src/arch/i386/core/pic8259.c

   1 /*
   2  * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 #include <gpxe/io.h>
  22 #include <pic8259.h>
  23
  24 /** @file
  25  *
  26  * Minimal support for the 8259 Programmable Interrupt Controller
  27  *
  28  */
  29
  30 /**
  31  * Send non-specific EOI(s)
  32  *
  33  * @v irq               IRQ number
  34  *
  35  * This seems to be inherently unsafe.
  36  */
  37 static inline void send_nonspecific_eoi ( unsigned int irq ) {
  38         DBG ( "Sending non-specific EOI for IRQ %d\n", irq );
  39         if ( irq >= IRQ_PIC_CUTOFF ) {
  40                 outb ( ICR_EOI_NON_SPECIFIC, PIC2_ICR );
  41         }
  42         outb ( ICR_EOI_NON_SPECIFIC, PIC1_ICR );
  43 }
  44
  45 /**
  46  * Send specific EOI(s)
  47  *
  48  * @v irq               IRQ number
  49  */
  50 static inline void send_specific_eoi ( unsigned int irq ) {
  51         DBG ( "Sending specific EOI for IRQ %d\n", irq );
  52         if ( irq >= IRQ_PIC_CUTOFF ) {
  53                 outb ( ( ICR_EOI_SPECIFIC | ICR_VALUE ( CHAINED_IRQ ) ),
  54                        ICR_REG ( CHAINED_IRQ ) );
  55         }
  56         outb ( ( ICR_EOI_SPECIFIC | ICR_VALUE ( irq ) ), ICR_REG ( irq ) );
  57 }
  58
  59 /**
  60  * Send End-Of-Interrupt to the PIC
  61  *
  62  * @v irq               IRQ number
  63  */
  64 void send_eoi ( unsigned int irq ) {
  65         send_specific_eoi ( irq );
  66 }