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author | 2015-05-13 11:17:36 +0300 | |
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committer | 2015-05-20 15:29:42 -0700 | |
commit | 35d5d20efad8a04c8c002c7f31241dff973977a6 (patch) | |
tree | 045dc48b80a78905640c6ff64f4429005ec151d2 | |
parent | mtd: brcmnand: do not make local variable static (diff) | |
download | linux-35d5d20efad8a04c8c002c7f31241dff973977a6.tar.gz linux-35d5d20efad8a04c8c002c7f31241dff973977a6.tar.bz2 linux-35d5d20efad8a04c8c002c7f31241dff973977a6.zip |
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 <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[baruch: declare oob_chunk_size; update comments; reword commit log]
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
-rw-r--r-- | drivers/mtd/nand/mxc_nand.c | 46 |
1 files changed, 31 insertions, 15 deletions
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); } } |