minix/kernel/system/do_devio.c

/* The kernel call implemented in this file:
 *   m_type:	SYS_DEVIO
 *
 * The parameters for this kernel call are:
 *   m2_i3:	DIO_REQUEST	(request input or output)	
 *   m2_i1:	DIO_TYPE	(flag indicating byte, word, or long)
 *   m2_l1:	DIO_PORT	(port to read/ write)	
 *   m2_l2:	DIO_VALUE	(value to write/ return value read)	
 */

#include "../system.h"
#include <minix/devio.h>

#if USE_DEVIO

/*===========================================================================*
 *			        do_devio                                     *
 *===========================================================================*/
PUBLIC int do_devio(m_ptr)
register message *m_ptr;	/* pointer to request message */
{
    struct proc *rp;
    struct priv *privp;
    port_t port;
    struct io_range *iorp;
    int i, size, nr_io_range;

    rp= proc_addr(m_ptr->m_source);
    privp= priv(rp);
    if (!privp)
    {
	kprintf("no priv structure!\n");
	goto doit;
    }
    if (privp->s_flags & CHECK_IO_PORT)
    {
	switch (m_ptr->DIO_TYPE)
	{
	case DIO_BYTE: size= 1; break;
	case DIO_WORD: size= 2; break;
	case DIO_LONG: size= 4; break;
	default: size= 4; break;	/* Be conservative */
	}
	port= m_ptr->DIO_PORT;
	nr_io_range= privp->s_nr_io_range;
	for (i= 0, iorp= privp->s_io_tab; i<nr_io_range; i++, iorp++)
	{
		if (port >= iorp->ior_base && port+size-1 <= iorp->ior_limit)
			break;
	}
	if (i >= nr_io_range)
	{
		kprintf(
		"do_devio: I/O port check failed for proc %d, port 0x%x\n",
			m_ptr->m_source, port);
		return EPERM;
	}
    }

doit:

/* Process a single I/O request for byte, word, and long values. */
    if (m_ptr->DIO_REQUEST == DIO_INPUT) { 
      switch (m_ptr->DIO_TYPE) {
        case DIO_BYTE: m_ptr->DIO_VALUE = inb(m_ptr->DIO_PORT); break; 
        case DIO_WORD: m_ptr->DIO_VALUE = inw(m_ptr->DIO_PORT); break; 
        case DIO_LONG: m_ptr->DIO_VALUE = inl(m_ptr->DIO_PORT); break; 
    	default: return(EINVAL);
      } 
    } else { 
      switch (m_ptr->DIO_TYPE) {
        case DIO_BYTE: outb(m_ptr->DIO_PORT, m_ptr->DIO_VALUE); break;  
        case DIO_WORD: outw(m_ptr->DIO_PORT, m_ptr->DIO_VALUE); break;  
        case DIO_LONG: outl(m_ptr->DIO_PORT, m_ptr->DIO_VALUE); break;  
    	default: return(EINVAL);
      } 
    }
    return(OK);
}

#endif /* USE_DEVIO */