[PATCH 2/3] mtd: rawnand: sunxi: support randomized OOB formats

[James Hilliard]

The controller randomizer covers the bad block marker along with the
rest of the OOB data. The driver currently compensates the marker bytes
before writes and after reads so that they remain plain on flash.

Allwinner NAND firmware instead stores the marker through the
randomizer. Media using that format appears to contain bad blocks unless
the randomizer is enabled while reading the marker.

Honor the allwinner,randomized-oob property by unconditionally enabling
page scrambling and leaving the marker in the randomizer data stream.
Keep the existing plain marker behavior when the property is absent.
This changes marker handling on all supported controllers; the H6/H616
protected user-data placement is handled separately.

Signed-off-by: James Hilliard <james.hilliard1 at gmail.com>
---
 drivers/mtd/nand/raw/sunxi_nand.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/sunxi_nand.c b/drivers/mtd/nand/raw/sunxi_nand.c
index 45ccbce91551..92b26371a6d1 100644
--- a/drivers/mtd/nand/raw/sunxi_nand.c
+++ b/drivers/mtd/nand/raw/sunxi_nand.c
@@ -264,6 +264,7 @@ struct sunxi_nfc_timings {
  * @clk_rate: clk_rate required for this NAND chip
  * @timing_cfg: TIMING_CFG register value for this NAND chip
  * @timing_ctl: TIMING_CTL register value for this NAND chip
+ * @randomized_oob: use the randomized normal-page OOB format
  * @nsels: number of CS lines required by the NAND chip
  * @sels: array of CS lines descriptions
  * @user_data_bytes: array of user data lengths for all ECC steps
@@ -276,6 +277,7 @@ struct sunxi_nand_chip {
 	u32 timing_cfg;
 	u32 timing_ctl;
 	u8 *user_data_bytes;
+	bool randomized_oob;
 	int nsels;
 	struct sunxi_nand_chip_sel sels[] __counted_by(nsels);
 };
@@ -945,7 +947,8 @@ static void sunxi_nfc_hw_ecc_get_prot_oob_bytes(struct nand_chip *nand, u8 *oob,
 	}
 
 	/* De-randomize the Bad Block Marker. */
-	if (bbm && (nand->options & NAND_NEED_SCRAMBLING))
+	if (bbm && (nand->options & NAND_NEED_SCRAMBLING) &&
+	    !sunxi_nand->randomized_oob)
 		sunxi_nfc_randomize_bbm(nand, page, oob);
 }
 
@@ -1006,7 +1009,8 @@ static void sunxi_nfc_hw_ecc_set_prot_oob_bytes(struct nand_chip *nand,
 	u8 *user_data = NULL;
 
 	/* Randomize the Bad Block Marker. */
-	if (bbm && (nand->options & NAND_NEED_SCRAMBLING)) {
+	if (bbm && (nand->options & NAND_NEED_SCRAMBLING) &&
+	    !sunxi_nand->randomized_oob) {
 		user_data = kmalloc(user_data_sz, GFP_KERNEL);
 		memcpy(user_data, oob, user_data_sz);
 		sunxi_nfc_randomize_bbm(nand, page, user_data);
@@ -2219,6 +2223,7 @@ static int sunxi_nand_hw_ecc_ctrl_init(struct nand_chip *nand,
 
 static int sunxi_nand_attach_chip(struct nand_chip *nand)
 {
+	struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(nand);
 	const struct nand_ecc_props *requirements =
 		nanddev_get_ecc_requirements(&nand->base);
 	struct nand_ecc_ctrl *ecc = &nand->ecc;
@@ -2228,6 +2233,9 @@ static int sunxi_nand_attach_chip(struct nand_chip *nand)
 	if (nand->bbt_options & NAND_BBT_USE_FLASH)
 		nand->bbt_options |= NAND_BBT_NO_OOB;
 
+	if (sunxi_nand->randomized_oob)
+		nand->options |= NAND_NEED_SCRAMBLING;
+
 	if (nand->options & NAND_NEED_SCRAMBLING)
 		nand->options |= NAND_NO_SUBPAGE_WRITE;
 
@@ -2457,6 +2465,9 @@ static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
 	if (!sunxi_nand)
 		return -ENOMEM;
 
+	sunxi_nand->randomized_oob =
+		of_property_read_bool(np, "allwinner,randomized-oob");
+
 	sunxi_nand->nsels = nsels;
 
 	for (i = 0; i < nsels; i++) {

-- 
2.53.0