1/*
 2 * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
 3 *
 4 * This program is free software; you can redistribute it and/or modify
 5 * it under the terms of the GNU General Public License version 2 as
 6 * published by the Free Software Foundation.
 7 */
 8
 9#ifndef __ASM_BARRIER_H
10#define __ASM_BARRIER_H
11
12#ifdef CONFIG_ISA_ARCV2
13
14/*
15 * ARCv2 based HS38 cores are in-order issue, but still weakly ordered
16 * due to micro-arch buffering/queuing of load/store, cache hit vs. miss ...
17 *
18 * Explicit barrier provided by DMB instruction
19 *  - Operand supports fine grained load/store/load+store semantics
20 *  - Ensures that selected memory operation issued before it will complete
21 *    before any subsequent memory operation of same type
22 *  - DMB guarantees SMP as well as local barrier semantics
23 *    (asm-generic/barrier.h ensures sane smp_*mb if not defined here, i.e.
24 *    UP: barrier(), SMP: smp_*mb == *mb)
25 *  - DSYNC provides DMB+completion_of_cache_bpu_maintenance_ops hence not needed
26 *    in the general case. Plus it only provides full barrier.
27 */
28
29#define mb()	asm volatile("dmb 3\n" : : : "memory")
30#define rmb()	asm volatile("dmb 1\n" : : : "memory")
31#define wmb()	asm volatile("dmb 2\n" : : : "memory")
32
33#elif !defined(CONFIG_ARC_PLAT_EZNPS)  /* CONFIG_ISA_ARCOMPACT */
34
35/*
36 * ARCompact based cores (ARC700) only have SYNC instruction which is super
37 * heavy weight as it flushes the pipeline as well.
38 * There are no real SMP implementations of such cores.
39 */
40
41#define mb()	asm volatile("sync\n" : : : "memory")
42
43#else	/* CONFIG_ARC_PLAT_EZNPS */
44
45#include <plat/ctop.h>
46
47#define mb()	asm volatile (".word %0" : : "i"(CTOP_INST_SCHD_RW) : "memory")
48#define rmb()	asm volatile (".word %0" : : "i"(CTOP_INST_SCHD_RD) : "memory")
49
50#endif
51
52#include <asm-generic/barrier.h>
53
54#endif