[U-Boot] [PATCH 0/3] imx: bootaux elf firmware support

[Marek Vasut]

On 04/03/2017 11:36 PM, Stefan Agner wrote:
> Hi Lukasz,
> 
> On 2017-04-03 04:20, Lukasz Majewski wrote:
>> Hi Stefan,
>>
>> Thanks for your patch. Please allow me to share some ideas for
>> improvements.
>>
>>> From: Stefan Agner <stefan.agner at toradex.com>
>>>
>>> This patchset enables to boot elf binaries on secondary Cortex-M
>>> class cores available on i.MX 6SoloX/7Solo/7Dual. This makes
>>> handling and loading firmwares much more convinient since all
>>> information where the firmware has to be loaded to is contained in
>>> the elf headers. A typical usage looks like this:
>>>
>>>   Colibri iMX7 # tftp ${loadaddr} firmware.elf && bootaux ${loadaddr}
>>>   Using FEC0 device
>>>   TFTP from server 192.168.10.1; our IP address is 192.168.10.2
>>>   Filename 'firmware.elf'.
>>>   Load address: 0x80800000
>>>   Loading: ##################################################  88.3
>>> KiB 5.4 MiB/s
>>>   done
>>>   Bytes transferred = 90424 (16138 hex)
>>>   ## Starting auxiliary core at 0x1FFF8311 ...
>>>   Colibri iMX7 #
>>
>> I can find some other platforms (not only IMX), which would benefit
>> from this code - the generic 'bootaux' command.
>>
>> One good example would to allow multiple binaries for different SoC
>> Cores (e.g. 2x Cortex-A8) to be loaded and started by u-boot.
>>
>> Hence, I'm wondering if you could make those patches usable for other
>> platforms as well?
> 
> I don't think that this is a good idea. bootaux is meant for auxiliary
> cores, which often use a different architecture and are not cache
> coherent (hence the cache flushes).
> 
> On SMP systems the main operating system normally starts the secondary
> core. Otherwise, if you want to run them separately using U-Boot, maybe
> a new command such as bootsmp would be more suited.
> 
Admitedly, I didn't look at the patch, but if you want to boot ad-hoc
cores, you can very well also boot secondary cores on the current CPU
complex with the same command. Why not ?

Also, I think this might come useful when booting stuff like "Altera
Sparrow" ...

-- 
Best regards,
Marek Vasut