From e5fd91f1ef340da553f7a79da9540c3db711c937 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Tue, 8 Sep 2015 01:01:14 -0300 Subject: Linux-libre 4.2-gnu --- include/linux/pmem.h | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 include/linux/pmem.h (limited to 'include/linux/pmem.h') diff --git a/include/linux/pmem.h b/include/linux/pmem.h new file mode 100644 index 000000000..d2114045a --- /dev/null +++ b/include/linux/pmem.h @@ -0,0 +1,152 @@ +/* + * Copyright(c) 2015 Intel Corporation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ +#ifndef __PMEM_H__ +#define __PMEM_H__ + +#include + +#ifdef CONFIG_ARCH_HAS_PMEM_API +#include +#else +static inline void arch_wmb_pmem(void) +{ + BUG(); +} + +static inline bool __arch_has_wmb_pmem(void) +{ + return false; +} + +static inline void __pmem *arch_memremap_pmem(resource_size_t offset, + unsigned long size) +{ + return NULL; +} + +static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src, + size_t n) +{ + BUG(); +} +#endif + +/* + * Architectures that define ARCH_HAS_PMEM_API must provide + * implementations for arch_memremap_pmem(), arch_memcpy_to_pmem(), + * arch_wmb_pmem(), and __arch_has_wmb_pmem(). + */ + +static inline void memcpy_from_pmem(void *dst, void __pmem const *src, size_t size) +{ + memcpy(dst, (void __force const *) src, size); +} + +static inline void memunmap_pmem(void __pmem *addr) +{ + iounmap((void __force __iomem *) addr); +} + +/** + * arch_has_wmb_pmem - true if wmb_pmem() ensures durability + * + * For a given cpu implementation within an architecture it is possible + * that wmb_pmem() resolves to a nop. In the case this returns + * false, pmem api users are unable to ensure durability and may want to + * fall back to a different data consistency model, or otherwise notify + * the user. + */ +static inline bool arch_has_wmb_pmem(void) +{ + if (IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)) + return __arch_has_wmb_pmem(); + return false; +} + +static inline bool arch_has_pmem_api(void) +{ + return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && arch_has_wmb_pmem(); +} + +/* + * These defaults seek to offer decent performance and minimize the + * window between i/o completion and writes being durable on media. + * However, it is undefined / architecture specific whether + * default_memremap_pmem + default_memcpy_to_pmem is sufficient for + * making data durable relative to i/o completion. + */ +static void default_memcpy_to_pmem(void __pmem *dst, const void *src, + size_t size) +{ + memcpy((void __force *) dst, src, size); +} + +static void __pmem *default_memremap_pmem(resource_size_t offset, + unsigned long size) +{ + return (void __pmem __force *)ioremap_wt(offset, size); +} + +/** + * memremap_pmem - map physical persistent memory for pmem api + * @offset: physical address of persistent memory + * @size: size of the mapping + * + * Establish a mapping of the architecture specific memory type expected + * by memcpy_to_pmem() and wmb_pmem(). For example, it may be + * the case that an uncacheable or writethrough mapping is sufficient, + * or a writeback mapping provided memcpy_to_pmem() and + * wmb_pmem() arrange for the data to be written through the + * cache to persistent media. + */ +static inline void __pmem *memremap_pmem(resource_size_t offset, + unsigned long size) +{ + if (arch_has_pmem_api()) + return arch_memremap_pmem(offset, size); + return default_memremap_pmem(offset, size); +} + +/** + * memcpy_to_pmem - copy data to persistent memory + * @dst: destination buffer for the copy + * @src: source buffer for the copy + * @n: length of the copy in bytes + * + * Perform a memory copy that results in the destination of the copy + * being effectively evicted from, or never written to, the processor + * cache hierarchy after the copy completes. After memcpy_to_pmem() + * data may still reside in cpu or platform buffers, so this operation + * must be followed by a wmb_pmem(). + */ +static inline void memcpy_to_pmem(void __pmem *dst, const void *src, size_t n) +{ + if (arch_has_pmem_api()) + arch_memcpy_to_pmem(dst, src, n); + else + default_memcpy_to_pmem(dst, src, n); +} + +/** + * wmb_pmem - synchronize writes to persistent memory + * + * After a series of memcpy_to_pmem() operations this drains data from + * cpu write buffers and any platform (memory controller) buffers to + * ensure that written data is durable on persistent memory media. + */ +static inline void wmb_pmem(void) +{ + if (arch_has_pmem_api()) + arch_wmb_pmem(); +} +#endif /* __PMEM_H__ */ -- cgit v1.2.3-54-g00ecf