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 #ifndef is_affinity_mask_valid 31 #define is_affinity_mask_valid(val) 1 32 #endif 33 34 int no_irq_affinity; 35 static int irq_affinity_write_proc(struct file *file, const char __user *buffer, 36 unsigned long count, void *data) 37 { 38 unsigned int irq = (int)(long)data, full_count = count, err; 39 cpumask_t new_value, tmp; 40 41 if (!irq_desc[irq].chip->set_affinity || no_irq_affinity || 42 irq_balancing_disabled(irq)) 43 return -EIO; 44 45 err = cpumask_parse_user(buffer, count, new_value); 46 if (err) 47 return err; 48 49 if (!is_affinity_mask_valid(new_value)) 50 return -EINVAL; 51 52 /* 53 * Do not allow disabling IRQs completely - it's a too easy 54 * way to make the system unusable accidentally :-) At least 55 * one online CPU still has to be targeted. 56 */ 57 cpus_and(tmp, new_value, cpu_online_map); 58 if (cpus_empty(tmp)) 59 /* Special case for empty set - allow the architecture 60 code to set default SMP affinity. */ 61 return select_smp_affinity(irq) ? -EINVAL : full_count; 62 63 irq_set_affinity(irq, new_value); 64 65 return full_count; 66 } 67 68 #endif 69 70 #define MAX_NAMELEN 128 71 72 static int name_unique(unsigned int irq, struct irqaction *new_action) 73 { 74 struct irq_desc *desc = irq_desc + irq; 75 struct irqaction *action; 76 unsigned long flags; 77 int ret = 1; 78 79 spin_lock_irqsave(&desc->lock, flags); 80 for (action = desc->action ; action; action = action->next) { 81 if ((action != new_action) && action->name && 82 !strcmp(new_action->name, action->name)) { 83 ret = 0; 84 break; 85 } 86 } 87 spin_unlock_irqrestore(&desc->lock, flags); 88 return ret; 89 } 90 91 void register_handler_proc(unsigned int irq, struct irqaction *action) 92 { 93 char name [MAX_NAMELEN]; 94 95 if (!irq_desc[irq].dir || action->dir || !action->name || 96 !name_unique(irq, action)) 97 return; 98 99 memset(name, 0, MAX_NAMELEN); 100 snprintf(name, MAX_NAMELEN, "%s", action->name); 101 102 /* create /proc/irq/1234/handler/ */ 103 action->dir = proc_mkdir(name, irq_desc[irq].dir); 104 } 105 106 #undef MAX_NAMELEN 107 108 #define MAX_NAMELEN 10 109 110 void register_irq_proc(unsigned int irq) 111 { 112 char name [MAX_NAMELEN]; 113 114 if (!root_irq_dir || 115 (irq_desc[irq].chip == &no_irq_chip) || 116 irq_desc[irq].dir) 117 return; 118 119 memset(name, 0, MAX_NAMELEN); 120 sprintf(name, "%d", irq); 121 122 /* create /proc/irq/1234 */ 123 irq_desc[irq].dir = proc_mkdir(name, root_irq_dir); 124 125 #ifdef CONFIG_SMP 126 { 127 struct proc_dir_entry *entry; 128 129 /* create /proc/irq/<irq>/smp_affinity */ 130 entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir); 131 132 if (entry) { 133 entry->data = (void *)(long)irq; 134 entry->read_proc = irq_affinity_read_proc; 135 entry->write_proc = irq_affinity_write_proc; 136 } 137 } 138 #endif 139 } 140 141 #undef MAX_NAMELEN 142 143 void unregister_handler_proc(unsigned int irq, struct irqaction *action) 144 { 145 if (action->dir) 146 remove_proc_entry(action->dir->name, irq_desc[irq].dir); 147 } 148 149 void init_irq_proc(void) 150 { 151 int i; 152 153 /* create /proc/irq */ 154 root_irq_dir = proc_mkdir("irq", NULL); 155 if (!root_irq_dir) 156 return; 157 158 /* 159 * Create entries for all existing IRQs. 160 */ 161 for (i = 0; i < NR_IRQS; i++) 162 register_irq_proc(i); 163 } 164 165