Re: [PATCH 2/7] arm-cci: Cleanup PMU driver code

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"Suzuki K. Poulose" <suzuki.poulose@xxxxxxx> writes:

> From: "Suzuki K. Poulose" <suzuki.poulose@xxxxxxx>
>
> This patch gets rid of the global struct cci_pmu variable and makes
> the code use the cci_pmu explicitly. Makes code a bit more robust
> and reader friendly.
>
> Cc: Punit Agrawal <punit.agrawal@xxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>

Acked-by: Punit Agrawal <punit.agrawal@xxxxxxx>

> ---
>  drivers/bus/arm-cci.c |  142 ++++++++++++++++++++++++++++---------------------
>  1 file changed, 80 insertions(+), 62 deletions(-)
>
> diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
> index 941b831..27cc200 100644
> --- a/drivers/bus/arm-cci.c
> +++ b/drivers/bus/arm-cci.c
> @@ -124,9 +124,9 @@ struct cci_pmu {
>  	int num_events;
>  	atomic_t active_events;
>  	struct mutex reserve_mutex;
> +	struct notifier_block cpu_nb;
>  	cpumask_t cpus;
>  };
> -static struct cci_pmu *pmu;
>  
>  #define to_cci_pmu(c)	(container_of(c, struct cci_pmu, pmu))
>  
> @@ -179,7 +179,7 @@ enum cci400_perf_events {
>  #define CCI_REV_R1_MASTER_PORT_MIN_EV	0x00
>  #define CCI_REV_R1_MASTER_PORT_MAX_EV	0x11
>  
> -static int pmu_validate_hw_event(unsigned long hw_event)
> +static int pmu_validate_hw_event(struct cci_pmu *cci_pmu, unsigned long hw_event)
>  {
>  	u8 ev_source = CCI_PMU_EVENT_SOURCE(hw_event);
>  	u8 ev_code = CCI_PMU_EVENT_CODE(hw_event);
> @@ -207,8 +207,8 @@ static int pmu_validate_hw_event(unsigned long hw_event)
>  		return -ENOENT;
>  	}
>  
> -	if (ev_code >= pmu->model->event_ranges[if_type].min &&
> -		ev_code <= pmu->model->event_ranges[if_type].max)
> +	if (ev_code >= cci_pmu->model->event_ranges[if_type].min &&
> +		ev_code <= cci_pmu->model->event_ranges[if_type].max)
>  		return hw_event;
>  
>  	return -ENOENT;
> @@ -239,29 +239,31 @@ static int pmu_is_valid_counter(struct cci_pmu *cci_pmu, int idx)
>  		idx <= CCI_PMU_CNTR_LAST(cci_pmu);
>  }
>  
> -static u32 pmu_read_register(int idx, unsigned int offset)
> +static u32 pmu_read_register(struct cci_pmu *cci_pmu, int idx, unsigned int offset)
>  {
> -	return readl_relaxed(pmu->base + CCI_PMU_CNTR_BASE(idx) + offset);
> +	return readl_relaxed(cci_pmu->base + CCI_PMU_CNTR_BASE(idx) + offset);
>  }
>  
> -static void pmu_write_register(u32 value, int idx, unsigned int offset)
> +static void pmu_write_register(struct cci_pmu *cci_pmu, u32 value,
> +			       int idx, unsigned int offset)
>  {
> -	return writel_relaxed(value, pmu->base + CCI_PMU_CNTR_BASE(idx) + offset);
> +	return writel_relaxed(value, cci_pmu->base +
> +			      CCI_PMU_CNTR_BASE(idx) + offset);
>  }
>  
> -static void pmu_disable_counter(int idx)
> +static void pmu_disable_counter(struct cci_pmu *cci_pmu, int idx)
>  {
> -	pmu_write_register(0, idx, CCI_PMU_CNTR_CTRL);
> +	pmu_write_register(cci_pmu, 0, idx, CCI_PMU_CNTR_CTRL);
>  }
>  
> -static void pmu_enable_counter(int idx)
> +static void pmu_enable_counter(struct cci_pmu *cci_pmu, int idx)
>  {
> -	pmu_write_register(1, idx, CCI_PMU_CNTR_CTRL);
> +	pmu_write_register(cci_pmu, 1, idx, CCI_PMU_CNTR_CTRL);
>  }
>  
> -static void pmu_set_event(int idx, unsigned long event)
> +static void pmu_set_event(struct cci_pmu *cci_pmu, int idx, unsigned long event)
>  {
> -	pmu_write_register(event, idx, CCI_PMU_EVT_SEL);
> +	pmu_write_register(cci_pmu, event, idx, CCI_PMU_EVT_SEL);
>  }
>  
>  static u32 pmu_get_max_counters(void)
> @@ -306,7 +308,8 @@ static int pmu_map_event(struct perf_event *event)
>  	if (config == CCI_PMU_CYCLES)
>  		mapping = config;
>  	else
> -		mapping = pmu_validate_hw_event(config);
> +		mapping = pmu_validate_hw_event(to_cci_pmu(event->pmu),
> +							config);
>  
>  	return mapping;
>  }
> @@ -319,7 +322,7 @@ static int pmu_request_irq(struct cci_pmu *cci_pmu, irq_handler_t handler)
>  	if (unlikely(!pmu_device))
>  		return -ENODEV;
>  
> -	if (pmu->nr_irqs < 1) {
> +	if (cci_pmu->nr_irqs < 1) {
>  		dev_err(&pmu_device->dev, "no irqs for CCI PMUs defined\n");
>  		return -ENODEV;
>  	}
> @@ -331,16 +334,16 @@ static int pmu_request_irq(struct cci_pmu *cci_pmu, irq_handler_t handler)
>  	 *
>  	 * This should allow handling of non-unique interrupt for the counters.
>  	 */
> -	for (i = 0; i < pmu->nr_irqs; i++) {
> -		int err = request_irq(pmu->irqs[i], handler, IRQF_SHARED,
> +	for (i = 0; i < cci_pmu->nr_irqs; i++) {
> +		int err = request_irq(cci_pmu->irqs[i], handler, IRQF_SHARED,
>  				"arm-cci-pmu", cci_pmu);
>  		if (err) {
>  			dev_err(&pmu_device->dev, "unable to request IRQ%d for ARM CCI PMU counters\n",
> -				pmu->irqs[i]);
> +				cci_pmu->irqs[i]);
>  			return err;
>  		}
>  
> -		set_bit(i, &pmu->active_irqs);
> +		set_bit(i, &cci_pmu->active_irqs);
>  	}
>  
>  	return 0;
> @@ -350,11 +353,11 @@ static void pmu_free_irq(struct cci_pmu *cci_pmu)
>  {
>  	int i;
>  
> -	for (i = 0; i < pmu->nr_irqs; i++) {
> -		if (!test_and_clear_bit(i, &pmu->active_irqs))
> +	for (i = 0; i < cci_pmu->nr_irqs; i++) {
> +		if (!test_and_clear_bit(i, &cci_pmu->active_irqs))
>  			continue;
>  
> -		free_irq(pmu->irqs[i], cci_pmu);
> +		free_irq(cci_pmu->irqs[i], cci_pmu);
>  	}
>  }
>  
> @@ -369,7 +372,7 @@ static u32 pmu_read_counter(struct perf_event *event)
>  		dev_err(&cci_pmu->plat_device->dev, "Invalid CCI PMU counter %d\n", idx);
>  		return 0;
>  	}
> -	value = pmu_read_register(idx, CCI_PMU_CNTR);
> +	value = pmu_read_register(cci_pmu, idx, CCI_PMU_CNTR);
>  
>  	return value;
>  }
> @@ -383,7 +386,7 @@ static void pmu_write_counter(struct perf_event *event, u32 value)
>  	if (unlikely(!pmu_is_valid_counter(cci_pmu, idx)))
>  		dev_err(&cci_pmu->plat_device->dev, "Invalid CCI PMU counter %d\n", idx);
>  	else
> -		pmu_write_register(value, idx, CCI_PMU_CNTR);
> +		pmu_write_register(cci_pmu, value, idx, CCI_PMU_CNTR);
>  }
>  
>  static u64 pmu_event_update(struct perf_event *event)
> @@ -427,7 +430,7 @@ static irqreturn_t pmu_handle_irq(int irq_num, void *dev)
>  {
>  	unsigned long flags;
>  	struct cci_pmu *cci_pmu = dev;
> -	struct cci_pmu_hw_events *events = &pmu->hw_events;
> +	struct cci_pmu_hw_events *events = &cci_pmu->hw_events;
>  	int idx, handled = IRQ_NONE;
>  
>  	raw_spin_lock_irqsave(&events->pmu_lock, flags);
> @@ -446,11 +449,12 @@ static irqreturn_t pmu_handle_irq(int irq_num, void *dev)
>  		hw_counter = &event->hw;
>  
>  		/* Did this counter overflow? */
> -		if (!(pmu_read_register(idx, CCI_PMU_OVRFLW) &
> +		if (!(pmu_read_register(cci_pmu, idx, CCI_PMU_OVRFLW) &
>  		      CCI_PMU_OVRFLW_FLAG))
>  			continue;
>  
> -		pmu_write_register(CCI_PMU_OVRFLW_FLAG, idx, CCI_PMU_OVRFLW);
> +		pmu_write_register(cci_pmu, CCI_PMU_OVRFLW_FLAG, idx,
> +							CCI_PMU_OVRFLW);
>  
>  		pmu_event_update(event);
>  		pmu_event_set_period(event);
> @@ -549,10 +553,10 @@ static void cci_pmu_start(struct perf_event *event, int pmu_flags)
>  
>  	/* Configure the event to count, unless you are counting cycles */
>  	if (idx != CCI_PMU_CYCLE_CNTR_IDX)
> -		pmu_set_event(idx, hwc->config_base);
> +		pmu_set_event(cci_pmu, idx, hwc->config_base);
>  
>  	pmu_event_set_period(event);
> -	pmu_enable_counter(idx);
> +	pmu_enable_counter(cci_pmu, idx);
>  
>  	raw_spin_unlock_irqrestore(&hw_events->pmu_lock, flags);
>  }
> @@ -575,7 +579,7 @@ static void cci_pmu_stop(struct perf_event *event, int pmu_flags)
>  	 * We always reprogram the counter, so ignore PERF_EF_UPDATE. See
>  	 * cci_pmu_start()
>  	 */
> -	pmu_disable_counter(idx);
> +	pmu_disable_counter(cci_pmu, idx);
>  	pmu_event_update(event);
>  	hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
>  }
> @@ -779,20 +783,27 @@ static int cci_pmu_event_init(struct perf_event *event)
>  	return err;
>  }
>  
> -static ssize_t pmu_attr_cpumask_show(struct device *dev,
> +static ssize_t pmu_cpumask_attr_show(struct device *dev,
>  				     struct device_attribute *attr, char *buf)
>  {
> +	struct dev_ext_attribute *eattr = container_of(attr,
> +					struct dev_ext_attribute, attr);
> +	struct cci_pmu *cci_pmu = eattr->var;
> +
>  	int n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
> -			  cpumask_pr_args(&pmu->cpus));
> +			  cpumask_pr_args(&cci_pmu->cpus));
>  	buf[n++] = '\n';
>  	buf[n] = '\0';
>  	return n;
>  }
>  
> -static DEVICE_ATTR(cpumask, S_IRUGO, pmu_attr_cpumask_show, NULL);
> +static struct dev_ext_attribute pmu_cpumask_attr = {
> +	__ATTR(cpumask, S_IRUGO, pmu_cpumask_attr_show, NULL),
> +	NULL,		/* Populated in cci_pmu_init */
> +};
>  
>  static struct attribute *pmu_attrs[] = {
> -	&dev_attr_cpumask.attr,
> +	&pmu_cpumask_attr.attr.attr,
>  	NULL,
>  };
>  
> @@ -808,6 +819,8 @@ static const struct attribute_group *pmu_attr_groups[] = {
>  static int cci_pmu_init(struct cci_pmu *cci_pmu, struct platform_device *pdev)
>  {
>  	char *name = cci_pmu->model->name;
> +
> +	pmu_cpumask_attr.var = cci_pmu;
>  	cci_pmu->pmu = (struct pmu) {
>  		.name		= cci_pmu->model->name,
>  		.task_ctx_nr	= perf_invalid_context,
> @@ -831,12 +844,14 @@ static int cci_pmu_init(struct cci_pmu *cci_pmu, struct platform_device *pdev)
>  static int cci_pmu_cpu_notifier(struct notifier_block *self,
>  				unsigned long action, void *hcpu)
>  {
> +	struct cci_pmu *cci_pmu = container_of(self,
> +					struct cci_pmu, cpu_nb);
>  	unsigned int cpu = (long)hcpu;
>  	unsigned int target;
>  
>  	switch (action & ~CPU_TASKS_FROZEN) {
>  	case CPU_DOWN_PREPARE:
> -		if (!cpumask_test_and_clear_cpu(cpu, &pmu->cpus))
> +		if (!cpumask_test_and_clear_cpu(cpu, &cci_pmu->cpus))
>  			break;
>  		target = cpumask_any_but(cpu_online_mask, cpu);
>  		if (target < 0) // UP, last CPU
> @@ -845,7 +860,7 @@ static int cci_pmu_cpu_notifier(struct notifier_block *self,
>  		 * TODO: migrate context once core races on event->ctx have
>  		 * been fixed.
>  		 */
> -		cpumask_set_cpu(target, &pmu->cpus);
> +		cpumask_set_cpu(target, &cci_pmu->cpus);
>  	default:
>  		break;
>  	}
> @@ -853,15 +868,6 @@ static int cci_pmu_cpu_notifier(struct notifier_block *self,
>  	return NOTIFY_OK;
>  }
>  
> -static struct notifier_block cci_pmu_cpu_nb = {
> -	.notifier_call	= cci_pmu_cpu_notifier,
> -	/*
> -	 * to migrate uncore events, our notifier should be executed
> -	 * before perf core's notifier.
> -	 */
> -	.priority	= CPU_PRI_PERF + 1,
> -};
> -
>  static struct cci_pmu_model cci_pmu_models[] = {
>  	[CCI_REV_R0] = {
>  		.name = "CCI_400",
> @@ -935,6 +941,7 @@ static bool is_duplicate_irq(int irq, int *irqs, int nr_irqs)
>  static int cci_pmu_probe(struct platform_device *pdev)
>  {
>  	struct resource *res;
> +	struct cci_pmu *cci_pmu;
>  	int i, ret, irq;
>  	const struct cci_pmu_model *model;
>  
> @@ -944,30 +951,30 @@ static int cci_pmu_probe(struct platform_device *pdev)
>  		return -ENODEV;
>  	}
>  
> -	pmu = devm_kzalloc(&pdev->dev, sizeof(*pmu), GFP_KERNEL);
> -	if (!pmu)
> +	cci_pmu = devm_kzalloc(&pdev->dev, sizeof(*cci_pmu), GFP_KERNEL);
> +	if (!cci_pmu)
>  		return -ENOMEM;
>  
> -	pmu->model = model;
> +	cci_pmu->model = model;
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	pmu->base = devm_ioremap_resource(&pdev->dev, res);
> -	if (IS_ERR(pmu->base))
> +	cci_pmu->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(cci_pmu->base))
>  		return -ENOMEM;
>  
>  	/*
>  	 * CCI PMU has 5 overflow signals - one per counter; but some may be tied
>  	 * together to a common interrupt.
>  	 */
> -	pmu->nr_irqs = 0;
> +	cci_pmu->nr_irqs = 0;
>  	for (i = 0; i < CCI_PMU_MAX_HW_EVENTS; i++) {
>  		irq = platform_get_irq(pdev, i);
>  		if (irq < 0)
>  			break;
>  
> -		if (is_duplicate_irq(irq, pmu->irqs, pmu->nr_irqs))
> +		if (is_duplicate_irq(irq, cci_pmu->irqs, cci_pmu->nr_irqs))
>  			continue;
>  
> -		pmu->irqs[pmu->nr_irqs++] = irq;
> +		cci_pmu->irqs[cci_pmu->nr_irqs++] = irq;
>  	}
>  
>  	/*
> @@ -980,20 +987,31 @@ static int cci_pmu_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> -	raw_spin_lock_init(&pmu->hw_events.pmu_lock);
> -	mutex_init(&pmu->reserve_mutex);
> -	atomic_set(&pmu->active_events, 0);
> -	cpumask_set_cpu(smp_processor_id(), &pmu->cpus);
> +	raw_spin_lock_init(&cci_pmu->hw_events.pmu_lock);
> +	mutex_init(&cci_pmu->reserve_mutex);
> +	atomic_set(&cci_pmu->active_events, 0);
> +	cpumask_set_cpu(smp_processor_id(), &cci_pmu->cpus);
>  
> -	ret = register_cpu_notifier(&cci_pmu_cpu_nb);
> +	cci_pmu->cpu_nb = (struct notifier_block) {
> +		.notifier_call	= cci_pmu_cpu_notifier,
> +		/*
> +		 * to migrate uncore events, our notifier should be executed
> +		 * before perf core's notifier.
> +		 */
> +		.priority	= CPU_PRI_PERF + 1,
> +	};
> +
> +	ret = register_cpu_notifier(&cci_pmu->cpu_nb);
>  	if (ret)
>  		return ret;
>  
> -	ret = cci_pmu_init(pmu, pdev);
> -	if (ret)
> +	ret = cci_pmu_init(cci_pmu, pdev);
> +	if (ret) {
> +		unregister_cpu_notifier(&cci_pmu->cpu_nb);
>  		return ret;
> +	}
>  
> -	pr_info("ARM %s PMU driver probed", pmu->model->name);
> +	pr_info("ARM %s PMU driver probed", cci_pmu->model->name);
>  	return 0;
>  }
--
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