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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>

[Linux commit: 477544c62a84d3bacd9f90ba75ffc16c04d78071]
This commit is contained in:
Masahiro Yamada 2017-11-22 02:38:27 +09:00
parent c7c553f249
commit 436fb2b84d
2 changed files with 10 additions and 0 deletions
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8
drivers/mtd/nand/nand_base.c
View File

@ -1720,6 +1720,9 @@ 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 = !IS_ALIGNED((unsigned long)buf,
chip->buf_align);
else
use_bufpoi = 0;
@ -2575,6 +2578,9 @@ 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 = !IS_ALIGNED((unsigned long)buf,
chip->buf_align);
else
use_bufpoi = 0;
@ -3119,6 +3125,8 @@ static void nand_set_defaults(struct nand_chip *chip, int busw)
init_waitqueue_head(&chip->controller->wq);
}
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

@ -752,6 +752,7 @@ nand_get_sdr_timings(const struct nand_data_interface *conf)
* 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
@ -893,6 +894,7 @@ struct nand_chip {
struct nand_ecc_ctrl ecc;
struct nand_buffers *buffers;
unsigned long buf_align;
struct nand_hw_control hwcontrol;
uint8_t *bbt;