diff options
Diffstat (limited to 'drivers/mtd/nand/atmel/nand-controller.c')
| -rw-r--r-- | drivers/mtd/nand/atmel/nand-controller.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/mtd/nand/atmel/nand-controller.c b/drivers/mtd/nand/atmel/nand-controller.c index 2c8baa0c2c4e..ceec21bd30c4 100644 --- a/drivers/mtd/nand/atmel/nand-controller.c +++ b/drivers/mtd/nand/atmel/nand-controller.c @@ -1364,7 +1364,18 @@ static int atmel_smc_nand_prepare_smcconf(struct atmel_nand *nand, ret = atmel_smc_cs_conf_set_timing(smcconf, ATMEL_HSMC_TIMINGS_TADL_SHIFT, ncycles); - if (ret) + /* + * Version 4 of the ONFI spec mandates that tADL be at least 400 + * nanoseconds, but, depending on the master clock rate, 400 ns may not + * fit in the tADL field of the SMC reg. We need to relax the check and + * accept the -ERANGE return code. + * + * Note that previous versions of the ONFI spec had a lower tADL_min + * (100 or 200 ns). It's not clear why this timing constraint got + * increased but it seems most NANDs are fine with values lower than + * 400ns, so we should be safe. + */ + if (ret && ret != -ERANGE) return ret; ncycles = DIV_ROUND_UP(conf->timings.sdr.tAR_min, mckperiodps); |