[PATCH linux dev-4.7] arm: configs: aspeed: Disable CONFIG_MTD_SPI_NOR_USE_4K_SECTORS

[Adriana Kobylak]

> On May 13, 2017, at 3:49 PM, Cédric Le Goater <clg at kaod.org> wrote:
> 
> On 05/11/2017 02:12 PM, Joel Stanley wrote:
>> On Thu, May 11, 2017 at 7:31 AM, Adriana Kobylak
>> <anoo at linux.vnet.ibm.com> wrote:
>>> Milton stopped by and mentioned that you had tried to modify the 4K erase
>>> sector previously for a perhaps bmc chip and saw some flash corruption when
>>> moving to an image that changed it?
>>> 
>>> Just wanted to add that this change only changes the pnor setting and I
>>> didn’t see any issues powering on a system after updating the BMC with an
>>> image with this change. Then I updated the pnor with an image that had the
>>> mbox enabled. Also checked with AndrewJ and the hostboot team and there’s no
>>> hard-coded assumptions in their side about the erase size.
>>> 
>>> With all this info let me know if you have any thoughts or concerns.
>> 
>> I recall issues relating to this option. I didn't record what they were 
>> though.
> 
> We tried to activate 4K erase on some chips, which supported it, 
> and that the OpenPOWER systems use. That was because the PNOR 
> sections were not aligned with the erase size and that caused 
> some issues in pflash. But it breaks the compatibility with 
> previously created jffs2 filesystems. jffs2 stores the erase 
> size. So we stepped back.
> 
>> Cedric, can you remind me what the issues are with the 4K kconfig option?
> 
> CONFIG_MTD_SPI_NOR_USE_4K_SECTORS enables the 4K erase commands, 
> and without it, the driver will use the sector erase command, most
> likely 64K. I suppose we could have the same problem as described 
> above, as it can change the default erase size of a chip. to be
> checked.
> 
Thanks Cedric for the info. It appears there are no issues when disabling the 4K sectors for the pnor chip (yes, the erase size is then 64K), probably because the pnor is not formatted with a jffs2 filesystem. We might need to clear the pnor chip anyways to be able to format it as a UBI volume. So would you say we’re ok with this patch?

> Cheers,
> 
> C. 
>