diff mbox series

[v3,1/4] acpi/irq: implement helper to create hierachical domains

Message ID 20190527112720.2266-2-ard.biesheuvel@linaro.org (mailing list archive)
State Superseded, archived
Headers show
Series synquacer: implement ACPI gpio/interrupt support | expand

Commit Message

Ard Biesheuvel May 27, 2019, 11:27 a.m. UTC
ACPI permits arbitrary producer->consumer interrupt links to be
described in AML, which means a topology such as the following
is perfectly legal:

  Device (EXIU) {
    Name (_HID, "SCX0008")
    Name (_UID, Zero)
    Name (_CRS, ResourceTemplate () {
      ...
    })
  }

  Device (GPIO) {
    Name (_HID, "SCX0007")
    Name (_UID, Zero)
    Name (_CRS, ResourceTemplate () {
      Memory32Fixed (ReadWrite, SYNQUACER_GPIO_BASE, SYNQUACER_GPIO_SIZE)
      Interrupt (ResourceConsumer, Edge, ActiveHigh, ExclusiveAndWake, 0, "\\_SB.EXIU") {
        7,
      }
    })
    ...
  }

The EXIU in this example is the external interrupt unit as can be found
on Socionext SynQuacer based platforms, which converts a block of 32 SPIs
from arbitrary polarity/trigger into level-high, with a separate set
of config/mask/unmask/clear controls.

The existing DT based driver in drivers/irqchip/irq-sni-exiu.c models
this as a hierarchical domain stacked on top of the GIC's irqdomain.
Since the GIC is modeled as a DT node as well, obtaining a reference
to this irqdomain is easily done by going through the parent link.

On ACPI systems, however, the GIC is not modeled as an object in the
namespace, and so device objects cannot refer to it directly. So in
order to obtain the irqdomain reference when driving the EXIU in ACPI
mode, we need a helper that implicitly grabs the default domain for
unqualified interrupts as the parent of the hierarchy.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/acpi/irq.c   | 20 ++++++++++++++++++++
 include/linux/acpi.h |  7 +++++++
 2 files changed, 27 insertions(+)

Comments

Mika Westerberg May 28, 2019, 10:07 a.m. UTC | #1
On Mon, May 27, 2019 at 01:27:17PM +0200, Ard Biesheuvel wrote:
> +
> +/**
> + * acpi_irq_create_hierarchy - Create a hierarchical IRQ domain with the default
> + *                             GSI domain as its parent.

Please document the arguments as well.

> + */
> +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> +					     unsigned int size,
> +					     struct fwnode_handle *fwnode,
> +					     const struct irq_domain_ops *ops,
> +					     void *host_data)

Otherwise looks good to me.

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Marc Zyngier May 28, 2019, 12:54 p.m. UTC | #2
Hi Ard,

On 27/05/2019 12:27, Ard Biesheuvel wrote:
> ACPI permits arbitrary producer->consumer interrupt links to be
> described in AML, which means a topology such as the following
> is perfectly legal:
> 
>   Device (EXIU) {
>     Name (_HID, "SCX0008")
>     Name (_UID, Zero)
>     Name (_CRS, ResourceTemplate () {
>       ...
>     })
>   }
> 
>   Device (GPIO) {
>     Name (_HID, "SCX0007")
>     Name (_UID, Zero)
>     Name (_CRS, ResourceTemplate () {
>       Memory32Fixed (ReadWrite, SYNQUACER_GPIO_BASE, SYNQUACER_GPIO_SIZE)
>       Interrupt (ResourceConsumer, Edge, ActiveHigh, ExclusiveAndWake, 0, "\\_SB.EXIU") {
>         7,
>       }
>     })
>     ...
>   }
> 
> The EXIU in this example is the external interrupt unit as can be found
> on Socionext SynQuacer based platforms, which converts a block of 32 SPIs
> from arbitrary polarity/trigger into level-high, with a separate set
> of config/mask/unmask/clear controls.
> 
> The existing DT based driver in drivers/irqchip/irq-sni-exiu.c models
> this as a hierarchical domain stacked on top of the GIC's irqdomain.
> Since the GIC is modeled as a DT node as well, obtaining a reference
> to this irqdomain is easily done by going through the parent link.
> 
> On ACPI systems, however, the GIC is not modeled as an object in the
> namespace, and so device objects cannot refer to it directly. So in
> order to obtain the irqdomain reference when driving the EXIU in ACPI
> mode, we need a helper that implicitly grabs the default domain for
> unqualified interrupts as the parent of the hierarchy.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  drivers/acpi/irq.c   | 20 ++++++++++++++++++++
>  include/linux/acpi.h |  7 +++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
> index c3b2222e2129..39824a6bbcd5 100644
> --- a/drivers/acpi/irq.c
> +++ b/drivers/acpi/irq.c
> @@ -295,3 +295,23 @@ void __init acpi_set_irq_model(enum acpi_irq_model_id model,
>  	acpi_irq_model = model;
>  	acpi_gsi_domain_id = fwnode;
>  }
> +
> +/**
> + * acpi_irq_create_hierarchy - Create a hierarchical IRQ domain with the default
> + *                             GSI domain as its parent.
> + */
> +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> +					     unsigned int size,
> +					     struct fwnode_handle *fwnode,
> +					     const struct irq_domain_ops *ops,
> +					     void *host_data)
> +{
> +	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> +							DOMAIN_BUS_ANY);
> +
> +	if (!d)
> +		return NULL;
> +
> +	return irq_domain_create_hierarchy(d, flags, size, fwnode, ops,
> +					   host_data);
> +}
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 98440df7fe42..70de4bc30cea 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -23,6 +23,7 @@
>  
>  #include <linux/errno.h>
>  #include <linux/ioport.h>	/* for struct resource */
> +#include <linux/irqdomain.h>
>  #include <linux/resource_ext.h>
>  #include <linux/device.h>
>  #include <linux/property.h>
> @@ -327,6 +328,12 @@ int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
>  void acpi_set_irq_model(enum acpi_irq_model_id model,
>  			struct fwnode_handle *fwnode);
>  
> +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> +					     unsigned int size,
> +					     struct fwnode_handle *fwnode,
> +					     const struct irq_domain_ops *ops,
> +					     void *host_data);
> +
>  #ifdef CONFIG_X86_IO_APIC
>  extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
>  #else
> 

Should we consider exporting this function to modules?

Otherwise (and with Mika's comments addressed), looks good to me.

Thanks,

	M.
Lorenzo Pieralisi May 28, 2019, 1:02 p.m. UTC | #3
On Mon, May 27, 2019 at 01:27:17PM +0200, Ard Biesheuvel wrote:
> ACPI permits arbitrary producer->consumer interrupt links to be
> described in AML, which means a topology such as the following
> is perfectly legal:
> 
>   Device (EXIU) {
>     Name (_HID, "SCX0008")
>     Name (_UID, Zero)
>     Name (_CRS, ResourceTemplate () {
>       ...
>     })
>   }
> 
>   Device (GPIO) {
>     Name (_HID, "SCX0007")
>     Name (_UID, Zero)
>     Name (_CRS, ResourceTemplate () {
>       Memory32Fixed (ReadWrite, SYNQUACER_GPIO_BASE, SYNQUACER_GPIO_SIZE)
>       Interrupt (ResourceConsumer, Edge, ActiveHigh, ExclusiveAndWake, 0, "\\_SB.EXIU") {
>         7,
>       }
>     })
>     ...
>   }
> 
> The EXIU in this example is the external interrupt unit as can be found
> on Socionext SynQuacer based platforms, which converts a block of 32 SPIs
> from arbitrary polarity/trigger into level-high, with a separate set
> of config/mask/unmask/clear controls.
> 
> The existing DT based driver in drivers/irqchip/irq-sni-exiu.c models
> this as a hierarchical domain stacked on top of the GIC's irqdomain.
> Since the GIC is modeled as a DT node as well, obtaining a reference
> to this irqdomain is easily done by going through the parent link.
> 
> On ACPI systems, however, the GIC is not modeled as an object in the
> namespace, and so device objects cannot refer to it directly. So in
> order to obtain the irqdomain reference when driving the EXIU in ACPI
> mode, we need a helper that implicitly grabs the default domain for
> unqualified interrupts as the parent of the hierarchy.

Nit: I do not think they are "unqualified".

ACPI 6.3, table 6-237, Extended Interrupt Descriptor Definition:

"Resource Source: (Optional) If present, the device that uses this
descriptor consumes its resources from the resources produces by the
named device object. If not present, the device consumes its resources
out of a global pool."

Where the global pool I _assume_ is the GSI domain, so it is the default
expected behaviour (for once :))

> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  drivers/acpi/irq.c   | 20 ++++++++++++++++++++
>  include/linux/acpi.h |  7 +++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
> index c3b2222e2129..39824a6bbcd5 100644
> --- a/drivers/acpi/irq.c
> +++ b/drivers/acpi/irq.c
> @@ -295,3 +295,23 @@ void __init acpi_set_irq_model(enum acpi_irq_model_id model,
>  	acpi_irq_model = model;
>  	acpi_gsi_domain_id = fwnode;
>  }
> +
> +/**
> + * acpi_irq_create_hierarchy - Create a hierarchical IRQ domain with the default
> + *                             GSI domain as its parent.

Yes please comment parameters even if it is just a wrapper around
the IRQ domain API.

> +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> +					     unsigned int size,
> +					     struct fwnode_handle *fwnode,
> +					     const struct irq_domain_ops *ops,
> +					     void *host_data)
> +{
> +	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> +							DOMAIN_BUS_ANY);
> +
> +	if (!d)
> +		return NULL;
> +
> +	return irq_domain_create_hierarchy(d, flags, size, fwnode, ops,
> +					   host_data);
> +}
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 98440df7fe42..70de4bc30cea 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -23,6 +23,7 @@
>  
>  #include <linux/errno.h>
>  #include <linux/ioport.h>	/* for struct resource */
> +#include <linux/irqdomain.h>
>  #include <linux/resource_ext.h>
>  #include <linux/device.h>
>  #include <linux/property.h>
> @@ -327,6 +328,12 @@ int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
>  void acpi_set_irq_model(enum acpi_irq_model_id model,
>  			struct fwnode_handle *fwnode);
>  
> +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> +					     unsigned int size,
> +					     struct fwnode_handle *fwnode,
> +					     const struct irq_domain_ops *ops,
> +					     void *host_data);
> +
>  #ifdef CONFIG_X86_IO_APIC
>  extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
>  #else

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Ard Biesheuvel May 28, 2019, 1:12 p.m. UTC | #4
On Tue, 28 May 2019 at 15:02, Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
>
> On Mon, May 27, 2019 at 01:27:17PM +0200, Ard Biesheuvel wrote:
> > ACPI permits arbitrary producer->consumer interrupt links to be
> > described in AML, which means a topology such as the following
> > is perfectly legal:
> >
> >   Device (EXIU) {
> >     Name (_HID, "SCX0008")
> >     Name (_UID, Zero)
> >     Name (_CRS, ResourceTemplate () {
> >       ...
> >     })
> >   }
> >
> >   Device (GPIO) {
> >     Name (_HID, "SCX0007")
> >     Name (_UID, Zero)
> >     Name (_CRS, ResourceTemplate () {
> >       Memory32Fixed (ReadWrite, SYNQUACER_GPIO_BASE, SYNQUACER_GPIO_SIZE)
> >       Interrupt (ResourceConsumer, Edge, ActiveHigh, ExclusiveAndWake, 0, "\\_SB.EXIU") {
> >         7,
> >       }
> >     })
> >     ...
> >   }
> >
> > The EXIU in this example is the external interrupt unit as can be found
> > on Socionext SynQuacer based platforms, which converts a block of 32 SPIs
> > from arbitrary polarity/trigger into level-high, with a separate set
> > of config/mask/unmask/clear controls.
> >
> > The existing DT based driver in drivers/irqchip/irq-sni-exiu.c models
> > this as a hierarchical domain stacked on top of the GIC's irqdomain.
> > Since the GIC is modeled as a DT node as well, obtaining a reference
> > to this irqdomain is easily done by going through the parent link.
> >
> > On ACPI systems, however, the GIC is not modeled as an object in the
> > namespace, and so device objects cannot refer to it directly. So in
> > order to obtain the irqdomain reference when driving the EXIU in ACPI
> > mode, we need a helper that implicitly grabs the default domain for
> > unqualified interrupts as the parent of the hierarchy.
>
> Nit: I do not think they are "unqualified".
>
> ACPI 6.3, table 6-237, Extended Interrupt Descriptor Definition:
>
> "Resource Source: (Optional) If present, the device that uses this
> descriptor consumes its resources from the resources produces by the
> named device object. If not present, the device consumes its resources
> out of a global pool."
>
> Where the global pool I _assume_ is the GSI domain, so it is the default
> expected behaviour (for once :))
>

By 'unqualified', I meant lacking an explicit description of the
producer of the resource. But I can change the wording if you prefer.

> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> >  drivers/acpi/irq.c   | 20 ++++++++++++++++++++
> >  include/linux/acpi.h |  7 +++++++
> >  2 files changed, 27 insertions(+)
> >
> > diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
> > index c3b2222e2129..39824a6bbcd5 100644
> > --- a/drivers/acpi/irq.c
> > +++ b/drivers/acpi/irq.c
> > @@ -295,3 +295,23 @@ void __init acpi_set_irq_model(enum acpi_irq_model_id model,
> >       acpi_irq_model = model;
> >       acpi_gsi_domain_id = fwnode;
> >  }
> > +
> > +/**
> > + * acpi_irq_create_hierarchy - Create a hierarchical IRQ domain with the default
> > + *                             GSI domain as its parent.
>
> Yes please comment parameters even if it is just a wrapper around
> the IRQ domain API.
>
> > +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> > +                                          unsigned int size,
> > +                                          struct fwnode_handle *fwnode,
> > +                                          const struct irq_domain_ops *ops,
> > +                                          void *host_data)
> > +{
> > +     struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> > +                                                     DOMAIN_BUS_ANY);
> > +
> > +     if (!d)
> > +             return NULL;
> > +
> > +     return irq_domain_create_hierarchy(d, flags, size, fwnode, ops,
> > +                                        host_data);
> > +}
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 98440df7fe42..70de4bc30cea 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -23,6 +23,7 @@
> >
> >  #include <linux/errno.h>
> >  #include <linux/ioport.h>    /* for struct resource */
> > +#include <linux/irqdomain.h>
> >  #include <linux/resource_ext.h>
> >  #include <linux/device.h>
> >  #include <linux/property.h>
> > @@ -327,6 +328,12 @@ int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
> >  void acpi_set_irq_model(enum acpi_irq_model_id model,
> >                       struct fwnode_handle *fwnode);
> >
> > +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> > +                                          unsigned int size,
> > +                                          struct fwnode_handle *fwnode,
> > +                                          const struct irq_domain_ops *ops,
> > +                                          void *host_data);
> > +
> >  #ifdef CONFIG_X86_IO_APIC
> >  extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
> >  #else
>
> Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Thanks,
Ard Biesheuvel May 28, 2019, 1:12 p.m. UTC | #5
On Tue, 28 May 2019 at 14:54, Marc Zyngier <marc.zyngier@arm.com> wrote:
>
> Hi Ard,
>
> On 27/05/2019 12:27, Ard Biesheuvel wrote:
> > ACPI permits arbitrary producer->consumer interrupt links to be
> > described in AML, which means a topology such as the following
> > is perfectly legal:
> >
> >   Device (EXIU) {
> >     Name (_HID, "SCX0008")
> >     Name (_UID, Zero)
> >     Name (_CRS, ResourceTemplate () {
> >       ...
> >     })
> >   }
> >
> >   Device (GPIO) {
> >     Name (_HID, "SCX0007")
> >     Name (_UID, Zero)
> >     Name (_CRS, ResourceTemplate () {
> >       Memory32Fixed (ReadWrite, SYNQUACER_GPIO_BASE, SYNQUACER_GPIO_SIZE)
> >       Interrupt (ResourceConsumer, Edge, ActiveHigh, ExclusiveAndWake, 0, "\\_SB.EXIU") {
> >         7,
> >       }
> >     })
> >     ...
> >   }
> >
> > The EXIU in this example is the external interrupt unit as can be found
> > on Socionext SynQuacer based platforms, which converts a block of 32 SPIs
> > from arbitrary polarity/trigger into level-high, with a separate set
> > of config/mask/unmask/clear controls.
> >
> > The existing DT based driver in drivers/irqchip/irq-sni-exiu.c models
> > this as a hierarchical domain stacked on top of the GIC's irqdomain.
> > Since the GIC is modeled as a DT node as well, obtaining a reference
> > to this irqdomain is easily done by going through the parent link.
> >
> > On ACPI systems, however, the GIC is not modeled as an object in the
> > namespace, and so device objects cannot refer to it directly. So in
> > order to obtain the irqdomain reference when driving the EXIU in ACPI
> > mode, we need a helper that implicitly grabs the default domain for
> > unqualified interrupts as the parent of the hierarchy.
> >
> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> >  drivers/acpi/irq.c   | 20 ++++++++++++++++++++
> >  include/linux/acpi.h |  7 +++++++
> >  2 files changed, 27 insertions(+)
> >
> > diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
> > index c3b2222e2129..39824a6bbcd5 100644
> > --- a/drivers/acpi/irq.c
> > +++ b/drivers/acpi/irq.c
> > @@ -295,3 +295,23 @@ void __init acpi_set_irq_model(enum acpi_irq_model_id model,
> >       acpi_irq_model = model;
> >       acpi_gsi_domain_id = fwnode;
> >  }
> > +
> > +/**
> > + * acpi_irq_create_hierarchy - Create a hierarchical IRQ domain with the default
> > + *                             GSI domain as its parent.
> > + */
> > +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> > +                                          unsigned int size,
> > +                                          struct fwnode_handle *fwnode,
> > +                                          const struct irq_domain_ops *ops,
> > +                                          void *host_data)
> > +{
> > +     struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
> > +                                                     DOMAIN_BUS_ANY);
> > +
> > +     if (!d)
> > +             return NULL;
> > +
> > +     return irq_domain_create_hierarchy(d, flags, size, fwnode, ops,
> > +                                        host_data);
> > +}
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 98440df7fe42..70de4bc30cea 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -23,6 +23,7 @@
> >
> >  #include <linux/errno.h>
> >  #include <linux/ioport.h>    /* for struct resource */
> > +#include <linux/irqdomain.h>
> >  #include <linux/resource_ext.h>
> >  #include <linux/device.h>
> >  #include <linux/property.h>
> > @@ -327,6 +328,12 @@ int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
> >  void acpi_set_irq_model(enum acpi_irq_model_id model,
> >                       struct fwnode_handle *fwnode);
> >
> > +struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
> > +                                          unsigned int size,
> > +                                          struct fwnode_handle *fwnode,
> > +                                          const struct irq_domain_ops *ops,
> > +                                          void *host_data);
> > +
> >  #ifdef CONFIG_X86_IO_APIC
> >  extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
> >  #else
> >
>
> Should we consider exporting this function to modules?
>

Good point, we probably should.


> Otherwise (and with Mika's comments addressed), looks good to me.
>
> Thanks,
>
>         M.
> --
> Jazz is not dead. It just smells funny...
diff mbox series

Patch

diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
index c3b2222e2129..39824a6bbcd5 100644
--- a/drivers/acpi/irq.c
+++ b/drivers/acpi/irq.c
@@ -295,3 +295,23 @@  void __init acpi_set_irq_model(enum acpi_irq_model_id model,
 	acpi_irq_model = model;
 	acpi_gsi_domain_id = fwnode;
 }
+
+/**
+ * acpi_irq_create_hierarchy - Create a hierarchical IRQ domain with the default
+ *                             GSI domain as its parent.
+ */
+struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
+					     unsigned int size,
+					     struct fwnode_handle *fwnode,
+					     const struct irq_domain_ops *ops,
+					     void *host_data)
+{
+	struct irq_domain *d = irq_find_matching_fwnode(acpi_gsi_domain_id,
+							DOMAIN_BUS_ANY);
+
+	if (!d)
+		return NULL;
+
+	return irq_domain_create_hierarchy(d, flags, size, fwnode, ops,
+					   host_data);
+}
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 98440df7fe42..70de4bc30cea 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -23,6 +23,7 @@ 
 
 #include <linux/errno.h>
 #include <linux/ioport.h>	/* for struct resource */
+#include <linux/irqdomain.h>
 #include <linux/resource_ext.h>
 #include <linux/device.h>
 #include <linux/property.h>
@@ -327,6 +328,12 @@  int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
 void acpi_set_irq_model(enum acpi_irq_model_id model,
 			struct fwnode_handle *fwnode);
 
+struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,
+					     unsigned int size,
+					     struct fwnode_handle *fwnode,
+					     const struct irq_domain_ops *ops,
+					     void *host_data);
+
 #ifdef CONFIG_X86_IO_APIC
 extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
 #else