diff options
Diffstat (limited to 'arch/riscv/include')
| -rw-r--r-- | arch/riscv/include/asm/io.h | 15 | ||||
| -rw-r--r-- | arch/riscv/include/asm/mmiowb.h | 14 |
2 files changed, 16 insertions, 13 deletions
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h index 1d9c1376dc64..744fd92e77bc 100644 --- a/arch/riscv/include/asm/io.h +++ b/arch/riscv/include/asm/io.h @@ -20,6 +20,7 @@ #define _ASM_RISCV_IO_H #include <linux/types.h> +#include <asm/mmiowb.h> extern void __iomem *ioremap(phys_addr_t offset, unsigned long size); @@ -100,18 +101,6 @@ static inline u64 __raw_readq(const volatile void __iomem *addr) #endif /* - * FIXME: I'm flip-flopping on whether or not we should keep this or enforce - * the ordering with I/O on spinlocks like PowerPC does. The worry is that - * drivers won't get this correct, but I also don't want to introduce a fence - * into the lock code that otherwise only uses AMOs (and is essentially defined - * by the ISA to be correct). For now I'm leaving this here: "o,w" is - * sufficient to ensure that all writes to the device have completed before the - * write to the spinlock is allowed to commit. I surmised this from reading - * "ACQUIRES VS I/O ACCESSES" in memory-barriers.txt. - */ -#define mmiowb() __asm__ __volatile__ ("fence o,w" : : : "memory"); - -/* * Unordered I/O memory access primitives. These are even more relaxed than * the relaxed versions, as they don't even order accesses between successive * operations to the I/O regions. @@ -165,7 +154,7 @@ static inline u64 __raw_readq(const volatile void __iomem *addr) #define __io_br() do {} while (0) #define __io_ar(v) __asm__ __volatile__ ("fence i,r" : : : "memory"); #define __io_bw() __asm__ __volatile__ ("fence w,o" : : : "memory"); -#define __io_aw() do {} while (0) +#define __io_aw() mmiowb_set_pending() #define readb(c) ({ u8 __v; __io_br(); __v = readb_cpu(c); __io_ar(__v); __v; }) #define readw(c) ({ u16 __v; __io_br(); __v = readw_cpu(c); __io_ar(__v); __v; }) diff --git a/arch/riscv/include/asm/mmiowb.h b/arch/riscv/include/asm/mmiowb.h new file mode 100644 index 000000000000..5d7e3a2b4e3b --- /dev/null +++ b/arch/riscv/include/asm/mmiowb.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_RISCV_MMIOWB_H +#define _ASM_RISCV_MMIOWB_H + +/* + * "o,w" is sufficient to ensure that all writes to the device have completed + * before the write to the spinlock is allowed to commit. + */ +#define mmiowb() __asm__ __volatile__ ("fence o,w" : : : "memory"); + +#include <asm-generic/mmiowb.h> + +#endif /* ASM_RISCV_MMIOWB_H */ |