FYI: 
I used put spd data in a stand alone C source code so that I can edit with vi directly.

unsigned char global_spd_data[256]  = __attribute__ ((section("spd_data"))) {
0x??, 0x??, ...
};

Note: I also put spd_data in the spd data section that is the end of my binary xloader code. 
I can easily edit with bvi editor too.

https://en.wikipedia.org/wiki/Serial_presence_detect


On Fri, Oct 23, 2015 at 11:35 AM, Aaron Durbin <adurbin@google.com> wrote:
This one's for Ron.

On Fri, Oct 23, 2015 at 10:32 AM, ron minnich <rminnich@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@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
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