[PATCH 1/4] mtd: rawnand: cadence: get meta data size from registers

[Piotr Sroka]

Add checking size of BCH meta data size in capabilities registers
instead of using fixed value. BCH meta data is used to keep data
from nand flash oob area.

Signed-off-by: Piotr Sroka <piotrs@xxxxxxxxxxx>
---
 .../mtd/nand/raw/cadence-nand-controller.c    | 21 ++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/nand/raw/cadence-nand-controller.c b/drivers/mtd/nand/raw/cadence-nand-controller.c
index f6c7102a1e32..5063a8b493a4 100644
--- a/drivers/mtd/nand/raw/cadence-nand-controller.c
+++ b/drivers/mtd/nand/raw/cadence-nand-controller.c
@@ -30,7 +30,6 @@
  * Generic mode is used for executing rest of commands.
  */
 
-#define MAX_OOB_SIZE_PER_SECTOR	32
 #define MAX_ADDRESS_CYC		6
 #define MAX_ERASE_ADDRESS_CYC	3
 #define MAX_DATA_SIZE		0xFFFC
@@ -190,6 +189,7 @@
 
 /* BCH Engine identification register 3. */
 #define BCH_CFG_3				0x844
+#define		BCH_CFG_3_METADATA_SIZE		GENMASK(23, 16)
 
 /* Ready/Busy# line status. */
 #define RBN_SETINGS				0x1004
@@ -499,6 +499,7 @@ struct cdns_nand_ctrl {
 
 	unsigned long assigned_cs;
 	struct list_head chips;
+	u8 bch_metadata_size;
 };
 
 struct cdns_nand_chip {
@@ -1077,6 +1078,14 @@ static int cadence_nand_read_bch_caps(struct cdns_nand_ctrl *cdns_ctrl)
 	int max_step_size = 0, nstrengths, i;
 	u32 reg;
 
+	reg = readl_relaxed(cdns_ctrl->reg + BCH_CFG_3);
+	cdns_ctrl->bch_metadata_size = FIELD_GET(BCH_CFG_3_METADATA_SIZE, reg);
+	if (cdns_ctrl->bch_metadata_size < 4) {
+		dev_err(cdns_ctrl->dev,
+			"Driver needs at least 4 bytes of BCH meta data\n");
+		return -EIO;
+	}
+
 	reg = readl_relaxed(cdns_ctrl->reg + BCH_CFG_0);
 	cdns_ctrl->ecc_strengths[0] = FIELD_GET(BCH_CFG_0_CORR_CAP_0, reg);
 	cdns_ctrl->ecc_strengths[1] = FIELD_GET(BCH_CFG_0_CORR_CAP_1, reg);
@@ -1170,7 +1179,8 @@ static int cadence_nand_hw_init(struct cdns_nand_ctrl *cdns_ctrl)
 	writel_relaxed(0xFFFFFFFF, cdns_ctrl->reg + INTR_STATUS);
 
 	cadence_nand_get_caps(cdns_ctrl);
-	cadence_nand_read_bch_caps(cdns_ctrl);
+	if (cadence_nand_read_bch_caps(cdns_ctrl))
+		return -EIO;
 
 	/*
 	 * Set IO width access to 8.
@@ -2587,7 +2597,6 @@ int cadence_nand_attach_chip(struct nand_chip *chip)
 	struct cdns_nand_chip *cdns_chip = to_cdns_nand_chip(chip);
 	u32 ecc_size = cdns_chip->sector_count * chip->ecc.bytes;
 	struct mtd_info *mtd = nand_to_mtd(chip);
-	u32 max_oob_data_size;
 	int ret;
 
 	if (chip->options & NAND_BUSWIDTH_16) {
@@ -2628,10 +2637,8 @@ int cadence_nand_attach_chip(struct nand_chip *chip)
 
 	cdns_chip->avail_oob_size = mtd->oobsize - ecc_size;
 
-	max_oob_data_size = MAX_OOB_SIZE_PER_SECTOR;
-
-	if (cdns_chip->avail_oob_size > max_oob_data_size)
-		cdns_chip->avail_oob_size = max_oob_data_size;
+	if (cdns_chip->avail_oob_size > cdns_ctrl->bch_metadata_size)
+		cdns_chip->avail_oob_size = cdns_ctrl->bch_metadata_size;
 
 	if ((cdns_chip->avail_oob_size + cdns_chip->bbm_len + ecc_size)
 	    > mtd->oobsize)
-- 
2.17.1