--- /dev/null
+/*
+ * linux/drivers/mtd/onenand/onenand_bbt.c
+ *
+ * Bad Block Table support for the OneNAND driver
+ *
+ * Copyright(c) 2005-2007 Samsung Electronics
+ * Kyungmin Park <kyungmin.park@samsung.com>
+ *
+ * TODO:
+ * Split BBT core and chip specific BBT.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <common.h>
+
+#ifdef CONFIG_CMD_ONENAND
+
+#include <linux/mtd/compat.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/onenand.h>
+#include <malloc.h>
+
+#include <asm/errno.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 = onenand_read_oob(mtd,
+ from + j * mtd->oobblock +
+ bd->offs, readlen, &retlen,
+ &buf[0]);
+
+ if (ret && ret != -EAGAIN) {
+ printk("ret = %d\n", 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 = malloc(len);
+ 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");
+ free(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 = malloc(sizeof(struct bbm_info));
+ 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);
+}
+
+#endif /* CFG_CMD_ONENAND */
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