Re: [PATCH V1 1/2] irqchip/loongson-pch-pic: Support to set irq type for ACPI path

[Jianmin Lv]

On 2022/9/28 下午10:49, Marc Zyngier wrote:
> On Mon, 15 Aug 2022 22:01:30 -0400,
> Jianmin Lv <lvjianmin@xxxxxxxxxxx> wrote:
> > For ACPI path, the translate callback used IRQ_TYPE_NONE and ignored
> > the irq type in fwspec->param[1]. For supporting to set type for
> > irqs of the irqdomain, fwspec->param[1] should be used to get irq
> > type.
> >
> > On Loongson platform, the irq trigger type of PCI devices is
> > high level, so high level triggered type is inputed to acpi_register_gsi
> > when create irq mapping for PCI devices.
> >
> > Signed-off-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> > ---
> >   drivers/acpi/pci_irq.c                 |  3 ++-
> >   drivers/irqchip/irq-loongson-pch-pic.c | 10 ++++++----
> >   2 files changed, 8 insertions(+), 5 deletions(-)
>
> $ ./scripts/get_maintainer.pl drivers/acpi/pci_irq.c
> Bjorn Helgaas <bhelgaas@xxxxxxxxxx> (supporter:PCI SUBSYSTEM)
> "Rafael J. Wysocki" <rafael@xxxxxxxxxx> (supporter:ACPI)
> Len Brown <lenb@xxxxxxxxxx> (reviewer:ACPI)
> linux-pci@xxxxxxxxxxxxxxx (open list:PCI SUBSYSTEM)
> linux-acpi@xxxxxxxxxxxxxxx (open list:ACPI)
> linux-kernel@xxxxxxxxxxxxxxx (open list)
>
> How about you start Cc-ing some of the relevant people?
Ok, thanks, I'll cc relevant people list here.

> > diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
> > index 08e1577..34483b3 100644
> > --- a/drivers/acpi/pci_irq.c
> > +++ b/drivers/acpi/pci_irq.c
> > @@ -393,7 +393,8 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
> >   	 * controller and must therefore be considered active high
> >   	 * as default.
> >   	 */
> > -	int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ?
> > +	int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ||
> > +		       acpi_irq_model == ACPI_IRQ_MODEL_LPIC ?
> >   				      ACPI_ACTIVE_HIGH : ACPI_ACTIVE_LOW;
>
> The comment just above this only talks about ARM. Should it be
> updated? 

Ok, I'll update the comment.


Is this a limitation of the underlying interrupt controller?
>
It's the limitation that pci interrupt source of LoongArch only sends 
high level trigger signal to interrupt controller(though, pci spec 
requires asserted low).


> >   	char *link = NULL;
> >   	char link_desc[16];
> > diff --git a/drivers/irqchip/irq-loongson-pch-pic.c b/drivers/irqchip/irq-loongson-pch-pic.c
> > index b6f1392..5067010 100644
> > --- a/drivers/irqchip/irq-loongson-pch-pic.c
> > +++ b/drivers/irqchip/irq-loongson-pch-pic.c
> > @@ -177,13 +177,15 @@ static int pch_pic_domain_translate(struct irq_domain *d,
> >   	if (fwspec->param_count < 1)
> >   		return -EINVAL;
> >   
> > -	if (of_node) {
> > +	if (of_node)
> >   		*hwirq = fwspec->param[0] + priv->ht_vec_base;
> > -		*type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> > -	} else {
> > +	else
> >   		*hwirq = fwspec->param[0] - priv->gsi_base;
> > +
> > +	if (fwspec->param_count > 1)
> > +		*type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
> > +	else
> >   		*type = IRQ_TYPE_NONE;
>
> Isn't that a change in behaviour if of_node is non-NULL and
> param_count==1?

It seems that current code here has bug that if fwspec->param_count==1 
and of_node is non-null, fwspec->param[1] will be accessed, which is 
introduced from previous patch(irqchip/loongson-pch-pic: Add ACPI init 
support). Before the patch, for non-null of_node, translate callback(use 
irq_domain_translate_twocell) will return -EINVAL if fwspec->param_count 
< 2.

For ACPI path, fwspec->param_count can be 1 or 2.

So in this patch, I'll fix the bug and change the code as following:

        if (fwspec->param_count < 1)
                return -EINVAL;

        if (of_node) {
                if (fwspec->param_count < 2)
                        return -EINVAL;

                *hwirq = fwspec->param[0] + priv->ht_vec_base;
                *type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
        } else {
                *hwirq = fwspec->param[0] - priv->gsi_base;

                if (fwspec->param_count > 1)
                        *type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
                else
                        *type = IRQ_TYPE_NONE;
        }


> > -	}
> >   
> >   	return 0;
> >   }
>
> This irqchip change should probably be a separate patch.

As a separate patch, the input trigger type of pci devices will be low 
level because of lacking of workaround to acpi_pci_irq_enable, which 
will cause kernel hang, unless the patch of workaround to 
acpi_pci_irq_enable is in front of this separated patch.


> 	M.