Re: [PATCH v2 3/3] irqchip/qcom-pdc: Start getting rid of the GPIO_NO_WAKE_IRQ

[Marc Zyngier <maz@kernel.org>]

On Thu, 19 Aug 2021 12:53:13 +0100,
Maulik Shah <mkshah@codeaurora.org> wrote:
> 
> From: Marc Zyngier <maz@kernel.org>
> 
> gpio_to_irq() reports error at irq_domain_trim_hierarchy() for non
> wakeup capable GPIOs that do not have dedicated interrupt at GIC.
> 
> Since PDC irqchip do not allocate irq at parent GIC domain for such
> GPIOs indicate same by using irq_domain_disconnect_hierarchy() for
> PDC and parent GIC domains.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> [mkshah: Add loop to disconnect for all parents]
> Tested-by: Maulik Shah <mkshah@codeaurora.org>
> ---
>  drivers/irqchip/qcom-pdc.c | 75 +++++++++++-----------------------------------
>  1 file changed, 18 insertions(+), 57 deletions(-)
> 
> diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
> index 32d5920..696afca 100644
> --- a/drivers/irqchip/qcom-pdc.c
> +++ b/drivers/irqchip/qcom-pdc.c
> @@ -53,26 +53,6 @@ static u32 pdc_reg_read(int reg, u32 i)
>  	return readl_relaxed(pdc_base + reg + i * sizeof(u32));
>  }
>  
> -static int qcom_pdc_gic_get_irqchip_state(struct irq_data *d,
> -					  enum irqchip_irq_state which,
> -					  bool *state)
> -{
> -	if (d->hwirq == GPIO_NO_WAKE_IRQ)
> -		return 0;
> -
> -	return irq_chip_get_parent_state(d, which, state);
> -}
> -
> -static int qcom_pdc_gic_set_irqchip_state(struct irq_data *d,
> -					  enum irqchip_irq_state which,
> -					  bool value)
> -{
> -	if (d->hwirq == GPIO_NO_WAKE_IRQ)
> -		return 0;
> -
> -	return irq_chip_set_parent_state(d, which, value);
> -}
> -
>  static void pdc_enable_intr(struct irq_data *d, bool on)
>  {
>  	int pin_out = d->hwirq;
> @@ -91,38 +71,16 @@ static void pdc_enable_intr(struct irq_data *d, bool on)
>  
>  static void qcom_pdc_gic_disable(struct irq_data *d)
>  {
> -	if (d->hwirq == GPIO_NO_WAKE_IRQ)
> -		return;
> -
>  	pdc_enable_intr(d, false);
>  	irq_chip_disable_parent(d);
>  }
>  
>  static void qcom_pdc_gic_enable(struct irq_data *d)
>  {
> -	if (d->hwirq == GPIO_NO_WAKE_IRQ)
> -		return;
> -
>  	pdc_enable_intr(d, true);
>  	irq_chip_enable_parent(d);
>  }
>  
> -static void qcom_pdc_gic_mask(struct irq_data *d)
> -{
> -	if (d->hwirq == GPIO_NO_WAKE_IRQ)
> -		return;
> -
> -	irq_chip_mask_parent(d);
> -}
> -
> -static void qcom_pdc_gic_unmask(struct irq_data *d)
> -{
> -	if (d->hwirq == GPIO_NO_WAKE_IRQ)
> -		return;
> -
> -	irq_chip_unmask_parent(d);
> -}
> -
>  /*
>   * GIC does not handle falling edge or active low. To allow falling edge and
>   * active low interrupts to be handled at GIC, PDC has an inverter that inverts
> @@ -159,14 +117,10 @@ enum pdc_irq_config_bits {
>   */
>  static int qcom_pdc_gic_set_type(struct irq_data *d, unsigned int type)
>  {
> -	int pin_out = d->hwirq;
>  	enum pdc_irq_config_bits pdc_type;
>  	enum pdc_irq_config_bits old_pdc_type;
>  	int ret;
>  
> -	if (pin_out == GPIO_NO_WAKE_IRQ)
> -		return 0;
> -
>  	switch (type) {
>  	case IRQ_TYPE_EDGE_RISING:
>  		pdc_type = PDC_EDGE_RISING;
> @@ -191,8 +145,8 @@ static int qcom_pdc_gic_set_type(struct irq_data *d, unsigned int type)
>  		return -EINVAL;
>  	}
>  
> -	old_pdc_type = pdc_reg_read(IRQ_i_CFG, pin_out);
> -	pdc_reg_write(IRQ_i_CFG, pin_out, pdc_type);
> +	old_pdc_type = pdc_reg_read(IRQ_i_CFG, d->hwirq);
> +	pdc_reg_write(IRQ_i_CFG, d->hwirq, pdc_type);
>  
>  	ret = irq_chip_set_type_parent(d, type);
>  	if (ret)
> @@ -216,12 +170,12 @@ static int qcom_pdc_gic_set_type(struct irq_data *d, unsigned int type)
>  static struct irq_chip qcom_pdc_gic_chip = {
>  	.name			= "PDC",
>  	.irq_eoi		= irq_chip_eoi_parent,
> -	.irq_mask		= qcom_pdc_gic_mask,
> -	.irq_unmask		= qcom_pdc_gic_unmask,
> +	.irq_mask		= irq_chip_mask_parent,
> +	.irq_unmask		= irq_chip_unmask_parent,
>  	.irq_disable		= qcom_pdc_gic_disable,
>  	.irq_enable		= qcom_pdc_gic_enable,
> -	.irq_get_irqchip_state	= qcom_pdc_gic_get_irqchip_state,
> -	.irq_set_irqchip_state	= qcom_pdc_gic_set_irqchip_state,
> +	.irq_get_irqchip_state	= irq_chip_get_parent_state,
> +	.irq_set_irqchip_state	= irq_chip_set_parent_state,
>  	.irq_retrigger		= irq_chip_retrigger_hierarchy,
>  	.irq_set_type		= qcom_pdc_gic_set_type,
>  	.flags			= IRQCHIP_MASK_ON_SUSPEND |
> @@ -282,7 +236,7 @@ static int qcom_pdc_alloc(struct irq_domain *domain, unsigned int virq,
>  
>  	parent_hwirq = get_parent_hwirq(hwirq);
>  	if (parent_hwirq == PDC_NO_PARENT_IRQ)
> -		return 0;
> +		return irq_domain_disconnect_hierarchy(domain->parent, virq);
>  
>  	if (type & IRQ_TYPE_EDGE_BOTH)
>  		type = IRQ_TYPE_EDGE_RISING;
> @@ -314,22 +268,29 @@ static int qcom_pdc_gpio_alloc(struct irq_domain *domain, unsigned int virq,
>  	irq_hw_number_t hwirq, parent_hwirq;
>  	unsigned int type;
>  	int ret;
> +	struct irq_domain *parent;
>  
>  	ret = qcom_pdc_translate(domain, fwspec, &hwirq, &type);
>  	if (ret)
>  		return ret;
>  
> +	if (hwirq == GPIO_NO_WAKE_IRQ) {
> +		for (parent = domain; parent; parent = parent->parent) {
> +			ret = irq_domain_disconnect_hierarchy(parent, virq);
> +			if (ret)
> +				return ret;
> +		}
> +		return 0;
> +	}
> +

No, this is wrong. Please read the documentation for
irq_domain_disconnect_hierarchy(): the disconnect can only take place
*once* per interrupt, right at the point where you need to terminate
the hierarchy.

irq_domain_trim_hierarchy() should already do the right thing by
iterating over the domains and free the unused irq_data.

	M.

-- 
Without deviation from the norm, progress is not possible.