Re: [Intel-gfx] [RFC 1/2] drm/i915: Add RPL-U CDCLK table

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 30 Nov 2022, Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> wrote:
> A new step of 480MHz has been added on SKUs that have a RPL-U
> device id. Add a new table which include this new CDCLK step.
>
> BSpec: 55409
>
> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_cdclk.c | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
> index 0c107a38f9d0..9bfeb1abba47 100644
> --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> @@ -180,6 +180,18 @@ static void i85x_get_cdclk(struct drm_i915_private *dev_priv,
>  	}
>  }
>  
> +static bool is_rplu(struct drm_i915_private *dev_priv)
> +{
> +	switch (INTEL_DEVID(dev_priv)) {
> +	case 0xA7A1:
> +	case 0xA721:
> +	case 0xA7A9:

No. Under no circumstances are you to sprinkle PCI ID checks directly in
code like this.

The only place where PCI IDs go are the macros in
include/drm/i915_pciids.h, and each PCI ID should be present there only
once.

Those macros should only be used in i915_pci.c and intel_device_info.c.

If you need a distinction between RPL-P and RPL-U like this (and I
didn't check this in the spec, just commenting on the implementation)
you need to split RPL-P and RPL-U definitions and add them as
subplatforms in intel_device_info.c.

As a general tip, when you consider using a function or a macro, look up
where it's used and how. INTEL_DEVID() isn't used like this anywhere.


BR,
Jani.


> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
>  static void i915gm_get_cdclk(struct drm_i915_private *dev_priv,
>  			     struct intel_cdclk_config *cdclk_config)
>  {
> @@ -1329,6 +1341,27 @@ static const struct intel_cdclk_vals adlp_cdclk_table[] = {
>  	{}
>  };
>  
> +static const struct intel_cdclk_vals rplu_cdclk_table[] = {
> +	{ .refclk = 19200, .cdclk = 172800, .divider = 3, .ratio = 27 },
> +	{ .refclk = 19200, .cdclk = 192000, .divider = 2, .ratio = 20 },
> +	{ .refclk = 19200, .cdclk = 480000, .divider = 2, .ratio = 50 },
> +	{ .refclk = 19200, .cdclk = 556800, .divider = 2, .ratio = 58 },
> +	{ .refclk = 19200, .cdclk = 652800, .divider = 2, .ratio = 68 },
> +
> +	{ .refclk = 24000, .cdclk = 176000, .divider = 3, .ratio = 22 },
> +	{ .refclk = 24000, .cdclk = 192000, .divider = 2, .ratio = 16 },
> +	{ .refclk = 24000, .cdclk = 480000, .divider = 2, .ratio = 40 },
> +	{ .refclk = 24000, .cdclk = 552000, .divider = 2, .ratio = 46 },
> +	{ .refclk = 24400, .cdclk = 648000, .divider = 2, .ratio = 54 },
> +
> +	{ .refclk = 38400, .cdclk = 179200, .divider = 3, .ratio = 14 },
> +	{ .refclk = 38400, .cdclk = 192000, .divider = 2, .ratio = 10 },
> +	{ .refclk = 38400, .cdclk = 480000, .divider = 2, .ratio = 25 },
> +	{ .refclk = 38400, .cdclk = 556800, .divider = 2, .ratio = 29 },
> +	{ .refclk = 38400, .cdclk = 652800, .divider = 2, .ratio = 34 },
> +	{}
> +};
> +
>  static const struct intel_cdclk_vals dg2_cdclk_table[] = {
>  	{ .refclk = 38400, .cdclk = 163200, .divider = 2, .ratio = 34, .waveform = 0x8888 },
>  	{ .refclk = 38400, .cdclk = 204000, .divider = 2, .ratio = 34, .waveform = 0x9248 },
> @@ -3353,6 +3386,12 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
>  		/* Wa_22011320316:adl-p[a0] */
>  		if (IS_ADLP_DISPLAY_STEP(dev_priv, STEP_A0, STEP_B0))
>  			dev_priv->display.cdclk.table = adlp_a_step_cdclk_table;
> +		/*
> +		 * BSpec: 55409
> +		 * 480 MHz supported on SKUs that have a RPL-U Device ID
> +		 */
> +		else if (is_rplu(dev_priv))
> +			dev_priv->cdclk.table = rplu_cdclk_table;
>  		else
>  			dev_priv->display.cdclk.table = adlp_cdclk_table;
>  	} else if (IS_ROCKETLAKE(dev_priv)) {

-- 
Jani Nikula, Intel Open Source Graphics Center