[PATCH v4 4/5] mtd: rawnand: meson: check buffer length

Arseniy Krasnov
2023-05-15T09:50:18Z

This NAND controller has limited buffer length, so check it before
command execution to avoid length trim. Also check MTD write size on
chip attach.

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
---
drivers/mtd/nand/raw/meson_nand.c | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index a31106c943d7..dc0d7160520b 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -111,6 +111,8 @@
#define NFC_USER_BYTES 2
#define NFC_OOB_PER_ECC(nand) ((nand)->ecc.bytes + NFC_USER_BYTES)

+#define NFC_CMD_RAW_LEN GENMASK(13, 0)
+
struct meson_nfc_nand_chip {
struct list_head node;
struct nand_chip nand;
@@ -284,7 +286,7 @@ static void meson_nfc_cmd_access(struct nand_chip *nand, int raw, bool dir,

if (raw) {
len = mtd->writesize + mtd->oobsize;
- cmd = (len & GENMASK(13, 0)) | scrambler | DMA_DIR(dir);
+ cmd = len | scrambler | DMA_DIR(dir);
writel(cmd, nfc->reg_base + NFC_REG_CMD);
return;
}
@@ -562,6 +564,9 @@ static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
u32 cmd;
u8 *info;

+ if (len > NFC_CMD_RAW_LEN)
+ return -EINVAL;
+
info = kzalloc(PER_INFO_BYTE, GFP_KERNEL);
if (!info)
return -ENOMEM;
@@ -571,7 +576,7 @@ static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
if (ret)
goto out;

- cmd = NFC_CMD_N2M | (len & GENMASK(13, 0));
+ cmd = NFC_CMD_N2M | len;
writel(cmd, nfc->reg_base + NFC_REG_CMD);

meson_nfc_drain_cmd(nfc);
@@ -590,12 +595,15 @@ static int meson_nfc_write_buf(struct nand_chip *nand, u8 *buf, int len)
int ret = 0;
u32 cmd;

+ if (len > NFC_CMD_RAW_LEN)
+ return -EINVAL;
+
ret = meson_nfc_dma_buffer_setup(nand, buf, len, NULL,
0, DMA_TO_DEVICE);
if (ret)
return ret;

- cmd = NFC_CMD_M2N | (len & GENMASK(13, 0));
+ cmd = NFC_CMD_M2N | len;
writel(cmd, nfc->reg_base + NFC_REG_CMD);

meson_nfc_drain_cmd(nfc);
@@ -1328,6 +1336,7 @@ static int meson_nand_attach_chip(struct nand_chip *nand)
struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
struct mtd_info *mtd = nand_to_mtd(nand);
int nsectors = mtd->writesize / 1024;
+ int raw_writesize;
int ret;

if (!mtd->name) {
@@ -1339,6 +1348,13 @@ static int meson_nand_attach_chip(struct nand_chip *nand)
return -ENOMEM;
}

+ raw_writesize = mtd->writesize + mtd->oobsize;
+ if (raw_writesize > NFC_CMD_RAW_LEN) {
+ dev_err(nfc->dev, "too big write size in raw mode: %d > %ld\n",
+ raw_writesize, NFC_CMD_RAW_LEN);
+ return -EINVAL;
+ }
+
if (nand->bbt_options & NAND_BBT_USE_FLASH)
nand->bbt_options |= NAND_BBT_NO_OOB;

--
2.35.0