1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #ifndef __PSTORE_ZONE_H_
4 #define __PSTORE_ZONE_H_
5 
6 #include <linux/types.h>
7 
8 typedef ssize_t (*pstore_zone_read_op)(char *, size_t, loff_t);
9 typedef ssize_t (*pstore_zone_write_op)(const char *, size_t, loff_t);
10 typedef ssize_t (*pstore_zone_erase_op)(size_t, loff_t);
11 /**
12  * struct pstore_zone_info - pstore/zone back-end driver structure
13  *
14  * @owner:	Module which is responsible for this back-end driver.
15  * @name:	Name of the back-end driver.
16  * @total_size: The total size in bytes pstore/zone can use. It must be greater
17  *		than 4096 and be multiple of 4096.
18  * @kmsg_size:	The size of oops/panic zone. Zero means disabled, otherwise,
19  *		it must be multiple of SECTOR_SIZE(512 Bytes).
20  * @max_reason: Maximum kmsg dump reason to store.
21  * @pmsg_size:	The size of pmsg zone which is the same as @kmsg_size.
22  * @console_size:The size of console zone which is the same as @kmsg_size.
23  * @ftrace_size:The size of ftrace zone which is the same as @kmsg_size.
24  * @read:	The general read operation. Both of the function parameters
25  *		@size and @offset are relative value to storage.
26  *		On success, the number of bytes should be returned, others
27  *		mean error.
28  * @write:	The same as @read, but the following error number:
29  *		-EBUSY means try to write again later.
30  *		-ENOMSG means to try next zone.
31  * @erase:	The general erase operation for device with special removing
32  *		job. Both of the function parameters @size and @offset are
33  *		relative value to storage.
34  *		Return 0 on success and others on failure.
35  * @panic_write:The write operation only used for panic case. It's optional
36  *		if you do not care panic log. The parameters are relative
37  *		value to storage.
38  *		On success, the number of bytes should be returned, others
39  *		excluding -ENOMSG mean error. -ENOMSG means to try next zone.
40  */
41 struct pstore_zone_info {
42 	struct module *owner;
43 	const char *name;
44 
45 	unsigned long total_size;
46 	unsigned long kmsg_size;
47 	int max_reason;
48 	unsigned long pmsg_size;
49 	unsigned long console_size;
50 	unsigned long ftrace_size;
51 	pstore_zone_read_op read;
52 	pstore_zone_write_op write;
53 	pstore_zone_erase_op erase;
54 	pstore_zone_write_op panic_write;
55 };
56 
57 extern int register_pstore_zone(struct pstore_zone_info *info);
58 extern void unregister_pstore_zone(struct pstore_zone_info *info);
59 
60 #endif
61