[PATCH 2/2] env: add CONFIG_ENV_SECT_SIZE_AUTO

[Joakim Tjernlund]

On Wed, 2020-05-06 at 12:00 +0200, Joakim Tjernlund wrote:
> On Wed, 2020-05-06 at 11:37 +0200, Rasmus Villemoes wrote:
> > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
> > 
> > 
> > On 06/05/2020 11.21, Joakim Tjernlund wrote:
> > 
> > > I can test NOR Flash ,I am on an older u-boot ATM but fw_setenv stuff should be simple to backport
> > > How would fw_env.config be dealt with? Just ignored when auto size?
> > 
> > AFAIK, the U-Boot configuration doesn't affect the userspace fw_env
> > tools, so auto size has to be opt-in separately in fw_env.config, which
> > is where I did use 0 to mean auto (see the referenced commit
> > e282c422e0). You should be able to test that part already with just
> > fw_setenv built from master and an appropriate fw_env.config [or perhaps
> > you need to add another "mtdinfo.type == ..." condition first].
> 
> Oh, I misunderstood then. I was mostly interested in fw_setenv ATM
> Looking at your fw_setenv commit I have one question:
> Will this auto mode also work when erase size < env size ?
> We have the case:
> 
> # MTD device name	Device offset	Env. size	Flash sector size

From my POV, this "Flash sector size" name is misleading. "Size to erase" would be better.
It must be >= Env. size and a multiple of EB size.
auto would mean to select a size >= Env. size, round up to closest multiple of EB size.

>  /dev/mtd1		0x0000		0x2000		0x00001000
> 
> Above does not work because EB < Env. size, one have to set the sector size
> to >= Env. size(0x2000)
> 
>  Jocke