From mboxrd@z Thu Jan 1 00:00:00 1970 From: M.Mann@arkona-technologies.de (Matthias Mann) Date: Sat, 07 Dec 2013 17:05:00 +0100 Subject: [PATCH v2] ARM: asm: add readq/writeq methods Message-ID: <52A3472C.4010203@arkona-technologies.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Add readq/writeq methods for 32 bit ARM to allow transfering 64 bit words over PCIe as a single transfer. Signed-off-by: Matthias Mann --- v2: Changed assembler according to comments from M?ns Rullg?rd Check for ARM architecture support and added preprocessor guards as requested by Russel King --- arch/arm/include/asm/io.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index 3c597c2..89d4ecd 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -112,6 +112,36 @@ static inline u32 __raw_readl(const volatile void __iomem *addr) return val; } +#if __LINUX_ARM_ARCH__ >= 5 +static inline u64 __raw_readq(const volatile void __iomem *addr) +{ + u64 val; +#if __LITTLE_ENDIAN + asm volatile("ldrd %Q1, %R1, %0" + : "+Q" (*(volatile u64 __force *)addr), + "=r" (val)); +#else + asm volatile("ldrd %R1, %Q1, %0" + : "+Q" (*(volatile u64 __force *)addr), + "=r" (val)); +#endif + return val; +} + +static inline void __raw_writeq(u64 val, volatile void __iomem *addr) +{ +#if __LITTLE_ENDIAN + asm volatile("strd %Q1, %R1, %0" + : "+Q" (*(volatile u64 __force *)addr) + : "r" (val)); +#else + asm volatile("strd %R1, %Q1, %0" + : "+Q" (*(volatile u64 __force *)addr) + : "r" (val)); +#endif +} +#endif /* __LINUX_ARM_ARCH__ >= 5 */ + /* * Architecture ioremap implementation. */ @@ -320,6 +350,23 @@ extern void _memset_io(volatile void __iomem *, int, size_t); #endif /* readl */ +#if __LINUX_ARM_ARCH__ >= 5 + +#ifndef readq +#define readq_relaxed(c) ({ u64 __r = le64_to_cpu((__force __le64) \ + __raw_readq(c)); __r; }) + +#define readq(c) ({ u64 __v = readq_relaxed(c); __iormb(); __v; }) +#endif /* readq */ + +#ifndef writeq +#define writeq_relaxed(v,c) __raw_writeq((__force u64) cpu_to_le64(v),c) + +#define writeq(v,c) ({ __iowmb(); writeq_relaxed(v,c); }) +#endif /* writeq */ + +#endif /* __LINUX_ARM_ARCH__ >= 5 */ + /* * ioremap and friends. * -- 1.8.3.2