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In separating the configuration of littlefs from the physical geometry of the underlying device, we can no longer rely solely on lfs_config to contain all of the information necessary for the simulated block devices we use for testing. This adds a new lfs_*bd_config struct for each of the block devices, and new erase_size/erase_count fields. The erase_* name was chosen since these reflect the (simulated) physical erase size and count of erase-sized blocks, unlike the block_* variants which represent logical block sizes used for littlefs's bookkeeping. It may be worth adopting erase_size/erase_count in littlefs's config at some point in the future, but at the moment doesn't seem necessary. Changing the lfs_bd_config structs to be required is probably a good idea anyways, as it moves us more towards separating the bds from littlefs. Though we can't quite get rid of the lfs_config parameter because of the block-device API in lfs_config. Eventually it would be nice to get rid of it, but that would require API breakage.
83 lines
1.8 KiB
C
83 lines
1.8 KiB
C
/*
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* Block device emulated in a file
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*
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* Copyright (c) 2022, The littlefs authors.
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* Copyright (c) 2017, Arm Limited. All rights reserved.
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#ifndef LFS_FILEBD_H
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#define LFS_FILEBD_H
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#include "lfs.h"
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#include "lfs_util.h"
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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// Block device specific tracing
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#ifndef LFS_FILEBD_TRACE
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#ifdef LFS_FILEBD_YES_TRACE
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#define LFS_FILEBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
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#else
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#define LFS_FILEBD_TRACE(...)
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#endif
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#endif
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// filebd config
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struct lfs_filebd_config {
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// Minimum size of a read operation in bytes.
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lfs_size_t read_size;
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// Minimum size of a program operation in bytes.
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lfs_size_t prog_size;
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// Size of an erase operation in bytes.
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lfs_size_t erase_size;
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// Number of erase blocks on the device.
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lfs_size_t erase_count;
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};
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// filebd state
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typedef struct lfs_filebd {
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int fd;
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const struct lfs_filebd_config *cfg;
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} lfs_filebd_t;
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// Create a file block device
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int lfs_filebd_create(const struct lfs_config *cfg, const char *path,
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const struct lfs_filebd_config *bdcfg);
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// Clean up memory associated with block device
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int lfs_filebd_destroy(const struct lfs_config *cfg);
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// Read a block
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int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
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lfs_off_t off, void *buffer, lfs_size_t size);
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// Program a block
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//
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// The block must have previously been erased.
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int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
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lfs_off_t off, const void *buffer, lfs_size_t size);
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// Erase a block
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//
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// A block must be erased before being programmed. The
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// state of an erased block is undefined.
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int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block);
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// Sync the block device
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int lfs_filebd_sync(const struct lfs_config *cfg);
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#endif
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