Re: [PATCH 2/5] char: tile-srom: Remove reference to platform_bus

From: Pawel Moll
Date: Fri Aug 08 2014 - 12:35:35 EST


On Tue, 2014-08-05 at 21:08 +0100, Chris Metcalf wrote:
> >> In addition, we also have user binaries
> >> in the wild that know to look for /sys/devices/platform/srom/ paths,
> >> so I'm pretty reluctant to change this path without good reason.
> > So what is the srom class for then if not for device discovery? And why
> > do they look for them in the first place? To get relevant character
> > device's data, if I understand it right?
> >
> > Maybe you could just register a simple "proper" platform device for all
> > the sroms and then hang the class devices from it? I can type some code
> > doing this if it sound reasonably?
>
> I'm not sure exactly what you mean by device discovery here.



> The
> subdirectories under /sys/devices/platform/srom/ correspond to partitions
> in the SPI-ROM, which are software constructs created by the Tilera hypervisor.
> By default we have three, where the first holds boot data that the chip
> can use to boot out of hardware, and the other two are smaller partitions
> for boot- and user-specific data. We use the /sys files primarily to get the
> page size and sector size for the sroms, and also export other interesting
> information like the total size of the particular srom device.
>
> Thank you for volunteering to write a bit of code; if that's the best
> way to clarify this for us, fantastic, or else pointing us at existing
> good practices or documentation would be great too.

I was thinking about something like the following (warning, untested)

8<-------------------------------------------