diff options
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/include/asm/Kbuild | 1 | ||||
| -rw-r--r-- | arch/arc/include/asm/barrier.h | 48 | ||||
| -rw-r--r-- | arch/arc/include/asm/io.h | 42 |
3 files changed, 87 insertions, 4 deletions
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild index be0c39e76f7c..59e2dd1d434f 100644 --- a/arch/arc/include/asm/Kbuild +++ b/arch/arc/include/asm/Kbuild @@ -1,5 +1,4 @@ generic-y += auxvec.h -generic-y += barrier.h generic-y += bitsperlong.h generic-y += bugs.h generic-y += clkdev.h diff --git a/arch/arc/include/asm/barrier.h b/arch/arc/include/asm/barrier.h new file mode 100644 index 000000000000..a7209983ee64 --- /dev/null +++ b/arch/arc/include/asm/barrier.h @@ -0,0 +1,48 @@ +/* + * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __ASM_BARRIER_H +#define __ASM_BARRIER_H + +#ifdef CONFIG_ISA_ARCV2 + +/* + * ARCv2 based HS38 cores are in-order issue, but still weakly ordered + * due to micro-arch buffering/queuing of load/store, cache hit vs. miss ... + * + * Explicit barrier provided by DMB instruction + * - Operand supports fine grained load/store/load+store semantics + * - Ensures that selected memory operation issued before it will complete + * before any subsequent memory operation of same type + * - DMB guarantees SMP as well as local barrier semantics + * (asm-generic/barrier.h ensures sane smp_*mb if not defined here, i.e. + * UP: barrier(), SMP: smp_*mb == *mb) + * - DSYNC provides DMB+completion_of_cache_bpu_maintenance_ops hence not needed + * in the general case. Plus it only provides full barrier. + */ + +#define mb() asm volatile("dmb 3\n" : : : "memory") +#define rmb() asm volatile("dmb 1\n" : : : "memory") +#define wmb() asm volatile("dmb 2\n" : : : "memory") + +#endif + +#ifdef CONFIG_ISA_ARCOMPACT + +/* + * ARCompact based cores (ARC700) only have SYNC instruction which is super + * heavy weight as it flushes the pipeline as well. + * There are no real SMP implementations of such cores. + */ + +#define mb() asm volatile("sync\n" : : : "memory") +#endif + +#include <asm-generic/barrier.h> + +#endif diff --git a/arch/arc/include/asm/io.h b/arch/arc/include/asm/io.h index cabd518cb253..00f97a2f5fa6 100644 --- a/arch/arc/include/asm/io.h +++ b/arch/arc/include/asm/io.h @@ -98,9 +98,45 @@ static inline void __raw_writel(u32 w, volatile void __iomem *addr) } -#define readb_relaxed readb -#define readw_relaxed readw -#define readl_relaxed readl +#ifdef CONFIG_ISA_ARCV2 +#include <asm/barrier.h> +#define __iormb() rmb() +#define __iowmb() wmb() +#else +#define __iormb() do { } while (0) +#define __iowmb() do { } while (0) +#endif + +/* + * MMIO can also get buffered/optimized in micro-arch, so barriers needed + * Based on ARM model for the typical use case + * + * <ST [DMA buffer]> + * <writel MMIO "go" reg> + * or: + * <readl MMIO "status" reg> + * <LD [DMA buffer]> + * + * http://lkml.kernel.org/r/20150622133656.GG1583@arm.com + */ +#define readb(c) ({ u8 __v = readb_relaxed(c); __iormb(); __v; }) +#define readw(c) ({ u16 __v = readw_relaxed(c); __iormb(); __v; }) +#define readl(c) ({ u32 __v = readl_relaxed(c); __iormb(); __v; }) + +#define writeb(v,c) ({ __iowmb(); writeb_relaxed(v,c); }) +#define writew(v,c) ({ __iowmb(); writew_relaxed(v,c); }) +#define writel(v,c) ({ __iowmb(); writel_relaxed(v,c); }) + +/* + * Relaxed API for drivers which can handle any ordering themselves + */ +#define readb_relaxed(c) __raw_readb(c) +#define readw_relaxed(c) __raw_readw(c) +#define readl_relaxed(c) __raw_readl(c) + +#define writeb_relaxed(v,c) __raw_writeb(v,c) +#define writew_relaxed(v,c) __raw_writew(v,c) +#define writel_relaxed(v,c) __raw_writel(v,c) #include <asm-generic/io.h> |