1 /* 2 * linux/kernel/irq/proc.c 3 * 4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar 5 * 6 * This file contains the /proc/irq/ handling code. 7 */ 8 9 #include <linux/irq.h> 10 #include <linux/proc_fs.h> 11 #include <linux/interrupt.h> 12 13 #include "internals.h" 14 15 static struct proc_dir_entry *root_irq_dir; 16 17 #ifdef CONFIG_SMP 18 19 static int irq_affinity_read_proc(char *page, char **start, off_t off, 20 int count, int *eof, void *data) 21 { 22 int len = cpumask_scnprintf(page, count, irq_desc[(long)data].affinity); 23 24 if (count - len < 2) 25 return -EINVAL; 26 len += sprintf(page + len, "\n"); 27 return len; 28 } 29 30 int no_irq_affinity; 31 static int irq_affinity_write_proc(struct file *file, const char __user *buffer, 32 unsigned long count, void *data) 33 { 34 unsigned int irq = (int)(long)data, full_count = count, err; 35 cpumask_t new_value, tmp; 36 37 if (!irq_desc[irq].chip->set_affinity || no_irq_affinity || 38 irq_balancing_disabled(irq)) 39 return -EIO; 40 41 err = cpumask_parse_user(buffer, count, new_value); 42 if (err) 43 return err; 44 45 /* 46 * Do not allow disabling IRQs completely - it's a too easy 47 * way to make the system unusable accidentally :-) At least 48 * one online CPU still has to be targeted. 49 */ 50 cpus_and(tmp, new_value, cpu_online_map); 51 if (cpus_empty(tmp)) 52 /* Special case for empty set - allow the architecture 53 code to set default SMP affinity. */ 54 return select_smp_affinity(irq) ? -EINVAL : full_count; 55 56 irq_set_affinity(irq, new_value); 57 58 return full_count; 59 } 60 61 #endif 62 63 #define MAX_NAMELEN 128 64 65 static int name_unique(unsigned int irq, struct irqaction *new_action) 66 { 67 struct irq_desc *desc = irq_desc + irq; 68 struct irqaction *action; 69 70 for (action = desc->action ; action; action = action->next) 71 if ((action != new_action) && action->name && 72 !strcmp(new_action->name, action->name)) 73 return 0; 74 return 1; 75 } 76 77 void register_handler_proc(unsigned int irq, struct irqaction *action) 78 { 79 char name [MAX_NAMELEN]; 80 81 if (!irq_desc[irq].dir || action->dir || !action->name || 82 !name_unique(irq, action)) 83 return; 84 85 memset(name, 0, MAX_NAMELEN); 86 snprintf(name, MAX_NAMELEN, "%s", action->name); 87 88 /* create /proc/irq/1234/handler/ */ 89 action->dir = proc_mkdir(name, irq_desc[irq].dir); 90 } 91 92 #undef MAX_NAMELEN 93 94 #define MAX_NAMELEN 10 95 96 void register_irq_proc(unsigned int irq) 97 { 98 char name [MAX_NAMELEN]; 99 100 if (!root_irq_dir || 101 (irq_desc[irq].chip == &no_irq_chip) || 102 irq_desc[irq].dir) 103 return; 104 105 memset(name, 0, MAX_NAMELEN); 106 sprintf(name, "%d", irq); 107 108 /* create /proc/irq/1234 */ 109 irq_desc[irq].dir = proc_mkdir(name, root_irq_dir); 110 111 #ifdef CONFIG_SMP 112 { 113 struct proc_dir_entry *entry; 114 115 /* create /proc/irq/<irq>/smp_affinity */ 116 entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir); 117 118 if (entry) { 119 entry->data = (void *)(long)irq; 120 entry->read_proc = irq_affinity_read_proc; 121 entry->write_proc = irq_affinity_write_proc; 122 } 123 } 124 #endif 125 } 126 127 #undef MAX_NAMELEN 128 129 void unregister_handler_proc(unsigned int irq, struct irqaction *action) 130 { 131 if (action->dir) 132 remove_proc_entry(action->dir->name, irq_desc[irq].dir); 133 } 134 135 void init_irq_proc(void) 136 { 137 int i; 138 139 /* create /proc/irq */ 140 root_irq_dir = proc_mkdir("irq", NULL); 141 if (!root_irq_dir) 142 return; 143 144 /* 145 * Create entries for all existing IRQs. 146 */ 147 for (i = 0; i < NR_IRQS; i++) 148 register_irq_proc(i); 149 } 150 151