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 #include <asm/trace.h>
38 #include <asm/pda.h>
39
40 static atomic_t irq_err_count;
41 static spinlock_t irq_controller_lock;
42
43 /*
44 * Dummy mask/unmask handler
45 */
dummy_mask_unmask_irq(unsigned int irq)46 void dummy_mask_unmask_irq(unsigned int irq)
47 {
48 }
49
ack_bad_irq(unsigned int irq)50 void ack_bad_irq(unsigned int irq)
51 {
52 atomic_inc(&irq_err_count);
53 printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
54 }
55
56 static struct irq_chip bad_chip = {
57 .ack = dummy_mask_unmask_irq,
58 .mask = dummy_mask_unmask_irq,
59 .unmask = dummy_mask_unmask_irq,
60 };
61
62 static struct irq_desc bad_irq_desc = {
63 .status = IRQ_DISABLED,
64 .chip = &bad_chip,
65 .handle_irq = handle_bad_irq,
66 .depth = 1,
67 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
68 #ifdef CONFIG_SMP
69 .affinity = CPU_MASK_ALL
70 #endif
71 };
72
show_interrupts(struct seq_file * p,void * v)73 int show_interrupts(struct seq_file *p, void *v)
74 {
75 int i = *(loff_t *) v, j;
76 struct irqaction *action;
77 unsigned long flags;
78
79 if (i < NR_IRQS) {
80 spin_lock_irqsave(&irq_desc[i].lock, flags);
81 action = irq_desc[i].action;
82 if (!action)
83 goto skip;
84 seq_printf(p, "%3d: ", i);
85 for_each_online_cpu(j)
86 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
87 seq_printf(p, " %8s", irq_desc[i].chip->name);
88 seq_printf(p, " %s", action->name);
89 for (action = action->next; action; action = action->next)
90 seq_printf(p, " %s", action->name);
91
92 seq_putc(p, '\n');
93 skip:
94 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
95 } else if (i == NR_IRQS) {
96 seq_printf(p, "NMI: ");
97 for_each_online_cpu(j)
98 seq_printf(p, "%10u ", cpu_pda[j].__nmi_count);
99 seq_printf(p, " CORE Non Maskable Interrupt\n");
100 seq_printf(p, "Err: %10u\n", atomic_read(&irq_err_count));
101 }
102 return 0;
103 }
104
105 /*
106 * do_IRQ handles all hardware IRQs. Decoded IRQs should not
107 * come via this function. Instead, they should provide their
108 * own 'handler'
109 */
110 #ifdef CONFIG_DO_IRQ_L1
111 __attribute__((l1_text))
112 #endif
asm_do_IRQ(unsigned int irq,struct pt_regs * regs)113 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
114 {
115 struct pt_regs *old_regs;
116 struct irq_desc *desc = irq_desc + irq;
117 #ifndef CONFIG_IPIPE
118 unsigned short pending, other_ints;
119 #endif
120 old_regs = set_irq_regs(regs);
121
122 /*
123 * Some hardware gives randomly wrong interrupts. Rather
124 * than crashing, do something sensible.
125 */
126 if (irq >= NR_IRQS)
127 desc = &bad_irq_desc;
128
129 irq_enter();
130 #ifdef CONFIG_DEBUG_STACKOVERFLOW
131 /* Debugging check for stack overflow: is there less than STACK_WARN free? */
132 {
133 long sp;
134
135 sp = __get_SP() & (THREAD_SIZE-1);
136
137 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
138 dump_stack();
139 printk(KERN_EMERG "%s: possible stack overflow while handling irq %i "
140 " only %ld bytes free\n",
141 __func__, irq, sp - sizeof(struct thread_info));
142 }
143 }
144 #endif
145 generic_handle_irq(irq);
146
147 #ifndef CONFIG_IPIPE
148 /*
149 * If we're the only interrupt running (ignoring IRQ15 which
150 * is for syscalls), lower our priority to IRQ14 so that
151 * softirqs run at that level. If there's another,
152 * lower-level interrupt, irq_exit will defer softirqs to
153 * that. If the interrupt pipeline is enabled, we are already
154 * running at IRQ14 priority, so we don't need this code.
155 */
156 CSYNC();
157 pending = bfin_read_IPEND() & ~0x8000;
158 other_ints = pending & (pending - 1);
159 if (other_ints == 0)
160 lower_to_irq14();
161 #endif /* !CONFIG_IPIPE */
162 irq_exit();
163
164 set_irq_regs(old_regs);
165 }
166
init_IRQ(void)167 void __init init_IRQ(void)
168 {
169 struct irq_desc *desc;
170 int irq;
171
172 spin_lock_init(&irq_controller_lock);
173 for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
174 *desc = bad_irq_desc;
175 }
176
177 init_arch_irq();
178
179 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
180 /* Now that evt_ivhw is set up, turn this on */
181 trace_buff_offset = 0;
182 bfin_write_TBUFCTL(BFIN_TRACE_ON);
183 printk(KERN_INFO "Hardware Trace expanded to %ik\n",
184 1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
185 #endif
186 }
187