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[MTD] [OneNAND] Add write-while-program support
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OneNAND write-while-program method of writing improves performance,
compared with ordinary writes, by transferring data to OneNAND's
RAM buffers atthe same time as programming the NAND core.

When writing several NAND pages at a time, an improvement of
12% to 25% is seen.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Kyungmin Park authored and David Woodhouse committed Mar 23, 2009
1 parent a29f280 commit 9ce9690
Showing 1 changed file with 96 additions and 49 deletions.
145 changes: 96 additions & 49 deletions drivers/mtd/onenand/onenand_base.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1455,7 +1455,8 @@ static int onenand_write_ops_nolock(struct mtd_info *mtd, loff_t to,
struct mtd_oob_ops *ops)
{
struct onenand_chip *this = mtd->priv;
int written = 0, column, thislen, subpage;
int written = 0, column, thislen = 0, subpage = 0;
int prev = 0, prevlen = 0, prev_subpage = 0, first = 1;
int oobwritten = 0, oobcolumn, thisooblen, oobsize;
size_t len = ops->len;
size_t ooblen = ops->ooblen;
Expand All @@ -1482,6 +1483,10 @@ static int onenand_write_ops_nolock(struct mtd_info *mtd, loff_t to,
return -EINVAL;
}

/* Check zero length */
if (!len)
return 0;

if (ops->mode == MTD_OOB_AUTO)
oobsize = this->ecclayout->oobavail;
else
Expand All @@ -1492,79 +1497,121 @@ static int onenand_write_ops_nolock(struct mtd_info *mtd, loff_t to,
column = to & (mtd->writesize - 1);

/* Loop until all data write */
while (written < len) {
u_char *wbuf = (u_char *) buf;
while (1) {
if (written < len) {
u_char *wbuf = (u_char *) buf;

thislen = min_t(int, mtd->writesize - column, len - written);
thisooblen = min_t(int, oobsize - oobcolumn, ooblen - oobwritten);
thislen = min_t(int, mtd->writesize - column, len - written);
thisooblen = min_t(int, oobsize - oobcolumn, ooblen - oobwritten);

cond_resched();
cond_resched();

this->command(mtd, ONENAND_CMD_BUFFERRAM, to, thislen);
this->command(mtd, ONENAND_CMD_BUFFERRAM, to, thislen);

/* Partial page write */
subpage = thislen < mtd->writesize;
if (subpage) {
memset(this->page_buf, 0xff, mtd->writesize);
memcpy(this->page_buf + column, buf, thislen);
wbuf = this->page_buf;
}
/* Partial page write */
subpage = thislen < mtd->writesize;
if (subpage) {
memset(this->page_buf, 0xff, mtd->writesize);
memcpy(this->page_buf + column, buf, thislen);
wbuf = this->page_buf;
}

this->write_bufferram(mtd, ONENAND_DATARAM, wbuf, 0, mtd->writesize);
this->write_bufferram(mtd, ONENAND_DATARAM, wbuf, 0, mtd->writesize);

if (oob) {
oobbuf = this->oob_buf;
if (oob) {
oobbuf = this->oob_buf;

/* We send data to spare ram with oobsize
* to prevent byte access */
memset(oobbuf, 0xff, mtd->oobsize);
if (ops->mode == MTD_OOB_AUTO)
onenand_fill_auto_oob(mtd, oobbuf, oob, oobcolumn, thisooblen);
else
memcpy(oobbuf + oobcolumn, oob, thisooblen);
/* We send data to spare ram with oobsize
* to prevent byte access */
memset(oobbuf, 0xff, mtd->oobsize);
if (ops->mode == MTD_OOB_AUTO)
onenand_fill_auto_oob(mtd, oobbuf, oob, oobcolumn, thisooblen);
else
memcpy(oobbuf + oobcolumn, oob, thisooblen);

oobwritten += thisooblen;
oob += thisooblen;
oobcolumn = 0;
oobwritten += thisooblen;
oob += thisooblen;
oobcolumn = 0;
} else
oobbuf = (u_char *) ffchars;

this->write_bufferram(mtd, ONENAND_SPARERAM, oobbuf, 0, mtd->oobsize);
} else
oobbuf = (u_char *) ffchars;
ONENAND_SET_NEXT_BUFFERRAM(this);

this->write_bufferram(mtd, ONENAND_SPARERAM, oobbuf, 0, mtd->oobsize);
/*
* 2 PLANE, MLC, and Flex-OneNAND doesn't support
* write-while-programe feature.
*/
if (!ONENAND_IS_2PLANE(this) && !first) {
ONENAND_SET_PREV_BUFFERRAM(this);

this->command(mtd, ONENAND_CMD_PROG, to, mtd->writesize);
ret = this->wait(mtd, FL_WRITING);

ret = this->wait(mtd, FL_WRITING);
/* In partial page write we don't update bufferram */
onenand_update_bufferram(mtd, prev, !ret && !prev_subpage);
if (ret) {
written -= prevlen;
printk(KERN_ERR "onenand_write_ops_nolock: write filaed %d\n", ret);
break;
}

/* In partial page write we don't update bufferram */
onenand_update_bufferram(mtd, to, !ret && !subpage);
if (ONENAND_IS_2PLANE(this)) {
ONENAND_SET_BUFFERRAM1(this);
onenand_update_bufferram(mtd, to + this->writesize, !ret && !subpage);
}
if (written == len) {
/* Only check verify write turn on */
ret = onenand_verify(mtd, buf - len, to - len, len);
if (ret)
printk(KERN_ERR "onenand_write_ops_nolock: verify failed %d\n", ret);
break;
}

if (ret) {
printk(KERN_ERR "onenand_write_ops_nolock: write filaed %d\n", ret);
break;
ONENAND_SET_NEXT_BUFFERRAM(this);
}

/* Only check verify write turn on */
ret = onenand_verify(mtd, buf, to, thislen);
if (ret) {
printk(KERN_ERR "onenand_write_ops_nolock: verify failed %d\n", ret);
break;
}
this->command(mtd, ONENAND_CMD_PROG, to, mtd->writesize);

written += thislen;
/*
* 2 PLANE, MLC, and Flex-OneNAND wait here
*/
if (ONENAND_IS_2PLANE(this)) {
ret = this->wait(mtd, FL_WRITING);

if (written == len)
break;
/* In partial page write we don't update bufferram */
onenand_update_bufferram(mtd, to, !ret && !subpage);
if (ret) {
printk(KERN_ERR "onenand_write_ops_nolock: write filaed %d\n", ret);
break;
}

/* Only check verify write turn on */
ret = onenand_verify(mtd, buf, to, thislen);
if (ret) {
printk(KERN_ERR "onenand_write_ops_nolock: verify failed %d\n", ret);
break;
}

written += thislen;

if (written == len)
break;

} else
written += thislen;

column = 0;
prev_subpage = subpage;
prev = to;
prevlen = thislen;
to += thislen;
buf += thislen;
first = 0;
}

/* In error case, clear all bufferrams */
if (written != len)
onenand_invalidate_bufferram(mtd, 0, -1);

ops->retlen = written;
ops->oobretlen = oobwritten;

return ret;
}
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