include/linux/pstore_blk.h

   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  */
  22 typedef 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  */
  38 struct 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
  49 int  register_pstore_blk(struct pstore_blk_info *info);
  50 void 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  */
  78 struct 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
  87 int  register_pstore_device(struct pstore_device_info *dev);
  88 void 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  */
 100 struct 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  */
 116 int pstore_blk_get_config(struct pstore_blk_config *info);
 117
 118 #endif