NAME

       rtapi_io.h - RTAPI wrappers for linux kernel functionality

SYNTAX

       #include <rtapi_io.h>

       unsigned char rtapi_inb(unsigned short int port);

       unsigned short rtapi_inw(unsigned short int port);

       unsigned int rtapi_inl(unsigned short int port);

       unsigned void rtapi_outb(unsigned char value, unsigned short int port);

       unsigned void rtapi_outw(unsigned short value, unsigned short int port);

       unsigned void rtapi_inl(unsigned int value, unsigned short int port);

       int rtapi_ioperm(unsigned long from, unsigned long num, int turn_on);

       unsigned void rtapi_outl(unsigned int value, unsigned short int port);

DESCRIPTION

       In kernel space, each rtapi_xxx or RTAPI_XXX identifier is mapped to the underlying kernel
       functionality, if available.

       In userspace, or in kernels where the  underlying  functionality  is  not  provided  by  a
       kernel,   generally   another   implementation--possibly  with  reduced  functionality--is
       provided.  (For example, the userspace implementation for  rtapi_device_register  and  the
       kernel space implementation of rtapi_ioperm always succeeds)

REALTIME CONSIDERATIONS

       Call  from  init/cleanup code and from realtime tasks.  These functions will cause illegal
       instruction exceptions in userspace components, as well as in uspace rtapi_app when it  is
       not setuid root.

RETURN VALUE

       As in Linux.

SEE ALSO

       inb(3), inw(3), inl(3), outb(3), outw(3), outl(3), ioperm(3),

AUTHOR

       Jeff Epler