1 /*
2  * Copyright (c) 2013-2018, 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 __ASSEMBLER__
15 #include <cdefs.h>
16 #include <stdbool.h>
17 #include <stdint.h>
18 
19 #include <lib/utils_def.h>
20 
21 /*****************************************************************************
22  * Internal helpers used by the bakery lock implementation.
23  ****************************************************************************/
24 
25 /* Convert a ticket to priority */
bakery_get_priority(unsigned int t,unsigned int pos)26 static inline unsigned int bakery_get_priority(unsigned int t, unsigned int pos)
27 {
28 	return (t << 8) | pos;
29 }
30 
31 #define CHOOSING_TICKET		U(0x1)
32 #define CHOSEN_TICKET		U(0x0)
33 
bakery_is_choosing(unsigned int info)34 static inline bool bakery_is_choosing(unsigned int info)
35 {
36 	return (info & 1U) == CHOOSING_TICKET;
37 }
38 
bakery_ticket_number(unsigned int info)39 static inline unsigned int bakery_ticket_number(unsigned int info)
40 {
41 	return (info >> 1) & 0x7FFFU;
42 }
43 
make_bakery_data(unsigned int choosing,unsigned int num)44 static inline uint16_t make_bakery_data(unsigned int choosing, unsigned int num)
45 {
46 	unsigned int val = (choosing & 0x1U) | (num << 1);
47 
48 	return (uint16_t) val;
49 }
50 
51 /*****************************************************************************
52  * External bakery lock interface.
53  ****************************************************************************/
54 #if USE_COHERENT_MEM
55 /*
56  * Bakery locks are stored in coherent memory
57  *
58  * Each lock's data is contiguous and fully allocated by the compiler
59  */
60 
61 typedef struct bakery_lock {
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[BAKERY_LOCK_MAX_CPUS];
69 } bakery_lock_t;
70 
71 #else
72 /*
73  * Bakery locks are stored in normal .bss memory
74  *
75  * Each lock's data is spread across multiple cache lines, one per CPU,
76  * but multiple locks can share the same cache line.
77  * The compiler will allocate enough memory for one CPU's bakery locks,
78  * the remaining cache lines are allocated by the linker script
79  */
80 
81 typedef struct bakery_info {
82 	/*
83 	 * The lock_data is a bit-field of 2 members:
84 	 * Bit[0]       : choosing. This field is set when the CPU is
85 	 *                choosing its bakery number.
86 	 * Bits[1 - 15] : number. This is the bakery number allocated.
87 	 */
88 	volatile uint16_t lock_data;
89 } bakery_info_t;
90 
91 typedef bakery_info_t bakery_lock_t;
92 
93 #endif /* __USE_COHERENT_MEM__ */
94 
bakery_lock_init(bakery_lock_t * bakery)95 static inline void bakery_lock_init(bakery_lock_t *bakery) {}
96 void bakery_lock_get(bakery_lock_t *bakery);
97 void bakery_lock_release(bakery_lock_t *bakery);
98 
99 #define DEFINE_BAKERY_LOCK(_name) bakery_lock_t _name __section("bakery_lock")
100 
101 #define DECLARE_BAKERY_LOCK(_name) extern bakery_lock_t _name
102 
103 
104 #endif /* __ASSEMBLER__ */
105 #endif /* BAKERY_LOCK_H */
106