NAME
pci_intr,
pci_intr_map,
pci_intr_string,
pci_intr_evcnt,
pci_intr_establish,
pci_intr_establish_xname,
pci_intr_disestablish,
pci_intr_type,
pci_intr_setattr —
PCI bus interrupt
manipulation functions
SYNOPSIS
#include <dev/pci/pcivar.h>
int
pci_intr_map(
const
struct pci_attach_args *pa,
pci_intr_handle_t *ih);
const char *
pci_intr_string(
pci_chipset_tag_t
pc,
pci_intr_handle_t
ih,
char *buf,
size_t len);
const struct evcnt *
pci_intr_evcnt(
pci_chipset_tag_t
pc,
pci_intr_handle_t
ih);
void *
pci_intr_establish(
pci_chipset_tag_t
pc,
pci_intr_handle_t
ih,
int ipl,
int (*intrhand)(void *),
void *intrarg);
void *
pci_intr_establish_xname(
pci_chipset_tag_t
pc,
pci_intr_handle_t
ih,
int ipl,
int (*intrhand)(void *),
void *intrarg,
const char *xname);
void
pci_intr_disestablish(
pci_chipset_tag_t
pc,
void *ih);
int
pci_intr_setattr(
pci_chipset_tag_t
pc,
pci_intr_handle_t
*ih,
int attr,
uint64_t data);
DESCRIPTION
The
pci_intr functions exist to allow device drivers
machine-independent access to PCI bus interrupts. The functions described in
this page are typically declared in a port's
<machine/pci_machdep.h> header file;
however, drivers should generally include
<dev/pci/pcivar.h> to get other
PCI-specific declarations as well.
Each driver has an
attach() function which has a bus-specific
attach_args structure. Each driver for a PCI device is
passed a pointer to an object of type
struct
pci_attach_args which contains, among other things, information about
the location of the device in the PCI bus topology sufficient to allow
interrupts from the device to be handled.
If a driver wishes to establish an interrupt handler for the device, it should
pass the
struct pci_attach_args * to the
pci_intr_map() function, which returns zero on success, and
nonzero on failure. The function sets the
pci_intr_handle_t pointed at by its second argument to a
machine-dependent value which identifies a particular interrupt source.
If the driver wishes to refer to the interrupt source in an attach or error
message, it should use the value returned by
pci_intr_string(). The buffer passed to
pci_intr_string() should be at least
PCI_INTRSTR_LEN
bytes.
Subsequently, when the driver is prepared to receive interrupts, it should call
pci_intr_establish() to actually establish the handler; when
the device interrupts,
intrhand will be called with a
single argument
intrarg, and will run at the interrupt
priority level
ipl.
The return value of
pci_intr_establish() may be saved and
passed to
pci_intr_disestablish() to disable the interrupt
handler when the driver is no longer interested in interrupts from the device.
pci_intr_establish_xname() is almost the same as
pci_intr_establish(). The difference is only
xname which is used by
intrctl(8) to show the device
name(s) of the interrupt id.
The
pci_intr_setattr() function sets an attribute
attr of the interrupt handler to
data. Currenty, only the following attribute is
supported:
-
-
PCI_INTR_MPSAFE
- If this attribute is set to
true
,
it specifies that the interrupt handler is multiprocessor safe and works
its own locking; otherwise the kernel lock will be held for the call to
the interrupt handler. The default is false
.
The
pci_intr_setattr() function returns zero on success, and
nonzero on failure.
The
pci_intr_evcnt() function should return an evcnt structure
pointer or
NULL
if there is no evcnt associated with
this interrupt. See
evcnt(9) for
more details.
PORTING
A port's implementation of
pci_intr_map() may use the
following members of
struct pci_attach_args to determine
how the device's interrupts are routed.
pci_chipset_tag_t pa_pc;
pcitag_t pa_tag;
pcitag_t pa_intrtag; /* intr. appears to come from here */
pci_intr_pin_t pa_intrpin; /* intr. appears on this pin */
pci_intr_line_t pa_intrline; /* intr. routing information */
pci_intr_pin_t pa_rawintrpin; /* unswizzled pin */
PCI-PCI bridges swizzle (permute) interrupt wiring. Depending on implementation
details, it may be more convenient to use either original or the swizzled
interrupt parameters. The original device tag and interrupt pin can be found
in
pa_tag and
pa_rawintrpin
respectively, while the swizzled tag and pin can be found in
pa_intrtag and
pa_intrpin.
When a device is attached to a primary bus, both pairs of fields contain the
same values. When a device is found behind one or more pci-pci bridges,
pa_intrpin contains the “swizzled” interrupt
pin number, while
pa_rawintrpin contains the original
interrupt pin;
pa_tag contains the PCI tag of the device
itself, and
pa_intrtag contains the PCI tag of the
uppermost bridge device.
SEE ALSO
evcnt(9),
pci(9),
pci_msi(9)
HISTORY
pci_intr_establish_xname() was added in
NetBSD 8.0 as part of MSI/MSI-X support.