Cregit: Linux 5.15: spinlock

Contributors: 5
Author	Tokens	Token Proportion	Commits	Commit Proportion
Ingo Molnar	33	50.00%	1	14.29%
Matthew Wilcox	18	27.27%	1	14.29%
Helge Deller	8	12.12%	1	14.29%
Thomas Gleixner	6	9.09%	3	42.86%
Greg Kroah-Hartman	1	1.52%	1	14.29%
Total	66		7

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_SPINLOCK_TYPES_H
#define __ASM_SPINLOCK_TYPES_H

typedef struct {
#ifdef CONFIG_PA20
	volatile unsigned int slock;
# define __ARCH_SPIN_LOCK_UNLOCKED { 1 }
#else
	volatile unsigned int lock[4];
# define __ARCH_SPIN_LOCK_UNLOCKED	{ { 1, 1, 1, 1 } }
#endif
} arch_spinlock_t;


/* counter:
 * Unlocked     : 0x0100_0000
 * Read lock(s) : 0x00FF_FFFF to 0x01  (Multiple Readers decrement it)
 * Write lock   : 0x0, but only if prior value is "unlocked" 0x0100_0000
 */
typedef struct {
	arch_spinlock_t		lock_mutex;
	volatile unsigned int	counter;
} arch_rwlock_t;

#define __ARCH_RW_LOCK_UNLOCKED__       0x01000000
#define __ARCH_RW_LOCK_UNLOCKED         { .lock_mutex = __ARCH_SPIN_LOCK_UNLOCKED, \
					.counter = __ARCH_RW_LOCK_UNLOCKED__ }

#endif

spinlock_types.h