[Intel-gfx] [PATCH v7 4/8] drm/i915/vdsc: Add function to read any PPS register

Kandpal, Suraj suraj.kandpal at intel.com
Wed Aug 16 09:35:15 UTC 2023


> 
> On Tue, 08 Aug 2023, Suraj Kandpal <suraj.kandpal at intel.com> 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]
> >
> > --v5
> > -Read dsc reg values using array rather than individual variables
> > [Ankit] -Loop the verification of all dsc engine reads to future proof
> > it [Ankit] -Keep the fix me comment in this patch and remove it in
> > later one where we add other readouts [Ankit] -Add switch statement
> > that fills in the required registers based on no of vdsc engines per
> > pipe.
> >
> > --v7
> > -Pass no of vdsc instances from read_reg function [Ankit] -Fix issue
> > where arrays do not get freed on return for read_and_verify func
> > [Ankit]
> >
> > Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_vdsc.c     | 129 +++++++++++++-----
> >  .../gpu/drm/i915/display/intel_vdsc_regs.h    |  12 ++
> >  2 files changed, 105 insertions(+), 36 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c
> > b/drivers/gpu/drm/i915/display/intel_vdsc.c
> > index dc86514d9e17..aa93228ca7af 100644
> > --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> > @@ -365,6 +365,28 @@ 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(const struct intel_crtc_state
> *crtc_state, int pps,
> > +				  i915_reg_t *dsc_reg, int no_vdsc_per_pipe)
> {
> > +	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;
> 
> Matter of taste, but to me that's four local variables too many for small things
> like this.
> 
> > +
> > +	pipe_dsc = is_pipe_dsc(crtc, cpu_transcoder);
> > +
> > +	switch (no_vdsc_per_pipe) {
> > +	case 2:
> > +		dsc_reg[1] = pipe_dsc ? ICL_DSC1_PPS_REG(pipe, pps) :
> DSCC_PPS_REG(pps);
> > +		fallthrough;
> > +	case 1:
> > +		dsc_reg[0] = pipe_dsc ? ICL_DSC0_PPS_REG(pipe, pps) :
> DSCA_PPS_REG(pps);
> > +		break;
> > +	default:
> > +		MISSING_CASE(no_vdsc_per_pipe);
> > +	}
> > +}
> > +
> >  static void intel_dsc_pps_configure(const struct intel_crtc_state
> > *crtc_state)  {
> >  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > @@ -994,17 +1016,83 @@ void intel_dsc_disable(const struct
> intel_crtc_state *old_crtc_state)
> >  	}
> >  }
> >
> > +static int 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);
> > +	const int no_vdsc_per_pipe =
> intel_dsc_get_vdsc_per_pipe(crtc_state);
> > +	i915_reg_t *dsc_reg;
> > +	u32 *pps_temp;
> > +	int i, ret = 0;
> > +
> > +	dsc_reg = kcalloc(no_vdsc_per_pipe, sizeof(dsc_reg), GFP_KERNEL);
> > +	if (!dsc_reg)
> > +		return -ENOMEM;
> > +
> > +	pps_temp = kcalloc(no_vdsc_per_pipe, sizeof(pps_temp),
> GFP_KERNEL);
> > +	if (!pps_temp) {
> > +		kfree(dsc_reg);
> > +		return -ENOMEM;
> > +	}
> 
> no_vdsc_per_pipe is at most 2. Temporary dynamic allocation is way overkill
> here.

Yes but Ankit was of the thought that we can future proof this going forward if by any chance we get more dsc engines

> 
> > +
> > +	*pps_val = 0;
> > +	intel_dsc_get_pps_reg(crtc_state, pps, dsc_reg, no_vdsc_per_pipe);
> > +	*pps_val = intel_de_read(i915, dsc_reg[0]);
> > +	if (no_vdsc_per_pipe > 1) {
> > +		for (i = 0; i < no_vdsc_per_pipe - 1; i++) {
> > +			pps_temp[i] = intel_de_read(i915, dsc_reg[i]);
> > +			pps_temp[i + 1] = intel_de_read(i915, dsc_reg[i + 1]);
> > +			if (pps_temp[i] != pps_temp[i + 1]) {
> > +				ret = 1;
> > +				break;
> > +			}
> > +		}
> > +	}
> 
> What is going on here? Feels like this has grown way more complicated than
> it needs to be since I last looked at this series. :(

In case of more than 2 vdsc engines (just for future proofing) this loops looks at all the registers being used for
that pipe and makes sure everyone has the same value

Regards,
Suraj Kandpal
> 
> > +
> > +	kfree(dsc_reg);
> > +	kfree(pps_temp);
> > +	return ret;
> > +}
> > +
> > +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);
> > +	int ret;
> > +
> > +	ret = intel_dsc_read_pps_reg(crtc_state, pps, pps_val);
> > +	drm_WARN_ON(&i915->drm, ret);
> > +}
> > +
> > +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;
> > +
> > +	/* FIXME: add more state readout as needed */
> > +
> > +	/* 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, pps_temp1;
> > -	int no_vdsc_instances_per_pipe;
> > +	u32 dss_ctl1, dss_ctl2;
> >
> >  	if (!intel_dsc_source_support(crtc_state))
> >  		return;
> > @@ -1025,38 +1113,7 @@ 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 */
> > -
> > -	no_vdsc_instances_per_pipe =
> intel_dsc_get_vdsc_per_pipe(crtc_state);
> > -
> > -	/* PPS0 & PPS1 */
> > -	if (!is_pipe_dsc(crtc, cpu_transcoder)) {
> > -		pps1 = intel_de_read(dev_priv,
> DSCA_PICTURE_PARAMETER_SET_1);
> > -		if (no_vdsc_instances_per_pipe > 1) {
> > -			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 (no_vdsc_instances_per_pipe > 1) {
> > -			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)
> 
> --
> Jani Nikula, Intel Open Source Graphics Center


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