1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 */ 6 #include <linux/init.h> 7 #include <linux/irq.h> 8 #include <linux/types.h> 9 10 #include <asm/barrier.h> 11 12 static DECLARE_BITMAP(irq_map, NR_IRQS); 13 allocate_irqno(void)14int allocate_irqno(void) 15 { 16 int irq; 17 18 again: 19 irq = find_first_zero_bit(irq_map, NR_IRQS); 20 21 if (irq >= NR_IRQS) 22 return -ENOSPC; 23 24 if (test_and_set_bit(irq, irq_map)) 25 goto again; 26 27 return irq; 28 } 29 30 /* 31 * Allocate the 16 legacy interrupts for i8259 devices. This happens early 32 * in the kernel initialization so treating allocation failure as BUG() is 33 * ok. 34 */ alloc_legacy_irqno(void)35void __init alloc_legacy_irqno(void) 36 { 37 int i; 38 39 for (i = 0; i <= 16; i++) 40 BUG_ON(test_and_set_bit(i, irq_map)); 41 } 42 free_irqno(unsigned int irq)43void free_irqno(unsigned int irq) 44 { 45 smp_mb__before_atomic(); 46 clear_bit(irq, irq_map); 47 smp_mb__after_atomic(); 48 } 49