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mtd: nand: allow drivers to request minimum alignment for passed buffer

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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: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit is contained in:
Masahiro Yamada 2017-03-30 17:15:05 +09:00 committed by Boris Brezillon
parent 3deb9979c7
commit 477544c62a
2 changed files with 10 additions and 2 deletions
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10
drivers/mtd/nand/nand_base.c
View File

@ -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 */

2
include/linux/mtd/nand.h
View File

@ -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;