1 /*
2 * Copyright (C) 2000 David J. Mckay (david.mckay@st.com)
3 *
4 * May be copied or modified under the terms of the GNU General Public
5 * License. See linux/COPYING for more information.
6 *
7 * Looks after interrupts on the HARP board.
8 *
9 * Bases on the IPR irq system
10 */
11
12 #include <linux/config.h>
13 #include <linux/init.h>
14 #include <linux/irq.h>
15
16 #include <asm/system.h>
17 #include <asm/io.h>
18
19 #include "harp.h"
20
21
22 #define NUM_EXTERNAL_IRQS 16
23
24 // Early versions of the STB1 Overdrive required this nasty frig
25 //#define INVERT_INTMASK_WRITES
26
27 static void enable_harp_irq(unsigned int irq);
28 static void disable_harp_irq(unsigned int irq);
29
30 /* shutdown is same as "disable" */
31 #define shutdown_harp_irq disable_harp_irq
32
33 static void mask_and_ack_harp(unsigned int);
34 static void end_harp_irq(unsigned int irq);
35
startup_harp_irq(unsigned int irq)36 static unsigned int startup_harp_irq(unsigned int irq)
37 {
38 enable_harp_irq(irq);
39 return 0; /* never anything pending */
40 }
41
42 static struct hw_interrupt_type harp_irq_type = {
43 "Harp-IRQ",
44 startup_harp_irq,
45 shutdown_harp_irq,
46 enable_harp_irq,
47 disable_harp_irq,
48 mask_and_ack_harp,
49 end_harp_irq
50 };
51
disable_harp_irq(unsigned int irq)52 static void disable_harp_irq(unsigned int irq)
53 {
54 unsigned val, flags;
55 unsigned maskReg;
56 unsigned mask;
57 int pri;
58
59 if (irq < 0 || irq >= NUM_EXTERNAL_IRQS)
60 return;
61
62 pri = 15 - irq;
63
64 if (pri < 8) {
65 maskReg = EPLD_INTMASK0;
66 } else {
67 maskReg = EPLD_INTMASK1;
68 pri -= 8;
69 }
70
71 save_and_cli(flags);
72 mask = ctrl_inl(maskReg);
73 mask &= (~(1 << pri));
74 #if defined(INVERT_INTMASK_WRITES)
75 mask ^= 0xff;
76 #endif
77 ctrl_outl(mask, maskReg);
78 restore_flags(flags);
79 }
80
enable_harp_irq(unsigned int irq)81 static void enable_harp_irq(unsigned int irq)
82 {
83 unsigned flags;
84 unsigned maskReg;
85 unsigned mask;
86 int pri;
87
88 if (irq < 0 || irq >= NUM_EXTERNAL_IRQS)
89 return;
90
91 pri = 15 - irq;
92
93 if (pri < 8) {
94 maskReg = EPLD_INTMASK0;
95 } else {
96 maskReg = EPLD_INTMASK1;
97 pri -= 8;
98 }
99
100 save_and_cli(flags);
101 mask = ctrl_inl(maskReg);
102
103
104 mask |= (1 << pri);
105
106 #if defined(INVERT_INTMASK_WRITES)
107 mask ^= 0xff;
108 #endif
109 ctrl_outl(mask, maskReg);
110
111 restore_flags(flags);
112 }
113
114 /* This functions sets the desired irq handler to be an overdrive type */
make_harp_irq(unsigned int irq)115 static void __init make_harp_irq(unsigned int irq)
116 {
117 disable_irq_nosync(irq);
118 irq_desc[irq].handler = &harp_irq_type;
119 disable_harp_irq(irq);
120 }
121
mask_and_ack_harp(unsigned int irq)122 static void mask_and_ack_harp(unsigned int irq)
123 {
124 disable_harp_irq(irq);
125 }
126
end_harp_irq(unsigned int irq)127 static void end_harp_irq(unsigned int irq)
128 {
129 enable_harp_irq(irq);
130 }
131
init_harp_irq(void)132 void __init init_harp_irq(void)
133 {
134 int i;
135
136 #if !defined(INVERT_INTMASK_WRITES)
137 // On the harp these are set to enable an interrupt
138 ctrl_outl(0x00, EPLD_INTMASK0);
139 ctrl_outl(0x00, EPLD_INTMASK1);
140 #else
141 // On the Overdrive the data is inverted before being stored in the reg
142 ctrl_outl(0xff, EPLD_INTMASK0);
143 ctrl_outl(0xff, EPLD_INTMASK1);
144 #endif
145
146 for (i = 0; i < NUM_EXTERNAL_IRQS; i++) {
147 make_harp_irq(i);
148 }
149 }
150