mmap_device_io()

Gain access to a device's registers

Synopsis:

#include <stdint.h>
#include <sys/mman.h>

uintptr_t mmap_device_io( size_t len,
                          uint64_t io );

Arguments:

len: The number of bytes of device I/O memory that you want to access. It can't be 0.
io: The address of the area that you want to access.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The mmap_device_io() function maps len bytes of device I/O memory at io and makes it accessible via the in*() and out*() functions in <hw/inout.h>.

Returns:

A handle to the device's I/O memory, or MAP_DEVICE_FAILED if an error occurs (errno is set).

Errors:

EINVAL: Invalid flags type, or len is 0.
ENOMEM: The address range requested is outside of the allowed process address range, or there wasn't enough memory to satisfy the request.
ENXIO: The address from io for len bytes is invalid.

Classification:

QNX Neutrino

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes

Caveats:

You need I/O privileges to use the result of the mmap_device_io() function. The calling thread may call ThreadCtl() with the _NTO_TCTL_IO command to establish these privileges.