minix/kernel/system/do_devio.c

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/* 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 */