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 55