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

[Maxime Ripard]

On Thu, Nov 30, 2017 at 09:22:07AM +0000, Andre Przywara wrote:
> 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.

Yeah, I saw those as well, and came to the same conclusion :)

> >>> +	"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.

Ok, I'll use them then.

Thanks!
maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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