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