Hi, On Wed, Mar 02, 2016 at 09:21:01AM -0800, Andrey Smirnov wrote: > On Wed, Mar 2, 2016 at 5:58 AM, Srinivas Kandagatla > <srinivas.kandaga...@linaro.org> wrote: > > > > > > On 01/03/16 16:59, Andrey Smirnov wrote: > >> > >> Add 'nvmem-blob' driver, which allows to access device tree embedded > >> data via NVMEM subsystem API. > > > > > > Patch itself looks simple. Before we review it further could you provide > > more details on the exact usecase or some background of this. > > The discussion on this topic originated on mailing list of Barebox > project(which borrows very heavily from Linux designs). Barebox > operates on two device tree blobs, one is used for its internal > initialization, whereas second one is passed to Linux kernel when > booting it. The problem I was trying to solve was to make possible to > specify in the first DT blob what data would be used for MAC address > fixup of the second DT blob(the one passed to Linux). > > My first approach was to implement a very limited DT code, however in > discussing it the consensus was that porting 'nvmem' subsystem from > the kernel and using for the same purpose would be a better approach. > First pass adoption of that subsystem revealed that there were two > use-cases that current design didn't allow us to handle: > > - Depending on the version i.MX SoC MAC address data stored in ROM > would have different layout so as a possible solution to that I > implemented "composite" driver(patch #3) > > - On i.MX28, part of the MAC address is hard-coded in > arch/arm/mach-mxs/mach-mxs.c and only a portion of it is read from > ROM, this patch in combination with the aforementioned one should > allow us to encode all needed info in DT. > > Ideally, since all of the above is as applicable to Linux as it is to > Barebox it would be good for BB not to invent its own custom 'nvmem' > flavor, so hence me trying to start a conversation about adding this > upstream.
If the only use-case is to store the MAC address, why not using the local-mac-address property directly? Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
signature.asc
Description: Digital signature
