On Wed, Nov 09, 2022 at 01:31:20PM +0530, Manivannan Sadhasivam wrote:
> Qcom CPUFreq hardware (EPSS/OSM) controls clock and voltage to the CPU
> cores. But this relationship is not represented with the clk framework
> so far.
>
> So, let's make the qcom-cpufreq-hw driver a clock provider. This makes the
> clock producer/consumer relationship cleaner and is also useful for CPU
> related frameworks like OPP to know the frequency at which the CPUs are
> running.
>
> The clock frequency provided by the driver is for each frequency domain.
> We cannot get the frequency of each CPU core because, not all platforms
> support per-core DCVS feature.
>
> Also the frequency supplied by the driver is the actual frequency that
> comes out of the EPSS/OSM block after the DCVS operation. This frequency is
> not same as what the CPUFreq framework has set but it is the one that gets
> supplied to the CPUs after throttling by LMh.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> ---
> drivers/cpufreq/qcom-cpufreq-hw.c | 41 +++++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index 5e0598730a04..c0e4b223f9c1 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -672,6 +693,26 @@ static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
>
> data->base = base;
> data->res = res;
> +
> + /* Register CPU clock for each frequency domain */
> + clk_init.name = devm_kasprintf(dev, GFP_KERNEL, "qcom_cpufreq%d", i);
This is still an allocation and can in theory fail.
But it is also unnecessary to keep these around after registering the
clocks so it's better to just reuse a single stack allocated buffer for
this.
> + clk_init.flags = CLK_GET_RATE_NOCACHE;
> + clk_init.ops = &qcom_cpufreq_hw_clk_ops;
> + data->cpu_clk.init = &clk_init;
> +
> + ret = devm_clk_hw_register(dev, &data->cpu_clk);
> + if (ret < 0) {
> + dev_err(dev, "Failed to register Qcom CPUFreq clock(%d)\n", i);
nit: This looks unnecessarily verbose. Using
"failed to register clock %d: %d\n", i, ret
should do just fine as you are using dev_err().
> + return ret;
> + }
> +
> + clk_data->hws[i] = &data->cpu_clk;
> + }
> +
> + ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, clk_data);
> + if (ret < 0) {
> + dev_err(dev, "Failed to add Qcom CPUFreq clock provider\n");
> + return ret;
> }
>
> ret = cpufreq_register_driver(&cpufreq_qcom_hw_driver);
Johan
