Re: [PATCH 3/5] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
From: Thara Gopinath
Date: Mon Jun 14 2021 - 22:27:56 EST
On 6/14/21 6:31 AM, Viresh Kumar wrote:
On 08-06-21, 18:29, 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@xxxxxxxxxx>
---
drivers/cpufreq/qcom-cpufreq-hw.c | 100 ++++++++++++++++++++++++++++++
1 file changed, 100 insertions(+)
diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
index f86859bf76f1..95e17330aa9d 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>
#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 +37,11 @@ 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;
+ cpumask_var_t cpus;
+ unsigned long throttled_freq;
+ int lmh_dcvs_irq;
};
static unsigned long cpu_hw_rate, xo_rate;
@@ -251,10 +259,79 @@ 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;
+ struct dev_pm_opp *opp;
+ struct device *dev;
+ unsigned long max_capacity, capacity, freq_hz;
+ unsigned int val, freq;
+
+ val = readl_relaxed(data->base + data->soc_data->reg_current_vote);
+ freq = qcom_lmh_vote_to_freq(val);
+ freq_hz = freq * HZ_PER_KHZ;
+
+ /* Do I need to calculate ceil and floor ? */
You don't know ?
stray comment! Will remove it.
+ dev = get_cpu_device(cpumask_first(data->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);
+
+ data->throttled_freq = freq_hz / HZ_PER_KHZ;
+
What exactly are we trying to do here ? A comment would be good as
well.
You want me to put a comment saying converting frequency in hz to khz ?
+ cpufreq_get_policy(&policy, cpumask_first(data->cpus));
+
+ /* Update thermal pressure */
+ max_capacity = arch_scale_cpu_capacity(cpumask_first(data->cpus));
Set capacity of a single CPU from a policy ?
Get maximum capacity of a cpu.
+ capacity = data->throttled_freq * max_capacity;
+ capacity /= policy.cpuinfo.max_freq;
+ /* Don't pass boost capacity to scheduler */
+ if (capacity > max_capacity)
+ capacity = max_capacity;
+ arch_set_thermal_pressure(data->cpus, max_capacity - capacity);
You should really be using policy->cpus instead of allocating
data->cpus..
Yes I should be. But I still need data->cpus to get the policy.
+}
+
+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);
You should really move the below stuff the disable_irq_nosync(), it
will make your life easier.
I don't understand your comment here. I want to disable irq. call
notify. Start polling. And in polling I want to call notify and if the
thermal event has passed stop polling else continue polling.
+ /**
+ * If h/w throttled frequency is higher than what cpufreq has requested for, stop
+ * polling and switch back to interrupt mechanism
+ */
+ if (data->throttled_freq >= qcom_cpufreq_hw_get(cpumask_first(data->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 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);
+ mod_delayed_work(system_highpri_wq, &c_data->lmh_dcvs_poll_work, msecs_to_jiffies(10));
+
+ 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,
Should this be a different patch ?
Why ? This is the register to read the throttled frequency.
.reg_perf_state = 0x920,
.lut_row_size = 32,
};
@@ -285,6 +362,7 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
void __iomem *base;
struct qcom_cpufreq_data *data;
int ret, index;
+ bool lmh_mitigation_enabled = false;
You just overwrite it below, no need to initialize it.
Sure.
cpu_dev = get_cpu_device(policy->cpu);
if (!cpu_dev) {
@@ -305,6 +383,8 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
index = args.args[0];
+ lmh_mitigation_enabled = of_property_read_bool(pdev->dev.of_node, "qcom,support-lmh");
+
res = platform_get_resource(pdev, IORESOURCE_MEM, index);
if (!res) {
dev_err(dev, "failed to get mem resource %d\n", index);
@@ -329,6 +409,11 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
goto unmap_base;
}
+ if (!alloc_cpumask_var(&data->cpus, GFP_KERNEL)) {
+ ret = -ENOMEM;
+ goto unmap_base;
+ }
+
data->soc_data = of_device_get_match_data(&pdev->dev);
data->base = base;
data->res = res;
@@ -347,6 +432,7 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
goto error;
}
+ cpumask_copy(data->cpus, policy->cpus);
policy->driver_data = data;
ret = qcom_cpufreq_hw_read_lut(cpu_dev, policy);
@@ -370,6 +456,20 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
dev_warn(cpu_dev, "failed to enable boost: %d\n", ret);
}
+ if (lmh_mitigation_enabled) {
Shouldn't you move the allocation and setting of data->cpus here ? I
suggest creating a separate routine for all initialization around this
stuff.
I should considering nothing else is using data->cpus. Yes I will create
a separate init function.
+ data->lmh_dcvs_irq = platform_get_irq(pdev, index);
+ if (data->lmh_dcvs_irq < 0) {
+ ret = data->lmh_dcvs_irq;
+ goto error;
+ }
+ ret = devm_request_irq(dev, data->lmh_dcvs_irq, qcom_lmh_dcvs_handle_irq,
+ 0, "dcvsh-irq", data);
I would rather pass policy as data here.
So policy for a cpu can change runtime, right ?
+ if (ret) {
+ dev_err(dev, "Error %d registering irq %x\n", ret, data->lmh_dcvs_irq);
+ goto error;
+ }
+ INIT_DEFERRABLE_WORK(&data->lmh_dcvs_poll_work, qcom_lmh_dcvs_poll);
+ }
return 0;
error:
kfree(data);
--
Warm Regards
Thara (She/Her/Hers)