linux/arch/parisc/include/asm/spinlock_types.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef __ASM_SPINLOCK_TYPES_H
   3#define __ASM_SPINLOCK_TYPES_H
   4
   5typedef struct {
   6#ifdef CONFIG_PA20
   7        volatile unsigned int slock;
   8# define __ARCH_SPIN_LOCK_UNLOCKED { 1 }
   9#else
  10        volatile unsigned int lock[4];
  11# define __ARCH_SPIN_LOCK_UNLOCKED      { { 1, 1, 1, 1 } }
  12#endif
  13} arch_spinlock_t;
  14
  15
  16/* counter:
  17 * Unlocked     : 0x0100_0000
  18 * Read lock(s) : 0x00FF_FFFF to 0x01  (Multiple Readers decrement it)
  19 * Write lock   : 0x0, but only if prior value is "unlocked" 0x0100_0000
  20 */
  21typedef struct {
  22        arch_spinlock_t         lock_mutex;
  23        volatile unsigned int   counter;
  24} arch_rwlock_t;
  25
  26#define __ARCH_RW_LOCK_UNLOCKED__       0x01000000
  27#define __ARCH_RW_LOCK_UNLOCKED         { .lock_mutex = __ARCH_SPIN_LOCK_UNLOCKED, \
  28                                        .counter = __ARCH_RW_LOCK_UNLOCKED__ }
  29
  30#endif
  31