Implement storedevs, prepare to port littlefs

kernel/fs/littlefs/bd/lfs_rambd.h

@@ -0,0 +1,85 @@
+/*
+ * Block device emulated in RAM
+ *
+ * Copyright (c) 2022, The littlefs authors.
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef LFS_RAMBD_H
+#define LFS_RAMBD_H
+
+#include "lfs.h"
+#include "lfs_util.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+
+// Block device specific tracing
+#ifndef LFS_RAMBD_TRACE
+#ifdef LFS_RAMBD_YES_TRACE
+#define LFS_RAMBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
+#else
+#define LFS_RAMBD_TRACE(...)
+#endif
+#endif
+
+// rambd config
+struct lfs_rambd_config {
+    // Minimum size of a read operation in bytes.
+    lfs_size_t read_size;
+
+    // Minimum size of a program operation in bytes.
+    lfs_size_t prog_size;
+
+    // Size of an erase operation in bytes.
+    lfs_size_t erase_size;
+
+    // Number of erase blocks on the device.
+    lfs_size_t erase_count;
+
+    // Optional statically allocated buffer for the block device.
+    void *buffer;
+};
+
+// rambd state
+typedef struct lfs_rambd {
+    uint8_t *buffer;
+    const struct lfs_rambd_config *cfg;
+} lfs_rambd_t;
+
+
+// Create a RAM block device
+int lfs_rambd_create(const struct lfs_config *cfg,
+        const struct lfs_rambd_config *bdcfg);
+
+// Clean up memory associated with block device
+int lfs_rambd_destroy(const struct lfs_config *cfg);
+
+// Read a block
+int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, void *buffer, lfs_size_t size);
+
+// Program a block
+//
+// The block must have previously been erased.
+int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, const void *buffer, lfs_size_t size);
+
+// Erase a block
+//
+// A block must be erased before being programmed. The
+// state of an erased block is undefined.
+int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block);
+
+// Sync the block device
+int lfs_rambd_sync(const struct lfs_config *cfg);
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif