Re: [PATCH v2] mtd: rawnand: meson: check buffer length

[Arseniy Krasnov]

Sorry, here is changelog:
v1 -> v2:
* Move checks from 'switch/case' which executes commands in 'meson_nfc_exec_op()' to a special
  separated function 'meson_nfc_check_op()' which is called before commands processing.

On 06.06.2023 13:16, Arseniy Krasnov wrote:
> Meson 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@xxxxxxxxxxxxxx>
> ---
>  drivers/mtd/nand/raw/meson_nand.c | 47 +++++++++++++++++++++++++++----
>  1 file changed, 42 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
> index 23a73268421b..db6b18753071 100644
> --- a/drivers/mtd/nand/raw/meson_nand.c
> +++ b/drivers/mtd/nand/raw/meson_nand.c
> @@ -111,6 +111,8 @@
>  
>  #define PER_INFO_BYTE		8
>  
> +#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);
> @@ -1007,6 +1009,31 @@ meson_nand_op_put_dma_safe_output_buf(const struct nand_op_instr *instr,
>  		kfree(buf);
>  }
>  
> +static int meson_nfc_check_op(struct nand_chip *chip,
> +			      const struct nand_operation *op)
> +{
> +	int op_id;
> +
> +	for (op_id = 0; op_id < op->ninstrs; op_id++) {
> +		const struct nand_op_instr *instr;
> +
> +		instr = &op->instrs[op_id];
> +
> +		switch (instr->type) {
> +		case NAND_OP_DATA_IN_INSTR:
> +		case NAND_OP_DATA_OUT_INSTR:
> +			if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
> +				return -ENOTSUPP;
> +
> +			break;
> +		default:
> +			break;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static int meson_nfc_exec_op(struct nand_chip *nand,
>  			     const struct nand_operation *op, bool check_only)
>  {
> @@ -1015,10 +1042,12 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
>  	const struct nand_op_instr *instr = NULL;
>  	void *buf;
>  	u32 op_id, delay_idle, cmd;
> +	int err;
>  	int i;
>  
> -	if (check_only)
> -		return 0;
> +	err = meson_nfc_check_op(nand, op);
> +	if (err || check_only)
> +		return err;
>  
>  	meson_nfc_select_chip(nand, op->cs);
>  	for (op_id = 0; op_id < op->ninstrs; op_id++) {
> @@ -1293,6 +1322,7 @@ 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 +1334,13 @@ 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;
>