[PATCH 4.15 072/105] mtd: nand: fsl_ifc: Fix eccstat array overflow for IFC ver >= 2.0.0

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jagdish Gediya <jagdish.gediya@xxxxxxx>

commit 843c3a59997f18060848b8632607dd04781b52d1 upstream.

Number of ECC status registers i.e. (ECCSTATx) has been increased in IFC
version 2.0.0 due to increase in SRAM size. This is causing eccstat
array to over flow.

So, replace eccstat array with u32 variable to make it fail-safe and
independent of number of ECC status registers or SRAM size.

Fixes: bccb06c353af ("mtd: nand: ifc: update bufnum mask for ver >= 2.0.0")
Cc: stable@xxxxxxxxxxxxxxx # 3.18+
Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@xxxxxxx>
Signed-off-by: Jagdish Gediya <jagdish.gediya@xxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mtd/nand/fsl_ifc_nand.c |   23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

--- a/drivers/mtd/nand/fsl_ifc_nand.c
+++ b/drivers/mtd/nand/fsl_ifc_nand.c
@@ -173,14 +173,9 @@ static void set_addr(struct mtd_info *mt
 
 /* returns nonzero if entire page is blank */
 static int check_read_ecc(struct mtd_info *mtd, struct fsl_ifc_ctrl *ctrl,
-			  u32 *eccstat, unsigned int bufnum)
+			  u32 eccstat, unsigned int bufnum)
 {
-	u32 reg = eccstat[bufnum / 4];
-	int errors;
-
-	errors = (reg >> ((3 - bufnum % 4) * 8)) & 15;
-
-	return errors;
+	return  (eccstat >> ((3 - bufnum % 4) * 8)) & 15;
 }
 
 /*
@@ -193,7 +188,7 @@ static void fsl_ifc_run_command(struct m
 	struct fsl_ifc_ctrl *ctrl = priv->ctrl;
 	struct fsl_ifc_nand_ctrl *nctrl = ifc_nand_ctrl;
 	struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;
-	u32 eccstat[4];
+	u32 eccstat;
 	int i;
 
 	/* set the chip select for NAND Transaction */
@@ -228,8 +223,8 @@ static void fsl_ifc_run_command(struct m
 	if (nctrl->eccread) {
 		int errors;
 		int bufnum = nctrl->page & priv->bufnum_mask;
-		int sector = bufnum * chip->ecc.steps;
-		int sector_end = sector + chip->ecc.steps - 1;
+		int sector_start = bufnum * chip->ecc.steps;
+		int sector_end = sector_start + chip->ecc.steps - 1;
 		__be32 *eccstat_regs;
 
 		if (ctrl->version >= FSL_IFC_VERSION_2_0_0)
@@ -237,10 +232,12 @@ static void fsl_ifc_run_command(struct m
 		else
 			eccstat_regs = ifc->ifc_nand.v1_nand_eccstat;
 
-		for (i = sector / 4; i <= sector_end / 4; i++)
-			eccstat[i] = ifc_in32(&eccstat_regs[i]);
+		eccstat = ifc_in32(&eccstat_regs[sector_start / 4]);
+
+		for (i = sector_start; i <= sector_end; i++) {
+			if (i != sector_start && !(i % 4))
+				eccstat = ifc_in32(&eccstat_regs[i / 4]);
 
-		for (i = sector; i <= sector_end; i++) {
 			errors = check_read_ecc(mtd, ctrl, eccstat, i);
 
 			if (errors == 15) {