mtd: nand: Add core infrastructure to deal with NAND devices
Add an intermediate layer to abstract NAND device interface so that
some logic can be shared between SPI NANDs, parallel/raw NANDs,
OneNANDs, ...
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jagan Teki <jagan@openedev.com>
diff --git a/drivers/mtd/nand/bbt.c b/drivers/mtd/nand/bbt.c
new file mode 100644
index 0000000..7e0ad31
--- /dev/null
+++ b/drivers/mtd/nand/bbt.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017 Free Electrons
+ *
+ * Authors:
+ * Boris Brezillon <boris.brezillon@free-electrons.com>
+ * Peter Pan <peterpandong@micron.com>
+ */
+
+#define pr_fmt(fmt) "nand-bbt: " fmt
+
+#include <linux/mtd/nand.h>
+#ifndef __UBOOT__
+#include <linux/slab.h>
+#endif
+
+/**
+ * nanddev_bbt_init() - Initialize the BBT (Bad Block Table)
+ * @nand: NAND device
+ *
+ * Initialize the in-memory BBT.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int nanddev_bbt_init(struct nand_device *nand)
+{
+ unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
+ unsigned int nblocks = nanddev_neraseblocks(nand);
+ unsigned int nwords = DIV_ROUND_UP(nblocks * bits_per_block,
+ BITS_PER_LONG);
+
+ nand->bbt.cache = kzalloc(nwords, GFP_KERNEL);
+ if (!nand->bbt.cache)
+ return -ENOMEM;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nanddev_bbt_init);
+
+/**
+ * nanddev_bbt_cleanup() - Cleanup the BBT (Bad Block Table)
+ * @nand: NAND device
+ *
+ * Undoes what has been done in nanddev_bbt_init()
+ */
+void nanddev_bbt_cleanup(struct nand_device *nand)
+{
+ kfree(nand->bbt.cache);
+}
+EXPORT_SYMBOL_GPL(nanddev_bbt_cleanup);
+
+/**
+ * nanddev_bbt_update() - Update a BBT
+ * @nand: nand device
+ *
+ * Update the BBT. Currently a NOP function since on-flash bbt is not yet
+ * supported.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int nanddev_bbt_update(struct nand_device *nand)
+{
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nanddev_bbt_update);
+
+/**
+ * nanddev_bbt_get_block_status() - Return the status of an eraseblock
+ * @nand: nand device
+ * @entry: the BBT entry
+ *
+ * Return: a positive number nand_bbt_block_status status or -%ERANGE if @entry
+ * is bigger than the BBT size.
+ */
+int nanddev_bbt_get_block_status(const struct nand_device *nand,
+ unsigned int entry)
+{
+ unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
+ unsigned long *pos = nand->bbt.cache +
+ ((entry * bits_per_block) / BITS_PER_LONG);
+ unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
+ unsigned long status;
+
+ if (entry >= nanddev_neraseblocks(nand))
+ return -ERANGE;
+
+ status = pos[0] >> offs;
+ if (bits_per_block + offs > BITS_PER_LONG)
+ status |= pos[1] << (BITS_PER_LONG - offs);
+
+ return status & GENMASK(bits_per_block - 1, 0);
+}
+EXPORT_SYMBOL_GPL(nanddev_bbt_get_block_status);
+
+/**
+ * nanddev_bbt_set_block_status() - Update the status of an eraseblock in the
+ * in-memory BBT
+ * @nand: nand device
+ * @entry: the BBT entry to update
+ * @status: the new status
+ *
+ * Update an entry of the in-memory BBT. If you want to push the updated BBT
+ * the NAND you should call nanddev_bbt_update().
+ *
+ * Return: 0 in case of success or -%ERANGE if @entry is bigger than the BBT
+ * size.
+ */
+int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry,
+ enum nand_bbt_block_status status)
+{
+ unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
+ unsigned long *pos = nand->bbt.cache +
+ ((entry * bits_per_block) / BITS_PER_LONG);
+ unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
+ unsigned long val = status & GENMASK(bits_per_block - 1, 0);
+
+ if (entry >= nanddev_neraseblocks(nand))
+ return -ERANGE;
+
+ pos[0] &= ~GENMASK(offs + bits_per_block - 1, offs);
+ pos[0] |= val << offs;
+
+ if (bits_per_block + offs > BITS_PER_LONG) {
+ unsigned int rbits = bits_per_block + offs - BITS_PER_LONG;
+
+ pos[1] &= ~GENMASK(rbits - 1, 0);
+ pos[1] |= val >> rbits;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nanddev_bbt_set_block_status);