LXR linux/include/linux/pstore

   1/* SPDX-License-Identifier: GPL-2.0 */
   2
   3#ifndef __PSTORE_BLK_H_
   4#define __PSTORE_BLK_H_
   5
   6#include <linux/types.h>
   7#include <linux/pstore.h>
   8#include <linux/pstore_zone.h>
   9
  10/**
  11 * typedef pstore_blk_panic_write_op - panic write operation to block device
  12 *
  13 * @buf: the data to write
  14 * @start_sect: start sector to block device
  15 * @sects: sectors count on buf
  16 *
  17 * Return: On success, zero should be returned. Others excluding -ENOMSG
  18 * mean error. -ENOMSG means to try next zone.
  19 *
  20 * Panic write to block device must be aligned to SECTOR_SIZE.
  21 */
  22typedef int (*pstore_blk_panic_write_op)(const char *buf, sector_t start_sect,
  23                sector_t sects);
  24
  25/**
  26 * struct pstore_blk_info - pstore/blk registration details
  27 *
  28 * @major:      Which major device number to support with pstore/blk
  29 * @flags:      The supported PSTORE_FLAGS_* from linux/pstore.h.
  30 * @panic_write:The write operation only used for the panic case.
  31 *              This can be NULL, but is recommended to avoid losing
  32 *              crash data if the kernel's IO path or work queues are
  33 *              broken during a panic.
  34 * @devt:       The dev_t that pstore/blk has attached to.
  35 * @nr_sects:   Number of sectors on @devt.
  36 * @start_sect: Starting sector on @devt.
  37 */
  38struct pstore_blk_info {
  39        unsigned int major;
  40        unsigned int flags;
  41        pstore_blk_panic_write_op panic_write;
  42
  43        /* Filled in by pstore/blk after registration. */
  44        dev_t devt;
  45        sector_t nr_sects;
  46        sector_t start_sect;
  47};
  48
  49int  register_pstore_blk(struct pstore_blk_info *info);
  50void unregister_pstore_blk(unsigned int major);
  51
  52/**
  53 * struct pstore_device_info - back-end pstore/blk driver structure.
  54 *
  55 * @total_size: The total size in bytes pstore/blk can use. It must be greater
  56 *              than 4096 and be multiple of 4096.
  57 * @flags:      Refer to macro starting with PSTORE_FLAGS defined in
  58 *              linux/pstore.h. It means what front-ends this device support.
  59 *              Zero means all backends for compatible.
  60 * @read:       The general read operation. Both of the function parameters
  61 *              @size and @offset are relative value to bock device (not the
  62 *              whole disk).
  63 *              On success, the number of bytes should be returned, others
  64 *              means error.
  65 * @write:      The same as @read, but the following error number:
  66 *              -EBUSY means try to write again later.
  67 *              -ENOMSG means to try next zone.
  68 * @erase:      The general erase operation for device with special removing
  69 *              job. Both of the function parameters @size and @offset are
  70 *              relative value to storage.
  71 *              Return 0 on success and others on failure.
  72 * @panic_write:The write operation only used for panic case. It's optional
  73 *              if you do not care panic log. The parameters are relative
  74 *              value to storage.
  75 *              On success, the number of bytes should be returned, others
  76 *              excluding -ENOMSG mean error. -ENOMSG means to try next zone.
  77 */
  78struct pstore_device_info {
  79        unsigned long total_size;
  80        unsigned int flags;
  81        pstore_zone_read_op read;
  82        pstore_zone_write_op write;
  83        pstore_zone_erase_op erase;
  84        pstore_zone_write_op panic_write;
  85};
  86
  87int  register_pstore_device(struct pstore_device_info *dev);
  88void unregister_pstore_device(struct pstore_device_info *dev);
  89
  90/**
  91 * struct pstore_blk_config - the pstore_blk backend configuration
  92 *
  93 * @device:             Name of the desired block device
  94 * @max_reason:         Maximum kmsg dump reason to store to block device
  95 * @kmsg_size:          Total size of for kmsg dumps
  96 * @pmsg_size:          Total size of the pmsg storage area
  97 * @console_size:       Total size of the console storage area
  98 * @ftrace_size:        Total size for ftrace logging data (for all CPUs)
  99 */
 100struct pstore_blk_config {
 101        char device[80];
 102        enum kmsg_dump_reason max_reason;
 103        unsigned long kmsg_size;
 104        unsigned long pmsg_size;
 105        unsigned long console_size;
 106        unsigned long ftrace_size;
 107};
 108
 109/**
 110 * pstore_blk_get_config - get a copy of the pstore_blk backend configuration
 111 *
 112 * @info:       The sturct pstore_blk_config to be filled in
 113 *
 114 * Failure returns negative error code, and success returns 0.
 115 */
 116int pstore_blk_get_config(struct pstore_blk_config *info);
 117
 118#endif
 119