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Commit 477544c6 authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Boris Brezillon
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mtd: nand: allow drivers to request minimum alignment for passed buffer 



In some cases, nand_do_{read,write}_ops is passed with unaligned
ops->datbuf.  Drivers using DMA will be unhappy about unaligned
buffer.

The new struct member, buf_align, represents the minimum alignment
the driver require for the buffer.  If the buffer passed from the
upper MTD layer does not have enough alignment, nand_do_*_ops will
use bufpoi.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 3deb9979

drivers/mtd/nand/nand_base.c

+8 −2
Original line number Diff line number Diff line
@@ -1954,7 +1954,9 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, 
		if (!aligned)

			use_bufpoi = 1;

		else if (chip->options & NAND_USE_BOUNCE_BUFFER)

			use_bufpoi = !virt_addr_valid(buf);

			use_bufpoi = !virt_addr_valid(buf) ||

				     !IS_ALIGNED((unsigned long)buf,

						 chip->buf_align);

		else

			use_bufpoi = 0;
@@ -2810,7 +2812,9 @@ static int nand_do_write_ops(struct mtd_info *mtd, loff_t to, 
		if (part_pagewr)

			use_bufpoi = 1;

		else if (chip->options & NAND_USE_BOUNCE_BUFFER)

			use_bufpoi = !virt_addr_valid(buf);

			use_bufpoi = !virt_addr_valid(buf) ||

				     !IS_ALIGNED((unsigned long)buf,

						 chip->buf_align);

		else

			use_bufpoi = 0;
@@ -3429,6 +3433,8 @@ static void nand_set_defaults(struct nand_chip *chip) 
		nand_hw_control_init(chip->controller);

	}



	if (!chip->buf_align)

		chip->buf_align = 1;

}



/* Sanitize ONFI strings so we can safely print them */

include/linux/mtd/nand.h

+2 −0
Original line number Diff line number Diff line
@@ -755,6 +755,7 @@ struct nand_manufacturer_ops { 
 *			setting the read-retry mode. Mostly needed for MLC NAND.

 * @ecc:		[BOARDSPECIFIC] ECC control structure

 * @buffers:		buffer structure for read/write

 * @buf_align:		minimum buffer alignment required by a platform

 * @hwcontrol:		platform-specific hardware control structure

 * @erase:		[REPLACEABLE] erase function

 * @scan_bbt:		[REPLACEABLE] function to scan bad block table
@@ -905,6 +906,7 @@ struct nand_chip { 


	struct nand_ecc_ctrl ecc;

	struct nand_buffers *buffers;

	unsigned long buf_align;

	struct nand_hw_control hwcontrol;



	uint8_t *bbt;