[PATCH V2 2/4] mtd: nand: mxs_nand_spl: Fix bad block skipping
Michael Nazzareno Trimarchi
michael at amarulasolutions.com
Thu Apr 28 07:01:14 CEST 2022
Hi
On Thu, Apr 28, 2022 at 2:27 AM Han Xu <han.xu at nxp.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Michael Trimarchi <michael at amarulasolutions.com>
> > Sent: Wednesday, April 27, 2022 12:50 AM
> > To: Han Xu <han.xu at nxp.com>; U-Boot-Denx <u-boot at lists.denx.de>
> > Cc: Ye Li <ye.li at nxp.com>; Stefano Babic <sbabic at denx.de>; Miquel Raynal
> > <miquel.raynal at bootlin.com>; Fabio Estevam <festevam at denx.de>; Dario
> > Binacchi <dario.binacchi at amarulasolutions.com>; Sean Anderson
> > <sean.anderson at seco.com>; linux-kernel at amarulasolutions.com; Jagan Teki
> > <jagan at amarulasolutions.com>; Ariel D'Alessandro
> > <ariel.dalessandro at collabora.com>; Fabio Estevam <festevam at gmail.com>
> > Subject: [PATCH V2 2/4] mtd: nand: mxs_nand_spl: Fix bad block skipping
> >
> > The specific implementation was having bug. Those bugs are since the beginning
> > of the implementation. Some manufactures can receive this bug in their SPL code.
> > This bug start to be more visible on architecture that has complicated boot
> > process like imx8mn. Older version of uboot has the same problem only if the
> > bad block appear in correspoding of befine of u-boot image. In order to adjust
> > the function we scan from the first block. The logic is not changed to have a
> > simple way to fix without get regression.
> >
> > The problematic part of old code was in this part:
> >
> > while (is_badblock(mtd, offs, 1)) {
> > page = page + nand_page_per_block;
> > /* Check i we've reached the end of flash. */
> > if (page >= mtd->size >> chip->page_shift) {
> > free(page_buf);
> > return -ENOMEM;
> > }
> > }
> >
> > Even we fix it adding increment of the offset of one erase block size we don't fix
> > the problem, because the first erase block where the image start is not checked.
>
> Could you please describe more details about your test? Thanks.
Suppose you have a badblock on 5 or 6. Let's start to have only 6
and you write uboot from 5 and let's the uboot be enough big to cover 5, 6, 7, 8
Case 1)
When you write the block 6 the code will skip it as bad during
programming. THe image of uboot (or flash.bin) will
be on 5 7 8 9, because the 6 is skipped. The while loop on spl will
read (from raw offset the 5) and then he will found the
bad block on next erase block in the while loop and will exists at the
end of the flash because the test
is done on the offset and not on the page that is not incremented
Case 2)
Now same example but let's suppose to have block 5 bad. So you write
your image and it will start
from a raw offset 5 but it will be written starting from 6. The spl
loader will fail because it will not skip
the first block and then will fail anyway to read the image. The patch
try to fix the above behavior
Case 3) can be any combination
Michael
>
> > The code was tested on an imx8mn where the boot rom api was not able to skip
> > it. Apart of that other architecure are using this code and all boards that has
> > nand as boot device can be affected
> >
> > Cc: Han Xu <han.xu at nxp.com>
> > Cc: Fabio Estevam <festevam at gmail.com>
> > Signed-off-by: Michael Trimarchi <michael at amarulasolutions.com>
> > ---
> > V1->V2:
> > - Adjust the commit message
> > - Add Cc Han Xu and Fabio
> > - fix size >= 0 to > 0
> > ---
> > drivers/mtd/nand/raw/mxs_nand_spl.c | 90 ++++++++++++++++-------------
> > 1 file changed, 49 insertions(+), 41 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/raw/mxs_nand_spl.c
> > b/drivers/mtd/nand/raw/mxs_nand_spl.c
> > index 59a67ee414..2bfb181007 100644
> > --- a/drivers/mtd/nand/raw/mxs_nand_spl.c
> > +++ b/drivers/mtd/nand/raw/mxs_nand_spl.c
> > @@ -218,14 +218,14 @@ void nand_init(void)
> > mxs_nand_setup_ecc(mtd);
> > }
> >
> > -int nand_spl_load_image(uint32_t offs, unsigned int size, void *buf)
> > +int nand_spl_load_image(uint32_t offs, unsigned int size, void *dst)
> > {
> > - struct nand_chip *chip;
> > - unsigned int page;
> > + unsigned int sz;
> > + unsigned int block, lastblock;
> > + unsigned int page, page_offset;
> > unsigned int nand_page_per_block;
> > - unsigned int sz = 0;
> > + struct nand_chip *chip;
> > u8 *page_buf = NULL;
> > - u32 page_off;
> >
> > chip = mtd_to_nand(mtd);
> > if (!chip->numchips)
> > @@ -235,47 +235,42 @@ int nand_spl_load_image(uint32_t offs, unsigned int
> > size, void *buf)
> > if (!page_buf)
> > return -ENOMEM;
> >
> > - page = offs >> chip->page_shift;
> > - page_off = offs & (mtd->writesize - 1);
> > + /* offs has to be aligned to a page address! */
> > + block = offs / mtd->erasesize;
> > + lastblock = (offs + size - 1) / mtd->erasesize;
> > + page = (offs % mtd->erasesize) / mtd->writesize;
> > + page_offset = offs % mtd->writesize;
> > nand_page_per_block = mtd->e
Copy Link
MA
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rasesize / mtd->writesize;
> >
> > - debug("%s offset:0x%08x len:%d page:%x\n", __func__, offs, size, page);
> > -
> > - while (size) {
> > - if (mxs_read_page_ecc(mtd, page_buf, page) < 0)
> > - return -1;
> > -
> > - if (size > (mtd->writesize - page_off))
> > - sz = (mtd->writesize - page_off);
> > - else
> > - sz = size;
> > -
> > - memcpy(buf, page_buf + page_off, sz);
> > -
> > - offs += mtd->writesize;
> > - page++;
> > - buf += (mtd->writesize - page_off);
> > - page_off = 0;
> > - size -= sz;
> > -
> > - /*
> > - * Check if we have crossed a block boundary, and if so
> > - * check for bad block.
> > - */
> > - if (!(page % nand_page_per_block)) {
> > - /*
> > - * Yes, new block. See if this block is good. If not,
> > - * loop until we find a good block.
> > - */
> > - while (is_badblock(mtd, offs, 1)) {
> > - page = page + nand_page_per_block;
> > - /* Check i we've reached the end of flash. */
> > - if (page >= mtd->size >> chip->page_shift) {
> > + while (block <= lastblock && size > 0) {
> > + if (!is_badblock(mtd, mtd->erasesize * block, 1)) {
> > + /* Skip bad blocks */
> > + while (page < nand_page_per_block) {
> > + int curr_page = nand_page_per_block * block +
> > page;
> > +
> > + if (mxs_read_page_ecc(mtd, page_buf, curr_page)
> > < 0) {
> > free(page_buf);
> > - return -ENOMEM;
> > + return -EIO;
> > }
> > +
> > + if (size > (mtd->writesize - page_offset))
> > + sz = (mtd->writesize - page_offset);
> > + else
> > + sz = size;
> > +
> > + memcpy(dst, page_buf + page_offset, sz);
> > + dst += sz;
> > + size -= sz;
> > + page_offset = 0;
> > + page++;
> > }
> > +
> > + page = 0;
> > + } else {
> > + lastblock++;
> > }
> > +
> > + block++;
> > }
> >
> > free(page_buf);
> > @@ -294,6 +289,19 @@ void nand_deselect(void)
> >
> > u32 nand_spl_adjust_offset(u32 sector, u32 offs) {
> > - /* Handle the offset adjust in nand_spl_load_image,*/
> > + unsigned int block, lastblock;
> > +
> > + block = sector / mtd->erasesize;
> > + lastblock = (sector + offs) / mtd->erasesize;
> > +
> > + while (block <= lastblock) {
> > + if (is_badblock(mtd, block * mtd->erasesize, 1)) {
> > + offs += mtd->erasesize;
> > + lastblock++;
> > + }
> > +
> > + block++;
> > + }
> > +
> > return offs;
> > }
> > --
> > 2.25.1
>
--
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael at amarulasolutions.com
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