UBI - Unsorted Block Images

UBI (Latin: "where?") manages multiple logical volumes on a single
flash device, specifically supporting NAND flash devices. UBI provides
a flexible partitioning concept which still allows for wear-levelling
across the whole flash device.

In a sense, UBI may be compared to the Logical Volume Manager
(LVM). Whereas LVM maps logical sector numbers to physical HDD sector
numbers, UBI maps logical eraseblocks to physical eraseblocks.

More information may be found in the UBI design documentation:
ubidesign.pdf. Which can be found here:
http://www.linux-mtd.infradead.org/doc/ubi.html

Partitioning/Re-partitioning

  An UBI volume occupies a certain number of erase blocks. This is
  limited by a configured maximum volume size, which could also be
  viewed as the partition size. Each individual UBI volume's size can
  be changed independently of the other UBI volumes, provided that the
  sum of all volume sizes doesn't exceed a certain limit.

  UBI supports dynamic volumes and static volumes. Static volumes are
  read-only and their contents are protected by CRC check sums.

Bad eraseblocks handling

  UBI transparently handles bad eraseblocks. When a physical
  eraseblock becomes bad, it is substituted by a good physical
  eraseblock, and the user does not even notice this.

Scrubbing

  On a NAND flash bit flips can occur on any write operation,
  sometimes also on read. If bit flips persist on the device, at first
  they can still be corrected by ECC, but once they accumulate,
  correction will become impossible. Thus it is best to actively scrub
  the affected eraseblock, by first copying it to a free eraseblock
  and then erasing the original. The UBI layer performs this type of
  scrubbing under the covers, transparently to the UBI volume users.

Erase Counts

  UBI maintains an erase count header per eraseblock. This frees
  higher-level layers (like file systems) from doing this and allows
  for centralized erase count management instead. The erase counts are
  used by the wear-levelling algorithm in the UBI layer. The algorithm
  itself is exchangeable.

Booting from NAND

  For booting directly from NAND flash the hardware must at least be
  capable of fetching and executing a small portion of the NAND
  flash. Some NAND flash controllers have this kind of support. They
  usually limit the window to a few kilobytes in erase block 0. This
  "initial program loader" (IPL) must then contain sufficient logic to
  load and execute the next boot phase.

  Due to bad eraseblocks, which may be randomly scattered over the
  flash device, it is problematic to store the "secondary program
  loader" (SPL) statically. Also, due to bit-flips it may become
  corrupted over time. UBI allows to solve this problem gracefully by
  storing the SPL in a small static UBI volume.

UBI volumes vs. static partitions

  UBI volumes are still very similar to static MTD partitions:

    * both consist of eraseblocks (logical eraseblocks in case of UBI
      volumes, and physical eraseblocks in case of static partitions;
    * both support three basic operations - read, write, erase.

  But UBI volumes have the following advantages over traditional
  static MTD partitions:

    * there are no eraseblock wear-leveling constraints in case of UBI
      volumes, so the user should not care about this;
    * there are no bit-flips and bad eraseblocks in case of UBI volumes.

  So, UBI volumes may be considered as flash devices with relaxed
  restrictions.

Where can it be found?

  Documentation, kernel code and applications can be found in the MTD
  gits.

What are the applications for?

  The applications help to create binary flash images for two
  purposes: pfi files (partial flash images) for in-system update of
  UBI volumes, and plain binary images, with or without OOB data in
  case of NAND, for a manufacturing step. Furthermore some tools
  are/and will be created that allow flash content analysis after a
  system has crashed.

Who did UBI?

  The original ideas, where UBI is based on, were developed by Andreas
  Arnez, Frank Haverkamp and Thomas Gleixner. Josh W. Boyer and
  some others were involved too. The implementation of the kernel
  layer was done by Artem B. Bityutskiy. The user-space applications
  and tools were written by Oliver Lohmann with contributions from
  Frank Haverkamp, Andreas Arnez, and Artem. Joern Engel contributed a
  patch which modifies JFFS2 so that it can be run on a UBI
  volume. Thomas Gleixner did modifications to the NAND layer and also
  some to JFFS2 to make it work.

Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>

1 files changed, 185 insertions, 0 deletions

diff --git a/ubi-utils/src/ubiinfo/ubiflash.h b/ubi-utils/src/ubiinfo/ubiflash.h
new file mode 100644
index 0000000..6883879
--- /dev/null
+++ b/ubi-utils/src/ubiinfo/ubiflash.h
@@ -0,0 +1,185 @@
+#ifndef _UBI_FLASH_H
+#define _UBI_FLASH_H
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * FLASH related data structures and constants for UBI.
+ * UBI scan analysis.
+ *
+ * IPL Initial Program Loader
+ * SPL Secondary Program Loader
+ */
+
+#include <stdint.h>
+#include <asm/byteorder.h>
+#include <mtd/ubi-header.h>
+
+#define UBI_BLOCK_IDENT_MAX  16
+
+/* Block status information constants */
+enum blockstat {
+	/* IO Error */
+	STAT_IO_FAILED	= 1,	/* 0xffffffff */
+	/* Block is bad */
+	STAT_BLOCK_BAD	= 2,	/* 0xfffffffe */
+	/* ECC unrecoverable error */
+	STAT_ECC_ERROR	= 3,	/* 0xfffffffd */
+	/* CRC checksum failed */
+	STAT_CRC_ERROR	= 4,	/* 0xfffffffc */
+	/* Magic number not available */
+	STAT_NO_MAGIC	= 5,	/* 0xfffffffb */
+	/* No image available */
+	STAT_NO_IMAGE	= 6,
+	/* Image is invalid */
+	STAT_INVALID_IMAGE	= 7,
+	/* Image is defect */
+	STAT_DEFECT_IMAGE	= 8,
+};
+
+/*
+ * Flash types
+ */
+enum flashtypes {
+	FLASH_TYPE_NAND = 1,
+	FLASH_TYPE_NOR,
+};
+
+/* Nand read buffer size: 2KiB + 64byte spare */
+#define NAND_READ_BUF_SIZE	(2048 + 64)
+
+/* Size of the CRC table */
+#define CRC32_TABLE_SIZE	256
+
+/* Image is not available marker for image offs */
+#define UBI_IMAGE_NOT_AVAILABLE	0xFFFFFFFF
+
+/* Increment this number, whenever you change the structure */
+#define UBI_SCAN_INFO_VERSION	2
+
+/* Time measurement as far as the code size allows us to do this */
+#define UBI_TIMESTAMPS		16
+
+/**
+ * struct ubi_scan_info - RAM table filled by IPL scan
+ *
+ * @version:		Version of the structure
+ * @bootstatus:		Boot status of the current boot
+ * @flashtype:		Flash type (NAND/NOR)
+ * @flashid:		ID of the flash chip
+ * @flashmfr:		Manufacturer ID of the flash chip
+ * @flashsize:		Size of the FLASH
+ * @blocksize:		Eraseblock size
+ * @blockshift:		Shift count to calc block number from offset
+ * @nrblocks:		Number of erase blocks on flash
+ * @pagesize:		Pagesize (NAND)
+ * @blockinfo:		Pointer to an array of block status information
+ *			filled by FLASH scan
+ * @images:		Pointer to FLASH block translation table sorted
+ *			by image type and load order
+ * @imageblocks:	Number of blocks found per image
+ * @imageoffs:		Offset per imagetype to the first
+ *			block in the translation table
+ * @imagedups		duplicate blocks (max. one per volume)
+ * @imagelen:		Length of the loaded image
+ * @crc32_table:	CRC32 table buffer
+ * @page_buf:		Page buffer for NAND FLASH
+ */
+struct ubi_scan_info {
+	int			version;
+	unsigned int		bootstatus;
+	unsigned int		flashtype;
+	unsigned int		flashid;
+	unsigned int		flashmfr;
+	unsigned int		flashsize;
+	unsigned int		blocksize;
+	unsigned int		blockshift;
+	unsigned int		nrblocks;
+	unsigned int		pagesize;
+
+	struct ubi_vid_hdr	*blockinfo;
+	struct ubi_vid_hdr	**images;
+	unsigned int		imageblocks[UBI_BLOCK_IDENT_MAX];
+	unsigned int		imageoffs[UBI_BLOCK_IDENT_MAX];
+	struct ubi_vid_hdr	*imagedups[UBI_BLOCK_IDENT_MAX];
+	unsigned int		imagelen;
+	uint32_t		crc32_table[CRC32_TABLE_SIZE];
+	uint8_t			page_buf[NAND_READ_BUF_SIZE];
+	unsigned int		times[UBI_TIMESTAMPS];
+};
+
+/* External function definition */
+extern int flash_read(void *buf, unsigned int offs, int len);
+extern int flash_read_slice(struct ubi_scan_info *fi, void *buf,
+			    unsigned int offs, int len);
+extern void ipl_main(struct ubi_scan_info *fi);
+
+#ifndef CFG_EXAMPLE_IPL
+extern int ipl_scan(struct ubi_scan_info *fi);
+extern int ipl_load(struct ubi_scan_info *fi, int nr, uint8_t *loadaddr);
+
+#define IPL_STATIC
+
+#else
+#define IPL_STATIC static
+#endif
+
+/**
+ * get_boot_status - get the boot status register
+ *
+ * Shift the lower 16 bit into the upper 16 bit and return
+ * the result.
+ */
+uint32_t get_boot_status(void);
+
+/**
+ * set_boot_status - Set the boot status register
+ *
+ * @status:	The status value to set
+ *
+ */
+void set_boot_status(uint32_t status);
+
+static inline unsigned int ubi_vid_offset(struct ubi_scan_info *fi)
+{
+	if (fi->flashtype == FLASH_TYPE_NOR)
+		return UBI_EC_HDR_SIZE;
+	else
+		return fi->pagesize - UBI_VID_HDR_SIZE;
+}
+
+static inline unsigned int ubi_data_offset(struct ubi_scan_info *fi)
+{
+	if (fi->flashtype == FLASH_TYPE_NOR)
+		return UBI_EC_HDR_SIZE + UBI_VID_HDR_SIZE;
+	else
+		return fi->pagesize;
+}
+
+/**
+ * IPL checkpoints
+ */
+#define CHKP_HWINIT		0x3030
+#define CHKP_IPLSCAN_FAILED	0x3034
+#define CHKP_SPL_START		0x3037
+#define CHKP_SPLLOAD_STATUS	0x3130
+
+extern void checkpoint(uint32_t cpoint);
+extern void switch_watchdog(void);
+
+#endif