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
