mmap_device_io()

Gain access to a device's registers

#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.

EPERM

The calling process doesn't have the required permission; see procmgr_ability() .

Classification:

QNX Neutrino

Caveats:

You need I/O privileges to use the result of the mmap_device_io() function. The calling thread must:

• have the PROCMGR_AID_IO ability enabled. For more information, see procmgr_ability() .
• call ThreadCtl() with the _NTO_TCTL_IO command to establish these privileges.