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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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81b23ba645
The mb() is the superset of dma and smp. Using bar.xxx to implement mb() will cause problem when sync data with dma device, becasue bar.xxx couldn't guarantee bus transactions finished at outside bus level. We must use sync.s instead of bar.xxx for dma data synchronization and it will guarantee retirement after getting the bus bresponse. Changes for V2: - Use sync.s for all mb, rmb, wmb, dma_wmb, dma_rmb. Signed-off-by: Guo Ren <ren_guo@c-sky.com> Cc: Arnd Bergmann <arnd@arndb.de>
49 lines
1.7 KiB
C
49 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#ifndef __ASM_CSKY_BARRIER_H
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#define __ASM_CSKY_BARRIER_H
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#ifndef __ASSEMBLY__
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#define nop() asm volatile ("nop\n":::"memory")
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/*
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* sync: completion barrier, all sync.xx instructions
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* guarantee the last response recieved by bus transaction
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* made by ld/st instructions before sync.s
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* sync.s: inherit from sync, but also shareable to other cores
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* sync.i: inherit from sync, but also flush cpu pipeline
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* sync.is: the same with sync.i + sync.s
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*
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* bar.brwarw: ordering barrier for all load/store instructions before it
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* bar.brwarws: ordering barrier for all load/store instructions before it
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* and shareable to other cores
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* bar.brar: ordering barrier for all load instructions before it
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* bar.brars: ordering barrier for all load instructions before it
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* and shareable to other cores
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* bar.bwaw: ordering barrier for all store instructions before it
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* bar.bwaws: ordering barrier for all store instructions before it
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* and shareable to other cores
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*/
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#ifdef CONFIG_CPU_HAS_CACHEV2
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#define mb() asm volatile ("sync.s\n":::"memory")
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#ifdef CONFIG_SMP
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#define __smp_mb() asm volatile ("bar.brwarws\n":::"memory")
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#define __smp_rmb() asm volatile ("bar.brars\n":::"memory")
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#define __smp_wmb() asm volatile ("bar.bwaws\n":::"memory")
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#endif /* CONFIG_SMP */
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#define sync_is() asm volatile ("sync.is\n":::"memory")
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#else /* !CONFIG_CPU_HAS_CACHEV2 */
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#define mb() asm volatile ("sync\n":::"memory")
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#endif
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#include <asm-generic/barrier.h>
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_CSKY_BARRIER_H */
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