aboutsummaryrefslogtreecommitdiffstats
path: root/arch/cris/kernel/irq.c
blob: d848b940745740b931d85d091e18c50c954dcfe3 (plain) (blame)
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
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
/*
 *
 *	linux/arch/cris/kernel/irq.c
 *
 *      Copyright (c) 2000,2001 Axis Communications AB
 *
 *      Authors: Bjorn Wesen (bjornw@axis.com)
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 *
 * Notice Linux/CRIS: these routines do not care about SMP
 *
 */

/*
 * IRQ's are in fact implemented a bit like signal handlers for the kernel.
 * Naturally it's not a 1:1 relation, but there are similarities.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/ptrace.h>

#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/errno.h>
#include <linux/bitops.h>

#include <asm/io.h>

/* Defined in arch specific irq.c */
extern void arch_setup_irq(int irq);
extern void arch_free_irq(int irq);

void
disable_irq(unsigned int irq_nr)
{
	unsigned long flags;
	
	local_save_flags(flags);
	local_irq_disable();
	mask_irq(irq_nr);
	local_irq_restore(flags);
}

void
enable_irq(unsigned int irq_nr)
{
	unsigned long flags;
	local_save_flags(flags);
	local_irq_disable();
	unmask_irq(irq_nr);
	local_irq_restore(flags);
}

unsigned long
probe_irq_on()
{
	return 0;
}

EXPORT_SYMBOL(probe_irq_on);

int
probe_irq_off(unsigned long x)
{
	return 0;
}

EXPORT_SYMBOL(probe_irq_off);

/*
 * Initial irq handlers.
 */

static struct irqaction *irq_action[NR_IRQS];

int show_interrupts(struct seq_file *p, void *v)
{
	int i = *(loff_t *) v;
	struct irqaction * action;
	unsigned long flags;

	if (i < NR_IRQS) {
		local_irq_save(flags);
		action = irq_action[i];
		if (!action) 
			goto skip;
		seq_printf(p, "%2d: %10u %c %s",
			i, kstat_this_cpu.irqs[i],
			(action->flags & SA_INTERRUPT) ? '+' : ' ',
			action->name);
		for (action = action->next; action; action = action->next) {
			seq_printf(p, ",%s %s",
				(action->flags & SA_INTERRUPT) ? " +" : "",
				action->name);
		}
		seq_putc(p, '\n');
skip:
		local_irq_restore(flags);
	}
	return 0;
}

/* called by the assembler IRQ entry functions defined in irq.h
 * to dispatch the interrupts to registred handlers
 * interrupts are disabled upon entry - depending on if the
 * interrupt was registred with SA_INTERRUPT or not, interrupts
 * are re-enabled or not.
 */

asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
{
	struct irqaction *action;
	int do_random, cpu;
        int ret, retval = 0;

        cpu = smp_processor_id();
        irq_enter();
	kstat_cpu(cpu).irqs[irq - FIRST_IRQ]++;
	action = irq_action[irq - FIRST_IRQ];

        if (action) {
                if (!(action->flags & SA_INTERRUPT))
                        local_irq_enable();
                do_random = 0;
                do {
			ret = action->handler(irq, action->dev_id, regs);
			if (ret == IRQ_HANDLED)
				do_random |= action->flags;
                        retval |= ret;
                        action = action->next;
                } while (action);

                if (retval != 1) {
			if (retval) {
				printk("irq event %d: bogus retval mask %x\n",
					irq, retval);
			} else {
				printk("irq %d: nobody cared\n", irq);
			}
		}

                if (do_random & SA_SAMPLE_RANDOM)
                        add_interrupt_randomness(irq);
		local_irq_disable();
        }
        irq_exit();
}

/* this function links in a handler into the chain of handlers for the
   given irq, and if the irq has never been registred, the appropriate
   handler is entered into the interrupt vector
*/

int setup_irq(int irq, struct irqaction * new)
{
	int shared = 0;
	struct irqaction *old, **p;
	unsigned long flags;

	p = irq_action + irq - FIRST_IRQ;
	if ((old = *p) != NULL) {
		/* Can't share interrupts unless both agree to */
		if (!(old->flags & new->flags & SA_SHIRQ))
			return -EBUSY;

		/* Can't share interrupts unless both are same type */
		if ((old->flags ^ new->flags) & SA_INTERRUPT)
			return -EBUSY;

		/* add new interrupt at end of irq queue */
		do {
			p = &old->next;
			old = *p;
		} while (old);
		shared = 1;
	}

	if (new->flags & SA_SAMPLE_RANDOM)
		rand_initialize_irq(irq);

	local_save_flags(flags);
	local_irq_disable();
	*p = new;

	if (!shared) {
		/* if the irq wasn't registred before, enter it into the vector table
		   and unmask it physically 
		*/
		arch_setup_irq(irq);
		unmask_irq(irq);
	}
	
	local_irq_restore(flags);
	return 0;
}

/* this function is called by a driver to register an irq handler
   Valid flags:
   SA_INTERRUPT -> it's a fast interrupt, handler called with irq disabled and
                   no signal checking etc is performed upon exit
   SA_SHIRQ -> the interrupt can be shared between different handlers, the handler
                is required to check if the irq was "aimed" at it explicitely
   SA_RANDOM -> the interrupt will add to the random generators entropy
*/

int request_irq(unsigned int irq, 
		irqreturn_t (*handler)(int, void *, struct pt_regs *),
		unsigned long irqflags, 
		const char * devname,
		void *dev_id)
{
	int retval;
	struct irqaction * action;

	if(!handler)
		return -EINVAL;

	/* allocate and fill in a handler structure and setup the irq */

	action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
	if (!action)
		return -ENOMEM;

	action->handler = handler;
	action->flags = irqflags;
	cpus_clear(action->mask);
	action->name = devname;
	action->next = NULL;
	action->dev_id = dev_id;

	retval = setup_irq(irq, action);

	if (retval)
		kfree(action);
	return retval;
}

EXPORT_SYMBOL(request_irq);
		
void free_irq(unsigned int irq, void *dev_id)
{
	struct irqaction * action, **p;
	unsigned long flags;

	if (irq >= NR_IRQS) {
		printk("Trying to free IRQ%d\n",irq);
		return;
	}
	for (p = irq - FIRST_IRQ + irq_action; (action = *p) != NULL; p = &action->next) {
		if (action->dev_id != dev_id)
			continue;

		/* Found it - now free it */
		local_save_flags(flags);
		local_irq_disable();
		*p = action->next;
		if (!irq_action[irq - FIRST_IRQ]) {
			mask_irq(irq);
			arch_free_irq(irq);
		}
		local_irq_restore(flags);
		kfree(action);
		return;
	}
	printk("Trying to free free IRQ%d\n",irq);
}

EXPORT_SYMBOL(free_irq);

void weird_irq(void)
{
	local_irq_disable();
	printk("weird irq\n");
	while(1);
}

#if defined(CONFIG_PROC_FS) && defined(CONFIG_SYSCTL)
/* Used by other archs to show/control IRQ steering during SMP */
void __init
init_irq_proc(void)
{
}
#endif