blob: 380a69fbeccceed32d4c26c5f621310fd66e0fdf [file] [log] [blame] [edit]
/**
* Copyright (c) 2020 The Fuchsia Authors.
*
* SPDX-License-Identifier: BSD-3-Clause
*
* The header file defines structures and functions for supporting abr wear-leveling
* algorithm. The logic are written in C as it needs to be used in both OS
* and bootloader.
*/
#ifndef ABR_WEAR_LEVELING_H_
#define ABR_WEAR_LEVELING_H_
#include <common.h>
#include "sysconfig-header.h"
#define ABR_WEAR_LEVELING_ABR_DATA_SIZE 32
#define ABR_WEAR_LEVELING_MAGIC_OFFSET ABR_WEAR_LEVELING_ABR_DATA_SIZE
#define ABR_WEAR_LEVELING_MAGIC_LEN 4
#define ABR_WEAR_LEVELING_MAGIC_BYTE_0 0xaa
#define ABR_WEAR_LEVELING_MAGIC_BYTE_1 0x55
#define ABR_WEAR_LEVELING_MAGIC_BYTE_2 0x11
#define ABR_WEAR_LEVELING_MAGIC_BYTE_3 0x22
#ifdef __cplusplus
extern "C" {
#endif
/**
* Abr metadata extended with a magic for wear-leveling.
* Though abr metadata itself comes with a magic. Here we use a separate magic
* to avoid exposing internal detail of abr logic to wear-leveling algorithm.
*/
struct abr_metadata_ext {
uint8_t abr_data[ABR_WEAR_LEVELING_ABR_DATA_SIZE];
uint8_t magic[ABR_WEAR_LEVELING_MAGIC_LEN];
} __attribute__((packed));
/**
* Checks whether an abr metadata page is valid in the context of wear-levelingn
* It simply checks the magic in abr_metadata_ext.
*
* Return true if valid, false otherwise.
*/
bool abr_metadata_page_valid(const struct abr_metadata_ext *abr_data);
/**
* Checks whether the sysconfig layout specified by <header> supports abr wear-leveling.
*
* Returns true if it supports, false otherwise.
*/
bool layout_support_wear_leveling(const struct sysconfig_header *header,
size_t page_size);
/**
* Finds the latest abr metadata in abr sub-partition given as a memory buffer.
* Copies the new data into <out>. The function will check the magic in each page.
* If no page contains valid magic, it copies from the first page.
*
* Returns the page index where the latest page resides.
*
*/
int find_latest_abr_metadata_page(const struct sysconfig_header *header,
const void *abr_subpart, uint64_t page_size,
struct abr_metadata_ext *out);
/**
* Finds an valid empty page for appending new abr metadata.
* The requirement of consecutive page programming is met by trying to find the
* immediate empty page after the last non-empty page in the sub-partition.
*
* Returns true if there is an empty page to write. The page index will be assigned
* to <out>. Returns false otherwise.
*/
bool find_empty_page_for_wear_leveling(const struct sysconfig_header *header,
const uint8_t *abr_subpart,
uint64_t page_size, int64_t *out);
/**
* Set the magic field of the given abr_metadata_ext struct.
*
*/
void set_abr_metadata_ext_magic(struct abr_metadata_ext *data);
#ifdef __cplusplus
}
#endif
#endif // LIB_SYSCONFIG_ABR_WEAR_LEVELING_H_