[PATCH v2 1/2] cmd: add fuse_blow/fuse_sense for the i.MX IIM fusebox

[Sascha Hauer]

On Thu, Aug 12, 2010 at 12:27:01PM +0300, Baruch Siach wrote:
> Hi Sascha,
> 
> On Thu, Aug 12, 2010 at 11:06:00AM +0200, Sascha Hauer wrote:
> > On Thu, Aug 12, 2010 at 11:35:04AM +0300, Baruch Siach wrote:
> > > This has only been tested on i.MX25, but should work on other i.MX chips with
> > > IIM.
> > 
> > I would prefer this command to be implemented as a device driver which
> > registers a file under /dev. This way we could use the standard md/mw
> > commands for this and look at a nice hexdump of all fuses and not only
> > one at a time.
> 
> There are two methods for getting fuses values, direct memory access, and 
> explicit sensing. Each method can independently be disabled with two dedicated 
> protect fuses. How can md choose the right sensing method?

By trying one method first and fall back to the other method.

> 
> The IIM block also has an override functionality. Direct memory write to the 
> fuse row overrides the value in this row. This feature can also be disabled 
> with an override protect fuse. How does mw know whether you want to blow the 
> fuses, or just override them?

You could override them when iim.writeenable=0 and blow them when
iim.writeenable=1. Return failure when the override protect fuse is
blown.

The fuse_blow/fuse_sense commands do not make this decision either, they
use the explicit sensing method hardcoded.

Sascha

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