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 }
67