Re: [PATCH] cpufreq: Add Kryo CPU scaling driver

Russell King - ARM Linux
2018-05-21T10:54:44Z

On Mon, May 21, 2018 at 01:31:30PM +0300, Ilia Lin wrote:
> +#define SILVER_LEAD 0
> +#define GOLD_LEAD 2

Okay, two different values here, but "GOLD_LEAD" appears unused.

> + cpu_dev_silver = get_cpu_device(SILVER_LEAD);
> + if (NULL == cpu_dev_silver)
> + return -ENODEV;
> +
> + cpu_dev_gold = get_cpu_device(SILVER_LEAD);
> + if (NULL == cpu_dev_gold)
> + return -ENODEV;

get_cpu_device() takes the logical CPU number. So the above gets CPU 0
each time, and so cpu_dev_silver == cpu_dev_gold here. So what's the
point of the second get_cpu_device() ? If it's supposed to be:

cpu_dev_gold = get_cpu_device(GOLD_LEAD);

That would get CPU 2, but in terms of these defines, it doesn't make that
much sense. What exactly does "silver lead" and "gold lead" refer to in
these definitions?

> + opp_silver = dev_pm_opp_set_supported_hw(cpu_dev_silver,&versions,1);
> + if (IS_ERR(opp_silver)) {
> + dev_err(cpu_dev_silver, "Failed to set supported hardware\n");
> + ret = PTR_ERR(opp_silver);
> + goto free_np;
> + }
> +
> + opp_gold = dev_pm_opp_set_supported_hw(cpu_dev_gold,&versions,1);
> + if (IS_ERR(opp_gold)) {
> + dev_err(cpu_dev_gold, "Failed to set supported hardware\n");
> + ret = PTR_ERR(opp_gold);
> + goto free_opp_silver;
> + }

Given that cpu_dev_silver == cpu_dev_gold, doesn't the second call to
dev_pm_opp_set_supported_hw() always fail, as opp_table->supported_hw
will be set by the first call?

To me, this driver looks completely useless as it will always fail to
initialise, and I question whether this code has even been runtime
tested.

--
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