Re: [RFC 1/6] drm/dp: get/set phy compliance pattern.

[Manasi Navare <manasi.d.navare@intel.com>]

On Thu, Oct 03, 2019 at 08:36:48PM +0530, Animesh Manna wrote:
> During phy complaince auto test mode source need to read
> requested test pattern from sink through DPCD. After processing
> the request source need to set the pattern. So set/get method
> added in drm layer as it is DP protocol.
> 
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>  drivers/gpu/drm/drm_dp_helper.c | 77 +++++++++++++++++++++++++++++++++
>  include/drm/drm_dp_helper.h     | 28 ++++++++++++
>  2 files changed, 105 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index f373798d82f6..3cb7170e55f4 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -1484,3 +1484,80 @@ int drm_dp_dsc_sink_supported_input_bpcs(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_S
>  	return num_bpc;
>  }
>  EXPORT_SYMBOL(drm_dp_dsc_sink_supported_input_bpcs);
> +
> +/**
> + * drm_dp_get_phy_test_pattern() - get the requested pattern from the sink.
> + * @aux: DisplayPort AUX channel
> + * @data: DP phy compliance test parameters.
> + *
> + * Returns 0 on success or a negative error code on failure.
> + */
> +int drm_dp_get_phy_test_pattern(struct drm_dp_aux *aux,
> +				struct drm_dp_phy_test_params *data)
> +{
> +	int err;
> +
> +	err = drm_dp_link_probe(aux, &data->link);
> +	if (err < 0)
> +		return err;
> +
> +	err = drm_dp_dpcd_read(aux, DP_TEST_PHY_PATTERN, &data->phy_pattern, 1);

Just use drm_dp_dpcd_readb

> +	if (err < 0)
> +		return err;
> +
> +	switch (data->phy_pattern) {
> +	case DP_TEST_PHY_PATTERN_80BIT_CUSTOM:
> +		err = drm_dp_dpcd_read(aux, DP_TEST_80BIT_CUSTOM_PATTERN_7_0,
> +				       &data->custom80, 10);
> +		if (err < 0)
> +			return err;
> +
> +		break;
> +	case DP_TEST_PHY_PATTERN_CP2520:
> +		err = drm_dp_dpcd_read(aux, DP_TEST_HBR2_SCRAMBLER_RESET,
> +				       &data->hbr2_reset, 2);
> +		if (err < 0)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_get_phy_test_pattern);
> +
> +/**
> + * drm_dp_set_phy_test_pattern() - set the pattern to the sink.
> + * @aux: DisplayPort AUX channel
> + * @data: DP phy compliance test parameters.
> + *
> + * Returns 0 on success or a negative error code on failure.
> + */
> +int drm_dp_set_phy_test_pattern(struct drm_dp_aux *aux,
> +				struct drm_dp_phy_test_params *data)
> +{
> +	int err, i;
> +	u8 test_pattern;
> +
> +	err = drm_dp_link_configure(aux, &data->link);
> +	if (err < 0)
> +		return err;
> +
> +	test_pattern = data->phy_pattern;
> +	if (data->link.revision < 0x12) {
> +		test_pattern = (test_pattern << 2) &
> +			       DP_LINK_QUAL_PATTERN_11_MASK;
> +		err = drm_dp_dpcd_write(aux, DP_TRAINING_PATTERN_SET,
> +					&test_pattern, 1);

Same, just use drm_dp_dpcd_writeb

> +		if (err < 0)
> +			return err;
> +	} else {
> +		for (i = 0; i < data->link.num_lanes; i++) {
> +			err = drm_dp_dpcd_write(aux, DP_LINK_QUAL_LANE0_SET + i,
> +						&test_pattern, 1);
> +			if (err < 0)
> +				return err;
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_set_phy_test_pattern);
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index ed1a985745ba..77dcf5879beb 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -691,6 +691,14 @@
>  # define DP_TEST_COUNT_MASK		    0xf
>  
>  #define DP_TEST_PHY_PATTERN                 0x248

This should be consistent with spec name DP_PHY_TEST_PATTERN

And since the bits below are part of the 2:0 PATTERN_SEL, I would prefer
having DP_PHY_TEST_PATTERN_SEL_MASK 0x7

> +# define DP_TEST_PHY_PATTERN_NONE           0
                                               ^ 0x0
> +# define DP_TEST_PHY_PATTERN_D10_2          1
                                               ^ 0x1 (to be consistent with other bit defs in .h file)

Manasi

> +# define DP_TEST_PHY_PATTERN_ERROR_COUNT    2
> +# define DP_TEST_PHY_PATTERN_PRBS7          3
> +# define DP_TEST_PHY_PATTERN_80BIT_CUSTOM   4
> +# define DP_TEST_PHY_PATTERN_CP2520         5
> +
> +#define DP_TEST_HBR2_SCRAMBLER_RESET        0x24A
>  #define DP_TEST_80BIT_CUSTOM_PATTERN_7_0    0x250
>  #define	DP_TEST_80BIT_CUSTOM_PATTERN_15_8   0x251
>  #define	DP_TEST_80BIT_CUSTOM_PATTERN_23_16  0x252
> @@ -1523,4 +1531,24 @@ static inline void drm_dp_cec_unset_edid(struct drm_dp_aux *aux)
>  
>  #endif
>  
> +/**
> + * struct drm_dp_phy_test_params - DP Phy Compliance parameters
> + * @link: Link information.
> + * @phy_pattern: DP Phy test pattern from DPCD 0x248 (sink)
> + * @hb2_reset: DP HBR2_COMPLIANCE_SCRAMBLER_RESET from DCPD
> + *            0x24A and 0x24B (sink)
> + * @custom80: DP Test_80BIT_CUSTOM_PATTERN from DPCDs 0x250
> + *               through 0x259.
> + */
> +struct drm_dp_phy_test_params {
> +	struct drm_dp_link link;
> +	u8 phy_pattern;
> +	u8 hbr2_reset[2];
> +	u8 custom80[10];
> +};
> +
> +int drm_dp_get_phy_test_pattern(struct drm_dp_aux *aux,
> +				struct drm_dp_phy_test_params *data);
> +int drm_dp_set_phy_test_pattern(struct drm_dp_aux *aux,
> +				struct drm_dp_phy_test_params *data);
>  #endif /* _DRM_DP_HELPER_H_ */
> -- 
> 2.22.0
> 
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