cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support

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>
[Viresh: Added changes for arch_topology.c to fix build errors ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 921312a..4340766 100644 (file)
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -149,6 +149,7 @@ void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
 }
 
 DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
+EXPORT_PER_CPU_SYMBOL_GPL(cpu_scale);
 
 void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
 {
@@ -165,6 +166,7 @@ void topology_set_thermal_pressure(const struct cpumask *cpus,
        for_each_cpu(cpu, cpus)
                WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
 }
+EXPORT_SYMBOL_GPL(topology_set_thermal_pressure);
 
 static ssize_t cpu_capacity_show(struct device *dev,
                                 struct device_attribute *attr,

diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index c2e71c4..6c2086c 100644 (file)
--- 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;
 };
@@ -34,6 +39,16 @@ struct qcom_cpufreq_data {
        void __iomem *base;
        struct resource *res;
        const struct qcom_cpufreq_soc_data *soc_data;
+
+       /*
+        * Mutex to synchronize between de-init sequence and re-starting LMh
+        * polling/interrupts
+        */
+       struct mutex throttle_lock;
+       int throttle_irq;
+       bool cancel_throttle;
+       struct delayed_work throttle_work;
+       struct cpufreq_policy *policy;
 };
 
 static unsigned long cpu_hw_rate, xo_rate;
@@ -251,10 +266,92 @@ 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)
+{
+       unsigned long max_capacity, capacity, freq_hz, throttled_freq;
+       struct cpufreq_policy *policy = data->policy;
+       int cpu = cpumask_first(policy->cpus);
+       struct device *dev = get_cpu_device(cpu);
+       struct dev_pm_opp *opp;
+       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;
+
+       opp = dev_pm_opp_find_freq_floor(dev, &freq_hz);
+       if (IS_ERR(opp) && PTR_ERR(opp) == -ERANGE)
+               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(cpu);
+       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 policy is unregistered do not enable
+        * polling or h/w interrupt
+        */
+       mutex_lock(&data->throttle_lock);
+       if (data->cancel_throttle)
+               goto out;
+
+       /*
+        * If h/w throttled frequency is higher than what cpufreq has requested
+        * for, then stop polling and switch back to interrupt mechanism.
+        */
+       if (throttled_freq >= qcom_cpufreq_hw_get(cpu))
+               enable_irq(data->throttle_irq);
+       else
+               mod_delayed_work(system_highpri_wq, &data->throttle_work,
+                                msecs_to_jiffies(10));
+
+out:
+       mutex_unlock(&data->throttle_lock);
+}
+
+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 +371,51 @@ 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;
+
+       mutex_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;
+
+       mutex_lock(&data->throttle_lock);
+       data->cancel_throttle = true;
+       mutex_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();
@@ -368,6 +510,10 @@ 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);
@@ -387,6 +533,7 @@ 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);