[PATCH 14/21] drm/msm/dpu: Reserve resources for CWB

Jessica Zhang quic_jesszhan at quicinc.com
Fri Aug 30 20:28:30 UTC 2024



On 8/30/2024 10:25 AM, Dmitry Baryshkov wrote:
> On Thu, Aug 29, 2024 at 01:48:35PM GMT, Jessica Zhang wrote:
>> Reserve dedicated pingpong blocks for CWB
> 
> Please explain design ideas. Having just a single phrase is usually not
> enough.
> 
>>
>> Signed-off-by: Jessica Zhang <quic_jesszhan at quicinc.com>
>> ---
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 17 ++++++--
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h |  1 +
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c      | 65 +++++++++++++++++++++++++++++
>>   3 files changed, 79 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> index 36b677cf9c7a..f1bd14d1f89e 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> @@ -2,7 +2,7 @@
>>   /*
>>    * Copyright (C) 2013 Red Hat
>>    * Copyright (c) 2014-2018, 2020-2021 The Linux Foundation. All rights reserved.
>> - * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
>> + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved.
>>    *
>>    * Author: Rob Clark <robdclark at gmail.com>
>>    */
>> @@ -1054,6 +1054,7 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>>   	struct dpu_hw_blk *hw_ctl[MAX_CHANNELS_PER_ENC];
>>   	struct dpu_hw_blk *hw_dsc[MAX_CHANNELS_PER_ENC];
>>   	int num_pp, num_dsc;
>> +	bool is_cwb_encoder;
>>   	unsigned int dsc_mask = 0;
>>   	int i;
>>   
>> @@ -1067,6 +1068,8 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>>   
>>   	priv = drm_enc->dev->dev_private;
>>   	dpu_kms = to_dpu_kms(priv->kms);
>> +	is_cwb_encoder = drm_crtc_in_clone_mode(crtc_state) &&
>> +		dpu_enc->disp_info.intf_type == INTF_WB;
>>   
>>   	global_state = dpu_kms_get_existing_global_state(dpu_kms);
>>   	if (IS_ERR_OR_NULL(global_state)) {
>> @@ -1077,9 +1080,15 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>>   	trace_dpu_enc_mode_set(DRMID(drm_enc));
>>   
>>   	/* Query resource that have been reserved in atomic check step. */
>> -	num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>> -		drm_enc->crtc, DPU_HW_BLK_PINGPONG, hw_pp,
>> -		ARRAY_SIZE(hw_pp));
>> +	if (is_cwb_encoder)
>> +		num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>> +			drm_enc->crtc, DPU_HW_BLK_DCWB_PINGPONG, hw_pp,
>> +			ARRAY_SIZE(hw_pp));
>> +	else
>> +		num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>> +			drm_enc->crtc, DPU_HW_BLK_PINGPONG, hw_pp,
>> +			ARRAY_SIZE(hw_pp));
> 
> Why is this necessary? Can we still use DPU_HW_BLK_PINGPONG?

Hi Dmitry,

Since both regular non-cwb pingpongs and pingpongs dedicated for cwb 
both share the same pingpong_to_crtc_id map, I need a way to distinguish 
between the real-time and dedicated cwb pingpongs.

If I don't do that, get_assigned_resources would populate the hw_pp 
array for both the real-time and WB encoders with *only* the real-time 
display pingpongs.

> 
>> +
>>   	dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>>   			drm_enc->crtc, DPU_HW_BLK_CTL, hw_ctl, ARRAY_SIZE(hw_ctl));
>>   
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h
>> index c43cb55fe1d2..c87790a1b940 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h
>> @@ -77,6 +77,7 @@ enum dpu_hw_blk_type {
>>   	DPU_HW_BLK_LM,
>>   	DPU_HW_BLK_CTL,
>>   	DPU_HW_BLK_PINGPONG,
>> +	DPU_HW_BLK_DCWB_PINGPONG,
>>   	DPU_HW_BLK_INTF,
>>   	DPU_HW_BLK_WB,
>>   	DPU_HW_BLK_DSPP,
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
>> index 13f84375e15d..afad26556cd5 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
>> @@ -236,6 +236,48 @@ static int _dpu_rm_get_lm_peer(struct dpu_rm *rm, int primary_idx)
>>   	return -EINVAL;
>>   }
>>   
>> +static int _dpu_rm_reserve_cwb_pingpong(struct dpu_rm *rm,
>> +		struct dpu_global_state *global_state, uint32_t crtc_id,
>> +		struct msm_display_topology *topology)
>> +{
>> +	int num_cwb_pp = topology->num_lm, cwb_pp_count = 0;
>> +	int cwb_pp_idx[MAX_BLOCKS];
>> +
>> +	/*
>> +	 * Reserve additional dedicated CWB pingpong blocks for each mixer
>> +	 *
>> +	 * TODO: add support for reserving non-dedicated CWB pingpong blocks
>> +	 */
>> +	for (int i = 0; i < ARRAY_SIZE(rm->mixer_blks) &&
>> +			cwb_pp_count < num_cwb_pp; i++) {
>> +		for (int j = PINGPONG_CWB_0 - PINGPONG_0;
>> +				j < ARRAY_SIZE(rm->pingpong_blks); j++) {
> 
> Alignment...

Ack -- for future reference, should I always align the second line with 
the bracket of the previous line?

I thought the general guideline was 2 tabs, but I might be misremembering.

Thanks,

Jessica Zhang

> 
>> +			/*
>> +			 * Odd LMs must be assigned to odd pingpongs and even
>> +			 * LMs with even pingpongs
>> +			 */
>> +			if (reserved_by_other(global_state->pingpong_to_crtc_id,
>> +						j, crtc_id) ||
>> +					i % 2 != j % 2)
>> +				continue;
>> +
>> +			cwb_pp_idx[cwb_pp_count] = j;
>> +			cwb_pp_count++;
>> +			break;
>> +		}
>> +	}
>> +
>> +	if (cwb_pp_count != num_cwb_pp) {
>> +		DPU_ERROR("Unable to reserve all cwb pingpongs\n");
>> +		return -ENAVAIL;
>> +	}
>> +
>> +	for (int i = 0; i < cwb_pp_count; i++)
>> +		global_state->pingpong_to_crtc_id[cwb_pp_idx[i]] = crtc_id;
>> +
>> +	return 0;
>> +}
>> +
>>   /**
>>    * _dpu_rm_check_lm_and_get_connected_blks - check if proposed layer mixer meets
>>    *	proposed use case requirements, incl. hardwired dependent blocks like
>> @@ -617,6 +659,14 @@ static int _dpu_rm_make_reservation(
>>   		return ret;
>>   	}
>>   
>> +	if (topology->cwb_enabled) {
>> +		ret = _dpu_rm_reserve_cwb_pingpong(rm, global_state,
>> +				crtc_id, topology);
>> +		if (ret) {
>> +			DPU_ERROR("unable to find appropriate dcwb pingpongs\n");
>> +			return ret;
>> +		}
>> +	}
>>   
>>   	ret = _dpu_rm_reserve_ctls(rm, global_state, crtc_id,
>>   			topology);
>> @@ -706,6 +756,7 @@ int dpu_rm_get_assigned_resources(struct dpu_rm *rm,
>>   
>>   	switch (type) {
>>   	case DPU_HW_BLK_PINGPONG:
>> +	case DPU_HW_BLK_DCWB_PINGPONG:
>>   		hw_blks = rm->pingpong_blks;
>>   		hw_to_crtc_id = global_state->pingpong_to_crtc_id;
>>   		max_blks = ARRAY_SIZE(rm->pingpong_blks);
>> @@ -745,6 +796,20 @@ int dpu_rm_get_assigned_resources(struct dpu_rm *rm,
>>   		if (hw_to_crtc_id[i] != crtc_id)
>>   			continue;
>>   
>> +		if (type == DPU_HW_BLK_PINGPONG) {
>> +			struct dpu_hw_pingpong *pp = to_dpu_hw_pingpong(hw_blks[i]);
>> +
>> +			if (pp->idx >= PINGPONG_CWB_0)
>> +				continue;
>> +		}
>> +
>> +		if (type == DPU_HW_BLK_DCWB_PINGPONG) {
>> +			struct dpu_hw_pingpong *pp = to_dpu_hw_pingpong(hw_blks[i]);
>> +
>> +			if (pp->idx < PINGPONG_CWB_0)
>> +				continue;
>> +		}
>> +
>>   		if (num_blks == blks_size) {
>>   			DPU_ERROR("More than %d resources assigned to crtc %d\n",
>>   				  blks_size, crtc_id);
>>
>> -- 
>> 2.34.1
>>
> 
> -- 
> With best wishes
> Dmitry


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