i.MX25 NFC with 8 bit ecc strength
Baruch Siach
baruch at tkos.co.il
Wed Apr 22 02:20:43 PDT 2015
Hi Uwe,
On Tue, Apr 21, 2015 at 09:39:36AM +0200, Uwe Kleine-König wrote:
> While understanding the problem I produced the following (untested)
> patch:
I intend to use this patch as part of a series fixing the large oob issue. Can
you add your SoB please?
Thanks,
baruch
> diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
> index dca63a70e783..fc835d352e1c 100644
> --- a/drivers/mtd/nand/mxc_nand.c
> +++ b/drivers/mtd/nand/mxc_nand.c
> @@ -807,32 +807,49 @@ static void mxc_nand_select_chip_v2(struct mtd_info *mtd, int chip)
> }
>
> /*
> - * Function to transfer data to/from spare area.
> + * The controller splits a page into data chunks of 512 bytes + partial oob.
> + * There are writesize / 512 such chunks, the size of the partial oob parts is
> + * oobsize / #chunks rounded down to a multiple of 2. The last oob chunk then
> + * contains additionally the byte lost by rounding (if any).
> + * This function handles the needed shuffling between host->data_buf (which
> + * holds a page in natural order, i.e. writesize bytes data + oobsize bytes
> + * spare) and the NFC buffer.
> */
> static void copy_spare(struct mtd_info *mtd, bool bfrom)
> {
> struct nand_chip *this = mtd->priv;
> struct mxc_nand_host *host = this->priv;
> u16 i, j;
> - u16 n = mtd->writesize >> 9;
> +
> + u16 num_chunks = mtd->writesize / 512;
> +
> u8 *d = host->data_buf + mtd->writesize;
> u8 __iomem *s = host->spare0;
> - u16 t = host->devtype_data->spare_len;
> + u16 sparebuf_size = host->devtype_data->spare_len;
>
> - j = (mtd->oobsize / n >> 1) << 1;
> + /* size of oob chunk for all but possibly the last one */
> + oob_chunk_size = (mtd->oobsize / num_chunks >> 1) << 1;
>
> if (bfrom) {
> - for (i = 0; i < n - 1; i++)
> - memcpy32_fromio(d + i * j, s + i * t, j);
> + for (i = 0; i < num_chunks - 1; i++)
> + memcpy32_fromio(d + i * oob_chunk_size,
> + s + i * sparebuf_size,
> + oob_chunk_size);
>
> /* the last section */
> - memcpy32_fromio(d + i * j, s + i * t, mtd->oobsize - i * j);
> + memcpy32_fromio(d + i * oob_chunk_size,
> + s + i * sparebuf_size,
> + mtd->oobsize - i * oob_chunk_size);
> } else {
> - for (i = 0; i < n - 1; i++)
> - memcpy32_toio(&s[i * t], &d[i * j], j);
> + for (i = 0; i < num_chunks - 1; i++)
> + memcpy32_toio(&s[i * sparebuf_size],
> + &d[i * oob_chunk_size],
> + oob_chunk_size);
>
> /* the last section */
> - memcpy32_toio(&s[i * t], &d[i * j], mtd->oobsize - i * j);
> + memcpy32_toio(&s[oob_chunk_size * sparebuf_size],
> + &d[i * oob_chunk_size],
> + mtd->oobsize - i * oob_chunk_size);
> }
> }
--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
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