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

[Marek Vasut]

On 9/11/24 12:45 PM, 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 to set new timeout for chip erase.

Is there a matching Linux kernel commit you could point to, from which 
this was ported over ?

> Fixes: b91a0822d752 ("mtd: spi-nor: Add CHIP_ERASE optimization")
> 
> Signed-off-by: Ye Li <ye.li at nxp.com>
> ---
>   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 aea611fef523..338e5856337e 100644
> --- a/drivers/mtd/spi/spi-nor-core.c
> +++ b/drivers/mtd/spi/spi-nor-core.c
> @@ -44,6 +44,12 @@
>   
>   #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 {
> @@ -991,6 +997,7 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
>   	bool addr_known = false;
>   	u32 addr, len, rem;
>   	int ret, err;
> +	unsigned long timeout = 0;

Keep the variables in reverse xmas-tree please.

>   	dev_dbg(nor->dev, "at 0x%llx, len %lld\n", (long long)instr->addr,
>   		(long long)instr->len);
> @@ -1026,6 +1033,15 @@ 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.
> +			 */
> +			timeout = max(CHIP_ERASE_2MB_READY_WAIT_JIFFIES,
> +				      CHIP_ERASE_2MB_READY_WAIT_JIFFIES *
> +				      (unsigned long)(mtd->size / SZ_2M));
Is the type cast needed ?

Thanks