minix/kernel/system/do_sdevio.c

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/* The kernel call implemented in this file:
* m_type: SYS_SDEVIO
*
* 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_p1: DIO_VEC_ADDR (virtual address of buffer)
* m2_l2: DIO_VEC_SIZE (number of elements)
* m2_i2: DIO_VEC_PROC (process where buffer is)
*/
#include "../system.h"
#include <minix/devio.h>
#if USE_SDEVIO
/*===========================================================================*
* do_sdevio *
*===========================================================================*/
PUBLIC int do_sdevio(m_ptr)
register message *m_ptr; /* pointer to request message */
{
int proc_nr = m_ptr->DIO_VEC_PROC;
int count = m_ptr->DIO_VEC_SIZE;
long port = m_ptr->DIO_PORT;
phys_bytes phys_buf;
/* Check if process number is OK. A process number is allowed here, because
* driver may directly provide a pointer to a buffer at the user-process
* that initiated the device I/O. Kernel processes, of course, are denied.
*/
if (proc_nr == SELF) proc_nr = m_ptr->m_source;
if (! isokprocn(proc_nr)) return(EINVAL);
if (iskerneln(proc_nr)) return(EPERM);
/* Get and check physical address. */
if ((phys_buf = numap_local(proc_nr, (vir_bytes) m_ptr->DIO_VEC_ADDR, count)) == 0)
return(EFAULT);
/* Perform device I/O for bytes and words. Longs are not supported. */
if (m_ptr->DIO_REQUEST == DIO_INPUT) {
switch (m_ptr->DIO_TYPE) {
case DIO_BYTE: phys_insb(port, phys_buf, count); break;
case DIO_WORD: phys_insw(port, phys_buf, count); break;
default: return(EINVAL);
}
} else if (m_ptr->DIO_REQUEST == DIO_OUTPUT) {
switch (m_ptr->DIO_TYPE) {
case DIO_BYTE: phys_outsb(port, phys_buf, count); break;
case DIO_WORD: phys_outsw(port, phys_buf, count); break;
default: return(EINVAL);
}
}
else {
return(EINVAL);
}
return(OK);
}
#endif /* USE_SDEVIO */