[PATCH 2/3] [MTD] [OneNAND] Add write-while-program support

Kyungmin Park
2009-03-03T06:37:18Z

It's similar with read-while-program method.
but it's write side performance improvement.

Here's brief performance results.
Note: Measured from OMAP3 with async OneNAND mode. (not sync mode)

=================================================================
speedtest: dev = 3
speedtest: Size=16777216 EB size=131072 Write size=2048 EB count=128
Pages per EB=64 Page size=2048
speedtest: scanning for bad blocks
speedtest: scanned 0
speedtest: scanned 128, found 0 bad
speedtest: erasing
speedtest: erased 0
speedtest: erased 128
speedtest: Testing eraseblock write speed
eraseblock write speed is 2592 KiB/s
speedtest: Testing eraseblock read speed
eraseblock read speed is 16786 KiB/s
speedtest: Testing page write speed
page write speed is 2966 KiB/s
speedtest: Testing page read speed
page read speed is 13277 KiB/s
speedtest: Testing 2 page write speed
2 page write speed is 3182 KiB/s
speedtest: Testing 2 page read speed
2 page read speed is 14773 KiB/s
speedtest: Testing erase speed
erase speed is 192752 KiB/s
speedtest: speedtest finished
=================================================================

Also it's passed all nand-tests.

>From Adrian

I have made a couple of tiny changes and tested this. I get
a 10% - 25% improvement in write speed when writing more than
1 page.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
---
drivers/mtd/onenand/onenand_base.c | 145 ++++++++++++++++++++++++------------
1 files changed, 96 insertions(+), 49 deletions(-)

diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 4481df7..7af863a 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -1778,7 +1778,8 @@ 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;
@@ -1805,6 +1806,10 @@ 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
@@ -1815,79 +1820,121 @@ 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;
}
--
1.5.3.3