1/*
2 * File:         arch/blackfin/kernel/irqchip.c
3 * Based on:
4 * Author:
5 *
6 * Created:
7 * Description:  This file contains the simple DMA Implementation for Blackfin
8 *
9 * Modified:
10 *               Copyright 2004-2006 Analog Devices Inc.
11 *
12 * Bugs:         Enter bugs at http://blackfin.uclinux.org/
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, see the file COPYING, or write
26 * to the Free Software Foundation, Inc.,
27 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
28 */
29
30#include <linux/kernel_stat.h>
31#include <linux/module.h>
32#include <linux/random.h>
33#include <linux/seq_file.h>
34#include <linux/kallsyms.h>
35#include <linux/interrupt.h>
36#include <linux/irq.h>
37
38static unsigned long irq_err_count;
39static spinlock_t irq_controller_lock;
40
41/*
42 * Dummy mask/unmask handler
43 */
44void dummy_mask_unmask_irq(unsigned int irq)
45{
46}
47
48void ack_bad_irq(unsigned int irq)
49{
50	irq_err_count += 1;
51	printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
52}
53EXPORT_SYMBOL(ack_bad_irq);
54
55static struct irq_chip bad_chip = {
56	.ack = dummy_mask_unmask_irq,
57	.mask = dummy_mask_unmask_irq,
58	.unmask = dummy_mask_unmask_irq,
59};
60
61static struct irq_desc bad_irq_desc = {
62	.chip = &bad_chip,
63	.handle_irq = handle_bad_irq,
64	.depth = 1,
65};
66
67int show_interrupts(struct seq_file *p, void *v)
68{
69	int i = *(loff_t *) v;
70	struct irqaction *action;
71	unsigned long flags;
72
73	if (i < NR_IRQS) {
74		spin_lock_irqsave(&irq_desc[i].lock, flags);
75		action = irq_desc[i].action;
76		if (!action)
77			goto unlock;
78
79		seq_printf(p, "%3d: %10u ", i, kstat_irqs(i));
80		seq_printf(p, "  %s", action->name);
81		for (action = action->next; action; action = action->next)
82			seq_printf(p, ", %s", action->name);
83
84		seq_putc(p, '\n');
85	      unlock:
86		spin_unlock_irqrestore(&irq_desc[i].lock, flags);
87	} else if (i == NR_IRQS) {
88		seq_printf(p, "Err: %10lu\n", irq_err_count);
89	}
90	return 0;
91}
92
93/*
94 * do_IRQ handles all hardware IRQs.  Decoded IRQs should not
95 * come via this function.  Instead, they should provide their
96 * own 'handler'
97 */
98
99#ifdef CONFIG_DO_IRQ_L1
100asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)__attribute__((l1_text));
101#endif
102
103asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
104{
105	struct pt_regs *old_regs;
106	struct irq_desc *desc = irq_desc + irq;
107	unsigned short pending, other_ints;
108
109	old_regs = set_irq_regs(regs);
110
111	/*
112	 * Some hardware gives randomly wrong interrupts.  Rather
113	 * than crashing, do something sensible.
114	 */
115	if (irq >= NR_IRQS)
116		desc = &bad_irq_desc;
117
118	irq_enter();
119
120	generic_handle_irq(irq);
121
122	/* If we're the only interrupt running (ignoring IRQ15 which is for
123	   syscalls), lower our priority to IRQ14 so that softirqs run at
124	   that level.  If there's another, lower-level interrupt, irq_exit
125	   will defer softirqs to that.  */
126	CSYNC();
127	pending = bfin_read_IPEND() & ~0x8000;
128	other_ints = pending & (pending - 1);
129	if (other_ints == 0)
130		lower_to_irq14();
131	irq_exit();
132
133	set_irq_regs(old_regs);
134}
135
136void __init init_IRQ(void)
137{
138	struct irq_desc *desc;
139	int irq;
140
141	spin_lock_init(&irq_controller_lock);
142	for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
143		*desc = bad_irq_desc;
144	}
145
146	init_arch_irq();
147}
148