[PATCH v2] mtd: spi-nor: Fix chip erase timeout issue

[Marek Vasut]

On 9/13/24 8:29 AM, Ye Li wrote:
> Chip erase support was added to spi_nor_erase, but the timeout
> for polling SR ready is not updated and still for sector erase.
> So the timeout value is not enough for chip erase on some NOR flash.
> Follow kernel implementation 09b6a377687b ("mtd: spi-nor: scale up
> timeout for full-chip erase") to set new timeout for chip erase.
> 
> Fixes: b91a0822d752 ("mtd: spi-nor: Add CHIP_ERASE optimization")
> 
> Signed-off-by: Ye Li <ye.li at nxp.com>
> ---
> Changes in v2:
>   - use do_div for u64
>   - Keep the variables in reverse xmas-tree
>   - Add kernel commit info
>   
>   drivers/mtd/spi/spi-nor-core.c | 21 ++++++++++++++++++++-
>   1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
> index ce01d42cfe0f..83335b235605 100644
> --- a/drivers/mtd/spi/spi-nor-core.c
> +++ b/drivers/mtd/spi/spi-nor-core.c
> @@ -45,6 +45,12 @@
>   
>   #define DEFAULT_READY_WAIT_JIFFIES		(40UL * HZ)
>   
> +/*
> + * For full-chip erase, calibrated to a 2MB flash (M25P16); should be scaled up
> + * for larger flash
> + */
> +#define CHIP_ERASE_2MB_READY_WAIT_JIFFIES	(40UL * HZ)
> +
>   #define ROUND_UP_TO(x, y)	(((x) + (y) - 1) / (y) * (y))
>   
>   struct sfdp_parameter_header {
> @@ -990,7 +996,9 @@ static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
>   static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
>   {
>   	struct spi_nor *nor = mtd_to_spi_nor(mtd);
> +	unsigned long timeout = 0;

Set this to = DEFAULT_READY_WAIT_JIFFIES; instead of = 0;

>   	bool addr_known = false;
> +	u64 sz = mtd->size;
>   	u32 addr, len, rem;
>   	int ret, err;
>   
> @@ -1028,6 +1036,14 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
>   		if (len == mtd->size &&
>   		    !(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
>   			ret = spi_nor_erase_chip(nor);
> +			/*
> +			 * Scale the timeout linearly with the size of the flash, with
> +			 * a minimum calibrated to an old 2MB flash. We could try to
> +			 * pull these from CFI/SFDP, but these values should be good
> +			 * enough for now.
> +			 */
> +			do_div(sz, SZ_2M);
> +			timeout = CHIP_ERASE_2MB_READY_WAIT_JIFFIES * max(1ULL, sz);
>   		} else {
>   			ret = spi_nor_erase_sector(nor, addr);
>   		}
> @@ -1037,7 +1053,10 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
>   		addr += ret;
>   		len -= ret;
>   
> -		ret = spi_nor_wait_till_ready(nor);

Finally, do a simple:

ret = spi_nor_wait_till_ready_with_timeout(nor, timeout);

here, no need for if/else statement anymore.

> +		if (timeout)
> +			ret = spi_nor_wait_till_ready_with_timeout(nor, timeout);
> +		else
> +			ret = spi_nor_wait_till_ready(nor);
>   		if (ret)
>   			goto erase_err;
>   	}

That should simplify the code I hope.