From 8fc82d456e40a073d7e85d7825a345698f4b5a40 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Wed, 8 Jun 2016 10:45:28 +0200 Subject: [PATCH] mtd: nand: samsung: Retrieve ECC requirements from extended ID On some nand controllers with hw-ecc the controller code wants to know the ecc strength and size and having these as 0, 0 is not accepted. Specifying these in devicetree is possible but undesirable as the nand may be different in different production runs of the same board, so it is better to get this info from the nand id where possible. This commit adds code to read the ecc strength and size from the nand for Samsung extended-id nands. This code is based on the info for the 5th id byte in the datasheets for the following Samsung nands: K9GAG08U0E, K9GAG08U0F, K9GAG08X0D, K9GBG08U0A, K9GBG08U0B. These all use these bits in the exact same way. Signed-off-by: Hans de Goede Acked-by: Richard Weinberger Signed-off-by: Boris Brezillon --- drivers/mtd/nand/nand_samsung.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/mtd/nand/nand_samsung.c b/drivers/mtd/nand/nand_samsung.c index 5c259dd5b652..9cfc4035a420 100644 --- a/drivers/mtd/nand/nand_samsung.c +++ b/drivers/mtd/nand/nand_samsung.c @@ -66,6 +66,26 @@ static void samsung_nand_decode_id(struct nand_chip *chip) extid >>= 2; mtd->erasesize = (128 * 1024) << (((extid >> 1) & 0x04) | (extid & 0x03)); + + /* Extract ECC requirements from 5th id byte*/ + extid = (chip->id.data[4] >> 4) & 0x07; + if (extid < 5) { + chip->ecc_step_ds = 512; + chip->ecc_strength_ds = 1 << extid; + } else { + chip->ecc_step_ds = 1024; + switch (extid) { + case 5: + chip->ecc_strength_ds = 24; + break; + case 6: + chip->ecc_strength_ds = 40; + break; + case 7: + chip->ecc_strength_ds = 60; + break; + } + } } else { nand_decode_ext_id(chip); }