@@ -32,6 +32,13 @@
/* NANDi BCH Controller properties */
#define NANDI_BCH_SECTOR_SIZE 1024
+/* BCH ECC sizes */
+static int bch_ecc_sizes[] = {
+ [BCH_18BIT_ECC] = 32,
+ [BCH_30BIT_ECC] = 54,
+ [BCH_NO_ECC] = 0,
+};
+
/* Bad Block Table (BBT) */
struct nandi_bbt_info {
uint32_t bbt_size; /* Size of bad-block table */
@@ -302,6 +309,25 @@ static void nandi_disable_interrupts(struct nandi_controller *nandi,
writel(val, nandi->base + NANDBCH_INT_EN);
}
+/* Select strongest ECC scheme compatible with OOB size */
+static int bch_set_ecc_auto(struct nandi_controller *nandi,
+ struct mtd_info *mtd)
+{
+ int oob_bytes_per_sector = mtd->oobsize / nandi->sectors_per_page;
+ int try_ecc_modes[] = { BCH_30BIT_ECC, BCH_18BIT_ECC, -1 };
+ int m, ecc_mode;
+
+ for (m = 0; try_ecc_modes[m] >= 0; m++) {
+ ecc_mode = try_ecc_modes[m];
+ if (oob_bytes_per_sector >= bch_ecc_sizes[ecc_mode]) {
+ nandi->bch_ecc_mode = ecc_mode;
+ return 0;
+ }
+ }
+
+ return -EINVAL;
+}
+
static void nandi_set_mtd_defaults(struct nandi_controller *nandi,
struct mtd_info *mtd, struct nand_chip *chip)
{
@@ -939,6 +965,23 @@ static int stm_nand_bch_probe(struct platform_device *pdev)
0x10000) ? true : false;
mtd->writebufsize = mtd->writesize;
+ /* Set ECC mode */
+ if (pdata->bch_ecc_cfg == BCH_ECC_AUTO) {
+ err = bch_set_ecc_auto(nandi, mtd);
+ if (err) {
+ dev_err(nandi->dev, "insufficient OOB for BCH ECC\n");
+ return err;
+ }
+ } else {
+ nandi->bch_ecc_mode = pdata->bch_ecc_cfg;
+ }
+
+ chip->ecc.size = NANDI_BCH_SECTOR_SIZE;
+ chip->ecc.bytes = mtd->oobsize;
+
+ info->ecclayout.eccbytes =
+ nandi->sectors_per_page * bch_ecc_sizes[nandi->bch_ecc_mode];
+
return 0;
}
Here we automatically select the strongest ECC scheme compatible with the size of the OOB. Signed-off-by: Lee Jones <lee.jones@linaro.org> --- drivers/mtd/nand/stm_nand_bch.c | 43 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+)