cleanup: include/: move fcb.h to fs/fcb.h

move fcb.h to fs/fcb.h and
create a shim for backward-compatibility.

No functional changes to the headers.
A warning in the shim can be controlled with CONFIG_COMPAT_INCLUDES.

Related to #16539

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

include/fs/fcb.h

@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2017 Nordic Semiconductor ASA
+ * Copyright (c) 2015 Runtime Inc
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_FS_FCB_H_
+#define ZEPHYR_INCLUDE_FS_FCB_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Flash circular buffer.
+ */
+#include <inttypes.h>
+#include <limits.h>
+
+#include <storage/flash_map.h>
+
+#include <kernel.h>
+
+#define FCB_MAX_LEN	(CHAR_MAX | CHAR_MAX << 7) /* Max length of element */
+
+/*
+ * Entry location is pointer to area (within fcb->f_sectors), and offset
+ * within that area.
+ */
+struct fcb_entry {
+	struct flash_sector *fe_sector;	/* ptr to sector */
+					/* within fcb->f_sectors */
+	u32_t fe_elem_off;		/* start of entry */
+	u32_t fe_data_off;		/* start of data */
+	u16_t fe_data_len;		/* size of data area */
+};
+
+/*
+ * Helper macro for calculate the data offset related to
+ * the fcb flash_area start offset.
+ */
+#define FCB_ENTRY_FA_DATA_OFF(entry) (entry.fe_sector->fs_off +\
+				      entry.fe_data_off)
+
+struct fcb_entry_ctx {
+	struct fcb_entry loc;
+	const struct flash_area *fap;
+};
+
+struct fcb {
+	/* Caller of fcb_init fills this in */
+	u32_t f_magic;		/* As placed on the disk */
+	u8_t f_version;		/* Current version number of the data */
+	u8_t f_sector_cnt;	/* Number of elements in sector array */
+	u8_t f_scratch_cnt;	/* How many sectors should be kept empty */
+	struct flash_sector *f_sectors; /* Array of sectors, */
+					/* must be contiguous */
+
+	/* Flash circular buffer internal state */
+	struct k_mutex f_mtx;	/* Locking for accessing the FCB data */
+	struct flash_sector *f_oldest;
+	struct fcb_entry f_active;
+	u16_t f_active_id;
+	u8_t f_align;		/* writes to flash have to aligned to this */
+
+	const struct flash_area *fap; /* Flash area used by the fcb instance */
+				     /* This can be transfer to FCB user    */
+};
+
+/*
+ * Error codes.
+ */
+#define FCB_OK		0
+#define FCB_ERR_ARGS	-1
+#define FCB_ERR_FLASH	-2
+#define FCB_ERR_NOVAR   -3
+#define FCB_ERR_NOSPACE	-4
+#define FCB_ERR_NOMEM	-5
+#define FCB_ERR_CRC	-6
+#define FCB_ERR_MAGIC   -7
+
+int fcb_init(int f_area_id, struct fcb *fcb);
+
+/*
+ * fcb_append() appends an entry to circular buffer. When writing the
+ * contents for the entry, use loc->fl_area and loc->fl_data_off with
+ * flash_area_write(). When you're finished, call fcb_append_finish() with
+ * loc as argument.
+ */
+int fcb_append(struct fcb *fcb, u16_t len, struct fcb_entry *loc);
+int fcb_append_finish(struct fcb *fcb, struct fcb_entry *append_loc);
+
+/*
+ * Walk over all log entries in FCB, or entries in a given flash_area.
+ * cb gets called for every entry. If cb wants to stop the walk, it should
+ * return non-zero value.
+ *
+ * Entry data can be read using flash_area_read(), using
+ * loc->fe_area, loc->fe_data_off, and loc->fe_data_len as arguments.
+ */
+typedef int (*fcb_walk_cb)(struct fcb_entry_ctx *loc_ctx, void *arg);
+int fcb_walk(struct fcb *fcb, struct flash_sector *sector, fcb_walk_cb cb,
+	     void *cb_arg);
+int fcb_getnext(struct fcb *fcb, struct fcb_entry *loc);
+
+/*
+ * Erases the data from oldest sector.
+ */
+int fcb_rotate(struct fcb *fcb);
+
+/*
+ * Start using the scratch block.
+ */
+int fcb_append_to_scratch(struct fcb *fcb);
+
+/*
+ * How many sectors are unused.
+ */
+int fcb_free_sector_cnt(struct fcb *fcb);
+
+/*
+ * Whether FCB has any data.
+ */
+int fcb_is_empty(struct fcb *fcb);
+
+/*
+ * Element at offset *entries* from last position (backwards).
+ */
+int fcb_offset_last_n(struct fcb *fcb, u8_t entries,
+		      struct fcb_entry *last_n_entry);
+
+/*
+ * Clears FCB passed to it
+ */
+int fcb_clear(struct fcb *fcb);
+
+int fcb_flash_read(const struct fcb *fcb, const struct flash_sector *sector,
+		   off_t off, void *dst, size_t len);
+int fcb_flash_write(const struct fcb *fcb, const struct flash_sector *sector,
+		    off_t off, const void *src, size_t len);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_FS_FCB_H_ */