[U-Boot] [PATCH 3/4] sunxi: Add default partition scheme

[Andre Przywara]

Hi,

On 30/11/17 07:56, Maxime Ripard wrote:
> Hi,
> 
> On Thu, Nov 30, 2017 at 12:23:06AM +0000, André Przywara wrote:
>> Hi Maxime,
>>
>> On 28/11/17 10:34, Maxime Ripard wrote:
>>> The partitions variable is especially useful to create a partition table
>>> from U-Boot, either directly from the U-Boot shell, or through flashing
>>> tools like fastboot and its oem format command.
>>>
>>> This is especially useful on devices with an eMMC you can't take out to
>>> flash from another system, and booting a Linux system first to flash our
>>> system then is not really practical.
>>>
>>> Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
>>> ---
>>>  include/configs/sunxi-common.h |  9 +++++++++
>>>  1 file changed, 9 insertions(+)
>>>
>>> diff --git a/include/configs/sunxi-common.h b/include/configs/sunxi-common.h
>>> index 4391a8cbc824..c9214a709221 100644
>>> --- a/include/configs/sunxi-common.h
>>> +++ b/include/configs/sunxi-common.h
>>> @@ -493,6 +493,12 @@ extern int soft_i2c_gpio_scl;
>>>  #define SUNXI_MTDPARTS_DEFAULT
>>>  #endif
>>>  
>>> +#define PARTS_DEFAULT \
>>> +	"name=loader1,start=8k,size=32k,uuid=${uuid_gpt_loader1};" \
>>> +	"name=loader2,size=984k,uuid=${uuid_gpt_loader2};" \
>>> +	"name=esp,size=128M,bootable,uuid=${uuid_gpt_esp};" \
>>
>> Those numbers look right to me, but I can't find the definition of
>> uuid_gpt_loader{1,2} in U-Boot. Only I see them referenced by some
>> rockchip header.
>> Is there some magic definition I missed or do we actually need to add them?
>> I guess you are after the Android-IA bootloader UUIDs from the Wikipedia
>> page, starting with 2568845D- and 114EAFFE-?
> 
> The fact that they have been left out is intentional. Without a UUID
> defined, U-Boot will generate a random one if you have
> CONFIG_RANDOM_UUID set. That kind of construct allow you to specifiy a
> UUID if you want, without modifying the partitions variable.

Ah, thanks for the explanation, I was afraid I missed something.

> I'm totally fine with having a default one though. I just couldn't
> find one that would be relevant, so I left it out.

I guess this is fine. Wikipedia[1] points me to Android-IA having
specified two UUIDs for boot loader partitions here [2], but I don't
think they are really authoritative.

>>> +	"name=system,size=-,uuid=${uuid_gpt_system};"
>>
>> So does fastboot require a system partition? And it wouldn't know where
>> to put the rootfs to without one?
>> In this case I guess it's fine, because it fits the use case.
>> But otherwise (as mentioned before) one giant partition to fill the rest
>> of the "disk" is more annoying than helpful for regular Linux installers.
> 
> So fasboot is dumber than you assume it to be ;)
> 
> The only thing you do is giving it a file and a partition. So yeah,
> you would need to have a partition defined for that.
> 
>>> +
>>>  #define CONSOLE_ENV_SETTINGS \
>>>  	CONSOLE_STDIN_SETTINGS \
>>>  	CONSOLE_STDOUT_SETTINGS
>>> @@ -511,6 +517,9 @@ extern int soft_i2c_gpio_scl;
>>>  	"console=ttyS0,115200\0" \
>>>  	SUNXI_MTDIDS_DEFAULT \
>>>  	SUNXI_MTDPARTS_DEFAULT \
>>> +	"uuid_gpt_esp=C12A7328-F81F-11D2-BA4B-00A0C93EC93B\0" \
>>> +	"uuid_gpt_system=0FC63DAF-8483-4772-8E79-3D69D8477DE4\0" \
>>
>> The ESP GUID is correct, the other is "Linux filesystem data", right?
>> Technically I guess root partition would be more suitable, but we would
>> need to know whether it's AArch64 or ARM, if I get this correctly.
>> Shall we use #ifdef CONFIG_ARM64 here?
> 
> We can, what UUID do you have in mind?

FreeDesktop [3] seems to define some UUIDs for Linux root partitions,
separated by architectures, and it lists ARM and AArch64.

Cheers,
Andre.

[1] https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs
[2]
https://github.com/android-ia/device-androidia-mixins/blob/master/groups/boot-arch/android_ia/gpt.ini
[3]
https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/