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Commit a8de85d5 authored by Adrian Hunter's avatar Adrian Hunter Committed by Artem Bityutskiy
Browse files

[MTD] OneNAND: Implement read-while-load 



Read-while-load enables higher performance read operations.

Signed-off-by: default avatarAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
parent 2fd32d4a

drivers/mtd/onenand/onenand_base.c

+42 −32
Original line number Original line Diff line number Diff line
@@ -727,40 +727,47 @@ static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len, 
	/* TODO handling oob */

	/* TODO handling oob */





	stats = mtd->ecc_stats;

	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)) {

 		if (!onenand_check_bufferram(mtd, from)) {

 			this->command(mtd, ONENAND_CMD_READ, from, mtd->writesize);

 			this->command(mtd, ONENAND_CMD_READ, from, mtd->writesize);



 			ret = this->wait(mtd, FL_READING);

 			ret = this->wait(mtd, FL_READING);

			/* First copy data and check return value for ECC handling */

 			onenand_update_bufferram(mtd, from, !ret);

 			onenand_update_bufferram(mtd, from, !ret);

 		}

 		}

 	}





		this->read_bufferram(mtd, ONENAND_DATARAM, buf, column, thislen);

 	thislen = min_t(int, mtd->writesize, len - read);

 	column = from & (mtd->writesize - 1);

 	if (column + thislen > mtd->writesize)

 		thislen = mtd->writesize - column;





		if (ret) {

 	while (!ret) {

			DEBUG(MTD_DEBUG_LEVEL0, "onenand_read: read failed = %d\n", ret);

 		/* If there is more to load then start next load */

			goto out;

 		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;

 		read += thislen;



 		if (read == len)

 		if (read == len)

 			break;

 			break;



 		/* Set up for next read from bufferRAM */

		from += thislen;

 		ONENAND_SET_NEXT_BUFFERRAM(this);

 		buf += thislen;

 		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);

 	}

 	}





out:

	/* Deselect and wake up anyone waiting on the device */

	/* Deselect and wake up anyone waiting on the device */

	onenand_release_device(mtd);

	onenand_release_device(mtd);
@@ -774,6 +781,9 @@ static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len, 
	if (mtd->ecc_stats.failed - stats.failed)

	if (mtd->ecc_stats.failed - stats.failed)

		return -EBADMSG;

		return -EBADMSG;





	if (ret)

		return ret;



	return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;

	return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;

}

}

include/linux/mtd/onenand.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -143,6 +143,7 @@ struct onenand_chip { 
#define ONENAND_CURRENT_BUFFERRAM(this)		(this->bufferram_index)

#define ONENAND_CURRENT_BUFFERRAM(this)		(this->bufferram_index)

#define ONENAND_NEXT_BUFFERRAM(this)		(this->bufferram_index ^ 1)

#define ONENAND_NEXT_BUFFERRAM(this)		(this->bufferram_index ^ 1)

#define ONENAND_SET_NEXT_BUFFERRAM(this)	(this->bufferram_index ^= 1)

#define ONENAND_SET_NEXT_BUFFERRAM(this)	(this->bufferram_index ^= 1)

#define ONENAND_SET_PREV_BUFFERRAM(this)	(this->bufferram_index ^= 1)





#define ONENAND_GET_SYS_CFG1(this)					\

#define ONENAND_GET_SYS_CFG1(this)					\

	(this->read_word(this->base + ONENAND_REG_SYS_CFG1))

	(this->read_word(this->base + ONENAND_REG_SYS_CFG1))