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

[Maxime Ripard]

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.

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.

> > +	"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?

Maxime

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