/*
* 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 <linux/io.h>
#ifdef CONFIG_ARCH_HAS_PMEM_API
#include <asm/pmem.h>
#else
static inline void arch_wmb_pmem(void)
{
BUG();
}
static inline bool arch_has_wmb_pmem(void)
{
return false;
}
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_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(struct device *dev, void __pmem *addr)
{
devm_memunmap(dev, (void __force *) addr);
}
/**
* arch_has_pmem_api - 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_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 inline void default_memcpy_to_pmem(void __pmem *dst, const void *src,
size_t size)
{
memcpy((void __force *) dst, src, 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(struct device *dev,
resource_size_t offset, unsigned long size)
{
#ifdef ARCH_MEMREMAP_PMEM
return (void __pmem *) devm_memremap(dev, offset, size,
ARCH_MEMREMAP_PMEM);
#else
return (void __pmem *) devm_memremap(dev, offset, size,
MEMREMAP_WT);
#endif
}
/**
* 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__ */
