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| author | Vineet Gupta <vgupta@synopsys.com> | 2016-05-05 10:02:34 +0200 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2016-05-05 13:05:28 +0200 |
| commit | e5bc0478ab6cf565619224536d75ecb2aedca43b (patch) | |
| tree | 03e3e24bd50b01e178bb10e9aad22fee0b7f5704 /arch | |
| parent | ARC: add support for reserved memory defined by device tree (diff) | |
| download | linux-e5bc0478ab6cf565619224536d75ecb2aedca43b.tar.xz linux-e5bc0478ab6cf565619224536d75ecb2aedca43b.zip | |
ARC: Add missing io barriers to io{read,write}{16,32}be()
While reviewing a different change to asm-generic/io.h Arnd spotted that
ARC ioread32 and ioread32be both of which come from asm-generic versions
are not symmetrical in terms of calling the io barriers.
generic ioread32 -> ARC readl() [ has barriers]
generic ioread32be -> __be32_to_cpu(__raw_readl()) [ lacks barriers]
While generic ioread32be is being remediated to call readl(), that involves
a swab32(), causing double swaps on ioread32be() on Big Endian systems.
So provide our versions of big endian IO accessors to ensure io barrier
calls while also keeping them optimal
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org [4.2+]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arc/include/asm/io.h | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/arch/arc/include/asm/io.h b/arch/arc/include/asm/io.h index 17f85c9c73cf..c22b181e8206 100644 --- a/arch/arc/include/asm/io.h +++ b/arch/arc/include/asm/io.h @@ -13,6 +13,15 @@ #include <asm/byteorder.h> #include <asm/page.h> +#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 + extern void __iomem *ioremap(phys_addr_t paddr, unsigned long size); extern void __iomem *ioremap_prot(phys_addr_t paddr, unsigned long size, unsigned long flags); @@ -31,6 +40,15 @@ extern void iounmap(const void __iomem *addr); #define ioremap_wc(phy, sz) ioremap(phy, sz) #define ioremap_wt(phy, sz) ioremap(phy, sz) +/* + * io{read,write}{16,32}be() macros + */ +#define ioread16be(p) ({ u16 __v = be16_to_cpu((__force __be16)__raw_readw(p)); __iormb(); __v; }) +#define ioread32be(p) ({ u32 __v = be32_to_cpu((__force __be32)__raw_readl(p)); __iormb(); __v; }) + +#define iowrite16be(v,p) ({ __iowmb(); __raw_writew((__force u16)cpu_to_be16(v), p); }) +#define iowrite32be(v,p) ({ __iowmb(); __raw_writel((__force u32)cpu_to_be32(v), p); }) + /* Change struct page to physical address */ #define page_to_phys(page) (page_to_pfn(page) << PAGE_SHIFT) @@ -108,15 +126,6 @@ static inline void __raw_writel(u32 w, volatile void __iomem *addr) } -#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 |