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

[Cédric Le Goater]

On 05/16/2017 03:30 PM, Adriana Kobylak wrote:
> 
>> On May 16, 2017, at 1:01 AM, Cédric Le Goater <clg at kaod.org <mailto:clg at kaod.org>> wrote:
>>
>> On 05/15/2017 02:41 AM, Adriana Kobylak wrote:
>>>
>>>> On May 13, 2017, at 3:49 PM, Cédric Le Goater <clg at kaod.org <mailto: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 <mailto: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?
>>
>> Well, what if the BMC is using a flash module with a 4K erase size ? 
> 
> All the mtd devices except PNOR in the P8 and P9 systems running openbmc 
> have already an erase size of 64K.

So everything is fine for these.

Cheers,

C. 


> Ex witherspoon:
> root at witherspoon:~# cat /proc/mtd 
> dev:    size   erasesize  name
> mtd0: 02000000 00010000 "bmc"
> mtd1: 00060000 00010000 "u-boot"
> mtd2: 00020000 00010000 "u-boot-env"
> mtd3: 00440000 00010000 "kernel"
> mtd4: 01740000 00010000 "rofs"
> mtd5: 00400000 00010000 "rwfs"
> mtd6: 02000000 00010000 "alt"
> mtd7: 08000000 00001000 “pnor”
> 
> Ex barreleye:
> root at barreleye:~# cat /proc/mtd 
> dev:    size   erasesize  name
> mtd0: 02000000 00010000 "bmc"
> mtd1: 00060000 00010000 "u-boot"
> mtd2: 00020000 00010000 "u-boot-env"
> mtd3: 00440000 00010000 "kernel"
> mtd4: 01740000 00010000 "rofs"
> mtd5: 00400000 00010000 "rwfs"
> mtd6: 04000000 00001000 "pnor"
> 
>>
>> C.
>