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mtd: nand: remove AG-AND support
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We have only one AG-AND driver and it was not touched since 2005. It looks
like AG-AND was not really make it to mass-production and can be considered
a dead technology.

Along with the AG-AND support, this patch removes the BBT_AUTO_REFRESH feature,
because the only user of this feature is AG-AND. And even though it is
implemented as a generic feature, I prefer to remove it because NAND flashes do
not really need it in this form.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Artem Bityutskiy authored and David Woodhouse committed Apr 5, 2013
1 parent 02f57fe commit 14c6578
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Showing 4 changed files with 2 additions and 132 deletions.
80 changes: 2 additions & 78 deletions drivers/mtd/nand/nand_base.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@
* Overview:
* This is the generic MTD driver for NAND flash devices. It should be
* capable of working with almost all NAND chips currently available.
* Basic support for AG-AND chips is provided.
*
* Additional technical information is available on
* http://www.linux-mtd.infradead.org/doc/nand.html
Expand All @@ -22,8 +21,6 @@
* Enable cached programming for 2k page size chips
* Check, if mtd->ecctype should be set to MTD_ECC_HW
* if we have HW ECC support.
* The AG-AND chips have nice features for speed improvement,
* which are not supported yet. Read / program 4 pages in one go.
* BBT table is not serialized, has to be fixed
*
* This program is free software; you can redistribute it and/or modify
Expand Down Expand Up @@ -836,10 +833,7 @@ static int nand_wait(struct mtd_info *mtd, struct nand_chip *chip)
*/
ndelay(100);

if ((state == FL_ERASING) && (chip->options & NAND_IS_AND))
chip->cmdfunc(mtd, NAND_CMD_STATUS_MULTI, -1, -1);
else
chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);

if (in_interrupt() || oops_in_progress)
panic_nand_wait(mtd, chip, timeo);
Expand Down Expand Up @@ -2480,24 +2474,6 @@ static void single_erase_cmd(struct mtd_info *mtd, int page)
chip->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);
}

/**
* multi_erase_cmd - [GENERIC] AND specific block erase command function
* @mtd: MTD device structure
* @page: the page address of the block which will be erased
*
* AND multi block erase command function. Erase 4 consecutive blocks.
*/
static void multi_erase_cmd(struct mtd_info *mtd, int page)
{
struct nand_chip *chip = mtd->priv;
/* Send commands to erase a block */
chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page++);
chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page++);
chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page++);
chip->cmdfunc(mtd, NAND_CMD_ERASE1, -1, page);
chip->cmdfunc(mtd, NAND_CMD_ERASE2, -1, -1);
}

/**
* nand_erase - [MTD Interface] erase block(s)
* @mtd: MTD device structure
Expand All @@ -2510,7 +2486,6 @@ 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_nand - [INTERN] erase block(s)
* @mtd: MTD device structure
Expand All @@ -2524,8 +2499,6 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
{
int page, status, pages_per_block, ret, chipnr;
struct nand_chip *chip = mtd->priv;
loff_t rewrite_bbt[NAND_MAX_CHIPS] = {0};
unsigned int bbt_masked_page = 0xffffffff;
loff_t len;

pr_debug("%s: start = 0x%012llx, len = %llu\n",
Expand Down Expand Up @@ -2556,15 +2529,6 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
goto erase_exit;
}

/*
* If BBT requires refresh, set the BBT page mask to see if the BBT
* should be rewritten. Otherwise the mask is set to 0xffffffff which
* can not be matched. This is also done when the bbt is actually
* erased to avoid recursive updates.
*/
if (chip->options & BBT_AUTO_REFRESH && !allowbbt)
bbt_masked_page = chip->bbt_td->pages[chipnr] & BBT_PAGE_MASK;

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

Expand Down Expand Up @@ -2610,15 +2574,6 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
goto erase_exit;
}

/*
* If BBT requires refresh, set the BBT rewrite flag to the
* page being erased.
*/
if (bbt_masked_page != 0xffffffff &&
(page & BBT_PAGE_MASK) == bbt_masked_page)
rewrite_bbt[chipnr] =
((loff_t)page << chip->page_shift);

/* Increment page address and decrement length */
len -= (1 << chip->phys_erase_shift);
page += pages_per_block;
Expand All @@ -2628,15 +2583,6 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
chipnr++;
chip->select_chip(mtd, -1);
chip->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 (bbt_masked_page != 0xffffffff &&
(chip->bbt_td->options & NAND_BBT_PERCHIP))
bbt_masked_page = chip->bbt_td->pages[chipnr] &
BBT_PAGE_MASK;
}
}
instr->state = MTD_ERASE_DONE;
Expand All @@ -2653,23 +2599,6 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
if (!ret)
mtd_erase_callback(instr);

/*
* If BBT requires refresh and erase was successful, rewrite any
* selected bad block tables.
*/
if (bbt_masked_page == 0xffffffff || ret)
return ret;

for (chipnr = 0; chipnr < chip->numchips; chipnr++) {
if (!rewrite_bbt[chipnr])
continue;
/* Update the BBT for chip */
pr_debug("%s: nand_update_bbt (%d:0x%0llx 0x%0x)\n",
__func__, chipnr, rewrite_bbt[chipnr],
chip->bbt_td->pages[chipnr]);
nand_update_bbt(mtd, rewrite_bbt[chipnr]);
}

/* Return more or less happy */
return ret;
}
Expand Down Expand Up @@ -3302,12 +3231,7 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
}

chip->badblockbits = 8;

/* Check for AND chips with 4 page planes */
if (chip->options & NAND_4PAGE_ARRAY)
chip->erase_cmd = multi_erase_cmd;
else
chip->erase_cmd = single_erase_cmd;
chip->erase_cmd = single_erase_cmd;

/* Do not replace user supplied command function! */
if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
Expand Down
25 changes: 0 additions & 25 deletions drivers/mtd/nand/nand_bbt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1240,15 +1240,6 @@ int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
*/
static uint8_t scan_ff_pattern[] = { 0xff, 0xff };

static uint8_t scan_agand_pattern[] = { 0x1C, 0x71, 0xC7, 0x1C, 0x71, 0xC7 };

static struct nand_bbt_descr agand_flashbased = {
.options = NAND_BBT_SCANEMPTY | NAND_BBT_SCANALLPAGES,
.offs = 0x20,
.len = 6,
.pattern = scan_agand_pattern
};

/* Generic flash bbt descriptors */
static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
Expand Down Expand Up @@ -1333,22 +1324,6 @@ int nand_default_bbt(struct mtd_info *mtd)
{
struct nand_chip *this = mtd->priv;

/*
* Default for AG-AND. We must use a flash based bad block table as the
* devices have factory marked _good_ blocks. Erasing those blocks
* leads to loss of the good / bad information, so we _must_ store this
* information in a good / bad table during startup.
*/
if (this->options & NAND_IS_AND) {
/* Use the default pattern descriptors */
if (!this->bbt_td) {
this->bbt_td = &bbt_main_descr;
this->bbt_md = &bbt_mirror_descr;
}
this->bbt_options |= NAND_BBT_USE_FLASH;
return nand_scan_bbt(mtd, &agand_flashbased);
}

/* Is a flash based bad block table requested? */
if (this->bbt_options & NAND_BBT_USE_FLASH) {
/* Use the default pattern descriptors */
Expand Down
13 changes: 0 additions & 13 deletions drivers/mtd/nand/nand_ids.c
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Original file line number Diff line number Diff line change
Expand Up @@ -134,19 +134,6 @@ struct nand_flash_dev nand_flash_ids[] = {
{"NAND 64GiB 1,8V 16-bit", 0x2E, 0, 65536, 0, LP_OPTIONS16},
{"NAND 64GiB 3,3V 16-bit", 0x4E, 0, 65536, 0, LP_OPTIONS16},

/*
* Renesas AND 1 Gigabit. Those chips do not support extended id and
* have a strange page/block layout ! The chosen minimum erasesize is
* 4 * 2 * 2048 = 16384 Byte, as those chips have an array of 4 page
* planes 1 block = 2 pages, but due to plane arrangement the blocks
* 0-3 consists of page 0 + 4,1 + 5, 2 + 6, 3 + 7 Anyway JFFS2 would
* increase the eraseblock size so we chose a combined one which can be
* erased in one go There are more speed improvements for reads and
* writes possible, but not implemented now
*/
{"AND 128MiB 3,3V 8-bit", 0x01, 2048, 128, 0x4000,
NAND_IS_AND | NAND_4PAGE_ARRAY | BBT_AUTO_REFRESH},

{NULL,}
};

Expand Down
16 changes: 0 additions & 16 deletions include/linux/mtd/nand.h
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Original file line number Diff line number Diff line change
Expand Up @@ -171,22 +171,6 @@ typedef enum {
#define NAND_CACHEPRG 0x00000008
/* Chip has copy back function */
#define NAND_COPYBACK 0x00000010
/*
* AND Chip which has 4 banks and a confusing page / block
* assignment. See Renesas datasheet for further information.
*/
#define NAND_IS_AND 0x00000020
/*
* Chip has a array of 4 pages which can be read without
* additional ready /busy waits.
*/
#define NAND_4PAGE_ARRAY 0x00000040
/*
* Chip requires that BBT is periodically rewritten to prevent
* bits from adjacent blocks from 'leaking' in altering data.
* This happens with the Renesas AG-AND chips, possibly others.
*/
#define BBT_AUTO_REFRESH 0x00000080
/*
* Chip requires ready check on read (for auto-incremented sequential read).
* True only for small page devices; large page devices do not support
Expand Down

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