[PATCH 2/2] env: add CONFIG_ENV_SECT_SIZE_AUTO

[Joakim Tjernlund]

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

 Jocke
> 
> /dev/mtd1		0x0000		0x2000		0x00001000
> 
> equivalent to
> 
> /dev/mtd1		0x0000		0x2000		0
> 
> if the flash does have 4k erase size, so my patch wouldn't make the
> latter work if the former didn't already. [But again, the reason I can't
> use the former is to be compatible with the boards that have 64K erase
> size].
> 
> Rasmus