[LEDE-DEV] [PATCH v2 2/3] ipq806x: Add support for new device: tew827dru

[Mathias Kresin]

2016-09-14 14:17 GMT+02:00 J Mo <jmomo at jmomo.net>:
> On 09/11/2016 01:39 AM, Mathias Kresin wrote:
>> 11.09.2016 03:36, J Mo:
>>> On 09/10/2016 10:27 AM, Mathias Kresin wrote:
>>>>
>>>> 10.09.2016 03:35, J Mo:
>>>>>
>>>>> --- a/include/image-commands.mk
>>>>> +++ b/include/image-commands.mk
>>>>> @@ -168,3 +168,19 @@ define Build/sysupgrade-tar
>>>>>          --rootfs $(call
>>>>> param_get_default,rootfs,$(1),$(IMAGE_ROOTFS)) \
>>>>>          $@
>>>>>  endef
>>>>> +
>>>>> +define Build/cameo-sig
>>>>> +    { \
>>>>> +        cameo_sig=$(word 1, $(1)) ;\
>>>>> +        align=$(if $(2),$(2),64) ;\
>>>>> +        oldsize=$$(stat -c %s $@) ;\
>>>>> +        sigsize=$$(echo -n $$cameo_sig | wc -c) ;\
>>>>> +        padsize=$$(( ( ( ( $$oldsize + $$sigsize ) / $$align ) + 1 )
>>>>> - ( ( $$oldsize + $$sigsize ) / $$align ) )) ;\
>>>>> +        newsize=$$(( $$oldsize + $$padsize )) ;\
>>>>> +        echo "Appending Cameo signature: \"$$cameo_sig\",
>>>>> oldsize=$$oldsize align=$$align sigsize=$$sigsize padsize=$$padsize
>>>>> newsize=$$newsize" ;\
>>>>> +        dd if=$@ of=$@.new bs=$$newsize count=1 conv=sync ;\
>>>>> +        echo -n "$$cameo_sig" >> $@.new ; \
>>>>> +    }
>>>>> +    @mv $@.new $@
>>>>> +endef
>>>>
>>>>
>>>
>>> I'm not doing anything obscure here. This should be self-evident. Add a
>>> byte-aligned signature. pad-to can't do that.
>>
>>
>> Well if it would be obvious what you are trying to do I wouldn't ask.
>>
>> I still don't get what and to which boundary you are trying to align.
>> After fixing the build errors I do get the following:
>>
>> Appending Cameo signature: "AP148AR9880-RT-150127-00", oldsize=5901955
>> align=64 sigsize=24 padsize=1 newsize=5901956
>>
>> PreFooter size: 5901956
>> PostFooter size: 5901979
>>
>> Neither the pre footer image nor the post footer image is padded to a
>> multiple of 64 byte.
>>
>> Do you want to add the signature to a 64 byte padded image or should the
>> image + signature padded to a multiple of 64byte? Where does the 64 byte
>> does come from? It doesn't seam to be related to the 128k blocksize of the
>> flash.
>>
>
> Okay, I apologize. I don't know WTF I was thinking when I did that. It was
> actually working before and then I changed it for reasons I can't explain
> properly without drugs.
>
> padsize=$$(( ( ( ( ( ( $$oldsize + $$sigsize ) / $$align ) + 1 ) * $$align )
> - $$oldsize ) - $$sigsize )) ;\
>
> This works.

I've to admit, I'm not sure if you try to troll me. I asked you two
times to _explain_ what you are trying to do here. The last time I
even provided boiler plate answers.

I mean how should one check the formula without knowing what they _should_ do.

Mathias