[RFC PATCH v5 5/6] mtd: rawnand: meson: check buffer length

Arseniy Krasnov
2023-06-01T06:24:16Z

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>
---
Changelog v4->v5:
* Move length checks from functions 'meson_nfc_read/write_buf()' to
'meson_nfc_exec_op()'.

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 23a73268421b..2a91916566f4 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;
}
@@ -573,7 +575,7 @@ 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);
@@ -597,7 +599,7 @@ static int meson_nfc_write_buf(struct nand_chip *nand, u8 *buf, int len)
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);
@@ -1044,6 +1046,9 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
break;

case NAND_OP_DATA_IN_INSTR:
+ if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
+ return -EINVAL;
+
buf = meson_nand_op_get_dma_safe_input_buf(instr);
if (!buf)
return -ENOMEM;
@@ -1052,6 +1057,9 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
break;

case NAND_OP_DATA_OUT_INSTR:
+ if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
+ return -EINVAL;
+
buf = meson_nand_op_get_dma_safe_output_buf(instr);
if (!buf)
return -ENOMEM;
@@ -1293,6 +1301,7 @@ 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) {
@@ -1304,6 +1313,13 @@ 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