1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Atomic operations for the Hexagon architecture
4 *
5 * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
6 */
7
8#ifndef _ASM_ATOMIC_H
9#define _ASM_ATOMIC_H
10
11#include <linux/types.h>
12#include <asm/cmpxchg.h>
13#include <asm/barrier.h>
14
15/*  Normal writes in our arch don't clear lock reservations  */
16
17static inline void atomic_set(atomic_t *v, int new)
18{
19	asm volatile(
20		"1:	r6 = memw_locked(%0);\n"
21		"	memw_locked(%0,p0) = %1;\n"
22		"	if (!P0) jump 1b;\n"
23		:
24		: "r" (&v->counter), "r" (new)
25		: "memory", "p0", "r6"
26	);
27}
28
29#define atomic_set_release(v, i)	atomic_set((v), (i))
30
31/**
32 * atomic_read - reads a word, atomically
33 * @v: pointer to atomic value
34 *
35 * Assumes all word reads on our architecture are atomic.
36 */
37#define atomic_read(v)		READ_ONCE((v)->counter)
38
39/**
40 * atomic_xchg - atomic
41 * @v: pointer to memory to change
42 * @new: new value (technically passed in a register -- see xchg)
43 */
44#define atomic_xchg(v, new)	(xchg(&((v)->counter), (new)))
45
46
47/**
48 * atomic_cmpxchg - atomic compare-and-exchange values
49 * @v: pointer to value to change
50 * @old:  desired old value to match
51 * @new:  new value to put in
52 *
53 * Parameters are then pointer, value-in-register, value-in-register,
54 * and the output is the old value.
55 *
56 * Apparently this is complicated for archs that don't support
57 * the memw_locked like we do (or it's broken or whatever).
58 *
59 * Kind of the lynchpin of the rest of the generically defined routines.
60 * Remember V2 had that bug with dotnew predicate set by memw_locked.
61 *
62 * "old" is "expected" old val, __oldval is actual old value
63 */
64static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
65{
66	int __oldval;
67
68	asm volatile(
69		"1:	%0 = memw_locked(%1);\n"
70		"	{ P0 = cmp.eq(%0,%2);\n"
71		"	  if (!P0.new) jump:nt 2f; }\n"
72		"	memw_locked(%1,P0) = %3;\n"
73		"	if (!P0) jump 1b;\n"
74		"2:\n"
75		: "=&r" (__oldval)
76		: "r" (&v->counter), "r" (old), "r" (new)
77		: "memory", "p0"
78	);
79
80	return __oldval;
81}
82
83#define ATOMIC_OP(op)							\
84static inline void atomic_##op(int i, atomic_t *v)			\
85{									\
86	int output;							\
87									\
88	__asm__ __volatile__ (						\
89		"1:	%0 = memw_locked(%1);\n"			\
90		"	%0 = "#op "(%0,%2);\n"				\
91		"	memw_locked(%1,P3)=%0;\n"			\
92		"	if (!P3) jump 1b;\n"				\
93		: "=&r" (output)					\
94		: "r" (&v->counter), "r" (i)				\
95		: "memory", "p3"					\
96	);								\
97}									\
98
99#define ATOMIC_OP_RETURN(op)						\
100static inline int atomic_##op##_return(int i, atomic_t *v)		\
101{									\
102	int output;							\
103									\
104	__asm__ __volatile__ (						\
105		"1:	%0 = memw_locked(%1);\n"			\
106		"	%0 = "#op "(%0,%2);\n"				\
107		"	memw_locked(%1,P3)=%0;\n"			\
108		"	if (!P3) jump 1b;\n"				\
109		: "=&r" (output)					\
110		: "r" (&v->counter), "r" (i)				\
111		: "memory", "p3"					\
112	);								\
113	return output;							\
114}
115
116#define ATOMIC_FETCH_OP(op)						\
117static inline int atomic_fetch_##op(int i, atomic_t *v)			\
118{									\
119	int output, val;						\
120									\
121	__asm__ __volatile__ (						\
122		"1:	%0 = memw_locked(%2);\n"			\
123		"	%1 = "#op "(%0,%3);\n"				\
124		"	memw_locked(%2,P3)=%1;\n"			\
125		"	if (!P3) jump 1b;\n"				\
126		: "=&r" (output), "=&r" (val)				\
127		: "r" (&v->counter), "r" (i)				\
128		: "memory", "p3"					\
129	);								\
130	return output;							\
131}
132
133#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
134
135ATOMIC_OPS(add)
136ATOMIC_OPS(sub)
137
138#undef ATOMIC_OPS
139#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op)
140
141ATOMIC_OPS(and)
142ATOMIC_OPS(or)
143ATOMIC_OPS(xor)
144
145#undef ATOMIC_OPS
146#undef ATOMIC_FETCH_OP
147#undef ATOMIC_OP_RETURN
148#undef ATOMIC_OP
149
150/**
151 * atomic_fetch_add_unless - add unless the number is a given value
152 * @v: pointer to value
153 * @a: amount to add
154 * @u: unless value is equal to u
155 *
156 * Returns old value.
157 *
158 */
159
160static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
161{
162	int __oldval;
163	register int tmp;
164
165	asm volatile(
166		"1:	%0 = memw_locked(%2);"
167		"	{"
168		"		p3 = cmp.eq(%0, %4);"
169		"		if (p3.new) jump:nt 2f;"
170		"		%1 = add(%0, %3);"
171		"	}"
172		"	memw_locked(%2, p3) = %1;"
173		"	{"
174		"		if (!p3) jump 1b;"
175		"	}"
176		"2:"
177		: "=&r" (__oldval), "=&r" (tmp)
178		: "r" (v), "r" (a), "r" (u)
179		: "memory", "p3"
180	);
181	return __oldval;
182}
183#define atomic_fetch_add_unless atomic_fetch_add_unless
184
185#endif
186