From: Uwe Kleine-König Date: Wed, 13 May 2015 08:17:36 +0000 (+0300) Subject: mtd: mxc_nand: cleanup copy_spare function X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=35d5d20efad8;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git mtd: mxc_nand: cleanup copy_spare function To give people without the reference manual at hand a chance to understand how spare area is handled in the i.MX nand controller, improve commenting, naming of variables and coding style. No functional change intended. Reviewed-by: Sascha Hauer Signed-off-by: Uwe Kleine-König [baruch: declare oob_chunk_size; update comments; reword commit log] Signed-off-by: Baruch Siach Signed-off-by: Brian Norris --- diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c index 2c46489eeee0..5bbc1c5062bc 100644 --- a/drivers/mtd/nand/mxc_nand.c +++ b/drivers/mtd/nand/mxc_nand.c @@ -807,32 +807,48 @@ 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 i, oob_chunk_size; + 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; if (bfrom) { - for (i = 0; i < n - 1; i++) - memcpy32_fromio(d + i * j, s + i * t, j); - - /* the last section */ - memcpy32_fromio(d + i * j, s + i * t, mtd->oobsize - i * 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 chunk */ + 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); - - /* the last section */ - memcpy32_toio(&s[i * t], &d[i * j], mtd->oobsize - i * 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 chunk */ + memcpy32_toio(&s[oob_chunk_size * sparebuf_size], + &d[i * oob_chunk_size], + mtd->oobsize - i * oob_chunk_size); } }