[U-Boot] [PATCH 1/6] arm: socfpga: cyclone5-socdk: Enabling mtd partitioning layout

[Marek Vasut]

On Saturday, December 12, 2015 at 07:30:46 AM, Chin Liang See wrote:
[...]
> > > > Is this the default Altera layout ?
> > > 
> > > Yah but believe it need to be updated
> > 
> > So you're not worried about compatibility I presume ?
> 
> I still need to care of compatiblity. Some of them will break due to
> size increase. But through the use of partition name and environment,
> user will be abstracted from this.

OK

> > > > > +#define MTDPARTS_DEFAULT	"mtdparts=ff705000.spi:"\
> > > > > +				"256k(spl),"		\
> > > > > +				"64k(env),"		\
> > > > > +				"64k(dtb),"		\
> > > > 
> > > > What happens if the DT grows over 64k ?
> > > 
> > > Hmmm rethinking of this, I will make Linux dtb, U-Boot and kernel
> > > as
> > > part of one big UBI partition called boot.
> > 
> > I am using this sort of layout on SoCkit internally:
> >         "mtdparts=ff705000.spi:"                \
> >         
> >                 "1m(u-boot),"                   \
> >                 "64k(env1),"                    \
> >                 "64k(env2),"                    \
> >                 "-(UBI)\0"
> 
> Hmmm I didn't see the area for SPL. Wonder is it part of u-boot
> partition?

Yes, the u-boot-with-spl-dtb.sfp (which contains 4 copies of SPL and U-Boot
image) goes into the 'u-boot' partition.

> > I have two environment blocks to implement redundant env, which is
> > useful
> > when deploying the system. It makes the system slightly more
> > resilient
> > against problems of aging flash.
> 
> Nice thought, will increase the environment partition to 256kB to cater
> this.

I am using env1 and env2, see above. That should be enough.

> > > > > +				"256k(boot),"		\
> > > > 
> > > > 256k is not enough for U-Boot (considering this is U-Boot).
> > > 
> > > Will create boot region to avoid worrying the size issue
> > > 
> > > > > +				"16m(kernel),"
> > > > > \
> > > > > +				"16m(rootfs),"
> > > > > \
> > > > 
> > > > Why don't you put kernel and rootfs onto the UBI volume instead ?
> > > 
> > > Yup, kernel will go into boot partition. It will be separated from
> > > rootfs as user might choose nfs.
> > 
> > Can you share the final layout before you roll out patches ?
> 
> Sure, plan to do so but need to away from desk just now.
> 
> Here is the old layout
> 256k(spl)
> 64k(env)
> 64k(dtb)
> 256k(boot)
> 16m(kernel)
> 16m(rootfs)
> 
> The new one would like this
> 256k(spl)

I'd say you should just call this u-boot, see above for the rationale.

> 256k(env)
> 15872k(boot)
> 16m(rootfs)
> 
> The boot partition can be used as ubi part or raw partition.
> It contains the linux dtb, u-boot and linux images.

Is that an UBIFS partition ? If so, why don't you just use two UBI volumes ?

> The environment will be used to determine the image offset for
> mentioned boot images from boot partition.
> 
> Thanks
> Chin Liang