QNX中 mmap_device_io()的使用

来源于QNX IDE

参考该文QNX中 mmap_device_memory()的使用

mmap_device_io()

Gain access to a device's registers//访问设备的寄存器

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. //可以是一个很大的数，比如0x1000

io

The address of the area that you want to access.//寄存器地址，0x01C14000   //32位

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