1 files changed, 246 insertions, 0 deletions

diff --git a/drivers/mtd/onenand/onenand_bbt.c b/drivers/mtd/onenand/onenand_bbt.c
new file mode 100644
index 0000000..f40190f
--- /dev/null
+++ b/drivers/mtd/onenand/onenand_bbt.c
@@ -0,0 +1,246 @@
+/*
+ *  linux/drivers/mtd/onenand/onenand_bbt.c
+ *
+ *  Bad Block Table support for the OneNAND driver
+ *
+ *  Copyright(c) 2005 Samsung Electronics
+ *  Kyungmin Park <kyungmin.park@samsung.com>
+ *
+ *  Derived from nand_bbt.c
+ *
+ *  TODO:
+ *    Split BBT core and chip specific BBT.
+ */
+
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/onenand.h>
+#include <linux/mtd/compatmac.h>
+
+/**
+ * check_short_pattern - [GENERIC] check if a pattern is in the buffer
+ * @param buf		the buffer to search
+ * @param len		the length of buffer to search
+ * @param paglen	the pagelength
+ * @param td		search pattern descriptor
+ *
+ * Check for a pattern at the given place. Used to search bad block
+ * tables and good / bad block identifiers. Same as check_pattern, but
+ * no optional empty check and the pattern is expected to start
+ * at offset 0.
+ *
+ */
+static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
+{
+	int i;
+	uint8_t *p = buf;
+
+	/* Compare the pattern */
+	for (i = 0; i < td->len; i++) {
+		if (p[i] != td->pattern[i])
+			return -1;
+	}
+        return 0;
+}
+
+/**
+ * create_bbt - [GENERIC] Create a bad block table by scanning the device
+ * @param mtd		MTD device structure
+ * @param buf		temporary buffer
+ * @param bd		descriptor for the good/bad block search pattern
+ * @param chip		create the table for a specific chip, -1 read all chips.
+ *              Applies only if NAND_BBT_PERCHIP option is set
+ *
+ * Create a bad block table by scanning the device
+ * for the given good/bad block identify pattern
+ */
+static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
+{
+	struct onenand_chip *this = mtd->priv;
+	struct bbm_info *bbm = this->bbm;
+	int i, j, numblocks, len, scanlen;
+	int startblock;
+	loff_t from;
+	size_t readlen, ooblen;
+
+	printk(KERN_INFO "Scanning device for bad blocks\n");
+
+	len = 1;
+
+	/* We need only read few bytes from the OOB area */
+	scanlen = ooblen = 0;
+	readlen = bd->len;
+
+	/* chip == -1 case only */
+	/* Note that numblocks is 2 * (real numblocks) here;
+	 * see i += 2 below as it makses shifting and masking less painful
+	 */
+	numblocks = mtd->size >> (bbm->bbt_erase_shift - 1);
+	startblock = 0;
+	from = 0;
+
+	for (i = startblock; i < numblocks; ) {
+		int ret;
+
+		for (j = 0; j < len; j++) {
+			size_t retlen;
+
+			/* No need to read pages fully,
+			 * just read required OOB bytes */
+			ret = mtd->read_oob(mtd, from + j * mtd->oobblock + bd->offs,
+						readlen, &retlen, &buf[0]);
+
+			if (ret)
+				return ret;
+
+			if (check_short_pattern(&buf[j * scanlen], scanlen, mtd->oobblock, bd)) {
+				bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
+				printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
+					i >> 1, (unsigned int) from);
+				break;
+			}
+		}
+		i += 2;
+		from += (1 << bbm->bbt_erase_shift);
+	}
+
+	return 0;
+}
+
+
+/**
+ * onenand_memory_bbt - [GENERIC] create a memory based bad block table
+ * @param mtd		MTD device structure
+ * @param bd		descriptor for the good/bad block search pattern
+ *
+ * The function creates a memory based bbt by scanning the device
+ * for manufacturer / software marked good / bad blocks
+ */
+static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
+{
+	unsigned char data_buf[MAX_ONENAND_PAGESIZE];
+
+        bd->options &= ~NAND_BBT_SCANEMPTY;
+        return create_bbt(mtd, data_buf, bd, -1);
+}
+
+/**
+ * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
+ * @param mtd		MTD device structure
+ * @param offs		offset in the device
+ * @param allowbbt	allow access to bad block table region
+ */
+static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
+{
+	struct onenand_chip *this = mtd->priv;
+	struct bbm_info *bbm = this->bbm;
+	int block;
+	uint8_t res;
+
+	/* Get block number * 2 */
+	block = (int) (offs >> (bbm->bbt_erase_shift - 1));
+	res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
+
+	DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
+		(unsigned int) offs, block >> 1, res);
+
+	switch ((int) res) {
+	case 0x00:	return 0;
+	case 0x01:	return 1;
+	case 0x02:	return allowbbt ? 0 : 1;
+	}
+
+	return 1;
+}
+
+/**
+ * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
+ * @param mtd		MTD device structure
+ * @param bd		descriptor for the good/bad block search pattern
+ *
+ * The function checks, if a bad block table(s) is/are already
+ * available. If not it scans the device for manufacturer
+ * marked good / bad blocks and writes the bad block table(s) to
+ * the selected place.
+ *
+ * The bad block table memory is allocated here. It must be freed
+ * by calling the onenand_free_bbt function.
+ *
+ */
+int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
+{
+	struct onenand_chip *this = mtd->priv;
+	struct bbm_info *bbm = this->bbm;
+	int len, ret = 0;
+
+	len = mtd->size >> (this->erase_shift + 2);
+	/* Allocate memory (2bit per block) */
+	bbm->bbt = kmalloc(len, GFP_KERNEL);
+	if (!bbm->bbt) {
+		printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");
+		return -ENOMEM;
+	}
+	/* Clear the memory bad block table */
+	memset(bbm->bbt, 0x00, len);
+
+	/* Set the bad block position */
+	bbm->badblockpos = ONENAND_BADBLOCK_POS;
+
+	/* Set erase shift */
+	bbm->bbt_erase_shift = this->erase_shift;
+
+	if (!bbm->isbad_bbt)
+		bbm->isbad_bbt = onenand_isbad_bbt;
+
+	/* Scan the device to build a memory based bad block table */
+	if ((ret = onenand_memory_bbt(mtd, bd))) {
+		printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
+		kfree(bbm->bbt);
+		bbm->bbt = NULL;
+	}
+
+	return ret;
+}
+
+/*
+ * Define some generic bad / good block scan pattern which are used
+ * while scanning a device for factory marked good / bad blocks.
+ */
+static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
+
+static struct nand_bbt_descr largepage_memorybased = {
+	.options = 0,
+	.offs = 0,
+	.len = 2,
+	.pattern = scan_ff_pattern,
+};
+
+/**
+ * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
+ * @param mtd		MTD device structure
+ *
+ * This function selects the default bad block table
+ * support for the device and calls the onenand_scan_bbt function
+ */
+int onenand_default_bbt(struct mtd_info *mtd)
+{
+	struct onenand_chip *this = mtd->priv;
+	struct bbm_info *bbm;
+
+	this->bbm = kmalloc(sizeof(struct bbm_info), GFP_KERNEL);
+	if (!this->bbm)
+		return -ENOMEM;
+
+	bbm = this->bbm;
+
+	memset(bbm, 0, sizeof(struct bbm_info));
+
+	/* 1KB page has same configuration as 2KB page */
+	if (!bbm->badblock_pattern)
+		bbm->badblock_pattern = &largepage_memorybased;
+
+	return onenand_scan_bbt(mtd, bbm->badblock_pattern);
+}
+
+EXPORT_SYMBOL(onenand_scan_bbt);
+EXPORT_SYMBOL(onenand_default_bbt);