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SubjectRe: [Patch v2 3/5] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
On 24-06-21, 07:58, Thara Gopinath wrote:
> Add interrupt support to notify the kernel of h/w initiated frequency
> throttling by LMh. Convey this to scheduler via thermal presssure
> interface.
>
> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> ---
>
> v1->v2:
> - Introduced qcom_cpufreq_hw_lmh_init to consolidate LMh related initializations
> as per Viresh's review comment.
> - Moved the piece of code restarting polling/re-enabling LMh interrupt to
> qcom_lmh_dcvs_notify therby simplifying isr and timer callback as per Viresh's
> suggestion.
> - Droped cpus from qcom_cpufreq_data and instead using cpus from cpufreq_policy in
> qcom_lmh_dcvs_notify as per Viresh's review comment.
> - Dropped dt property qcom,support-lmh as per Bjorn's suggestion.
> - Other minor/cosmetic fixes
>
> drivers/cpufreq/qcom-cpufreq-hw.c | 103 ++++++++++++++++++++++++++++++
> 1 file changed, 103 insertions(+)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index f86859bf76f1..241f6f2b441f 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -13,6 +13,7 @@
> #include <linux/of_platform.h>
> #include <linux/pm_opp.h>
> #include <linux/slab.h>
> +#include <linux/interrupt.h>

Please don't break the alphabetical order here.

> #define LUT_MAX_ENTRIES 40U
> #define LUT_SRC GENMASK(31, 30)
> @@ -22,10 +23,13 @@
> #define CLK_HW_DIV 2
> #define LUT_TURBO_IND 1
>
> +#define HZ_PER_KHZ 1000
>
> struct qcom_cpufreq_soc_data {
> u32 reg_enable;
> u32 reg_freq_lut;
> u32 reg_volt_lut;
> + u32 reg_current_vote;
> u32 reg_perf_state;
> u8 lut_row_size;
> };
> @@ -33,7 +37,10 @@ struct qcom_cpufreq_soc_data {
> struct qcom_cpufreq_data {
> void __iomem *base;
> struct resource *res;
> + struct delayed_work lmh_dcvs_poll_work;
> const struct qcom_cpufreq_soc_data *soc_data;
> + struct cpufreq_policy *policy;
> + int lmh_dcvs_irq;
> };
>
> static unsigned long cpu_hw_rate, xo_rate;
> @@ -251,10 +258,79 @@ static void qcom_get_related_cpus(int index, struct cpumask *m)
> }
> }
>
> +static inline unsigned long qcom_lmh_vote_to_freq(u32 val)
> +{
> + return (val & 0x3FF) * 19200;
> +}
> +
> +static void qcom_lmh_dcvs_notify(struct qcom_cpufreq_data *data)
> +{
> + struct cpufreq_policy *policy = data->policy;
> + struct dev_pm_opp *opp;
> + struct device *dev;
> + unsigned long max_capacity, capacity, freq_hz, throttled_freq;
> + unsigned int val, freq;
> +
> + /*
> + * Get the h/w throttled frequency, normalize it using the
> + * registered opp table and use it to calculate thermal pressure.
> + */
> + val = readl_relaxed(data->base + data->soc_data->reg_current_vote);
> + freq = qcom_lmh_vote_to_freq(val);
> + freq_hz = freq * HZ_PER_KHZ;
> +
> + dev = get_cpu_device(cpumask_first(policy->cpus));
> + opp = dev_pm_opp_find_freq_floor(dev, &freq_hz);
> + if (IS_ERR(opp) && PTR_ERR(opp) == -ERANGE)
> + opp = dev_pm_opp_find_freq_ceil(dev, &freq_hz);
> +
> + throttled_freq = freq_hz / HZ_PER_KHZ;
> +
> + /* Update thermal pressure */
> + max_capacity = arch_scale_cpu_capacity(cpumask_first(policy->cpus));
> + capacity = throttled_freq * max_capacity;
> + capacity /= policy->cpuinfo.max_freq;
> + /* Don't pass boost capacity to scheduler */
> + if (capacity > max_capacity)
> + capacity = max_capacity;

I wonder why this check isn't present for cpufreq_cooling.c .

> + arch_set_thermal_pressure(policy->cpus, max_capacity - capacity);
> + /*

Whenever you mix code and comments, please separate them with a blank
line, else it becomes a bit messy and harder to read.

> + * If h/w throttled frequency is higher than what cpufreq has requested for, stop
> + * polling and switch back to interrupt mechanism
> + */
> + if (throttled_freq >= qcom_cpufreq_hw_get(cpumask_first(policy->cpus)))
> + /* Clear the existing interrupts and enable it back */
> + enable_irq(data->lmh_dcvs_irq);
> + else
> + mod_delayed_work(system_highpri_wq, &data->lmh_dcvs_poll_work,
> + msecs_to_jiffies(10));
> +}
> +
> +static void qcom_lmh_dcvs_poll(struct work_struct *work)
> +{
> + struct qcom_cpufreq_data *data;
> +
> + data = container_of(work, struct qcom_cpufreq_data, lmh_dcvs_poll_work.work);
> +
> + qcom_lmh_dcvs_notify(data);
> +}
> +
> +static irqreturn_t qcom_lmh_dcvs_handle_irq(int irq, void *data)
> +{
> + struct qcom_cpufreq_data *c_data = data;
> +
> + /* Disable interrupt and enable polling */
> + disable_irq_nosync(c_data->lmh_dcvs_irq);
> + qcom_lmh_dcvs_notify(c_data);
> +
> + return 0;
> +}
> +
> static const struct qcom_cpufreq_soc_data qcom_soc_data = {
> .reg_enable = 0x0,
> .reg_freq_lut = 0x110,
> .reg_volt_lut = 0x114,
> + .reg_current_vote = 0x704,
> .reg_perf_state = 0x920,
> .lut_row_size = 32,
> };
> @@ -274,6 +350,23 @@ static const struct of_device_id qcom_cpufreq_hw_match[] = {
> };
> MODULE_DEVICE_TABLE(of, qcom_cpufreq_hw_match);
>
> +static void qcom_cpufreq_hw_lmh_init(struct cpufreq_policy *policy)
> +{
> + struct qcom_cpufreq_data *data = policy->driver_data;
> + struct platform_device *pdev = cpufreq_get_driver_data();
> + struct device *dev = &pdev->dev;
> + int ret;
> +
> + ret = devm_request_irq(dev, data->lmh_dcvs_irq, qcom_lmh_dcvs_handle_irq,
> + 0, "dcvsh-irq", data);
> + if (ret) {
> + dev_err(dev, "Error %d registering irq %x\n", ret, data->lmh_dcvs_irq);
> + return;
> + }
> + data->policy = policy;
> + INIT_DEFERRABLE_WORK(&data->lmh_dcvs_poll_work, qcom_lmh_dcvs_poll);
> +}
> +
> static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
> {
> struct platform_device *pdev = cpufreq_get_driver_data();
> @@ -370,6 +463,16 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
> dev_warn(cpu_dev, "failed to enable boost: %d\n", ret);
> }
>
> + /* Look for LMh interrupt. If no interrupt line is specified /
> + * if there is an error, allow cpufreq to be enabled as usual.
> + */

Proper comment style please..

> + data->lmh_dcvs_irq = platform_get_irq(pdev, index);
> + if (data->lmh_dcvs_irq > 0) {
> + qcom_cpufreq_hw_lmh_init(policy);
> + } else if (data->lmh_dcvs_irq != -ENXIO) {
> + ret = data->lmh_dcvs_irq;
> + goto error;
> + }

Move all of this to qcom_cpufreq_hw_lmh_init().

And I don't see any cleanup for this stuff. There is no guarantee that
the irq won't fire and queue up a work right after cpufreq driver is
unregistered and before the devm_ stuff gets released.

> return 0;
> error:
> kfree(data);
> --
> 2.25.1

--
viresh

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