xref: /openbmc/linux/drivers/nvdimm/pfn.h (revision 842ed298)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (c) 2014-2015, Intel Corporation.
4  */
5 
6 #ifndef __NVDIMM_PFN_H
7 #define __NVDIMM_PFN_H
8 
9 #include <linux/types.h>
10 #include <linux/mmzone.h>
11 
12 #define PFN_SIG_LEN 16
13 #define PFN_SIG "NVDIMM_PFN_INFO\0"
14 #define DAX_SIG "NVDIMM_DAX_INFO\0"
15 
16 struct nd_pfn_sb {
17 	u8 signature[PFN_SIG_LEN];
18 	u8 uuid[16];
19 	u8 parent_uuid[16];
20 	__le32 flags;
21 	__le16 version_major;
22 	__le16 version_minor;
23 	__le64 dataoff; /* relative to namespace_base + start_pad */
24 	__le64 npfns;
25 	__le32 mode;
26 	/* minor-version-1 additions for section alignment */
27 	/**
28 	 * @start_pad: Deprecated attribute to pad start-misaligned namespaces
29 	 *
30 	 * start_pad is deprecated because the original definition did
31 	 * not comprehend that dataoff is relative to the base address
32 	 * of the namespace not the start_pad adjusted base. The result
33 	 * is that the dax path is broken, but the block-I/O path is
34 	 * not. The kernel will no longer create namespaces using start
35 	 * padding, but it still supports block-I/O for legacy
36 	 * configurations mainly to allow a backup, reconfigure the
37 	 * namespace, and restore flow to repair dax operation.
38 	 */
39 	__le32 start_pad;
40 	__le32 end_trunc;
41 	/* minor-version-2 record the base alignment of the mapping */
42 	__le32 align;
43 	/* minor-version-3 guarantee the padding and flags are zero */
44 	/* minor-version-4 record the page size and struct page size */
45 	__le32 page_size;
46 	__le16 page_struct_size;
47 	u8 padding[3994];
48 	__le64 checksum;
49 };
50 
51 #endif /* __NVDIMM_PFN_H */
52