| Message ID | 1490861708-27813-4-git-send-email-yamada.masahiro@socionext.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
Hi Boris, 2017-03-30 17:15 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>: > 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> > --- > > I was hit by this problem when I ran > # mount -t jffs2 /dev/mtdblock* /mnt > > The buffer passed to nand_do_*_ops has 4 byte offset. > The Denali IP cannot do DMA to/from this buffer because it > requires 16 byte alignment for DMA. > > > Changes in v3: > - Newly added > > Changes in v2: None > > drivers/mtd/nand/nand_base.c | 12 ++++++++---- > include/linux/mtd/nand.h | 2 ++ > 2 files changed, 10 insertions(+), 4 deletions(-) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index e9d3195..b528ffa 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -1953,9 +1953,10 @@ 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); > - else > + else if (chip->options & NAND_USE_BOUNCE_BUFFER) { > + use_bufpoi = !virt_addr_valid(buf) || > + !IS_ALIGNED((unsigned long)buf, chip->buf_align); > + } else > use_bufpoi = 0; I noticed I added unneeded braces here by mistake. (When I was testing this part, I inserted printk here, then I forgot to remove the {} . ) Can you fix-up it? If requested, I can re-send it. -- Best Regards Masahiro Yamada
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index e9d3195..b528ffa 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -1953,9 +1953,10 @@ 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); - else + else if (chip->options & NAND_USE_BOUNCE_BUFFER) { + use_bufpoi = !virt_addr_valid(buf) || + !IS_ALIGNED((unsigned long)buf, chip->buf_align); + } else use_bufpoi = 0; /* Is the current page in the buffer? */ @@ -2810,7 +2811,8 @@ 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; @@ -3426,6 +3428,8 @@ static void nand_set_defaults(struct nand_chip *chip, int busw) nand_hw_control_init(chip->controller); } + if (!chip->buf_align) + chip->buf_align = 1; } /* Sanitize ONFI strings so we can safely print them */ diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 69cccd1..2ae781e 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -750,6 +750,7 @@ 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 @@ -901,6 +902,7 @@ struct nand_chip { struct nand_ecc_ctrl ecc; struct nand_buffers *buffers; + unsigned long buf_align; struct nand_hw_control hwcontrol; uint8_t *bbt;
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> --- I was hit by this problem when I ran # mount -t jffs2 /dev/mtdblock* /mnt The buffer passed to nand_do_*_ops has 4 byte offset. The Denali IP cannot do DMA to/from this buffer because it requires 16 byte alignment for DMA. Changes in v3: - Newly added Changes in v2: None drivers/mtd/nand/nand_base.c | 12 ++++++++---- include/linux/mtd/nand.h | 2 ++ 2 files changed, 10 insertions(+), 4 deletions(-) -- 2.7.4