1 /*
2  * Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
3  *
4  * SPDX-License-Identifier: BSD-3-Clause
5  */
6 
7 #ifndef __BAKERY_LOCK_H__
8 #define __BAKERY_LOCK_H__
9 
10 #include <platform_def.h>
11 
12 #define BAKERY_LOCK_MAX_CPUS		PLATFORM_CORE_COUNT
13 
14 #ifndef __ASSEMBLY__
15 #include <stdint.h>
16 
17 /*****************************************************************************
18  * Internal helper macros used by the bakery lock implementation.
19  ****************************************************************************/
20 /* Convert a ticket to priority */
21 #define PRIORITY(t, pos)	(((t) << 8) | (pos))
22 
23 #define CHOOSING_TICKET		0x1
24 #define CHOSEN_TICKET		0x0
25 
26 #define bakery_is_choosing(info)	(info & 0x1)
27 #define bakery_ticket_number(info)	((info >> 1) & 0x7FFF)
28 #define make_bakery_data(choosing, number) \
29 		(((choosing & 0x1) | (number << 1)) & 0xFFFF)
30 
31 /*****************************************************************************
32  * External bakery lock interface.
33  ****************************************************************************/
34 #if USE_COHERENT_MEM
35 /*
36  * Bakery locks are stored in coherent memory
37  *
38  * Each lock's data is contiguous and fully allocated by the compiler
39  */
40 
41 typedef struct bakery_lock {
42 	/*
43 	 * The lock_data is a bit-field of 2 members:
44 	 * Bit[0]       : choosing. This field is set when the CPU is
45 	 *                choosing its bakery number.
46 	 * Bits[1 - 15] : number. This is the bakery number allocated.
47 	 */
48 	volatile uint16_t lock_data[BAKERY_LOCK_MAX_CPUS];
49 } bakery_lock_t;
50 
51 #else
52 /*
53  * Bakery locks are stored in normal .bss memory
54  *
55  * Each lock's data is spread across multiple cache lines, one per CPU,
56  * but multiple locks can share the same cache line.
57  * The compiler will allocate enough memory for one CPU's bakery locks,
58  * the remaining cache lines are allocated by the linker script
59  */
60 
61 typedef struct bakery_info {
62 	/*
63 	 * The lock_data is a bit-field of 2 members:
64 	 * Bit[0]       : choosing. This field is set when the CPU is
65 	 *                choosing its bakery number.
66 	 * Bits[1 - 15] : number. This is the bakery number allocated.
67 	 */
68 	volatile uint16_t lock_data;
69 } bakery_info_t;
70 
71 typedef bakery_info_t bakery_lock_t;
72 
73 #endif /* __USE_COHERENT_MEM__ */
74 
bakery_lock_init(bakery_lock_t * bakery)75 static inline void bakery_lock_init(bakery_lock_t *bakery) {}
76 void bakery_lock_get(bakery_lock_t *bakery);
77 void bakery_lock_release(bakery_lock_t *bakery);
78 
79 #define DEFINE_BAKERY_LOCK(_name) bakery_lock_t _name __section("bakery_lock")
80 
81 #define DECLARE_BAKERY_LOCK(_name) extern bakery_lock_t _name
82 
83 
84 #endif /* __ASSEMBLY__ */
85 #endif /* __BAKERY_LOCK_H__ */
86