[U-Boot] [PATCH 8/8] Migrate generic bootcount to Kconfig

[Lukasz Majewski]

Hi Alex,

> On Mon, Feb 12, 2018 at 8:48 AM, Lukasz Majewski <lukma at denx.de>
> wrote:
> > Hi Alex,
> >  
> >> On Sun, Feb 11, 2018 at 9:44 PM, Lukasz Majewski <lukma at denx.de>
> >> wrote:  
> >> > On Sun, 11 Feb 2018 21:04:46 +0000
> >> > Alex Kiernan <alex.kiernan at gmail.com> wrote:
> >> >  
> >> >>
> >> >> That said, squashing in that change doesn't obviously break
> >> >> anything for me, and is probably a step in the right direction.
> >> >>
> >> >> I'll see what Travis thinks.
> >> >>  
> >> >
> >> > We will probably receive build breaks...  
> >>
> >> Yup... https://travis-ci.org/akiernan/u-boot/jobs/340344489
> >>
> >> Just tried again on one of those failures (x600) with the the
> >> default removed and just set the on board that uses CONFIG_EXT,
> >> but that then fails at config time.  
> >
> > Ok. I see
> >  
> >>
> >> TBH I'd actually like to take it out of Kconfig (which I realise is
> >> the wrong direction) as it just feels fundamentally wrong the way
> >> it is.  
> >
> > To finish moving SYS_BOOTCOUNT_ADDR to Kconfig we would need to add
> > its definition to each eligible ./configs/<board>_defconfig file.
> >
> > Then we would have the previous behaviour preserved.
> >  
> >> I don't know what the U-Boot approach configuration like this
> >> is... struggling to find prior art.  
> >
> > Let's ask Tom for his opinion as he did much such work before.
> >  
> 
> Thoughts:
> 
> - Do nothing, leave CONFIG_SYS_BOOTCOUNT_ADDR as a purely CONFIG_EXT
> piece of Kconfig
> - Rename CONFIG_SYS_BOOTCOUNT_ADDR to something like
> CONFIG_SYS_BOOTCOUNT_ADDR_EXT for just CONFIG_EXT
> - Remove CONFIG_SYS_BOOTCOUNT_ADDR from Kconfig altogether (and rename
> to say SYS_BOOTCOUNT_ADDR)
> - Pick through every config building defaults - okay for some boards,
> but lots have it defined based on other memory offsets
> 
> I think the only real options are the last two.

I would go for third option - Remove the SYS_BOOTCOUNT_ADDR from
Kconfig (also for EXT).

> 
> Whatever we do, I think CONFIG_SYS_BOOTCOUNT_ADDR wants splitting into
> at least two:
> 
> - I2C - an offset from an I2C base for the bootcounter
  - RAM/SoC memory - location of special register to store bootcounter
> - Others - an actual address used for storing the bootcounter



> 
> I'm struggling to see why EXT is the way it is - AFAICS the location
> it uses to access/return the bootcounter is basically local to the two
> functions in bootcount_ext and could just be a local variable.
> 

Maybe we can replace it with local, static variable then?


As said above - I would remove the (wrongly?) used BOOTCOUNT_ADDR in
Kconfig. 

Then, for next merge window we can play around with moving
CONFIG_SYS_BOOTCOUNT_ADDR per boards if needed. 

I just do have a feeling that -rc2 is too late for it.... 

Also, wrong SYS_BOOTCOUNT_ADDR will not be caught in build testing and
may cause boards to silency break.


Best regards,

Lukasz Majewski

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