PCI_INTR(9) | Kernel Developer's Manual | PCI_INTR(9) |
pci_intr
, pci_intr_map
,
pci_intr_string
,
pci_intr_evcnt
,
pci_intr_establish
,
pci_intr_establish_xname
,
pci_intr_disestablish
,
pci_intr_setattr
—
#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);
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
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.
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.
pci_intr_establish_xname
() was added in
NetBSD 8.0 as part of MSI/MSI-X support.
September 20, 2018 | NetBSD 9.2 |