From: Brian Norris <computersforpe...@gmail.com>
Currently nand_bbt.c is tied with struct nand_chip, and it makes other
NAND family chips hard to use nand_bbt.c. Maybe it's the reason why
onenand has own bbt(onenand_bbt.c).
Separate struct nand_chip from BBT code can make current BBT shareable.
We create struct nand_bbt to take place of nand_chip in nand_bbt.c
Below is mtd folder structure we want:
drivers/mtd/nand/<all-nand-core-code>
drivers/mtd/nand/raw/<raw-nand-controller-drivers>
drivers/mtd/nand/spi/<spi-nand-code>
drivers/mtd/nand/onenand/<onenand-code>
drivers/mtd/nand/chips/<manufacturer-spcific-code>
Of course, nand_bbt.c should be part of <all-nand-core-code>.
We put every chip layout related information BBT needed into struct
nand_chip_layout_info.
@numchips: number of physical chips, required for NAND_BBT_PERCHIP
@chipsize: the size of one chip for multichip arrays
@chip_shift: number of address bits in one chip
@bbt_erase_shift: number of address bits in a bbt entry
@page_shift: number of address bits in a page
We defined a struct nand_bbt_ops for BBT ops. Struct
@is_bad_bbm: check if a block is factory bad block
@erase: erase block bypassing resvered checks
Struct nand_bbt includes all BBT information:
@mtd: pointer to MTD device structure
@bbt_options: bad block specific options. All options used
here must come from nand_bbt.h.
@bbt_ops: struct nand_bbt_ops pointer.
@info: struct nand_chip_layout_info pointer.
@bbt_td: bad block table descriptor for flash lookup.
@bbt_md: bad block table mirror descriptor
@bbt: bad block table pointer
Signed-off-by: Brian Norris <computersforpe...@gmail.com>
[Peter: 1. correct comment style
2. introduce struct nand_bbt_ops and nand_chip_layout_info]
Signed-off-by: Peter Pan <peterpand...@micron.com>
---
include/linux/mtd/nand_bbt.h | 67 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)
diff --git a/include/linux/mtd/nand_bbt.h b/include/linux/mtd/nand_bbt.h
index 5a65230..cfb22c8 100644
--- a/include/linux/mtd/nand_bbt.h
+++ b/include/linux/mtd/nand_bbt.h
@@ -18,6 +18,8 @@
#ifndef __LINUX_MTD_NAND_BBT_H
#define __LINUX_MTD_NAND_BBT_H
+struct mtd_info;
+
/* The maximum number of NAND chips in an array */
#define NAND_MAX_CHIPS 8
@@ -115,4 +117,69 @@ struct nand_bbt_descr {
/* The maximum number of blocks to scan for a bbt */
#define NAND_BBT_SCAN_MAXBLOCKS 4
+struct nand_bbt;
+
+/**
+ * struct nand_bbt_ops - bad block table operations
+ * @is_bad_bbm: check if a block is factory bad block
+ * @erase: erase block bypassing resvered checks
+ */
+struct nand_bbt_ops {
+ /*
+ * This is important to abstract out of nand_bbt.c and provide
+ * separately in nand_base.c and spi-nand-base.c -- it's sort of
+ * duplicated in nand_block_bad() (nand_base) and
+ * scan_block_fast() (nand_bbt) right now
+ *
+ * Note that this also means nand_chip.badblock_pattern should
+ * be removed from nand_bbt.c
+ */
+ int (*is_bad_bbm)(struct mtd_info *mtd, loff_t ofs);
+
+ /* Erase a block, bypassing reserved checks */
+ int (*erase)(struct mtd_info *mtd, loff_t ofs);
+};
+
+/**
+ * struct nand_chip_layout_info - strucure contains all chip layout
+ * information that BBT needed.
+ * @numchips: number of physical chips, required for NAND_BBT_PERCHIP
+ * @chipsize: the size of one chip for multichip arrays
+ * @chip_shift: number of address bits in one chip
+ * @bbt_erase_shift: number of address bits in a bbt entry
+ * @page_shift: number of address bits in a page
+ */
+struct nand_chip_layout_info {
+ int numchips;
+ u64 chipsize;
+ int chip_shift;
+ int bbt_erase_shift;
+ int page_shift;
+};
+
+/**
+ * struct nand_bbt - bad block table structure
+ * @mtd: pointer to MTD device structure
+ * @bbt_options: bad block specific options. All options used
+ * here must come from nand_bbt.h.
+ * @bbt_ops: struct nand_bbt_ops pointer.
+ * @info: struct nand_chip_layout_info pointer.
+ * @bbt_td: bad block table descriptor for flash lookup.
+ * @bbt_md: bad block table mirror descriptor
+ * @bbt: bad block table pointer
+ */
+struct nand_bbt {
+ struct mtd_info *mtd;
+ unsigned int bbt_options;
+ const struct nand_bbt_ops *bbt_ops;
+ struct nand_chip_layout_info *info;
+ /*
+ * Discourage new custom usages here; suggest usage of the
+ * relevant NAND_BBT_* options instead
+ */
+ struct nand_bbt_descr *bbt_td;
+ struct nand_bbt_descr *bbt_md;
+ u8 *bbt;
+};
+
#endif /* __LINUX_MTD_NAND_BBT_H */
--
1.9.1
