| Ralf Baechle | cb2224d | 2015-06-09 15:04:38 +0200 | [diff] [blame] | 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 | |
| 14 | int 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 | */ |
| 35 | void __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 | |
| 43 | void free_irqno(unsigned int irq) |
| 44 | { |
| 45 | smp_mb__before_atomic(); |
| 46 | clear_bit(irq, irq_map); |
| 47 | smp_mb__after_atomic(); |
| 48 | } |