Re: [PATCH v6 2/4] media: venus: Update clock scaling

Stanimir Varbanov
2019-07-29T08:35:35Z

Hi Aniket,

On 7/22/19 12:07 PM, 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@codeaurora.org>
> ---
> drivers/media/platform/qcom/venus/helpers.c | 91 +++++++++++++++++++++++++++--
> 1 file changed, 87 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/platform/qcom/venus/helpers.c b/drivers/media/platform/qcom/venus/helpers.c
> index 7492373..2c976e4 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 +399,89 @@ static int load_scale_clocks(struct venus_core *core)
> return ret;
> }
>
> +static unsigned long calculate_vpp_freq(struct venus_inst *inst)
> +{
> + unsigned long vpp_freq = 0;
> + u32 mbs_per_sec;
> +
> + mbs_per_sec = load_per_instance(inst);
> + vpp_freq = mbs_per_sec * inst->clk_data.codec_freq_data->vpp_freq;
> + /* 21 / 20 is overhead factor */
> + vpp_freq += vpp_freq / 20;
> +
> + return vpp_freq;
> +}
> +
> +static int scale_clocks_v4(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;
> + struct clk *clk = core->clks[0];
> + struct device *dev = core->dev;
> + unsigned int i;
> + unsigned long freq = 0, freq_core1 = 0, freq_core2 = 0;
> + int ret;
> +
> + freq = calculate_vpp_freq(inst);
> +
> + if (freq > table[0].freq)
> + dev_warn(dev, "HW is overloaded, needed: %lu max: %lu\n",
> + freq, table[0].freq);
> +

...

> + for (i = 0; i < num_rows; i++) {
> + if (freq > table[i].freq)
> + break;
> + freq = table[i].freq;
> + }

The above code snippet will select the biggest table[0].freq always.
Infact do we need to "normalize" the calculated freq to the table of
possible clock rates? I think tjat should be made after sum all needed
frequencies for all cores.

> +
> + 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_core1 += inst->clk_data.freq;
> + } else if (inst->clk_data.core_id == VIDC_CORE_ID_2) {
> + freq_core2 += inst->clk_data.freq;
> + } else if (inst->clk_data.core_id == VIDC_CORE_ID_3) {
> + freq_core1 += inst->clk_data.freq;
> + freq_core2 += inst->clk_data.freq;
> + }
> + }
> + mutex_unlock(&core->lock);
> +
> + freq = max(freq_core1, freq_core2);
> +
> + ret = clk_set_rate(clk, freq);
> + if (ret)
> + goto err;
> +
> + ret = clk_set_rate(core->core0_clk, freq);
> + if (ret)
> + goto err;
> +
> + ret = clk_set_rate(core->core1_clk, freq);
> + if (ret)
> + goto err;

This is duplicated in both scale_clocks and scale_clocks_v4, and could
be a common function.

> +
> + 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_V4(inst->core))
> + return scale_clocks_v4(inst);
> +
> + if (inst->state == INST_START)
> + return 0;

I'm still not sure about this check of the instance state.

If we look into load_per_instance() it already doing similar check :

!(inst->state >= INST_INIT && inst->state < INST_STOP)

> +
> + return scale_clocks(inst);
> +}
> +
> static void fill_buffer_desc(const struct venus_buffer *buf,
> struct hfi_buffer_desc *bd, bool response)
> {
> @@ -1053,7 +1137,7 @@ 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 +1154,6 @@ 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 +1164,7 @@ 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