[PATCH 2/2] env: add CONFIG_ENV_SECT_SIZE_AUTO

[Joakim Tjernlund]

On Wed, 2020-05-06 at 13:06 +0200, Joakim Tjernlund wrote:
> On Wed, 2020-05-06 at 12:47 +0200, Rasmus Villemoes wrote:
> > On 06/05/2020 12.18, Joakim Tjernlund wrote:
> > > 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.
> > 
> > No, it is indeed supposed to be the flash sector size, and _not_ the
> > size to erase; that's why the code has logic to compute how many sectors
> > to erase (which you can also optionally specify in a fifth column, but
> > as I said, that's done automatically if not specified), and the erase
> > size is then, later yet, of course computed as (erase size)*#sectors.
> > 
> > All that has nothing at all to do with my patch, that's how it all used
> > to work.
> > 
> > > >  /dev/mtd1		0x0000		0x2000		0x00001000
> > > > 
> > > > Above does not work because EB < Env. size, one have to set the sector size
> > > > to >= Env. size(0x2000)
> > 
> > Are you sure? As I said, it works just fine on my end. The only thing my
> > auto-patch does is to make
> 
> Yes, but then my fw_setenv is from 2015.04, not much has happened to fw_setenv since then though
> I will test you auto fw_setenv soon

Some docs about this new auto mode in fw_env.config would probably be a good idea too.