[MTD] NAND workaround for AG-AND disturb issue. AG-AND recovery (30f464b7) · Commits · git / linux-net

drivers/mtd/nand/nand_base.c

+69 −5

Original line number	Diff line number	Diff line
		@@ -28,6 +28,20 @@
		* among multiple independend devices. Suggestions and initial patch
		* from Ben Dooks <ben-mtd@fluff.org>
		*
		* 12-05-2004 dmarlin: add workaround for Renesas AG-AND chips "disturb" issue.
		* Basically, any block not rewritten may lose data when surrounding blocks
		* are rewritten many times. JFFS2 ensures this doesn't happen for blocks
		* it uses, but the Bad Block Table(s) may not be rewritten. To ensure they
		* do not lose data, force them to be rewritten when some of the surrounding
		* blocks are erased. Rather than tracking a specific nearby block (which
		* could itself go bad), use a page address 'mask' to select several blocks
		* in the same area, and rewrite the BBT when any of them are erased.
		*
		* 01-03-2005 dmarlin: added support for the device recovery command sequence for Renesas
		* AG-AND chips. If there was a sudden loss of power during an erase operation,
		* a "device recovery" operation must be performed when power is restored
		* to ensure correct operation.
		*
		* Credits:
		* David Woodhouse for adding multichip support
		*
		@@ -41,7 +55,7 @@
		* The AG-AND chips have nice features for speed improvement,
		* which are not supported yet. Read / program 4 pages in one go.
		*
		* $Id: nand_base.c,v 1.126 2004/12/13 11:22:25 lavinen Exp $
		* $Id: nand_base.c,v 1.127 2005/01/17 18:35:22 dmarlin Exp $
		*
		* 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
		@@ -619,7 +633,7 @@ static void nand_command_lp (struct mtd_info *mtd, unsigned command, int column,
		/* Begin command latch cycle */
		this->hwcontrol(mtd, NAND_CTL_SETCLE);
		/* Write out the command to the device. */
		this->write_byte(mtd, command);
		this->write_byte(mtd, (command & 0xff));
		/* End command latch cycle */
		this->hwcontrol(mtd, NAND_CTL_CLRCLE);

		@@ -647,7 +661,7 @@ static void nand_command_lp (struct mtd_info *mtd, unsigned command, int column,

		/*
		* program and erase have their own busy handlers
		* status and sequential in needs no delay
		* status, sequential in, and deplete1 need no delay
		*/
		switch (command) {

		@@ -657,8 +671,19 @@ static void nand_command_lp (struct mtd_info *mtd, unsigned command, int column,
		case NAND_CMD_ERASE2:
		case NAND_CMD_SEQIN:
		case NAND_CMD_STATUS:
		case NAND_CMD_DEPLETE1:
		return;

		/*
		* read error status commands require only a short delay
		*/
		case NAND_CMD_STATUS_ERROR:
		case NAND_CMD_STATUS_ERROR0:
		case NAND_CMD_STATUS_ERROR1:
		case NAND_CMD_STATUS_ERROR2:
		case NAND_CMD_STATUS_ERROR3:
		udelay(this->chip_delay);
		return;

		case NAND_CMD_RESET:
		if (this->dev_ready)
		@@ -1987,6 +2012,7 @@ static int nand_erase (struct mtd_info mtd, struct erase_info instr)
		return nand_erase_nand (mtd, instr, 0);
		}

		#define BBT_PAGE_MASK 0xffffff3f
		/**
		* nand_erase_intern - [NAND Interface] erase block(s)
		* @mtd: MTD device structure
		@@ -1999,6 +2025,10 @@ int nand_erase_nand (struct mtd_info mtd, struct erase_info instr, int allowbb
		{
		int page, len, status, pages_per_block, ret, chipnr;
		struct nand_chip *this = mtd->priv;
		int rewrite_bbt[NAND_MAX_CHIPS]={0}; /* flags to indicate the page, if bbt needs to be rewritten. */
		unsigned int bbt_masked_page; /* bbt mask to compare to page being erased. */
		/* It is used to see if the current page is in the same */
		/* 256 block group and the same bank as the bbt. */

		DEBUG (MTD_DEBUG_LEVEL3,
		"nand_erase: start = 0x%08x, len = %i\n", (unsigned int) instr->addr, (unsigned int) instr->len);
		@@ -2044,6 +2074,13 @@ int nand_erase_nand (struct mtd_info mtd, struct erase_info instr, int allowbb
		goto erase_exit;
		}

		/* if BBT requires refresh, set the BBT page mask to see if the BBT should be rewritten */
		if (this->options & BBT_AUTO_REFRESH) {
		bbt_masked_page = this->bbt_td->pages[chipnr] & BBT_PAGE_MASK;
		} else {
		bbt_masked_page = 0xffffffff; /* should not match anything */
		}

		/* Loop through the pages */
		len = instr->len;

		@@ -2074,6 +2111,14 @@ int nand_erase_nand (struct mtd_info mtd, struct erase_info instr, int allowbb
		goto erase_exit;
		}

		/* if BBT requires refresh, set the BBT rewrite flag to the page being erased */
		if (this->options & BBT_AUTO_REFRESH) {
		if (((page & BBT_PAGE_MASK) == bbt_masked_page) &&
		(page != this->bbt_td->pages[chipnr])) {
		rewrite_bbt[chipnr] = (page << this->page_shift);
		}
		}

		/* Increment page address and decrement length */
		len -= (1 << this->phys_erase_shift);
		page += pages_per_block;
		@@ -2083,6 +2128,13 @@ int nand_erase_nand (struct mtd_info mtd, struct erase_info instr, int allowbb
		chipnr++;
		this->select_chip(mtd, -1);
		this->select_chip(mtd, chipnr);

		/* if BBT requires refresh and BBT-PERCHIP,
		* set the BBT page mask to see if this BBT should be rewritten */
		if ((this->options & BBT_AUTO_REFRESH) && (this->bbt_td->options & NAND_BBT_PERCHIP)) {
		bbt_masked_page = this->bbt_td->pages[chipnr] & BBT_PAGE_MASK;
		}

		}
		}
		instr->state = MTD_ERASE_DONE;
		@@ -2097,6 +2149,18 @@ int nand_erase_nand (struct mtd_info mtd, struct erase_info instr, int allowbb
		/* Deselect and wake up anyone waiting on the device */
		nand_release_device(mtd);

		/* if BBT requires refresh and erase was successful, rewrite any selected bad block tables */
		if ((this->options & BBT_AUTO_REFRESH) && (!ret)) {
		for (chipnr = 0; chipnr < this->numchips; chipnr++) {
		if (rewrite_bbt[chipnr]) {
		/* update the BBT for chip */
		DEBUG (MTD_DEBUG_LEVEL0, "nand_erase_nand: nand_update_bbt (%d:0x%0x 0x%0x)\n",
		chipnr, rewrite_bbt[chipnr], this->bbt_td->pages[chipnr]);
		nand_update_bbt (mtd, rewrite_bbt[chipnr]);
		}
		}
		}

		/* Return more or less happy */
		return ret;
		}