[RFC 05/13] drm/i915: Add support for starting FRL training for HDMI2.1 via PCON

[Nautiyal, Ankit K]

On 10/19/2020 3:44 AM, Shankar, Uma wrote:
>
>> -----Original Message-----
>> From: Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>
>> Sent: Thursday, October 15, 2020 4:23 PM
>> To: intel-gfx at lists.freedesktop.org
>> Cc: dri-devel at lists.freedesktop.org; Shankar, Uma <uma.shankar at intel.com>;
>> Kulkarni, Vandita <vandita.kulkarni at intel.com>; ville.syrjala at linux.intel.com;
>> Sharma, Swati2 <swati2.sharma at intel.com>
>> Subject: [RFC 05/13] drm/i915: Add support for starting FRL training for HDMI2.1
>> via PCON
>>
>> This patch adds functions to start FRL training for an HDMI2.1 sink, connected via
>> a PCON as a DP branch device.
>> This patch also adds a new structure for storing frl training related data, when
>> FRL training is completed.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>> ---
>>   .../drm/i915/display/intel_display_types.h    |   7 +
>>   drivers/gpu/drm/i915/display/intel_dp.c       | 200 ++++++++++++++++++
>>   drivers/gpu/drm/i915/display/intel_dp.h       |   2 +
>>   3 files changed, 209 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
>> b/drivers/gpu/drm/i915/display/intel_display_types.h
>> index e2f58d0575a2..6c69922313d6 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>> @@ -1287,6 +1287,11 @@ struct intel_dp_compliance {
>>   u8 test_lane_count;
>>   };
>>
>> +struct intel_dp_pcon_frl {
>> +bool is_trained;
>> +int trained_rate_gbps;
>> +};
>> +
>>   struct intel_dp {
>>   i915_reg_t output_reg;
>>   u32 DP;
>> @@ -1408,6 +1413,8 @@ struct intel_dp {
>>
>>   bool hobl_failed;
>>   bool hobl_active;
>> +
>> +struct intel_dp_pcon_frl frl;
>>   };
>>
>>   enum lspcon_vendor {
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>> b/drivers/gpu/drm/i915/display/intel_dp.c
>> index cd6934f28f32..c1342b5e7781 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -2885,6 +2885,9 @@ static void intel_dp_prepare(struct intel_encoder
>> *encoder,
>>   intel_dp->DP |= DP_PIPE_SEL_CHV(crtc->pipe);
>>   else
>>   intel_dp->DP |= DP_PIPE_SEL(crtc->pipe);
>> +
>> +intel_dp->frl.is_trained = false;
>> +intel_dp->frl.trained_rate_gbps = 0;
>>   }
>>   }
>>
>> @@ -3781,6 +3784,9 @@ static void intel_disable_dp(struct intel_atomic_state
>> *state,
>>   intel_edp_backlight_off(old_conn_state);
>>   intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
>>   intel_edp_panel_off(intel_dp);
>> +
>> +intel_dp->frl.is_trained = false;
>> +intel_dp->frl.trained_rate_gbps = 0;
>>   }
>>
>>   static void g4x_disable_dp(struct intel_atomic_state *state, @@ -3876,6
>> +3882,200 @@ cpt_set_link_train(struct intel_dp *intel_dp,
>>   intel_de_posting_read(dev_priv, intel_dp->output_reg);  }
>>
>> +static int intel_dp_get_max_rate_gbps(struct intel_dp *intel_dp) {
>> +int max_link_clock, max_lanes, max_rate_khz, max_rate_gbps;
>> +
>> +max_link_clock = intel_dp_max_link_rate(intel_dp);
>> +max_lanes = intel_dp_max_lane_count(intel_dp);
>> +max_rate_khz = intel_dp_max_data_rate(max_link_clock, max_lanes);
>> +max_rate_gbps = 8 * DIV_ROUND_UP(max_rate_khz, 1000000);
>> +
>> +return max_rate_gbps;
>> +}
>> +
>> +static int intel_dp_pcon_get_frl_mask(u8 frl_bw_mask) {
>> +int bw_gbps[] = {9, 18, 24, 32, 40, 48};
>> +int i;
>> +
>> +for (i = ARRAY_SIZE(bw_gbps) - 1; i >= 0; i--) {
>> +if (frl_bw_mask & (1 << i))
>> +return bw_gbps[i];
>> +}
>> +return 0;
>> +}
>> +
>> +static int intel_dp_pcon_set_frl_mask(int max_frl) {
>> +int max_frl_mask = 0;
>> +
>> +switch (max_frl) {
>> +case 48:
>> +max_frl_mask |= DP_PCON_FRL_BW_MASK_48GBPS;
> Just say it as return DP_PCON_FRL_BW_MASK_48GBPS.
> Do it universally.


Makes sense. Will change this in next version.

>
>> +break;
>> +case 40:
>> +max_frl_mask |= DP_PCON_FRL_BW_MASK_40GBPS;
>> +break;
>> +case 32:
>> +max_frl_mask |= DP_PCON_FRL_BW_MASK_32GBPS;
>> +break;
>> +case 24:
>> +max_frl_mask |= DP_PCON_FRL_BW_MASK_24GBPS;
>> +break;
>> +case 18:
>> +max_frl_mask |= DP_PCON_FRL_BW_MASK_18GBPS;
>> +break;
>> +case 9:
>> +max_frl_mask |= DP_PCON_FRL_BW_MASK_9GBPS;
>> +break;
>> +default:
>> +max_frl_mask = 0;
>> +}
>> +
>> +return max_frl_mask;
>> +}
>> +
>> +static int intel_dp_hdmi_sink_max_frl(struct intel_dp *intel_dp) {
>> +struct intel_connector *intel_connector = intel_dp->attached_connector;
>> +struct drm_connector *connector = &intel_connector->base;
>> +
>> +return (connector->display_info.hdmi.max_frl_rate_per_lane *
>> +connector->display_info.hdmi.max_lanes);
>> +}
>> +
>> +static int intel_dp_pcon_start_frl_training(struct intel_dp *intel_dp)
>> +{ #define PCON_EXTENDED_TRAIN_MODE true#define
>> PCON_CONCURRENT_MODE
>> +true #define PCON_SEQUENTIAL_MODE !PCON_CONCURRENT_MODE #define
>> +PCON_NORMAL_TRAIN_MODE !PCON_EXTENDED_TRAIN_MODE #define
> Don't use true instead 1 < 0 as true is not the right thing to be used here.


Alright. I think you mean to use (1 > 0) as true here.

Will use (1 > 0) instead of true in the macro.

>
>> +TIMEOUT_FRL_READY_MS 500 #define TIMEOUT_HDMI_LINK_ACTIVE_MS 1000
>> +
>> +struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>> +int max_frl, max_pcon_frl, max_sink_frl, max_rate_gbps, max_frl_edid,
>> ret;
>> +u8 max_frl_mask = 0, frl_trained_mask;
>> +bool is_active;
>> +
>> +ret = drm_dp_pcon_reset_frl_config(&intel_dp->aux);
>> +if (ret < 0)
>> +return ret;
>> +
>> +max_rate_gbps = intel_dp_get_max_rate_gbps(intel_dp);
>> +drm_dbg(&i915->drm, "Source max rate = %d Gbps\n", max_rate_gbps);
>> +
>> +max_pcon_frl = intel_dp->dfp.pcon_max_frl;
> Append it with rate or bw.


Agreed, will be using it in the next version.

>
>> +drm_dbg(&i915->drm, "PCON max rate = %d Gbps\n", max_pcon_frl);
>> +
>> +/* Double Check from HDMI SINK EDID */
>> +max_frl_edid = intel_dp_hdmi_sink_max_frl(intel_dp);
>> +drm_dbg(&i915->drm, "Sink max rate from EDID = %d Gbps\n",
>> +max_frl_edid);
>> +
>> +max_sink_frl = intel_dp->dfp.sink_max_frl;
>> +drm_dbg(&i915->drm, "Sink max rate from PCON = %d Gbps\n",
>> +max_sink_frl);
>> +
>> +/* TODO MAX SINK FRL from PCON is not enumerated. Using MAX FRL
>> value
> Use multi line comment style.
Agreed.
>
>> + * directly from EDID. Need to confirm from Spec.
>> + */
>> +max_frl = min(max_rate_gbps, min(max_frl_edid, max_pcon_frl));
>> +
>> +if (max_frl <= 0)
>> +return -EINVAL;
>> +
>> +ret = drm_dp_pcon_frl_prepare(&intel_dp->aux, false);
>> +if (ret < 0)
>> +return ret;
>> +/* Wait for PCON to be FRL Ready */
>> +wait_for(is_active = drm_dp_pcon_is_frl_ready(&intel_dp->aux) == true,
>> +TIMEOUT_FRL_READY_MS);
>> +
>> +if (!is_active)
>> +return -ETIMEDOUT;
>> +
>> +max_frl_mask = intel_dp_pcon_set_frl_mask(max_frl);
>> +ret = drm_dp_pcon_frl_configure_1(&intel_dp->aux, max_frl,
>> PCON_SEQUENTIAL_MODE);
>> +if (ret < 0)
>> +return ret;
>> +ret = drm_dp_pcon_frl_configure_2(&intel_dp->aux, max_frl_mask,
>> PCON_NORMAL_TRAIN_MODE);
>> +if (ret < 0)
>> +return ret;
>> +ret = drm_dp_pcon_frl_enable(&intel_dp->aux);
>> +if (ret < 0)
>> +return ret;
>> +/*
>> + * Wait for FRL to be completed
>> + * Check if the HDMI Link is up and active.
>> + */
>> +wait_for(is_active = drm_dp_pcon_hdmi_link_active(&intel_dp->aux) ==
>> +true, TIMEOUT_HDMI_LINK_ACTIVE_MS);
>> +
>> +if (!is_active)
>> +return -ETIMEDOUT;
>> +/*
>> + * Verify HDMI Link configuration shows FRL Mode.
>> + */
>> +if (DP_PCON_HDMI_MODE_FRL !=
>> drm_dp_pcon_hdmi_link_mode(&intel_dp->aux, &frl_trained_mask)) {
>> +drm_dbg(&i915->drm, "HDMI couldn't be trained in FRL
>> Mode\n");
>> +return -EINVAL;
>> +}
>> +drm_dbg(&i915->drm, "MAX_FRL_MASK = %u, FRL_TRAINED_MASK =
>> %u\n",
>> +max_frl_mask, frl_trained_mask);
>> +
>> +/*
>> + * Read HDMI_LINK_STATUS_TRAINED 0x2005 bit 5
>> + * TODO: Details not mentioned in spec. Need to check.
>> + */
>> +
>> +intel_dp->frl.trained_rate_gbps =
>> intel_dp_pcon_get_frl_mask(frl_trained_mask);
>> +intel_dp->frl.is_trained = true;
>> +drm_dbg(&i915->drm, "FRL trained with : %d Gbps\n",
>> +intel_dp->frl.trained_rate_gbps);
>> +
>> +return 0;
>> +}
>> +
>> +static bool intel_dp_is_frl_required(struct intel_dp *intel_dp) {
>> +if (!intel_dp->frl.is_trained)
>> +return true;
>> +/*
>> + * #TODO check if the mode really required FRL or can work
>> + * with TMDS mode.
>> + */
>> +
>> +return false;
>> +}
>> +
>> +static bool intel_dp_is_hdmi_2_1_sink(struct intel_dp *intel_dp) {
>> +if (drm_dp_is_branch(intel_dp->dpcd) &&
>> +    intel_dp_hdmi_sink_max_frl(intel_dp) > 0)
>> +return true;
>> +
>> +return false;
>> +}
>> +
>> +void intel_dp_check_frl_training(struct intel_dp *intel_dp) {
>> +struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>> +
>> +if (!intel_dp_is_hdmi_2_1_sink(intel_dp) ||
>> +    !intel_dp_is_frl_required(intel_dp))
>> +return;
>> +
>> +if (intel_dp_pcon_start_frl_training(intel_dp) < 0) {
>> +int ret, mode;
>> +
>> +drm_dbg(&dev_priv->drm, "Couldnt set FRL mode, continuing
>> with TMDS mode\n");
>> +ret = drm_dp_pcon_reset_frl_config(&intel_dp->aux);
>> +mode = drm_dp_pcon_hdmi_link_mode(&intel_dp->aux, NULL);
>> +
>> +if (ret < 0 || mode != DP_PCON_HDMI_MODE_TMDS)
>> +drm_dbg(&dev_priv->drm, "Issue with PCON, cannot set
>> TMDS mode\n");
>> +}
>> +
>> +else
> Move it up and enclose in { to match the above if style.


Agreed. Will fix the styling issue here.


Regards,

Ankit

>
>> +drm_dbg(&dev_priv->drm, "FRL training Completed\n"); }
>> +
>>   static void
>>   g4x_set_link_train(struct intel_dp *intel_dp,
>>      const struct intel_crtc_state *crtc_state, diff --git
>> a/drivers/gpu/drm/i915/display/intel_dp.h
>> b/drivers/gpu/drm/i915/display/intel_dp.h
>> index fcc28eb242f2..81d83d88cd41 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.h
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
>> @@ -143,4 +143,6 @@ bool intel_dp_initial_fastset_check(struct intel_encoder
>> *encoder,  void intel_dp_sync_state(struct intel_encoder *encoder,
>>    const struct intel_crtc_state *crtc_state);
>>
>> +void intel_dp_check_frl_training(struct intel_dp *intel_dp);
>> +
>>   #endif /* __INTEL_DP_H__ */
>> --
>> 2.17.1