[MTD] OneNAND: Implement read-while-load
Read-while-load enables higher performance read operations.
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index e80857b..abbe160 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -727,40 +727,47 @@
/* TODO handling oob */
stats = mtd->ecc_stats;
- while (read < len) {
- cond_resched();
- thislen = min_t(int, mtd->writesize, len - read);
+ /* Read-while-load method */
- column = from & (mtd->writesize - 1);
- if (column + thislen > mtd->writesize)
- thislen = mtd->writesize - column;
+ /* Do first load to bufferRAM */
+ if (read < len) {
+ if (!onenand_check_bufferram(mtd, from)) {
+ this->command(mtd, ONENAND_CMD_READ, from, mtd->writesize);
+ ret = this->wait(mtd, FL_READING);
+ onenand_update_bufferram(mtd, from, !ret);
+ }
+ }
- if (!onenand_check_bufferram(mtd, from)) {
- this->command(mtd, ONENAND_CMD_READ, from, mtd->writesize);
+ thislen = min_t(int, mtd->writesize, len - read);
+ column = from & (mtd->writesize - 1);
+ if (column + thislen > mtd->writesize)
+ thislen = mtd->writesize - column;
- ret = this->wait(mtd, FL_READING);
- /* First copy data and check return value for ECC handling */
- onenand_update_bufferram(mtd, from, !ret);
- }
+ while (!ret) {
+ /* If there is more to load then start next load */
+ from += thislen;
+ if (read + thislen < len) {
+ this->command(mtd, ONENAND_CMD_READ, from, mtd->writesize);
+ ONENAND_SET_PREV_BUFFERRAM(this);
+ }
+ /* While load is going, read from last bufferRAM */
+ this->read_bufferram(mtd, ONENAND_DATARAM, buf, column, thislen);
+ /* See if we are done */
+ read += thislen;
+ if (read == len)
+ break;
+ /* Set up for next read from bufferRAM */
+ ONENAND_SET_NEXT_BUFFERRAM(this);
+ buf += thislen;
+ thislen = min_t(int, mtd->writesize, len - read);
+ column = 0;
+ cond_resched();
+ /* Now wait for load */
+ ret = this->wait(mtd, FL_READING);
+ onenand_update_bufferram(mtd, from, !ret);
+ }
- this->read_bufferram(mtd, ONENAND_DATARAM, buf, column, thislen);
-
- if (ret) {
- DEBUG(MTD_DEBUG_LEVEL0, "onenand_read: read failed = %d\n", ret);
- goto out;
- }
-
- read += thislen;
-
- if (read == len)
- break;
-
- from += thislen;
- buf += thislen;
- }
-
-out:
/* Deselect and wake up anyone waiting on the device */
onenand_release_device(mtd);
@@ -774,6 +781,9 @@
if (mtd->ecc_stats.failed - stats.failed)
return -EBADMSG;
+ if (ret)
+ return ret;
+
return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
}