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 static struct proc_dir_entry *root_irq_dir, *irq_dir[NR_IRQS]; 14 15 #ifdef CONFIG_SMP 16 17 /* 18 * The /proc/irq/<irq>/smp_affinity values: 19 */ 20 static struct proc_dir_entry *smp_affinity_entry[NR_IRQS]; 21 22 void __attribute__((weak)) 23 proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val) 24 { 25 irq_affinity[irq] = mask_val; 26 irq_desc[irq].handler->set_affinity(irq, mask_val); 27 } 28 29 static int irq_affinity_read_proc(char *page, char **start, off_t off, 30 int count, int *eof, void *data) 31 { 32 int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]); 33 34 if (count - len < 2) 35 return -EINVAL; 36 len += sprintf(page + len, "\n"); 37 return len; 38 } 39 40 int no_irq_affinity; 41 static int irq_affinity_write_proc(struct file *file, const char __user *buffer, 42 unsigned long count, void *data) 43 { 44 unsigned int irq = (int)(long)data, full_count = count, err; 45 cpumask_t new_value, tmp; 46 47 if (!irq_desc[irq].handler->set_affinity || no_irq_affinity) 48 return -EIO; 49 50 err = cpumask_parse(buffer, count, new_value); 51 if (err) 52 return err; 53 54 /* 55 * Do not allow disabling IRQs completely - it's a too easy 56 * way to make the system unusable accidentally :-) At least 57 * one online CPU still has to be targeted. 58 */ 59 cpus_and(tmp, new_value, cpu_online_map); 60 if (cpus_empty(tmp)) 61 return -EINVAL; 62 63 proc_set_irq_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 77 for (action = desc->action ; action; action = action->next) 78 if ((action != new_action) && action->name && 79 !strcmp(new_action->name, action->name)) 80 return 0; 81 return 1; 82 } 83 84 void register_handler_proc(unsigned int irq, struct irqaction *action) 85 { 86 char name [MAX_NAMELEN]; 87 88 if (!irq_dir[irq] || action->dir || !action->name || 89 !name_unique(irq, action)) 90 return; 91 92 memset(name, 0, MAX_NAMELEN); 93 snprintf(name, MAX_NAMELEN, "%s", action->name); 94 95 /* create /proc/irq/1234/handler/ */ 96 action->dir = proc_mkdir(name, irq_dir[irq]); 97 } 98 99 #undef MAX_NAMELEN 100 101 #define MAX_NAMELEN 10 102 103 void register_irq_proc(unsigned int irq) 104 { 105 char name [MAX_NAMELEN]; 106 107 if (!root_irq_dir || 108 (irq_desc[irq].handler == &no_irq_type) || 109 irq_dir[irq]) 110 return; 111 112 memset(name, 0, MAX_NAMELEN); 113 sprintf(name, "%d", irq); 114 115 /* create /proc/irq/1234 */ 116 irq_dir[irq] = proc_mkdir(name, root_irq_dir); 117 118 #ifdef CONFIG_SMP 119 { 120 struct proc_dir_entry *entry; 121 122 /* create /proc/irq/<irq>/smp_affinity */ 123 entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]); 124 125 if (entry) { 126 entry->nlink = 1; 127 entry->data = (void *)(long)irq; 128 entry->read_proc = irq_affinity_read_proc; 129 entry->write_proc = irq_affinity_write_proc; 130 } 131 smp_affinity_entry[irq] = entry; 132 } 133 #endif 134 } 135 136 #undef MAX_NAMELEN 137 138 void unregister_handler_proc(unsigned int irq, struct irqaction *action) 139 { 140 if (action->dir) 141 remove_proc_entry(action->dir->name, irq_dir[irq]); 142 } 143 144 void init_irq_proc(void) 145 { 146 int i; 147 148 /* create /proc/irq */ 149 root_irq_dir = proc_mkdir("irq", NULL); 150 if (!root_irq_dir) 151 return; 152 153 /* 154 * Create entries for all existing IRQs. 155 */ 156 for (i = 0; i < NR_IRQS; i++) 157 register_irq_proc(i); 158 } 159 160