kernel/system/do_devio.c

   1 /* The kernel call implemented in this file:
   2  *   m_type:    SYS_DEVIO
   3  *
   4  * The parameters for this kernel call are:
   5  *   m2_i3:     DIO_REQUEST     (request input or output)
   6  *   m2_l1:     DIO_PORT        (port to read/ write)
   7  *   m2_l2:     DIO_VALUE       (value to write/ return value read)
   8  */
   9
  10 #include "../system.h"
  11 #include <minix/devio.h>
  12 #include <minix/endpoint.h>
  13 #include <minix/portio.h>
  14
  15 #if USE_DEVIO
  16
  17 /*===========================================================================*
  18  *                              do_devio                                     *
  19  *===========================================================================*/
  20 PUBLIC int do_devio(m_ptr)
  21 register message *m_ptr;        /* pointer to request message */
  22 {
  23     struct proc *rp;
  24     struct priv *privp;
  25     port_t port;
  26     struct io_range *iorp;
  27     int i, size, nr_io_range;
  28     int io_type, io_dir;
  29
  30     io_type = m_ptr->DIO_REQUEST & _DIO_TYPEMASK;
  31     io_dir  = m_ptr->DIO_REQUEST & _DIO_DIRMASK;
  32
  33     rp= proc_addr(who_p);
  34     privp= priv(rp);
  35     if (!privp)
  36     {
  37         kprintf("no priv structure!\n");
  38         goto doit;
  39     }
  40     if (privp->s_flags & CHECK_IO_PORT)
  41     {
  42         switch (io_type)
  43         {
  44         case _DIO_BYTE: size= 1; break;
  45         case _DIO_WORD: size= 2; break;
  46         case _DIO_LONG: size= 4; break;
  47         default: size= 4; break;        /* Be conservative */
  48         }
  49         port= m_ptr->DIO_PORT;
  50         nr_io_range= privp->s_nr_io_range;
  51         for (i= 0, iorp= privp->s_io_tab; i<nr_io_range; i++, iorp++)
  52         {
  53                 if (port >= iorp->ior_base && port+size-1 <= iorp->ior_limit)
  54                         break;
  55         }
  56         if (i >= nr_io_range)
  57         {
  58                 kprintf(
  59                 "do_devio: I/O port check failed for proc %d, port 0x%x\n",
  60                         m_ptr->m_source, port);
  61                 return EPERM;
  62         }
  63     }
  64
  65 doit:
  66
  67 /* Process a single I/O request for byte, word, and long values. */
  68     if (io_dir == _DIO_INPUT) {
  69       switch (io_type) {
  70         /* maybe "it" should not be called ports */
  71         case _DIO_BYTE: m_ptr->DIO_VALUE = inb(m_ptr->DIO_PORT); break;
  72         case _DIO_WORD: m_ptr->DIO_VALUE = inw(m_ptr->DIO_PORT); break;
  73         case _DIO_LONG: m_ptr->DIO_VALUE = inl(m_ptr->DIO_PORT); break;
  74         default: return(EINVAL);
  75       }
  76     } else {
  77       switch (io_type) {
  78         case _DIO_BYTE: outb(m_ptr->DIO_PORT, m_ptr->DIO_VALUE); break;
  79         case _DIO_WORD: outw(m_ptr->DIO_PORT, m_ptr->DIO_VALUE); break;
  80         case _DIO_LONG: outl(m_ptr->DIO_PORT, m_ptr->DIO_VALUE); break;
  81         default: return(EINVAL);
  82       }
  83     }
  84     return(OK);
  85 }
  86
  87 #endif /* USE_DEVIO */