[3/5] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support

Message ID 20210608222926.2707768-4-thara.gopinath@linaro.org
State New
Headers show
Series
  • [1/5] firmware: qcom_scm: Introduce SCM calls to access LMh
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Commit Message

Thara Gopinath June 8, 2021, 10:29 p.m.
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>
---
 drivers/cpufreq/qcom-cpufreq-hw.c | 100 ++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

Comments

Viresh Kumar June 14, 2021, 10:31 a.m. | #1
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@linaro.org>

> ---

>  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 ?

> +	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.

> +	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 ?

> +	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..

> +}

> +

> +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.

> +	/**

> +	 * 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 ?

>  	.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.

>  

>  	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.

> +		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.

> +		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);


-- 
viresh
Thara Gopinath June 15, 2021, 1:58 a.m. | #2
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@linaro.org>

>> ---

>>   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)
Bjorn Andersson June 18, 2021, 6:16 p.m. | #3
On Tue 08 Jun 17:29 CDT 2021, Thara Gopinath wrote:
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
[..]
> @@ -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");

Rather than adding a new interrupt _and_ a flag to tell the driver that
this new interrupt should be used, wouldn't it be sufficient to just see
if the interrupt is specified?

> +
>  	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) {
> +		data->lmh_dcvs_irq = platform_get_irq(pdev, index);
> +		if (data->lmh_dcvs_irq < 0) {

This will be -ENXIO if the interrupt isn't specified and <0 for other
errors, so you should be able to distinguish the two failure cases.

Regards,
Bjorn

> +			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);
> +		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);
> -- 
> 2.25.1
>
Thara Gopinath June 18, 2021, 9:55 p.m. | #4
On 6/18/21 2:16 PM, Bjorn Andersson wrote:
> On Tue 08 Jun 17:29 CDT 2021, Thara Gopinath wrote:

>> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c

> [..]

>> @@ -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");

> 

> Rather than adding a new interrupt _and_ a flag to tell the driver that

> this new interrupt should be used, wouldn't it be sufficient to just see

> if the interrupt is specified?


Yes. you are right. It should be. Though when I wrote it there was some 
reason which I forget now. I will remove it.

-- 
Warm Regards
Thara (She/Her/Hers)

> 

>> +

>>   	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) {

>> +		data->lmh_dcvs_irq = platform_get_irq(pdev, index);

>> +		if (data->lmh_dcvs_irq < 0) {

> 

> This will be -ENXIO if the interrupt isn't specified and <0 for other

> errors, so you should be able to distinguish the two failure cases.

> 

> Regards,

> Bjorn

> 

>> +			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);

>> +		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);

>> -- 

>> 2.25.1

>>

Patch

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 ? */
+	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;
+
+	cpufreq_get_policy(&policy, cpumask_first(data->cpus));
+
+	/* Update thermal pressure */
+	max_capacity = arch_scale_cpu_capacity(cpumask_first(data->cpus));
+	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);
+}
+
+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);
+	/**
+	 * 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,
 	.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;
 
 	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) {
+		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);
+		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);