From 64e2c6738b4d49d69d697b5887f72ad07c206ab3 Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Thu, 5 Apr 2018 09:09:09 -0400 Subject: [PATCH] io: define several IO & PIO barrier types for the asm-generic version Getting ready to harden readX()/writeX() and inX()/outX() semantics for the generic implementation. Defining two set of macros as __io_br() and __io_ar() to indicate actions to be taken before and after MMIO read. Defining two set of macros as __io_bw() and __io_aw() to indicate actions to be taken before and after MMIO write. Defining two set of macros as __io_pbw() and __io_paw() to indicate actions to be taken before and after Port IO write. Defining two set of macros as __io_pbr() and __io_par() to indicate actions to be taken before and after Port IO read. If rmb() is available for the architecture, prefer rmb() as the default implementation of __io_ar()/__io_par(). If wmb() is available for the architecture, prefer wmb() as the default implementation of __io_bw()/__io_pbw(). Signed-off-by: Sinan Kaya Signed-off-by: Arnd Bergmann --- include/asm-generic/io.h | 44 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index b4531e3b2120..570433b34180 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -25,6 +25,50 @@ #define mmiowb() do {} while (0) #endif +#ifndef __io_br +#define __io_br() barrier() +#endif + +/* prevent prefetching of coherent DMA data ahead of a dma-complete */ +#ifndef __io_ar +#ifdef rmb +#define __io_ar() rmb() +#else +#define __io_ar() barrier() +#endif +#endif + +/* flush writes to coherent DMA data before possibly triggering a DMA read */ +#ifndef __io_bw +#ifdef wmb +#define __io_bw() wmb() +#else +#define __io_bw() barrier() +#endif +#endif + +/* serialize device access against a spin_unlock, usually handled there. */ +#ifndef __io_aw +#define __io_aw() barrier() +#endif + +#ifndef __io_pbw +#define __io_pbw() __io_bw() +#endif + +#ifndef __io_paw +#define __io_paw() __io_aw() +#endif + +#ifndef __io_pbr +#define __io_pbr() __io_br() +#endif + +#ifndef __io_par +#define __io_par() __io_ar() +#endif + + /* * __raw_{read,write}{b,w,l,q}() access memory in native endianness. * -- 2.25.1