[U-Boot] [PATCH 1/4] x86: microcode-tool: Write pure data to the dtsi file

[Simon Glass]

Hi Bin,

On 7 August 2015 at 18:47, Bin Meng <bmeng.cn at gmail.com> wrote:
> Hi Simon,
>
> On Sat, Aug 8, 2015 at 3:26 AM, Simon Glass <sjg at chromium.org> wrote:
>> Hi Bin,
>>
>> On 7 August 2015 at 03:28, Bin Meng <bmeng.cn at gmail.com> wrote:
>>> Currently the microcode-tool writes microcode into a data block as
>>> well as the device tree properties which represents the first 48
>>> bytes in the microcode data. Now we change the tool to only write
>>> the microcode without device tree stuff so that multiple microcode
>>> data blocks can be included in a single property.
>>>
>>> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>> ---
>>>
>>>  tools/microcode-tool.py | 23 ++++++++++++-----------
>>>  1 file changed, 12 insertions(+), 11 deletions(-)
>>
>> I would rather than we use a tool to pack the microcode together (e.g.
>> ifdtool) rather than changing the source data. I realise that the FSP
>> requires this packing, but I quite dislike the approach of making the
>> source files fit the object files.
>>
>
> Could you roughly describe how you want to do using ifdtool? Is the
> microcode source still from dtb?

Yes I think it can be done by adding an option to generate the
microcode blob (since for non-FSP platforms it is unnecessary). It can
scan the available microcode nodes and pack them into a single block,
then put a pointer to it into the ROM.

We already add the pointer with this:

IFDTOOL_FLAGS += -m 0x$(shell $(NM) u-boot |grep _dt_ucode_base_size
|cut -d' ' -f1)

but now it will need to go in a separate place in the ROM. I suggest
immediately above the device tree.

See the write_uboot() which does all sorts of wacky stuff already.
Hopefully we can just replace that code with something that creates
the blob.

>
>> If you like I can take a look at adding this feature to ifdtool.
>>

Regards,
Simon