kernel2/pic.c

   1 /*
   2     meinOS - A unix-like x86 microkernel operating system
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include <pic.h>
  20 #include <ioport.h>
  21
  22 int pic_init() {
  23   int offset1 = 0x20;
  24   int offset2 = 0x28;
  25   char a1,a2;
  26   a1 = inb(PIC1_DATA);                     // save masks
  27   a2 = inb(PIC2_DATA);
  28
  29   outb(PIC1_COMMAND,ICW1_INIT+ICW1_ICW4);  // starts the initialization sequence
  30   outb(PIC2_COMMAND,ICW1_INIT+ICW1_ICW4);
  31   outb(PIC1_DATA,offset1);                 // define the PIC vectors
  32   outb(PIC2_DATA,offset2);
  33   outb(PIC1_DATA,4);                       // continue initialization sequence
  34   outb(PIC2_DATA,2);
  35   outb(PIC1_DATA,ICW4_8086);
  36   outb(PIC2_DATA,ICW4_8086);
  37
  38   outb(PIC1_DATA,a1);   // restore saved masks.
  39   outb(PIC2_DATA,a2);
  40
  41   return 0;
  42 }
  43
  44 /**
  45  * Gets IRQ mask
  46  *  @param irq IRQ
  47  *  @return IRQ mask
  48  */
  49 unsigned int pic_getmask(int irq) {
  50   unsigned int mask = inb(PIC1_DATA);
  51   mask |= inb(PIC2_DATA)<<8;
  52   return mask;
  53 }
  54
  55 /**
  56  * Sets IRQ mask
  57  *  @param irq IRQ
  58  *  @param mask IRQ mask
  59  */
  60 void pic_setmask(int irq,unsigned int mask) {
  61   outb(PIC1_DATA,mask);
  62   outb(PIC2_DATA,mask>>8);
  63 }
  64
  65 /**
  66  * Sends EOI to PIC
  67  *  @param irq IRQ
  68  */
  69 void pic_eoi(int irq) {
  70   if (irq>=8) outb(PIC2_COMMAND,PIC_EOI);
  71   outb(PIC1_COMMAND,PIC_EOI);
  72 }
  73
  74 /**
  75  * Sets interval of PIT
  76  *  @param interval Interval
  77  *  @param channel Channel
  78  *  @return 0=Success; -1=Failure
  79  */
  80 int pic_pit_setinterval(int channel,unsigned int interval) {
  81   unsigned int val = PIT_FREQ*interval/1000;
  82   if (channel<4) {
  83     outb(PIT_CHANNELS+channel,val);
  84     outb(PIT_CHANNELS+channel,(val>>8));
  85     return 0;
  86   }
  87   else return -1;
  88 }