include/linux/pmem.h

   1 /*
   2  * Copyright(c) 2015 Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  */
  13 #ifndef __PMEM_H__
  14 #define __PMEM_H__
  15
  16 #include <linux/io.h>
  17 #include <linux/uio.h>
  18
  19 #ifdef CONFIG_ARCH_HAS_PMEM_API
  20 #define ARCH_MEMREMAP_PMEM MEMREMAP_WB
  21 #include <asm/pmem.h>
  22 #else
  23 #define ARCH_MEMREMAP_PMEM MEMREMAP_WT
  24 /*
  25  * These are simply here to enable compilation, all call sites gate
  26  * calling these symbols with arch_has_pmem_api() and redirect to the
  27  * implementation in asm/pmem.h.
  28  */
  29 static inline void arch_memcpy_to_pmem(void *dst, const void *src, size_t n)
  30 {
  31         BUG();
  32 }
  33
  34 static inline int arch_memcpy_from_pmem(void *dst, const void *src, size_t n)
  35 {
  36         BUG();
  37         return -EFAULT;
  38 }
  39
  40 static inline size_t arch_copy_from_iter_pmem(void *addr, size_t bytes,
  41                 struct iov_iter *i)
  42 {
  43         BUG();
  44         return 0;
  45 }
  46
  47 static inline void arch_clear_pmem(void *addr, size_t size)
  48 {
  49         BUG();
  50 }
  51
  52 static inline void arch_wb_cache_pmem(void *addr, size_t size)
  53 {
  54         BUG();
  55 }
  56
  57 static inline void arch_invalidate_pmem(void *addr, size_t size)
  58 {
  59         BUG();
  60 }
  61 #endif
  62
  63 static inline bool arch_has_pmem_api(void)
  64 {
  65         return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
  66 }
  67
  68 /*
  69  * memcpy_from_pmem - read from persistent memory with error handling
  70  * @dst: destination buffer
  71  * @src: source buffer
  72  * @size: transfer length
  73  *
  74  * Returns 0 on success negative error code on failure.
  75  */
  76 static inline int memcpy_from_pmem(void *dst, void const *src, size_t size)
  77 {
  78         if (arch_has_pmem_api())
  79                 return arch_memcpy_from_pmem(dst, src, size);
  80         else
  81                 memcpy(dst, src, size);
  82         return 0;
  83 }
  84
  85 /**
  86  * memcpy_to_pmem - copy data to persistent memory
  87  * @dst: destination buffer for the copy
  88  * @src: source buffer for the copy
  89  * @n: length of the copy in bytes
  90  *
  91  * Perform a memory copy that results in the destination of the copy
  92  * being effectively evicted from, or never written to, the processor
  93  * cache hierarchy after the copy completes.  After memcpy_to_pmem()
  94  * data may still reside in cpu or platform buffers, so this operation
  95  * must be followed by a blkdev_issue_flush() on the pmem block device.
  96  */
  97 static inline void memcpy_to_pmem(void *dst, const void *src, size_t n)
  98 {
  99         if (arch_has_pmem_api())
 100                 arch_memcpy_to_pmem(dst, src, n);
 101         else
 102                 memcpy(dst, src, n);
 103 }
 104
 105 /**
 106  * copy_from_iter_pmem - copy data from an iterator to PMEM
 107  * @addr:       PMEM destination address
 108  * @bytes:      number of bytes to copy
 109  * @i:          iterator with source data
 110  *
 111  * Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'.
 112  * See blkdev_issue_flush() note for memcpy_to_pmem().
 113  */
 114 static inline size_t copy_from_iter_pmem(void *addr, size_t bytes,
 115                 struct iov_iter *i)
 116 {
 117         if (arch_has_pmem_api())
 118                 return arch_copy_from_iter_pmem(addr, bytes, i);
 119         return copy_from_iter_nocache(addr, bytes, i);
 120 }
 121
 122 /**
 123  * clear_pmem - zero a PMEM memory range
 124  * @addr:       virtual start address
 125  * @size:       number of bytes to zero
 126  *
 127  * Write zeros into the memory range starting at 'addr' for 'size' bytes.
 128  * See blkdev_issue_flush() note for memcpy_to_pmem().
 129  */
 130 static inline void clear_pmem(void *addr, size_t size)
 131 {
 132         if (arch_has_pmem_api())
 133                 arch_clear_pmem(addr, size);
 134         else
 135                 memset(addr, 0, size);
 136 }
 137
 138 /**
 139  * invalidate_pmem - flush a pmem range from the cache hierarchy
 140  * @addr:       virtual start address
 141  * @size:       bytes to invalidate (internally aligned to cache line size)
 142  *
 143  * For platforms that support clearing poison this flushes any poisoned
 144  * ranges out of the cache
 145  */
 146 static inline void invalidate_pmem(void *addr, size_t size)
 147 {
 148         if (arch_has_pmem_api())
 149                 arch_invalidate_pmem(addr, size);
 150 }
 151
 152 /**
 153  * wb_cache_pmem - write back processor cache for PMEM memory range
 154  * @addr:       virtual start address
 155  * @size:       number of bytes to write back
 156  *
 157  * Write back the processor cache range starting at 'addr' for 'size' bytes.
 158  * See blkdev_issue_flush() note for memcpy_to_pmem().
 159  */
 160 static inline void wb_cache_pmem(void *addr, size_t size)
 161 {
 162         if (arch_has_pmem_api())
 163                 arch_wb_cache_pmem(addr, size);
 164 }
 165 #endif /* __PMEM_H__ */