linux-kernel - Re: [PATCH 3/5] media: venus: Update clock scaling

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Message-ID: <e1903711-b8c1-d528-2da8-ffd511a2da72@linaro.org>
Date:   Mon, 17 Jun 2019 11:58:17 +0300
From:   Stanimir Varbanov <stanimir.varbanov@...aro.org>
To:     Aniket Masule <amasule@...eaurora.org>,
        linux-media@...r.kernel.org, stanimir.varbanov@...aro.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        vgarodia@...eaurora.org
Subject: Re: [PATCH 3/5] media: venus: Update clock scaling

Hi Aniket,

On 6/11/19 9:05 AM, Aniket Masule wrote:
> Current clock scaling calculations are same for vpu4 and
> previous versions. For vpu4, Clock scaling calculations
> are updated with cycles/mb. This helps in getting precise
> clock required.
> 
> Signed-off-by: Aniket Masule <amasule@...eaurora.org>
> ---
>  drivers/media/platform/qcom/venus/helpers.c | 88 +++++++++++++++++++++++++++--
>  1 file changed, 84 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/venus/helpers.c b/drivers/media/platform/qcom/venus/helpers.c
> index f7f724b..7bcc1e6 100644
> --- a/drivers/media/platform/qcom/venus/helpers.c
> +++ b/drivers/media/platform/qcom/venus/helpers.c
> @@ -348,8 +348,9 @@ static u32 load_per_type(struct venus_core *core, u32 session_type)
>  	return mbs_per_sec;
>  }
>  
> -static int load_scale_clocks(struct venus_core *core)
> +static int scale_clocks(struct venus_inst *inst)
>  {
> +	struct venus_core *core = inst->core;
>  	const struct freq_tbl *table = core->res->freq_tbl;
>  	unsigned int num_rows = core->res->freq_tbl_size;
>  	unsigned long freq = table[0].freq;
> @@ -398,6 +399,86 @@ static int load_scale_clocks(struct venus_core *core)
>  	return ret;
>  }
>  
> +static unsigned long calculate_inst_freq(struct venus_inst *inst)
> +{
> +	unsigned long vpp_cycles = 0;
> +	u32 mbs_per_sec;
> +
> +	mbs_per_sec = load_per_instance(inst);
> +	vpp_cycles = mbs_per_sec * inst->clk_data.codec_data->vpp_cycles;
> +	/* 21 / 20 is overhead factor */
> +	vpp_cycles += vpp_cycles / 20;

shouldn't you multiply by 21?

> +
> +	return vpp_cycles;

It is not clear to me is that vpp_cycles or frequency (rate)? I just
lost in dimensions used here.

If you return vpp_cycles could you rename the function name?

> +}
> +
> +static int scale_clocks_vpu4(struct venus_inst *inst)

does vpu4 equivalent to HFI_VERSION_4XX? If so could you rename function
to scale_clocks_v4.

> +{
> +	struct venus_core *core = inst->core;
> +	const struct freq_tbl *table = core->res->freq_tbl;
> +	unsigned int num_rows = core->res->freq_tbl_size;
> +
> +	struct clk *clk = core->clks[0];
> +	struct device *dev = core->dev;
> +	unsigned int i;
> +	unsigned long freq = 0, freq_core0 = 0, freq_core1 = 0;
> +	int ret;
> +
> +	freq = calculate_inst_freq(inst);
> +
> +	if (freq > table[0].freq)
> +		goto err;
> +
> +	for (i = 0; i < num_rows; i++) {
> +		if (freq > table[i].freq)
> +			break;
> +		freq = table[i].freq;
> +	}
> +
> +	inst->clk_data.freq = freq;
> +
> +	mutex_lock(&core->lock);
> +	list_for_each_entry(inst, &core->instances, list) {
> +		if (inst->clk_data.core_id == VIDC_CORE_ID_1) {
> +			freq_core0 += inst->clk_data.freq;
> +		} else if (inst->clk_data.core_id == VIDC_CORE_ID_2) {
> +			freq_core1 += inst->clk_data.freq;
> +		} else if (inst->clk_data.core_id == VIDC_CORE_ID_3) {
> +			freq_core0 += inst->clk_data.freq;
> +			freq_core1 += inst->clk_data.freq;
> +		}
> +	}
> +	mutex_unlock(&core->lock);
> +
> +	freq = max(freq_core0, freq_core1);

hmm, this doesn't look right. core0 and core1 frequencies can be
different why you get the bigger and set it on both?

> +
> +	ret = clk_set_rate(clk, freq);
> +	if (ret)
> +		goto err;
> +
> +	ret = clk_set_rate(core->core0_clk, freq);

IMO this should set freq_core0

> +	if (ret)
> +		goto err;
> +
> +	ret = clk_set_rate(core->core1_clk, freq);

set freq_core1

> +	if (ret)
> +		goto err;
> +
> +	return 0;
> +
> +err:
> +	dev_err(dev, "failed to set clock rate %lu (%d)\n", freq, ret);
> +	return ret;
> +}
> +
> +static int load_scale_clocks(struct venus_inst *inst)
> +{
> +	if (IS_V3(inst->core) || IS_V1(inst->core))
> +		return scale_clocks(inst);
> +	else
> +		return scale_clocks_vpu4(inst);

could you reorder this to:

	if (IS_V4())
		return scale_clocks_v4(inst);

	return scale_clocks(inst);

> +}
> +
>  static void fill_buffer_desc(const struct venus_buffer *buf,
>  			     struct hfi_buffer_desc *bd, bool response)
>  {
> @@ -1053,7 +1134,7 @@ void venus_helper_vb2_stop_streaming(struct vb2_queue *q)
>  
>  		venus_helper_free_dpb_bufs(inst);
>  
> -		load_scale_clocks(core);
> +		load_scale_clocks(inst);
>  		INIT_LIST_HEAD(&inst->registeredbufs);
>  	}
>  
> @@ -1070,7 +1151,6 @@ void venus_helper_vb2_stop_streaming(struct vb2_queue *q)
>  
>  int venus_helper_vb2_start_streaming(struct venus_inst *inst)
>  {
> -	struct venus_core *core = inst->core;
>  	int ret;
>  
>  	ret = intbufs_alloc(inst);
> @@ -1081,7 +1161,7 @@ int venus_helper_vb2_start_streaming(struct venus_inst *inst)
>  	if (ret)
>  		goto err_bufs_free;
>  
> -	load_scale_clocks(core);
> +	load_scale_clocks(inst);
>  
>  	ret = hfi_session_load_res(inst);
>  	if (ret)
> 

-- 
regards,
Stan