[Intel-gfx] [PATCH v4 3/7] drm/i915/vdsc: Add function to read any PPS register

Nautiyal, Ankit K ankit.k.nautiyal at intel.com
Wed Aug 2 05:35:20 UTC 2023


Hi Suraj,

I agree with overall approach, but I suggest that we use num of vdsc 
engines per pipe to avoid changes in future.

This would perhaps need a small patch first to get num of vdsc engines 
per pipe though, more details inline for the case:

On 7/20/2023 1:37 PM, Suraj Kandpal wrote:
> Add function to read any PPS register based on the
> intel_dsc_pps enum provided. Add a function which will call the
> new pps read function and place it in crtc state. Only PPS0 and
> PPS1 are readout the rest of the registers will be read in upcoming
> patches.
>
> --v2
> -Changes in read function as PPS enum is removed
> -Initialize pps_val as 0 in pps_read func itself [Jani]
> -Create a function that gets the required register and call that
> in the common read function [Jani]
> -Move the drm_WARN_ON one abstraction layer above [Jani]
>
> --v3
> -Send both reg values regardless of dsc engine no [Jani]
> -Don't use num_vdsc_instances stick to dsc_split field [Ankit]
>
> --v4
> -Manipulate the reg values instead of creating MACRO to change
> name of pps [Ankit]
>
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_vdsc.c     | 103 ++++++++++++------
>   .../gpu/drm/i915/display/intel_vdsc_regs.h    |  12 ++
>   2 files changed, 82 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c b/drivers/gpu/drm/i915/display/intel_vdsc.c
> index 9196329d998d..58eb19f8d35b 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> @@ -303,6 +303,25 @@ int intel_dsc_get_num_vdsc_instances(const struct intel_crtc_state *crtc_state)
>   	return num_vdsc_instances;
>   }
>   
> +static void intel_dsc_get_pps_reg(struct intel_crtc_state *crtc_state, int pps,
> +				  i915_reg_t *dsc_reg0, i915_reg_t *dsc_reg1)

It would be good if we can send *dsc_reg, num_vdsc in the function.

IMHO lets calculate the num of vdsc engines in dsc_get_config and pass 
it from there to the other functions :intel_dsc_read_and_verify_pps_reg 
and all.


> +{
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> +	enum pipe pipe = crtc->pipe;
> +	bool pipe_dsc;
> +
> +	pipe_dsc = is_pipe_dsc(crtc, cpu_transcoder);
> +
> +	if (pipe_dsc) {
> +		*dsc_reg0 = ICL_DSC0_PPS_REG(pipe, pps);
> +		*dsc_reg1 = ICL_DSC1_PPS_REG(pipe, pps);
> +	} else {
> +		*dsc_reg0 = DSCA_PPS_REG(pps);
> +		*dsc_reg1 = DSCC_PPS_REG(pps);
> +	}
> +}
> +
>   static void intel_dsc_pps_configure(const struct intel_crtc_state *crtc_state)
>   {
>   	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> @@ -930,16 +949,63 @@ void intel_dsc_disable(const struct intel_crtc_state *old_crtc_state)
>   	}
>   }
>   
> +static bool intel_dsc_read_pps_reg(struct intel_crtc_state *crtc_state,
> +				   int pps, u32 *pps_val)
> +{
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
> +	bool dsc_split = crtc_state->dsc.dsc_split;
> +	i915_reg_t dsc_reg0, dsc_reg1;
> +	u32 pps_temp;
> +
> +	*pps_val = 0;
> +
> +	intel_dsc_get_pps_reg(crtc_state, pps, &dsc_reg0, &dsc_reg1);
> +	*pps_val = intel_de_read(i915, dsc_reg0);
> +	if (dsc_split) {
> +		pps_temp = intel_de_read(i915, dsc_reg1);
> +		if (*pps_val != pps_temp)
> +			return false;
> +	}


With the num of vdsc engines available we can have a loop something like:

intel_dsc_get_pps_reg(crtc_state, pps, &dsc_reg, num);

for (i=0; i < num; i++) {
     pps_val[i] = intel_de_read(i915, dsc_reg[i]);
     if (i > 0)
         if (pps_val[i] != pps_val[i-1])
             return false;
}

return true;

> +	return true;
> +}
> +
> +static void intel_dsc_read_and_verify_pps_reg(struct intel_crtc_state *crtc_state,
> +					      int pps, u32 *pps_val)
> +{
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
> +	bool is_dsc_eq;
> +
> +	is_dsc_eq = intel_dsc_read_pps_reg(crtc_state, pps, pps_val);
> +	drm_WARN_ON(&i915->drm, !is_dsc_eq);
> +}
> +
> +static void intel_dsc_get_pps_config(struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config;
> +	u32 pps_temp1, pps_temp2;
> +
> +	/* Readout PPS_0 and PPS_1 registers */
> +	intel_dsc_read_and_verify_pps_reg(crtc_state, 0, &pps_temp1);
> +	intel_dsc_read_and_verify_pps_reg(crtc_state, 1, &pps_temp2);
> +
> +	vdsc_cfg->bits_per_pixel = pps_temp2;
> +
> +	if (pps_temp1 & DSC_NATIVE_420_ENABLE)
> +		vdsc_cfg->bits_per_pixel >>= 1;
> +
> +	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel >> 4;
> +}
> +
>   void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
>   {
>   	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>   	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> -	struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config;
>   	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> -	enum pipe pipe = crtc->pipe;
>   	enum intel_display_power_domain power_domain;
>   	intel_wakeref_t wakeref;
> -	u32 dss_ctl1, dss_ctl2, pps0 = 0, pps1 = 0, pps_temp0 = 0, pps_temp1 = 1;
> +	u32 dss_ctl1, dss_ctl2;
>   
>   	if (!intel_dsc_source_support(crtc_state))
>   		return;
> @@ -960,36 +1026,7 @@ void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
>   	crtc_state->dsc.dsc_split = (dss_ctl2 & RIGHT_BRANCH_VDSC_ENABLE) &&
>   		(dss_ctl1 & JOINER_ENABLE);
>   
> -	/* FIXME: add more state readout as needed */


We are still reading 2 PPS only so lets retain this line in the patch.


Regards,

Ankit


> -
> -	/* PPS0 & PPS1 */
> -	if (!is_pipe_dsc(crtc, cpu_transcoder)) {
> -		pps1 = intel_de_read(dev_priv, DSCA_PICTURE_PARAMETER_SET_1);
> -		if (crtc_state->dsc.dsc_split) {
> -			pps_temp1 = intel_de_read(dev_priv, DSCC_PICTURE_PARAMETER_SET_1);
> -			drm_WARN_ON(&dev_priv->drm, pps1 != pps_temp1);
> -		}
> -	} else {
> -		pps0 = intel_de_read(dev_priv,
> -				     ICL_DSC0_PICTURE_PARAMETER_SET_0(pipe));
> -		pps1 = intel_de_read(dev_priv,
> -				     ICL_DSC0_PICTURE_PARAMETER_SET_1(pipe));
> -		if (crtc_state->dsc.dsc_split) {
> -			pps_temp0 = intel_de_read(dev_priv,
> -						  ICL_DSC1_PICTURE_PARAMETER_SET_0(pipe));
> -			pps_temp1 = intel_de_read(dev_priv,
> -						  ICL_DSC1_PICTURE_PARAMETER_SET_1(pipe));
> -			drm_WARN_ON(&dev_priv->drm, pps0 != pps_temp0);
> -			drm_WARN_ON(&dev_priv->drm, pps1 != pps_temp1);
> -		}
> -	}
> -
> -	vdsc_cfg->bits_per_pixel = pps1;
> -
> -	if (pps0 & DSC_NATIVE_420_ENABLE)
> -		vdsc_cfg->bits_per_pixel >>= 1;
> -
> -	crtc_state->dsc.compressed_bpp = vdsc_cfg->bits_per_pixel >> 4;
> +	intel_dsc_get_pps_config(crtc_state);
>   out:
>   	intel_display_power_put(dev_priv, power_domain, wakeref);
>   }
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc_regs.h b/drivers/gpu/drm/i915/display/intel_vdsc_regs.h
> index 785ede31116e..862dc708c5fc 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc_regs.h
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc_regs.h
> @@ -78,6 +78,10 @@
>   /* Icelake Display Stream Compression Registers */
>   #define DSCA_PICTURE_PARAMETER_SET_0		_MMIO(0x6B200)
>   #define DSCC_PICTURE_PARAMETER_SET_0		_MMIO(0x6BA00)
> +#define DSCA_PPS_0				0x6B200
> +#define DSCC_PPS_0				0x6BA00
> +#define DSCA_PPS_REG(pps)			_MMIO(DSCA_PPS_0 + (pps) * 4)
> +#define DSCC_PPS_REG(pps)			_MMIO(DSCC_PPS_0 + (pps) * 4)
>   #define _ICL_DSC0_PICTURE_PARAMETER_SET_0_PB	0x78270
>   #define _ICL_DSC1_PICTURE_PARAMETER_SET_0_PB	0x78370
>   #define _ICL_DSC0_PICTURE_PARAMETER_SET_0_PC	0x78470
> @@ -88,6 +92,14 @@
>   #define ICL_DSC1_PICTURE_PARAMETER_SET_0(pipe)	_MMIO_PIPE((pipe) - PIPE_B, \
>   							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PB, \
>   							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PC)
> +#define ICL_DSC0_PPS_0(pipe)			_PICK_EVEN((pipe) - PIPE_B, \
> +							   _ICL_DSC0_PICTURE_PARAMETER_SET_0_PB, \
> +							   _ICL_DSC0_PICTURE_PARAMETER_SET_0_PC)
> +#define ICL_DSC1_PPS_0(pipe)			_PICK_EVEN((pipe) - PIPE_B, \
> +							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PB, \
> +							   _ICL_DSC1_PICTURE_PARAMETER_SET_0_PC)
> +#define  ICL_DSC0_PPS_REG(pipe, pps)		_MMIO(ICL_DSC0_PPS_0(pipe) + ((pps) * 4))
> +#define  ICL_DSC1_PPS_REG(pipe, pps)		_MMIO(ICL_DSC1_PPS_0(pipe) + ((pps) * 4))
>   #define  DSC_NATIVE_422_ENABLE		BIT(23)
>   #define  DSC_NATIVE_420_ENABLE		BIT(22)
>   #define  DSC_ALT_ICH_SEL		(1 << 20)


More information about the Intel-gfx mailing list