[coreboot] SPD binaries in coreboot

[Carl-Daniel Hailfinger]

On 23.10.2015 21:15, Martin Roth wrote:
> I like what I understand Nico's proposal to be: Store the SPD data as
> a c struct with all of the different JEDEC fields broken out.  it
> would relatively trivial to compile this into an SPD binary, or it can
> be used in whatever other fashion is desired.  A tool to convert from
> a binary SPD to the structure file would be desirable to help the
> transition, but it's out of the build path.
>
> I believe this satisfies all the requirements:
> - It's easy to review differences.
> - It can be be built with no new tools.
> - The fields are broken out, so you can actually tell what you're doing.

Now that would be a nice way to combine the benefits of diffable source
and no-tool builds.

Ron, is that solution is acceptable to you?

Side note: There is a tool called decode-dimms which can be fed with
binary SPD dumps. It decodes everything in the SPD and could serve as a
nice way to verify the output of Ron's magic SPD tool.


Regards,
Carl-Daniel

> On Fri, Oct 23, 2015 at 12:44 PM, ron minnich <rminnich at gmail.com> wrote:
>> Aaron is my hero :-)
>>
>> ron
>>
>> On Fri, Oct 23, 2015 at 11:35 AM Aaron Durbin <adurbin at google.com> wrote:
>>> This one's for Ron.
>>>
>>> On Fri, Oct 23, 2015 at 10:32 AM, ron minnich <rminnich at gmail.com> wrote:
>>>> Build the tool in go. It's trivial. If you have an idea how it ought to
>>>> work
>>>> I can set it up in the playground in a few minutes.
>>>>
>>>> ron
>>>>
>>>> On Fri, Oct 23, 2015 at 8:24 AM Patrick Georgi <pgeorgi at google.com>
>>>> wrote:
>>>>> Hi,
>>>>>
>>>>> Some mainboards come with soldered-on memory without SPD ROM. For
>>>>> these, we carry the SPD data in coreboot.
>>>>>
>>>>> Currently, they're stored in a hexdump format that is then converted
>>>>> to binary at build time. The various mechanisms of doing so fail on
>>>>> some platform or another:
>>>>>  - "echo -e -n $stuff" isn't well-liked by some shells (emits "e -n
>>>>> $stuff")
>>>>>  - "printf '\x42'" isn't well-liked by some shells (or /usr/bin/printf
>>>>> tools) that don't support hexadecimal formats
>>>>>  - "printf '\0377'" isn't well-liked by some non-conforming, but
>>>>> existing
>>>>> shells
>>>>>  - xxd -rg1 $file > $file.bin requires xxd, which comes with vim and
>>>>> may just not exist
>>>>>
>>>>> I see essentially two ways out of this, before we can start reducing
>>>>> duplication across the tree in that area:
>>>>> We could build our own tool to parse hex files and dump binary, or we
>>>>> could ship SPD data as binary from the start (and only have to
>>>>> concatenate them).
>>>>>
>>>>> The second option has the appeal of being much simpler (and there
>>>>> isn't really a "preferred form" for editing SPD data that I'm aware of
>>>>> - is there?), but looks icky at a glance because it's binary (but it's
>>>>> really just as impenetrable as the equivalent hexdump).
>>>>>
>>>>> So what do these files contain? Parameters (as in: facts) about the
>>>>> hardware's size, layout, and timing, and a bunch of vendor/model
>>>>> identifier strings.
>>>>>
>>>>>
>>>>> So, is there a third option that I'm missing? Other opinions?
>>>>> Patrick
>>>>>