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

[Lei YU]

On Tue, May 16, 2017 at 9:59 PM, Cédric Le Goater <clg at kaod.org> wrote:
> 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.

The same question as Cedric, PNOR has sections that are not 64K
aligned but 4K aligned,
e.g. HBEL, GARD:
ID=02            HBEL 000a0000..000c4000 (actual=00024000) [ECC]
ID=03           GUARD 000d0000..000d5000 (actual=00005000) [ECC]

When using gard tool to clear GARD partition, it will fail if erasing
size is 64K.

Do we have a plan to support this case?

>>>>>
>>>> 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.
>>
>