1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
|
/*
* (C) Copyright 2002
* John W. Linville <linville@tuxdriver.com>
*
* Copied and modified from original code by Josh Huber. Original
* copyright notice preserved below.
*
* (C) Copyright 2001
* Josh Huber <huber@mclx.com>, Mission Critical Linux, Inc.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* interrupts.c - just enough support for the decrementer/timer
*/
#include <common.h>
#include <asm/processor.h>
#include <command.h>
#include "i8259.h"
#undef DEBUG
#ifdef DEBUG
#define PRINTF(fmt,args...) printf (fmt ,##args)
#else
#define PRINTF(fmt,args...)
#endif
#define NR_IRQS 16
void irq_alloc_init(void);
long irq_alloc(long wanted);
/****************************************************************************/
unsigned decrementer_count; /* count value for 1e6/HZ microseconds */
struct irq_action {
interrupt_handler_t *handler;
void *arg;
ulong count;
};
static struct irq_action irq_handlers[NR_IRQS];
/****************************************************************************/
static __inline__ unsigned long
get_msr(void)
{
unsigned long msr;
asm volatile("mfmsr %0" : "=r" (msr) :);
return msr;
}
static __inline__ void
set_msr(unsigned long msr)
{
asm volatile("mtmsr %0" : : "r" (msr));
}
static __inline__ unsigned long
get_dec(void)
{
unsigned long val;
asm volatile("mfdec %0" : "=r" (val) :);
return val;
}
static __inline__ void
set_dec(unsigned long val)
{
asm volatile("mtdec %0" : : "r" (val));
}
void
enable_interrupts(void)
{
set_msr (get_msr() | MSR_EE);
}
/* returns flag if MSR_EE was set before */
int
disable_interrupts(void)
{
ulong msr;
msr = get_msr();
set_msr (msr & ~MSR_EE);
return ((msr & MSR_EE) != 0);
}
/****************************************************************************/
int interrupt_init (void)
{
extern void new_reset(void);
extern void new_reset_end(void);
#ifdef DEBUG
puts("interrupt_init: setting decrementer_count\n");
#endif
decrementer_count = get_tbclk() / CFG_HZ;
#ifdef DEBUG
puts("interrupt_init: setting actual decremter\n");
#endif
set_dec (get_tbclk() / CFG_HZ);
#ifdef DEBUG
puts("interrupt_init: clearing external interrupt table\n");
#endif
/* clear external interrupt table here */
memset(irq_handlers, 0, sizeof(irq_handlers));
#ifdef DEBUG
puts("interrupt_init: initializing interrupt controller\n");
#endif
i8259_init();
#ifdef DEBUG
puts("Copying reset trampoline\n");
#endif
/* WARNING: Assmues that the first megabyte is CACHEINHIBIT! */
memcpy((void *)0x100, new_reset, new_reset_end - new_reset);
#ifdef DEBUG
PRINTF("interrupt_init: enabling interrupts (msr = %08x)\n",
get_msr());
#endif
set_msr (get_msr() | MSR_EE);
#ifdef DEBUG
PRINTF("interrupt_init: done. (msr = %08x)\n", get_msr());
#endif
}
/****************************************************************************/
/*
* Handle external interrupts
*/
void
external_interrupt(struct pt_regs *regs)
{
extern int i8259_irq(void);
int irq, unmask = 1;
irq = i8259_irq(); /*i8259_get_irq(regs); */
/* printf("irq = %d, handler at %p ack=%d\n", irq, irq_handlers[irq].handler, *(volatile unsigned char *)0xFEF00000); */
i8259_mask_and_ack(irq);
if (irq_handlers[irq].handler != NULL)
(*irq_handlers[irq].handler)(irq_handlers[irq].arg);
else {
PRINTF ("\nBogus External Interrupt IRQ %d\n", irq);
/*
* turn off the bogus interrupt, otherwise it
* might repeat forever
*/
unmask = 0;
}
if (unmask) i8259_unmask_irq(irq);
}
volatile ulong timestamp = 0;
/*
* timer_interrupt - gets called when the decrementer overflows,
* with interrupts disabled.
* Trivial implementation - no need to be really accurate.
*/
void
timer_interrupt(struct pt_regs *regs)
{
set_dec(decrementer_count);
timestamp++;
}
/****************************************************************************/
void
reset_timer(void)
{
timestamp = 0;
}
ulong
get_timer(ulong base)
{
return (timestamp - base);
}
void
set_timer(ulong t)
{
timestamp = t;
}
/****************************************************************************/
/*
* Install and free a interrupt handler.
*/
void
irq_install_handler(int irq, interrupt_handler_t *handler, void *arg)
{
if (irq < 0 || irq >= NR_IRQS) {
PRINTF("irq_install_handler: bad irq number %d\n", irq);
return;
}
if (irq_handlers[irq].handler != NULL)
PRINTF("irq_install_handler: 0x%08lx replacing 0x%08lx\n",
(ulong)handler, (ulong)irq_handlers[irq].handler);
irq_handlers[irq].handler = handler;
irq_handlers[irq].arg = arg;
i8259_unmask_irq(irq);
}
void
irq_free_handler(int irq)
{
if (irq < 0 || irq >= NR_IRQS) {
PRINTF("irq_free_handler: bad irq number %d\n", irq);
return;
}
i8259_mask_irq(irq);
irq_handlers[irq].handler = NULL;
irq_handlers[irq].arg = NULL;
}
/****************************************************************************/
void
do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
{
puts("IRQ related functions are unimplemented currently.\n");
}
|
