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authorBrian Norris <computersforpeace@gmail.com>2016-04-25 22:53:55 -0700
committerBoris Brezillon <boris.brezillon@free-electrons.com>2016-05-05 23:55:15 +0200
commit666b65683dad9aa90efaa4aad24ef3710101e3aa (patch)
treec784f713f3cbf7c94aede09cf6008666ed020060 /drivers
parentbd2e778c9ee361c23ccb2b10591712e129d97893 (diff)
downloadlinux-666b65683dad9aa90efaa4aad24ef3710101e3aa.tar.gz
mtd: brcmnand: respect ECC algorithm set by NAND subsystem
This is more obvious than guessing based on ECC strength. It allows
using NAND on devices with BCH-1 (e.g. D-Link DIR-885L).

This maintains DT backward compatibility by defaulting to Hamming if a
1-bit ECC algorithm is specified without a corresponding algorithm
selection. i.e., to use BCH-1, you must specify:

  nand-ecc-strength = <1>;
  nand-ecc-step-size = <512>;
  nand-ecc-algo = "bch";

Also adds a check to ensure we haven't allowed someone to get by with SW
ECC. If we want to support SW ECC, we need to refactor some other pieces
of this driver.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/mtd/nand/brcmnand/brcmnand.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index c3331ffcaffd..b76ad7c0144f 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -1925,9 +1925,31 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
 	cfg->col_adr_bytes = 2;
 	cfg->blk_adr_bytes = get_blk_adr_bytes(mtd->size, mtd->writesize);
 
+	if (chip->ecc.mode != NAND_ECC_HW) {
+		dev_err(ctrl->dev, "only HW ECC supported; selected: %d\n",
+			chip->ecc.mode);
+		return -EINVAL;
+	}
+
+	if (chip->ecc.algo == NAND_ECC_UNKNOWN) {
+		if (chip->ecc.strength == 1 && chip->ecc.size == 512)
+			/* Default to Hamming for 1-bit ECC, if unspecified */
+			chip->ecc.algo = NAND_ECC_HAMMING;
+		else
+			/* Otherwise, BCH */
+			chip->ecc.algo = NAND_ECC_BCH;
+	}
+
+	if (chip->ecc.algo == NAND_ECC_HAMMING && (chip->ecc.strength != 1 ||
+						   chip->ecc.size != 512)) {
+		dev_err(ctrl->dev, "invalid Hamming params: %d bits per %d bytes\n",
+			chip->ecc.strength, chip->ecc.size);
+		return -EINVAL;
+	}
+
 	switch (chip->ecc.size) {
 	case 512:
-		if (chip->ecc.strength == 1) /* Hamming */
+		if (chip->ecc.algo == NAND_ECC_HAMMING)
 			cfg->ecc_level = 15;
 		else
 			cfg->ecc_level = chip->ecc.strength;