Re: [PATCH v2 16/22] drm/msm/dpu: Configure CWB in writeback encoder

[Jessica Zhang <quic_jesszhan@quicinc.com>]

On 9/24/2024 4:41 PM, Dmitry Baryshkov wrote:
> On Tue, Sep 24, 2024 at 03:59:32PM GMT, Jessica Zhang wrote:
>> Cache the CWB block mask in the DPU virtual encoder and configure CWB
>> according to the CWB block mask within the writeback phys encoder
>>
>> Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
>> ---
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c        | 83 +++++++++++++++++++++-
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h   | 16 ++++-
>>   .../gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c    |  4 +-
>>   3 files changed, 100 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> index b2f0bf412451..2628f2d55cb3 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> @@ -24,6 +24,7 @@
>>   #include "dpu_hw_catalog.h"
>>   #include "dpu_hw_intf.h"
>>   #include "dpu_hw_ctl.h"
>> +#include "dpu_hw_cwb.h"
>>   #include "dpu_hw_dspp.h"
>>   #include "dpu_hw_dsc.h"
>>   #include "dpu_hw_merge3d.h"
>> @@ -139,6 +140,7 @@ enum dpu_enc_rc_states {
>>    *			num_phys_encs.
>>    * @hw_dsc:		Handle to the DSC blocks used for the display.
>>    * @dsc_mask:		Bitmask of used DSC blocks.
>> + * @cwb_mask		Bitmask of used CWB muxes
>>    * @intfs_swapped:	Whether or not the phys_enc interfaces have been swapped
>>    *			for partial update right-only cases, such as pingpong
>>    *			split where virtual pingpong does not generate IRQs
>> @@ -185,6 +187,7 @@ struct dpu_encoder_virt {
>>   	struct dpu_hw_dsc *hw_dsc[MAX_CHANNELS_PER_ENC];
>>   
>>   	unsigned int dsc_mask;
>> +	unsigned int cwb_mask;
>>   
>>   	bool intfs_swapped;
>>   
>> @@ -1063,6 +1066,7 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>>   	int num_cwb = 0;
>>   	bool is_cwb_encoder;
>>   	unsigned int dsc_mask = 0;
>> +	unsigned int cwb_mask = 0;
>>   	int i;
>>   
>>   	if (!drm_enc) {
>> @@ -1103,8 +1107,12 @@ static void dpu_encoder_virt_atomic_mode_set(struct drm_encoder *drm_enc,
>>   						       ARRAY_SIZE(hw_pp));
>>   	}
>>   
>> -	for (i = 0; i < num_cwb; i++)
>> +	for (i = 0; i < num_cwb; i++) {
>>   		dpu_enc->hw_cwb[i] = to_dpu_hw_cwb(hw_cwb[i]);
>> +		cwb_mask |= BIT(dpu_enc->hw_cwb[i]->idx - CWB_0);
>> +	}
>> +
>> +	dpu_enc->cwb_mask = cwb_mask;
>>   
>>   	dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>>   			drm_enc->crtc, DPU_HW_BLK_CTL, hw_ctl, ARRAY_SIZE(hw_ctl));
>> @@ -2071,6 +2079,9 @@ void dpu_encoder_helper_phys_cleanup(struct dpu_encoder_phys *phys_enc)
>>   		}
>>   	}
>>   
>> +	if (dpu_enc->cwb_mask)
>> +		dpu_encoder_helper_phys_setup_cwb(phys_enc, false);
>> +
>>   	/* reset the merge 3D HW block */
>>   	if (phys_enc->hw_pp && phys_enc->hw_pp->merge_3d) {
>>   		phys_enc->hw_pp->merge_3d->ops.setup_3d_mode(phys_enc->hw_pp->merge_3d,
>> @@ -2114,6 +2125,68 @@ void dpu_encoder_helper_phys_cleanup(struct dpu_encoder_phys *phys_enc)
>>   	ctl->ops.clear_pending_flush(ctl);
>>   }
>>   
>> +void dpu_encoder_helper_phys_setup_cwb(struct dpu_encoder_phys *phys_enc,
>> +				       bool enable)
>> +{
>> +	struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(phys_enc->parent);
>> +	struct dpu_hw_cwb *hw_cwb;
>> +	struct dpu_hw_cwb_setup_cfg cwb_cfg;
>> +
>> +	struct dpu_kms *dpu_kms;
>> +	struct dpu_global_state *global_state;
>> +	struct dpu_hw_blk *rt_pp_list[MAX_CHANNELS_PER_ENC];
>> +	int num_pp, rt_pp_idx[MAX_CHANNELS_PER_ENC];
>> +
>> +	if (!phys_enc || !phys_enc->hw_wb || !dpu_enc->cwb_mask)
>> +		return;
> 
> We have already dereferened phys_enc, so checking that it's not NULL is
> futile. Also we know that the function is only called if cwb_mask is not
> zero, so the last check is also useless.

Hi Dmitry,

Ack.

> 
>> +
>> +	dpu_kms = phys_enc->dpu_kms;
>> +	global_state = dpu_kms_get_existing_global_state(dpu_kms);
>> +	num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>> +					       phys_enc->parent->crtc,
>> +					       DPU_HW_BLK_PINGPONG, rt_pp_list,
>> +					       ARRAY_SIZE(rt_pp_list));
>> +
>> +	if (num_pp == 0 || num_pp > MAX_CHANNELS_PER_ENC) {
>> +		DPU_DEBUG_ENC(dpu_enc, "invalid num_pp %d\n", num_pp);
>> +		return;
>> +	}
>> +
>> +	for (int i = 0; i < num_pp; i++) {
>> +		struct dpu_hw_pingpong *hw_pp = to_dpu_hw_pingpong(rt_pp_list[i]);
>> +
>> +		for (int j = 0; j < ARRAY_SIZE(dpu_enc->hw_cwb); j++) {
>> +			hw_cwb = dpu_enc->hw_cwb[i];
>> +
>> +			/*
>> +			 * Even CWB muxes must take input from even real-time
>> +			 * pingpongs and odd CWB muxes must take input from odd
>> +			 * pingpongs
>> +			 */
>> +			if (hw_pp->idx % 2 == hw_cwb->idx % 2) {
> 
> What about `if (a != b) continue;`?
> 
>> +				rt_pp_idx[i] = enable ? hw_pp->idx : PINGPONG_NONE;
> 
> Can we call config_cwb() here directly with no intermediate arrays?

Yes -- I should drop this for loop (and the associated array) as RM 
should reserve the CWB muxes and real-time pingpongs in the correct order.

> 
>> +				break;
>> +			}
>> +		}
>> +	}
>> +
>> +	/*
>> +	 * The CWB mux supports using LM or DSPP as tap points. For now,
>> +	 * always use LM tap point
>> +	 */
>> +	cwb_cfg.input = INPUT_MODE_LM_OUT;
>> +
>> +	for (int i = 0; i < MAX_CHANNELS_PER_ENC; i++) {
>> +		hw_cwb = dpu_enc->hw_cwb[i];
>> +		if (!hw_cwb)
>> +			continue;
>> +
>> +		cwb_cfg.pp_idx = rt_pp_idx[i];
>> +
>> +		hw_cwb->ops.config_cwb(hw_cwb, &cwb_cfg);
>> +	}
>> +}
>> +
>>   void dpu_encoder_helper_phys_setup_cdm(struct dpu_encoder_phys *phys_enc,
>>   				       const struct msm_format *dpu_fmt,
>>   				       u32 output_type)
>> @@ -2557,6 +2630,14 @@ enum dpu_intf_mode dpu_encoder_get_intf_mode(struct drm_encoder *encoder)
>>   	return INTF_MODE_NONE;
>>   }
>>   
>> +unsigned int dpu_encoder_helper_get_cwb(struct dpu_encoder_phys *phys_enc)
> 
> it's called get_cwb, but it returns a mask?

I'd based this function off of dpu_encoder_helper_get_dsc(), but I can 
rename this to *_get_cwb_mask() instead

> 
>> +{
>> +	struct drm_encoder *encoder = phys_enc->parent;
>> +	struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(encoder);
>> +
>> +	return dpu_enc->cwb_mask;
>> +}
>> +
>>   unsigned int dpu_encoder_helper_get_dsc(struct dpu_encoder_phys *phys_enc)
>>   {
>>   	struct drm_encoder *encoder = phys_enc->parent;
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
>> index e77ebe3a68da..d7a02d1f8053 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
>> @@ -1,6 +1,6 @@
>>   /* SPDX-License-Identifier: GPL-2.0-only */
>>   /*
>> - * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
>> + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved.
>>    * Copyright (c) 2015-2018 The Linux Foundation. All rights reserved.
>>    */
>>   
>> @@ -331,6 +331,12 @@ static inline enum dpu_3d_blend_mode dpu_encoder_helper_get_3d_blend_mode(
>>   	return BLEND_3D_NONE;
>>   }
>>   
>> +/**
>> + * dpu_encoder_helper_get_cwb - get CWB blocks mask for the DPU encoder
>> + * @phys_enc: Pointer to physical encoder structure
>> + */
> 
> All kerneldoc at the function definition, please. I plan to go through
> the existing codebase and move existing docs. It seems to be the only
> way to get kerneldoc-related warnings.

Ack.

Thanks,

Jessica Zhang

> 
>> +unsigned int dpu_encoder_helper_get_cwb(struct dpu_encoder_phys *phys_enc);
>> +
>>   /**
>>    * dpu_encoder_helper_get_dsc - get DSC blocks mask for the DPU encoder
>>    *   This helper function is used by physical encoder to get DSC blocks mask
>> @@ -400,6 +406,14 @@ int dpu_encoder_helper_wait_for_irq(struct dpu_encoder_phys *phys_enc,
>>    */
>>   void dpu_encoder_helper_phys_cleanup(struct dpu_encoder_phys *phys_enc);
>>   
>> +/**
>> + * dpu_encoder_helper_phys_setup_cwb - helper to configure CWB muxes
>> + * @phys_enc: Pointer to physical encoder structure
>> + * @enable: Enable CWB mux
>> + */
>> +void dpu_encoder_helper_phys_setup_cwb(struct dpu_encoder_phys *phys_enc,
>> +				       bool enable);
>> +
>>   /**
>>    * dpu_encoder_helper_phys_setup_cdm - setup chroma down sampling block
>>    * @phys_enc: Pointer to physical encoder
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>> index 882c717859ce..e88c4d91041f 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>> @@ -1,6 +1,6 @@
>>   // SPDX-License-Identifier: GPL-2.0-only
>>   /*
>> - * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
>> + * Copyright (c) 2022-2024 Qualcomm Innovation Center, Inc. All rights reserved.
>>    */
>>   
>>   #define pr_fmt(fmt)	"[drm:%s:%d] " fmt, __func__, __LINE__
>> @@ -342,6 +342,8 @@ static void dpu_encoder_phys_wb_setup(
>>   
>>   	dpu_encoder_helper_phys_setup_cdm(phys_enc, dpu_fmt, CDM_CDWN_OUTPUT_WB);
>>   
>> +	dpu_encoder_helper_phys_setup_cwb(phys_enc, true);
>> +
>>   	dpu_encoder_phys_wb_setup_ctl(phys_enc);
>>   }
>>   
>>
>> -- 
>> 2.34.1
>>
> 
> -- 
> With best wishes
> Dmitry