Commit 8fc82d45 authored by Hans de Goede's avatar Hans de Goede Committed by Boris Brezillon

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: default avatarHans de Goede <hdegoede@redhat.com>
Acked-by: default avatarRichard Weinberger <richard@nod.at>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 3b5206f4
...@@ -66,6 +66,26 @@ static void samsung_nand_decode_id(struct nand_chip *chip) ...@@ -66,6 +66,26 @@ static void samsung_nand_decode_id(struct nand_chip *chip)
extid >>= 2; extid >>= 2;
mtd->erasesize = (128 * 1024) << mtd->erasesize = (128 * 1024) <<
(((extid >> 1) & 0x04) | (extid & 0x03)); (((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 { } else {
nand_decode_ext_id(chip); nand_decode_ext_id(chip);
} }
......
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