +	for (i = 0; table[i].refclk; i++)
> +		if (table[i].refclk == dev_priv->cdclk.hw.ref &&
> +		    table[i].cdclk == cdclk)
> +			return dev_priv->cdclk.hw.ref * table[i].ratio;
> +
> +	WARN(1, "cdclk %d not valid for refclk %u\n",
> +	     cdclk, dev_priv->cdclk.hw.ref);
> +	return 0;
>  }
>  
>  static u8 bxt_calc_voltage_level(int cdclk)
> @@ -1220,52 +1280,6 @@ static u8 ehl_calc_voltage_level(int cdclk)
>  		return 0;
>  }
>  
> -static int bxt_de_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
> -{
> -	int ratio;
> -
> -	if (cdclk == dev_priv->cdclk.hw.bypass)
> -		return 0;
> -
> -	switch (cdclk) {
> -	default:
> -		MISSING_CASE(cdclk);
> -		/* fall through */
> -	case 144000:
> -	case 288000:
> -	case 384000:
> -	case 576000:
> -		ratio = 60;
> -		break;
> -	case 624000:
> -		ratio = 65;
> -		break;
> -	}
> -
> -	return dev_priv->cdclk.hw.ref * ratio;
> -}
> -
> -static int glk_de_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
> -{
> -	int ratio;
> -
> -	if (cdclk == dev_priv->cdclk.hw.bypass)
> -		return 0;
> -
> -	switch (cdclk) {
> -	default:
> -		MISSING_CASE(cdclk);
> -		/* fall through */
> -	case  79200:
> -	case 158400:
> -	case 316800:
> -		ratio = 33;
> -		break;
> -	}
> -
> -	return dev_priv->cdclk.hw.ref * ratio;
> -}
> -
>  static void cnl_readout_refclk(struct drm_i915_private *dev_priv,
>  			       struct intel_cdclk_state *cdclk_state)
>  {
> @@ -1576,13 +1590,8 @@ static void bxt_init_cdclk(struct drm_i915_private *dev_priv)
>  	 * - The initial CDCLK needs to be read from VBT.
>  	 *   Need to make this change after VBT has changes for BXT.
>  	 */
> -	if (IS_GEMINILAKE(dev_priv)) {
> -		cdclk_state.cdclk = glk_calc_cdclk(0);
> -		cdclk_state.vco = glk_de_pll_vco(dev_priv, cdclk_state.cdclk);
> -	} else {
> -		cdclk_state.cdclk = bxt_calc_cdclk(0);
> -		cdclk_state.vco = bxt_de_pll_vco(dev_priv, cdclk_state.cdclk);
> -	}
> +	cdclk_state.cdclk = bxt_calc_cdclk(dev_priv, 0);
> +	cdclk_state.vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk_state.cdclk);
>  	cdclk_state.voltage_level = bxt_calc_voltage_level(cdclk_state.cdclk);
>  
>  	bxt_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
> @@ -1599,16 +1608,6 @@ static void bxt_uninit_cdclk(struct drm_i915_private *dev_priv)
>  	bxt_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
>  }
>  
> -static int cnl_calc_cdclk(int min_cdclk)
> -{
> -	if (min_cdclk > 336000)
> -		return 528000;
> -	else if (min_cdclk > 168000)
> -		return 336000;
> -	else
> -		return 168000;
> -}
> -
>  static void cnl_cdclk_pll_disable(struct drm_i915_private *dev_priv)
>  {
>  	u32 val;
> @@ -1718,29 +1717,6 @@ static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
>  	dev_priv->cdclk.hw.voltage_level = cdclk_state->voltage_level;
>  }
>  
> -static int cnl_cdclk_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
> -{
> -	int ratio;
> -
> -	if (cdclk == dev_priv->cdclk.hw.bypass)
> -		return 0;
> -
> -	switch (cdclk) {
> -	default:
> -		MISSING_CASE(cdclk);
> -		/* fall through */
> -	case 168000:
> -	case 336000:
> -		ratio = dev_priv->cdclk.hw.ref == 19200 ? 35 : 28;
> -		break;
> -	case 528000:
> -		ratio = dev_priv->cdclk.hw.ref == 19200 ? 55 : 44;
> -		break;
> -	}
> -
> -	return dev_priv->cdclk.hw.ref * ratio;
> -}
> -
>  static void cnl_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  {
>  	u32 cdctl, expected;
> @@ -1783,77 +1759,6 @@ static void cnl_sanitize_cdclk(struct drm_i915_private *dev_priv)
>  	dev_priv->cdclk.hw.vco = -1;
>  }
>  
> -static int icl_calc_cdclk(int min_cdclk, unsigned int ref)
> -{
> -	static const int ranges_24[] = { 180000, 192000, 312000, 324000,
> -					 552000, 648000 };
> -	static const int ranges_19_38[] = { 172800, 192000, 307200, 326400,
> -					    556800, 652800 };
> -	const int *ranges;
> -	int len, i;
> -
> -	switch (ref) {
> -	default:
> -		MISSING_CASE(ref);
> -		/* fall through */
> -	case 24000:
> -		ranges = ranges_24;
> -		len = ARRAY_SIZE(ranges_24);
> -		break;
> -	case 19200:
> -	case 38400:
> -		ranges = ranges_19_38;
> -		len = ARRAY_SIZE(ranges_19_38);
> -		break;
> -	}
> -
> -	for (i = 0; i < len; i++) {
> -		if (min_cdclk <= ranges[i])
> -			return ranges[i];
> -	}
> -
> -	WARN_ON(min_cdclk > ranges[len - 1]);
> -	return ranges[len - 1];
> -}
> -
> -static int icl_calc_cdclk_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
> -{
> -	int ratio;
> -
> -	if (cdclk == dev_priv->cdclk.hw.bypass)
> -		return 0;
> -
> -	switch (cdclk) {
> -	default:
> -		MISSING_CASE(cdclk);
> -		/* fall through */
> -	case 172800:
> -	case 307200:
> -	case 326400:
> -	case 556800:
> -	case 652800:
> -		WARN_ON(dev_priv->cdclk.hw.ref != 19200 &&
> -			dev_priv->cdclk.hw.ref != 38400);
> -		break;
> -	case 180000:
> -	case 312000:
> -	case 324000:
> -	case 552000:
> -	case 648000:
> -		WARN_ON(dev_priv->cdclk.hw.ref != 24000);
> -		break;
> -	case 192000:
> -		WARN_ON(dev_priv->cdclk.hw.ref != 19200 &&
> -			dev_priv->cdclk.hw.ref != 38400 &&
> -			dev_priv->cdclk.hw.ref != 24000);
> -		break;
> -	}
> -
> -	ratio = cdclk / (dev_priv->cdclk.hw.ref / 2);
> -
> -	return dev_priv->cdclk.hw.ref * ratio;
> -}
> -
>  static void icl_init_cdclk(struct drm_i915_private *dev_priv)
>  {
>  	struct intel_cdclk_state sanitized_state;
> @@ -1882,8 +1787,8 @@ static void icl_init_cdclk(struct drm_i915_private *dev_priv)
>  	DRM_DEBUG_KMS("Sanitizing cdclk programmed by pre-os\n");
>  
>  	sanitized_state.ref = dev_priv->cdclk.hw.ref;
> -	sanitized_state.cdclk = icl_calc_cdclk(0, sanitized_state.ref);
> -	sanitized_state.vco = icl_calc_cdclk_pll_vco(dev_priv,
> +	sanitized_state.cdclk = bxt_calc_cdclk(dev_priv, 0);
> +	sanitized_state.vco = bxt_calc_cdclk_pll_vco(dev_priv,
>  						     sanitized_state.cdclk);
>  	if (IS_ELKHARTLAKE(dev_priv))
>  		sanitized_state.voltage_level =
> @@ -1923,8 +1828,8 @@ static void cnl_init_cdclk(struct drm_i915_private *dev_priv)
>  
>  	cdclk_state = dev_priv->cdclk.hw;
>  
> -	cdclk_state.cdclk = cnl_calc_cdclk(0);
> -	cdclk_state.vco = cnl_cdclk_pll_vco(dev_priv, cdclk_state.cdclk);
> +	cdclk_state.cdclk = bxt_calc_cdclk(dev_priv, 0);
> +	cdclk_state.vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk_state.cdclk);
>  	cdclk_state.voltage_level = cnl_calc_voltage_level(cdclk_state.cdclk);
>  
>  	cnl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
> @@ -2426,13 +2331,8 @@ static int bxt_modeset_calc_cdclk(struct intel_atomic_state *state)
>  	if (min_cdclk < 0)
>  		return min_cdclk;
>  
> -	if (IS_GEMINILAKE(dev_priv)) {
> -		cdclk = glk_calc_cdclk(min_cdclk);
> -		vco = glk_de_pll_vco(dev_priv, cdclk);
> -	} else {
> -		cdclk = bxt_calc_cdclk(min_cdclk);
> -		vco = bxt_de_pll_vco(dev_priv, cdclk);
> -	}
> +	cdclk = bxt_calc_cdclk(dev_priv, min_cdclk);
> +	vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk);
>  
>  	state->cdclk.logical.vco = vco;
>  	state->cdclk.logical.cdclk = cdclk;
> @@ -2440,13 +2340,8 @@ static int bxt_modeset_calc_cdclk(struct intel_atomic_state *state)
>  		bxt_calc_voltage_level(cdclk);
>  
>  	if (!state->active_pipes) {
> -		if (IS_GEMINILAKE(dev_priv)) {
> -			cdclk = glk_calc_cdclk(state->cdclk.force_min_cdclk);
> -			vco = glk_de_pll_vco(dev_priv, cdclk);
> -		} else {
> -			cdclk = bxt_calc_cdclk(state->cdclk.force_min_cdclk);
> -			vco = bxt_de_pll_vco(dev_priv, cdclk);
> -		}
> +		cdclk = bxt_calc_cdclk(dev_priv, state->cdclk.force_min_cdclk);
> +		vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk);
>  
>  		state->cdclk.actual.vco = vco;
>  		state->cdclk.actual.cdclk = cdclk;
> @@ -2468,8 +2363,8 @@ static int cnl_modeset_calc_cdclk(struct intel_atomic_state *state)
>  	if (min_cdclk < 0)
>  		return min_cdclk;
>  
> -	cdclk = cnl_calc_cdclk(min_cdclk);
> -	vco = cnl_cdclk_pll_vco(dev_priv, cdclk);
> +	cdclk = bxt_calc_cdclk(dev_priv, min_cdclk);
> +	vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk);
>  
>  	state->cdclk.logical.vco = vco;
>  	state->cdclk.logical.cdclk = cdclk;
> @@ -2478,8 +2373,8 @@ static int cnl_modeset_calc_cdclk(struct intel_atomic_state *state)
>  		    cnl_compute_min_voltage_level(state));
>  
>  	if (!state->active_pipes) {
> -		cdclk = cnl_calc_cdclk(state->cdclk.force_min_cdclk);
> -		vco = cnl_cdclk_pll_vco(dev_priv, cdclk);
> +		cdclk = bxt_calc_cdclk(dev_priv, state->cdclk.force_min_cdclk);
> +		vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk);
>  
>  		state->cdclk.actual.vco = vco;
>  		state->cdclk.actual.cdclk = cdclk;
> @@ -2495,15 +2390,14 @@ static int cnl_modeset_calc_cdclk(struct intel_atomic_state *state)
>  static int icl_modeset_calc_cdclk(struct intel_atomic_state *state)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
> -	unsigned int ref = state->cdclk.logical.ref;
>  	int min_cdclk, cdclk, vco;
>  
>  	min_cdclk = intel_compute_min_cdclk(state);
>  	if (min_cdclk < 0)
>  		return min_cdclk;
>  
> -	cdclk = icl_calc_cdclk(min_cdclk, ref);
> -	vco = icl_calc_cdclk_pll_vco(dev_priv, cdclk);
> +	cdclk = bxt_calc_cdclk(dev_priv, min_cdclk);
> +	vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk);
>  
>  	state->cdclk.logical.vco = vco;
>  	state->cdclk.logical.cdclk = cdclk;
> @@ -2517,8 +2411,8 @@ static int icl_modeset_calc_cdclk(struct intel_atomic_state *state)
>  			    cnl_compute_min_voltage_level(state));
>  
>  	if (!state->active_pipes) {
> -		cdclk = icl_calc_cdclk(state->cdclk.force_min_cdclk, ref);
> -		vco = icl_calc_cdclk_pll_vco(dev_priv, cdclk);
> +		cdclk = bxt_calc_cdclk(dev_priv, state->cdclk.force_min_cdclk);
> +		vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk);
>  
>  		state->cdclk.actual.vco = vco;
>  		state->cdclk.actual.cdclk = cdclk;
> @@ -2754,12 +2648,15 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
>  	if (INTEL_GEN(dev_priv) >= 11) {
>  		dev_priv->display.set_cdclk = cnl_set_cdclk;
>  		dev_priv->display.modeset_calc_cdclk = icl_modeset_calc_cdclk;
> +		dev_priv->cdclk.table = icl_cdclk_table;
>  	} else if (IS_CANNONLAKE(dev_priv)) {
>  		dev_priv->display.set_cdclk = cnl_set_cdclk;
>  		dev_priv->display.modeset_calc_cdclk = cnl_modeset_calc_cdclk;
> +		dev_priv->cdclk.table = cnl_cdclk_table;
>  	} else if (IS_GEN9_LP(dev_priv)) {
>  		dev_priv->display.set_cdclk = bxt_set_cdclk;
>  		dev_priv->display.modeset_calc_cdclk = bxt_modeset_calc_cdclk;
> +		dev_priv->cdclk.table = bxt_cdclk_table;
>  	} else if (IS_GEN9_BC(dev_priv)) {
>  		dev_priv->display.set_cdclk = skl_set_cdclk;
>  		dev_priv->display.modeset_calc_cdclk = skl_modeset_calc_cdclk;
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.h b/drivers/gpu/drm/i915/display/intel_cdclk.h
> index 4d6f7f5f8930..ca6d651946b9 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.h
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.h
> @@ -15,6 +15,13 @@ struct intel_atomic_state;
>  struct intel_cdclk_state;
>  struct intel_crtc_state;
>  
> +struct intel_cdclk_vals {
> +	u32 refclk;
> +	u32 cdclk;
> +	u8 divider;	/* CD2X divider * 2 */
> +	u8 ratio;
> +};
> +
>  int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state);
>  void intel_cdclk_init(struct drm_i915_private *i915);
>  void intel_cdclk_uninit(struct drm_i915_private *i915);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index e289b4ffd34b..ff6aff2a4866 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1420,6 +1420,9 @@ struct drm_i915_private {
>  		/* The current hardware cdclk state */
>  		struct intel_cdclk_state hw;
>  
> +		/* cdclk, divider, and ratio table from bspec */
> +		const struct intel_cdclk_vals *table;
> +
>  		int force_min_cdclk;
>  	} cdclk;
>  
> -- 
> 2.20.1

-- 
Ville Syrjälä
Intel
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx