mtd: nand: remove multiplied-by-2 block logic
The parent commit 771c568bcf915e708ae819ef9d07d862f7e2da86 ("mtd: nand: add
accessors, macros for in-memory BBT") makes the following comment obsolete:
/*
* Note that numblocks is 2 * (real numblocks) here, see i+=2
* below as it makes shifting and masking less painful
*/
I don't think it ever could have been "less painful" to have to shift an
extra bit (or 2, or 3) at various points in nand_bbt.c (and even
outside, since we leak our in-memory format). But now it is certainly
more painful, since we have nice macros and functions to retrieve the
relevant portions of the BBT.
This patch removes any points where the block number is
doubled/halved/otherwise-shifted, instead representing the block number
in its most natural form: as the actual block number.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 4c57a9b..3ff9d36 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -181,7 +181,7 @@
* @page: the starting page
* @num: the number of bbt descriptors to read
* @td: the bbt describtion table
- * @offs: offset in the memory table
+ * @offs: block number offset in the table
*
* Read the bad block table starting from page.
*/
@@ -231,15 +231,15 @@
/* Analyse data */
for (i = 0; i < len; i++) {
uint8_t dat = buf[i];
- for (j = 0; j < 8; j += bits, act += 2) {
+ for (j = 0; j < 8; j += bits, act++) {
uint8_t tmp = (dat >> j) & msk;
if (tmp == msk)
continue;
if (reserved_block_code && (tmp == reserved_block_code)) {
pr_info("nand_read_bbt: reserved block at 0x%012llx\n",
- (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
- bbt_mark_entry(this, (offs << 2) +
- (act >> 1),
+ (loff_t)(offs + act) <<
+ this->bbt_erase_shift);
+ bbt_mark_entry(this, offs + act,
BBT_BLOCK_RESERVED);
mtd->ecc_stats.bbtblocks++;
continue;
@@ -249,15 +249,14 @@
* move this message to pr_debug.
*/
pr_info("nand_read_bbt: bad block at 0x%012llx\n",
- (loff_t)((offs << 2) + (act >> 1)) << this->bbt_erase_shift);
+ (loff_t)(offs + act) <<
+ this->bbt_erase_shift);
/* Factory marked bad or worn out? */
if (tmp == 0)
- bbt_mark_entry(this, (offs << 2) +
- (act >> 1),
+ bbt_mark_entry(this, offs + act,
BBT_BLOCK_FACTORY_BAD);
else
- bbt_mark_entry(this, (offs << 2) +
- (act >> 1),
+ bbt_mark_entry(this, offs + act,
BBT_BLOCK_WORN);
mtd->ecc_stats.badblocks++;
}
@@ -293,7 +292,7 @@
td, offs);
if (res)
return res;
- offs += this->chipsize >> (this->bbt_erase_shift + 2);
+ offs += this->chipsize >> this->bbt_erase_shift;
}
} else {
res = read_bbt(mtd, buf, td->pages[0],
@@ -517,11 +516,7 @@
}
if (chip == -1) {
- /*
- * Note that numblocks is 2 * (real numblocks) here, see i+=2
- * below as it makes shifting and masking less painful
- */
- numblocks = mtd->size >> (this->bbt_erase_shift - 1);
+ numblocks = mtd->size >> this->bbt_erase_shift;
startblock = 0;
from = 0;
} else {
@@ -530,16 +525,16 @@
chip + 1, this->numchips);
return -EINVAL;
}
- numblocks = this->chipsize >> (this->bbt_erase_shift - 1);
+ numblocks = this->chipsize >> this->bbt_erase_shift;
startblock = chip * numblocks;
numblocks += startblock;
- from = (loff_t)startblock << (this->bbt_erase_shift - 1);
+ from = (loff_t)startblock << this->bbt_erase_shift;
}
if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
from += mtd->erasesize - (mtd->writesize * numpages);
- for (i = startblock; i < numblocks;) {
+ for (i = startblock; i < numblocks; i++) {
int ret;
BUG_ON(bd->options & NAND_BBT_NO_OOB);
@@ -554,13 +549,12 @@
return ret;
if (ret) {
- bbt_mark_entry(this, i >> 1, BBT_BLOCK_FACTORY_BAD);
+ bbt_mark_entry(this, i, BBT_BLOCK_FACTORY_BAD);
pr_warn("Bad eraseblock %d at 0x%012llx\n",
- i >> 1, (unsigned long long)from);
+ i, (unsigned long long)from);
mtd->ecc_stats.badblocks++;
}
- i += 2;
from += (1 << this->bbt_erase_shift);
}
return 0;
@@ -683,9 +677,9 @@
{
struct nand_chip *this = mtd->priv;
struct erase_info einfo;
- int i, j, res, chip = 0;
+ int i, res, chip = 0;
int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
- int nrchips, bbtoffs, pageoffs, ooboffs;
+ int nrchips, pageoffs, ooboffs;
uint8_t msk[4];
uint8_t rcode = td->reserved_block_code;
size_t retlen, len = 0;
@@ -775,8 +769,6 @@
default: return -EINVAL;
}
- bbtoffs = chip * (numblocks >> 2);
-
to = ((loff_t)page) << this->page_shift;
/* Must we save the block contents? */
@@ -841,16 +833,12 @@
buf[ooboffs + td->veroffs] = td->version[chip];
/* Walk through the memory table */
- for (i = 0; i < numblocks;) {
+ for (i = 0; i < numblocks; i++) {
uint8_t dat;
- dat = bbt_get_entry(this, (bbtoffs << 2) + i);
- for (j = 0; j < 4; j++, i++) {
- int sftcnt = (i << (3 - sft)) & sftmsk;
- /* Do not store the reserved bbt blocks! */
- buf[offs + (i >> sft)] &=
- ~(msk[dat & 0x03] << sftcnt);
- dat >>= 2;
- }
+ int sftcnt = (i << (3 - sft)) & sftmsk;
+ dat = bbt_get_entry(this, chip * numblocks + i);
+ /* Do not store the reserved bbt blocks! */
+ buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
}
memset(&einfo, 0, sizeof(einfo));
@@ -1053,12 +1041,12 @@
if (td->pages[i] == -1)
continue;
block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);
- block <<= 1;
- oldval = bbt_get_entry(this, block >> 1);
- bbt_mark_entry(this, block >> 1, BBT_BLOCK_RESERVED);
+ oldval = bbt_get_entry(this, block);
+ bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
if ((oldval != BBT_BLOCK_RESERVED) &&
td->reserved_block_code)
- nand_update_bbt(mtd, (loff_t)block << (this->bbt_erase_shift - 1));
+ nand_update_bbt(mtd, (loff_t)block <<
+ this->bbt_erase_shift);
continue;
}
update = 0;
@@ -1066,13 +1054,12 @@
block = ((i + 1) * nrblocks) - td->maxblocks;
else
block = i * nrblocks;
- block <<= 1;
for (j = 0; j < td->maxblocks; j++) {
- oldval = bbt_get_entry(this, block >> 1);
- bbt_mark_entry(this, block >> 1, BBT_BLOCK_RESERVED);
+ oldval = bbt_get_entry(this, block);
+ bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);
if (oldval != BBT_BLOCK_RESERVED)
update = 1;
- block += 2;
+ block++;
}
/*
* If we want reserved blocks to be recorded to flash, and some
@@ -1080,7 +1067,8 @@
* bbts. This should only happen once.
*/
if (update && td->reserved_block_code)
- nand_update_bbt(mtd, (loff_t)(block - 2) << (this->bbt_erase_shift - 1));
+ nand_update_bbt(mtd, (loff_t)(block - 1) <<
+ this->bbt_erase_shift);
}
}
@@ -1385,13 +1373,12 @@
int block;
uint8_t res;
- /* Get block number * 2 */
- block = (int)(offs >> (this->bbt_erase_shift - 1));
- res = bbt_get_entry(this, block >> 1);
+ block = (int)(offs >> this->bbt_erase_shift);
+ res = bbt_get_entry(this, block);
pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: "
"(block %d) 0x%02x\n",
- (unsigned int)offs, block >> 1, res);
+ (unsigned int)offs, block, res);
switch ((int)res) {
case BBT_BLOCK_GOOD: