Re: [PATCH v8 1/3] cpufreq: mediatek-hw: Add support for CPUFREQ HW

Hector Yuan
2020-11-19T13:43:29Z

On Thu, 2020-11-19 at 12:41 +0000, Lukasz Luba wrote:
> Hi Hector,
>
> On 10/26/20 8:19 AM, Hector Yuan wrote:
> > From: "Hector.Yuan" <hector.yuan@mediatek.com>
> >
> > Add cpufreq HW support.
> >
> > Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
>
> [snip]
>
> > +
> > +static int mtk_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
> > +{
> > + struct cpufreq_mtk *c;
> > + struct device *cpu_dev;
> > + struct em_data_callback em_cb = EM_DATA_CB(mtk_cpufreq_get_cpu_power);
> > + struct pm_qos_request *qos_request;
> > + int sig, pwr_hw = CPUFREQ_HW_STATUS | SVS_HW_STATUS;
> > +
> > + qos_request = kzalloc(sizeof(*qos_request), GFP_KERNEL);
> > + if (!qos_request)
> > + return -ENOMEM;
> > +
> > + cpu_dev = get_cpu_device(policy->cpu);
> > + if (!cpu_dev) {
> > + pr_err("failed to get cpu%d device\n", policy->cpu);
> > + return -ENODEV;
> > + }
> > +
> > + c = mtk_freq_domain_map[policy->cpu];
> > + if (!c) {
> > + pr_err("No scaling support for CPU%d\n", policy->cpu);
> > + return -ENODEV;
> > + }
> > +
> > + cpumask_copy(policy->cpus, &c->related_cpus);
> > +
> > + policy->freq_table = c->table;
> > + policy->driver_data = c;
>
> To control frequency transition rate in schedutil, you might
> be interested in setting:
>
> policy->cpuinfo.transition_latency = <mtk_value_here>;
>
> Example, when this latency value comes from FW [1]
>
OK, I will add it in v9.
> > +
> > + /* Let CPUs leave idle-off state for SVS CPU initializing */
> > + cpu_latency_qos_add_request(qos_request, 0);
> > +
> > + /* HW should be in enabled state to proceed now */
> > + writel_relaxed(0x1, c->reg_bases[REG_FREQ_ENABLE]);
> > +
> > + if (readl_poll_timeout(c->reg_bases[REG_FREQ_HW_STATE], sig,
> > + (sig & pwr_hw) == pwr_hw, POLL_USEC,
> > + TIMEOUT_USEC)) {
> > + if (!(sig & CPUFREQ_HW_STATUS)) {
> > + pr_info("cpufreq hardware of CPU%d is not enabled\n",
> > + policy->cpu);
> > + return -ENODEV;
> > + }
> > +
> > + pr_info("SVS of CPU%d is not enabled\n", policy->cpu);
> > + }
> > +
> > + em_dev_register_perf_domain(cpu_dev, c->nr_opp, &em_cb, policy->cpus);
>
> Please keep in mind that this is going to be changed soon with a new
> argument: 'milliwatts'. It's queued in pm/linux-next [2].
>
OK, thanks for the remind.
> Regards,
> Lukasz
>
> [1]
> https://elixir.bootlin.com/linux/latest/source/drivers/cpufreq/scmi-cpufreq.c#L194
> [2]
> https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/commit/?h=linux-next&id=c250d50fe2ce627ca9805d9c8ac11cbbf922a4a6