nioprobe(D3DK) —

.IX \f4nioprobe\fP(D3DK)

NAME

nioprobe − probe an I/O address for a device

SYNOPSIS

#include <sys/types.h>
#include <sys/buf.h>
#include <sys/iosystm.h>
int nioprobe(u_int access, addr_t addr, u_int ∗data);

ARGUMENTS

accessThe type of probe desired.

addrThe address to probe.

dataThe data read or written by nioprobe.

DESCRIPTION

nioprobe is used in driver initialization routines to probe for a controller at addr.

The controller may be probed in different ways depending on the value of access. The following constants are used to define the access type:

IOP_READ	0
IOP_WRITE	1
IOP_BYTE	2
IOP_SHORT	4
IOP_LONG	6
IOP_DEFBUS	0
IOP_VIRTUAL	8

nioprobe is called with an access value that is a combination (bit-wise “or”) of these constants. Acceptable access values (defined in sys/iosystm.h) and the resulting behavior of ioprobe follow:

IOP_READ\|IOP_BYTE\|IOP_DEFBUS	Read a byte from addr.
IOP_READ\|IOP_SHORT\|IOP_DEFBUS	Read an unsigned short integer from addr.
IOP_READ\|IOP_LONG\|IOP_DEFBUS	Read an unsigned long integer from addr.
IOP_WRITE\|IOP_BYTE\|IOP_DEFBUS	Write a byte to addr.
IOP_WRITE\|IOP_SHORT\|IOP_DEFBUS	Write a short to addr.
IOP_WRITE\|IOP_LONG\|IOP_DEFBUS	Write a long to addr.

nioprobe normally reads or writes physical addresses. However, if IOP_VIRTUAL is used in place of IOP_DEFBUS, then it will read or write a virtual address. It is up to the caller in this case to ensure that the address has been mapped. As a rule of thumb, if IOP_DEFBUS is specified, then addr is a value that could be used as the addr parameter of niomapin. However, if IOP_VIRTUAL is specified to nioprobe, then addr is a value that could be directly referenced by the driver such as an address returned from niomapin.

nioprobe is not guaranteed to work when called from interrupt level without IOP_VIRTUAL.

If addr is invalid or nonexistent, nioprobe returns −1.

RETURN VALUES

Zero if the probe suceeds, or −1 if no device responded or if IOP_VIRTUAL was specified and the specified virtual address is not mapped.

LEVEL

Base or Interrupt

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