> From: Ezequiel Garcia [...] > But: on the other hand, I'd really like you to convince me as to > why is it so bad to require the DTB to have the proper GPMC bus width. > No its not at all bad, all I want is either of the one way (not mixture of both). - Either depend on DT completely (which is current case for all drivers) - OR depend on ONFI and nand_flash_id[] for bus-width detection. > Once again: > 1. the NAND devices aren't hot-pluggable > 2. the "user" (who is actually an engineer, not some regular dummy user) > knows perfectly well the width of the device. > > What's the problem with describing the hardware in the DT and saving us > lots of runtime re-configuration trouble? I agree with both your arguments above. So shouldn't we kill NAND_BUSWIDTH_AUTO ? And probably therefore NAND_BUSWIDTH_AUTO isn't that popular. Now what remains is ONFI probe, which should always happen in x8 mode. So for that below patch should be sufficient .. ---------------------- diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index ec1db1e..d1220fb 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2942,14 +2942,8 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, chip->read_byte(mtd) != 'F' || chip->read_byte(mtd) != 'I') return 0; - /* - * ONFI must be probed in 8-bit mode or with NAND_BUSWIDTH_AUTO, not - * with NAND_BUSWIDTH_16 - */ - if (chip->options & NAND_BUSWIDTH_16) { - pr_err("ONFI cannot be probed in 16-bit mode; aborting\n"); - return 0; - } + /* ONFI must be probed in 8-bit mode only */ + nand_set_defaults(chip, 0); chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1); for (i = 0; i < 3; i++) { @@ -2962,7 +2956,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, if (i == 3) { pr_err("Could not find valid ONFI parameter page; aborting\n"); - return 0; + goto return_error; } /* Check version */ @@ -2980,7 +2974,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, if (!chip->onfi_version) { pr_info("%s: unsupported ONFI version: %d\n", __func__, val); - return 0; + goto return_error; } sanitize_string(p->manufacturer, sizeof(p->manufacturer)); @@ -3033,6 +3027,12 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, } return 1; + +return_error: + /* revert original bus-width */ + nand_set_defaults( chip->options & NAND_BUSWIDTH_16); + return 0; + } /* ------------------------- with regards, pekon ��.n��������+%������w��{.n�����{�������ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f