[U-Boot] [PATCH] configs: Remove CONFIG_SPL_FS_EXT4 for all MX6 platforms

[Marek Vasut]

On 5/26/19 1:46 PM, Lukasz Majewski wrote:
> Hi Tom,
> 
>> On Sun, May 26, 2019 at 10:22:00AM +0200, Lukasz Majewski wrote:
>>> Dear Marek, Tom,
>>>   
>>>> On 5/26/19 1:23 AM, Tom Rini wrote:  
>>>>> On Sun, May 26, 2019 at 01:20:34AM +0200, Marek Vasut wrote:    
>>>>>> On 5/26/19 1:08 AM, Tom Rini wrote:    
>>>>>>> On Sun, May 26, 2019 at 12:57:08AM +0200, Marek Vasut
>>>>>>> wrote:    
>>>>>>>> On 5/26/19 12:45 AM, Ezequiel Garcia wrote:    
>>>>>>>>> On Sun, 2019-05-26 at 00:24 +0200, Marek Vasut wrote:    
>>>>>>>>>> On 5/25/19 11:47 PM, Ezequiel Garcia wrote:    
>>>>>>>>>>> On Sat, 2019-05-25 at 22:15 +0200, Marek Vasut wrote:    
>>>>>>>>>>>> On 5/25/19 6:49 PM, Ezequiel Garcia wrote:    
>>>>>>>>>>>>> i.MX6 platforms boot U-Boot second-stage from
>>>>>>>>>>>>> unformatted space, and should not need Ext filesystem
>>>>>>>>>>>>> support on SPL.
>>>>>>>>>>>>>
>>>>>>>>>>>>> The commit was generated with:
>>>>>>>>>>>>>
>>>>>>>>>>>>> git grep -l MX6 -- configs/ | xargs grep -l SPL_FS_EXT4
>>>>>>>>>>>>> | xargs sed -i -e '/CONFIG_SPL_FS_EXT4=y/d'
>>>>>>>>>>>>>
>>>>>>>>>>>>> This change has a dramatic impact on SPL size:
>>>>>>>>>>>>>
>>>>>>>>>>>>> ./scripts/bloat-o-meter old new
>>>>>>>>>>>>> add/remove: 0/59 grow/shrink: 0/3 up/down: 0/-8674
>>>>>>>>>>>>> (-8674) [..]
>>>>>>>>>>>>> Total: Before=38320, After=29646, chg -22.64%
>>>>>>>>>>>>>
>>>>>>>>>>>>> Cc: Otavio Salvador <otavio at ossystems.com.br>
>>>>>>>>>>>>> Cc: Fabio Estevam <fabio.estevam at nxp.com>
>>>>>>>>>>>>> Cc: Peng Fan <peng.fan at nxp.com>
>>>>>>>>>>>>> Cc: Marek Vasut <marex at denx.de>
>>>>>>>>>>>>> Cc: Stefano Babic <sbabic at denx.de>
>>>>>>>>>>>>> Cc: Stefan Roese <sr at denx.de>
>>>>>>>>>>>>> Cc: "Eric Bénard" <eric at eukrea.com>
>>>>>>>>>>>>> Cc: Breno Lima <breno.lima at nxp.com>
>>>>>>>>>>>>> Cc: Francesco Montefoschi
>>>>>>>>>>>>> <francesco.montefoschi at udoo.org> Signed-off-by:
>>>>>>>>>>>>> Ezequiel Garcia <ezequiel at collabora.com> ---
>>>>>>>>>>>>> Tested on Wandboard only. Maintainers, please ACK or
>>>>>>>>>>>>> NAK!
>>>>>>>>>>>>>
>>>>>>>>>>>>>  configs/cgtqmx6eval_defconfig       | 1 -
>>>>>>>>>>>>>  configs/mx6cuboxi_defconfig         | 1 -
>>>>>>>>>>>>>  configs/mx6sabreauto_defconfig      | 1 -
>>>>>>>>>>>>>  configs/mx6sabresd_defconfig        | 1 -
>>>>>>>>>>>>>  configs/mx6slevk_spl_defconfig      | 1 -
>>>>>>>>>>>>>  configs/mx6sxsabresd_spl_defconfig  | 1 -
>>>>>>>>>>>>>  configs/mx6ul_14x14_evk_defconfig   | 1 -
>>>>>>>>>>>>>  configs/mx6ul_9x9_evk_defconfig     | 1 -
>>>>>>>>>>>>>  configs/novena_defconfig            | 1 -    
>>>>>>>>>>>>
>>>>>>>>>>>> NAK, I boot my Novena from ext4 and this just broke it.
>>>>>>>>>>>>
>>>>>>>>>>>> And also, NAK, this removes functionality from SPL which
>>>>>>>>>>>> worked fine before.   
>>>>>>>>>>>
>>>>>>>>>>> I'll drop from Novena, but I think the patch still makes
>>>>>>>>>>> some sense, why do you want Ext4 on SPL?    
>>>>>>>>>>
>>>>>>>>>> What other filesystem is available in SPL and doesn't have
>>>>>>>>>> patent problems ?   
>>>>>>>>>
>>>>>>>>> Sorry for not being clear. I am asking why turn on a feature
>>>>>>>>> that is so heavy, on a system that won't need it (such as
>>>>>>>>> Sabre* boards, Wandboard and similar)?    
>>>>>>>>
>>>>>>>> Two reasons:
>>>>>>>> 1) It was enabled, disabling it means removing functionality
>>>>>>>> for no good reason (oops, bloat, is not a good reason), and
>>>>>>>> that is not desired. 2) Booting from block device implies
>>>>>>>> booting from a filesystem, otherwise you might overwrite
>>>>>>>> various things on the block device when updating the file
>>>>>>>> (u-boot image).    
>>>>>>>
>>>>>>> So, are you using SPL to load something from ext4 or not?    
>>>>>>
>>>>>> Yes, I think that's what I said.
>>>>>>    
>>>>>>> There are
>>>>>>> setups where people have configured the system such that SPL
>>>>>>> loads something from ext4 and that's why we have it
>>>>>>> available.  Is anyone doing that on Novena?  Or any iMX
>>>>>>> system?    
>>>>>>
>>>>>> Quoting my first response in this thread:
>>>>>> "
>>>>>> NAK, I boot my Novena from ext4 and this just broke it.
>>>>>> "    
>>>>>
>>>>> Actually, I wasn't sure from your first response if you're using
>>>>> SPL to load u-boot from EXT4 or not.  So, Novena is a no and we
>>>>> should wait for more board maintainers to speak up to see if
>>>>> they use it or not, thanks!    
>>>>
>>>> Novena is certainly a no. Since I use a couple of wandboards,
>>>> those are no as well.
>>>>
>>>> But I do not want to see useful functionality removed from SPL
>>>> only to make space for useless DM/DT bloat. Temporarily
>>>> band-aiding this real problem by removing functionality is a
>>>> no-go, no matter how you slice it. The real fix is to fix the
>>>> DM/DT and figure out a way to reduce it's size and _retain_ _all_
>>>> the functionality. 
>>>
>>> I fully agree with Marek here - the DM/DT SPL support (in the form
>>> as it is now) is a bloat. The SPL size increases considerably.
>>>
>>> The _real_ issue is the lack of OF_PLATDATA support for DM/DTS
>>> drivers, which are used when we convert u-boot to DM/DTS.

Better yet, the ability to short-circuit the whole DM functionality for
systems which only have one driver per subsystem in the SPL, and
optimize the entire DM machinery out in such a case, since it's all not
required only to track one driver instance.

[...]

> I do agree with the above sentence. If the feature is not used - it
> shall be removed. However, if somebody deployed it already - then -
> well it must be supported or other, acceptable solution needs to be
> used (e.g. EXT4 -> VFAT conversion).

VFAT is a patent minefield, which is why people use ext4 in the first
place. Migrating from ext4 -> VFAT is like moving from a good thing to
bad thing.

-- 
Best regards,
Marek Vasut