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@xxxxxxxxxx> --- v3->v4: - Dropped devm_ versions of request_irq and free_irq as per comments on mailing list. - Introduced locking to prevent race between LMh de-init sequence and re-enabling of interrupts/polling after a thermal throttle event. - Moved the LMh de-init sequence to qcom_cpufreq_hw_lmh_exit as per Viresh's review comments - Code rearrangement as per Bjorn's review comments. - Moved the interrupt handling to threaded interrupt handling since Steev reported some scheduling while atomic bug on the mailing list. v2->v3: - Cosmetic fixes from review comments on the list. - Moved all LMh initializations to qcom_cpufreq_hw_lmh_init. - Added freeing of LMh interrupt and cancelling the polling worker to qcom_cpufreq_hw_cpu_exit as per Viresh's suggestion. - LMh interrupts are now tied to cpu dev and not cpufreq dev. This will be useful for further generation of SoCs where the same interrupt signals multiple cpu clusters. 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 | 142 ++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c index f86859bf76f1..3cc27d9e2ed1 100644 --- a/drivers/cpufreq/qcom-cpufreq-hw.c +++ b/drivers/cpufreq/qcom-cpufreq-hw.c @@ -7,12 +7,14 @@ #include <linux/cpufreq.h> #include <linux/init.h> #include <linux/interconnect.h> +#include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of_address.h> #include <linux/of_platform.h> #include <linux/pm_opp.h> #include <linux/slab.h> +#include <linux/spinlock.h> #define LUT_MAX_ENTRIES 40U #define LUT_SRC GENMASK(31, 30) @@ -22,10 +24,13 @@ #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 +38,13 @@ struct qcom_cpufreq_soc_data { struct qcom_cpufreq_data { void __iomem *base; struct resource *res; + struct delayed_work throttle_work; const struct qcom_cpufreq_soc_data *soc_data; + struct cpufreq_policy *policy; + /* Lock to synchronize between de-init sequence and re-starting LMh polling/interrupts */ + spinlock_t throttle_lock; + int throttle_irq; + bool cancel_throttle; }; static unsigned long cpu_hw_rate, xo_rate; @@ -251,10 +262,92 @@ static void qcom_get_related_cpus(int index, struct cpumask *m) } } +static unsigned int qcom_lmh_get_throttle_freq(struct qcom_cpufreq_data *data) +{ + unsigned int val = readl_relaxed(data->base + data->soc_data->reg_current_vote); + + 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 freq; + + /* + * Get the h/w throttled frequency, normalize it using the + * registered opp table and use it to calculate thermal pressure. + */ + freq = qcom_lmh_get_throttle_freq(data); + 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 = mult_frac(max_capacity, throttled_freq, policy->cpuinfo.max_freq); + /* Don't pass boost capacity to scheduler */ + if (capacity > max_capacity) + capacity = max_capacity; + + arch_set_thermal_pressure(policy->cpus, max_capacity - capacity); + + /* In the unlikely case cpufreq is de-registered do not enable polling or h/w interrupt */ + + spin_lock(&data->throttle_lock); + if (data->cancel_throttle) { + spin_unlock(&data->throttle_lock); + return; + } + spin_unlock(&data->throttle_lock); + + /* + * 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->throttle_irq); + else + mod_delayed_work(system_highpri_wq, &data->throttle_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, throttle_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->throttle_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 +367,50 @@ static const struct of_device_id qcom_cpufreq_hw_match[] = { }; MODULE_DEVICE_TABLE(of, qcom_cpufreq_hw_match); +static int qcom_cpufreq_hw_lmh_init(struct cpufreq_policy *policy, int index) +{ + struct qcom_cpufreq_data *data = policy->driver_data; + struct platform_device *pdev = cpufreq_get_driver_data(); + char irq_name[15]; + int ret; + + /* + * Look for LMh interrupt. If no interrupt line is specified / + * if there is an error, allow cpufreq to be enabled as usual. + */ + data->throttle_irq = platform_get_irq(pdev, index); + if (data->throttle_irq <= 0) + return data->throttle_irq == -EPROBE_DEFER ? -EPROBE_DEFER : 0; + + data->cancel_throttle = false; + data->policy = policy; + + spin_lock_init(&data->throttle_lock); + INIT_DEFERRABLE_WORK(&data->throttle_work, qcom_lmh_dcvs_poll); + + snprintf(irq_name, sizeof(irq_name), "dcvsh-irq-%u", policy->cpu); + ret = request_threaded_irq(data->throttle_irq, NULL, qcom_lmh_dcvs_handle_irq, + IRQF_ONESHOT, irq_name, data); + if (ret) { + dev_err(&pdev->dev, "Error registering %s: %d\n", irq_name, ret); + return 0; + } + + return 0; +} + +static void qcom_cpufreq_hw_lmh_exit(struct qcom_cpufreq_data *data) +{ + if (data->throttle_irq <= 0) + return; + + spin_lock(&data->throttle_lock); + data->cancel_throttle = true; + spin_unlock(&data->throttle_lock); + cancel_delayed_work_sync(&data->throttle_work); + free_irq(data->throttle_irq, data); +} + static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy) { struct platform_device *pdev = cpufreq_get_driver_data(); @@ -370,6 +507,10 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy) dev_warn(cpu_dev, "failed to enable boost: %d\n", ret); } + ret = qcom_cpufreq_hw_lmh_init(policy, index); + if (ret) + goto error; + return 0; error: kfree(data); @@ -389,6 +530,7 @@ static int qcom_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy) dev_pm_opp_remove_all_dynamic(cpu_dev); dev_pm_opp_of_cpumask_remove_table(policy->related_cpus); + qcom_cpufreq_hw_lmh_exit(data); kfree(policy->freq_table); kfree(data); iounmap(base); -- 2.25.1