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Graeme Russ77290ee2009-02-24 21:13:40 +11001/*
2 * (C) Copyright 2009
Graeme Russ45fc1d82011-04-13 19:43:26 +10003 * Graeme Russ, <graeme.russ@gmail.com>
Graeme Russ77290ee2009-02-24 21:13:40 +11004 *
5 * (C) Copyright 2002
Albert ARIBAUD60fbc8d2011-08-04 18:45:45 +02006 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
Graeme Russ77290ee2009-02-24 21:13:40 +11007 *
Wolfgang Denkd79de1d2013-07-08 09:37:19 +02008 * SPDX-License-Identifier: GPL-2.0+
Graeme Russ77290ee2009-02-24 21:13:40 +11009 */
10
11/*
12 * This file provides the interrupt handling functionality for systems
13 * based on the standard PC/AT architecture using two cascaded i8259
14 * Programmable Interrupt Controllers.
15 */
16
17#include <common.h>
18#include <asm/io.h>
19#include <asm/i8259.h>
20#include <asm/ibmpc.h>
21#include <asm/interrupt.h>
22
Bin Mengcb9d9cb2014-11-20 16:11:16 +080023int i8259_init(void)
Graeme Russ77290ee2009-02-24 21:13:40 +110024{
25 u8 i;
26
Graeme Russ77290ee2009-02-24 21:13:40 +110027 /* Mask all interrupts */
28 outb(0xff, MASTER_PIC + IMR);
29 outb(0xff, SLAVE_PIC + IMR);
30
Bin Mengcb68a1a2015-10-22 19:13:28 -070031 /*
32 * Master PIC
33 * Place master PIC interrupts at INT20
34 */
35 outb(ICW1_SEL | ICW1_EICW4, MASTER_PIC + ICW1);
Graeme Russ77290ee2009-02-24 21:13:40 +110036 outb(0x20, MASTER_PIC + ICW2);
37 outb(IR2, MASTER_PIC + ICW3);
38 outb(ICW4_PM, MASTER_PIC + ICW4);
39
40 for (i = 0; i < 8; i++)
41 outb(OCW2_SEOI | i, MASTER_PIC + OCW2);
42
Bin Mengcb68a1a2015-10-22 19:13:28 -070043 /*
44 * Slave PIC
45 * Place slave PIC interrupts at INT28
46 */
47 outb(ICW1_SEL | ICW1_EICW4, SLAVE_PIC + ICW1);
Graeme Russ77290ee2009-02-24 21:13:40 +110048 outb(0x28, SLAVE_PIC + ICW2);
49 outb(0x02, SLAVE_PIC + ICW3);
50 outb(ICW4_PM, SLAVE_PIC + ICW4);
51
52 for (i = 0; i < 8; i++)
53 outb(OCW2_SEOI | i, SLAVE_PIC + OCW2);
54
55 /*
56 * Enable cascaded interrupts by unmasking the cascade IRQ pin of
57 * the master PIC
58 */
Graeme Russ883c6032011-11-08 02:33:15 +000059 unmask_irq(2);
Graeme Russ77290ee2009-02-24 21:13:40 +110060
Simon Glass0e9c6332014-11-14 18:18:31 -070061 /* Interrupt 9 should be level triggered (SCI). The OS might do this */
62 configure_irq_trigger(9, true);
63
Graeme Russ77290ee2009-02-24 21:13:40 +110064 return 0;
65}
66
67void mask_irq(int irq)
68{
69 int imr_port;
70
Bin Menge7a76e52015-10-22 19:13:26 -070071 if (irq >= SYS_NUM_IRQS)
Graeme Russ77290ee2009-02-24 21:13:40 +110072 return;
73
74 if (irq > 7)
75 imr_port = SLAVE_PIC + IMR;
76 else
77 imr_port = MASTER_PIC + IMR;
78
79 outb(inb(imr_port) | (1 << (irq & 7)), imr_port);
80}
81
82void unmask_irq(int irq)
83{
84 int imr_port;
85
Bin Menge7a76e52015-10-22 19:13:26 -070086 if (irq >= SYS_NUM_IRQS)
Graeme Russ77290ee2009-02-24 21:13:40 +110087 return;
88
89 if (irq > 7)
90 imr_port = SLAVE_PIC + IMR;
91 else
92 imr_port = MASTER_PIC + IMR;
93
94 outb(inb(imr_port) & ~(1 << (irq & 7)), imr_port);
95}
96
97void specific_eoi(int irq)
98{
Bin Menge7a76e52015-10-22 19:13:26 -070099 if (irq >= SYS_NUM_IRQS)
Graeme Russ77290ee2009-02-24 21:13:40 +1100100 return;
101
102 if (irq > 7) {
103 /*
104 * IRQ is on the slave - Issue a corresponding EOI to the
105 * slave PIC and an EOI for IRQ2 (the cascade interrupt)
106 * on the master PIC
107 */
108 outb(OCW2_SEOI | (irq & 7), SLAVE_PIC + OCW2);
109 irq = SEOI_IR2;
110 }
111
112 outb(OCW2_SEOI | irq, MASTER_PIC + OCW2);
113}
Simon Glass0e9c6332014-11-14 18:18:31 -0700114
Simon Glass0e9c6332014-11-14 18:18:31 -0700115void configure_irq_trigger(int int_num, bool is_level_triggered)
116{
117 u16 int_bits = inb(ELCR1) | (((u16)inb(ELCR2)) << 8);
118
119 debug("%s: current interrupts are 0x%x\n", __func__, int_bits);
120 if (is_level_triggered)
121 int_bits |= (1 << int_num);
122 else
123 int_bits &= ~(1 << int_num);
124
125 /* Write new values */
126 debug("%s: try to set interrupts 0x%x\n", __func__, int_bits);
127 outb((u8)(int_bits & 0xff), ELCR1);
128 outb((u8)(int_bits >> 8), ELCR2);
Simon Glass0e9c6332014-11-14 18:18:31 -0700129}