[U-Boot] [PATCH 2/2] sandbox: Convert SANDBOX_BITS_PER_LONG to Kconfig

[sjg at google.com]

Hi Bin,

On 13 August 2017 at 19:26, Bin Meng <bmeng.cn at gmail.com> wrote:
> Hi Simon,
>
> On Sun, Aug 13, 2017 at 11:35 PM, Simon Glass <sjg at chromium.org> wrote:
>> Hi Bin,
>>
>> On 6 August 2017 at 03:13, Bin Meng <bmeng.cn at gmail.com> wrote:
>>> Hi Simon,
>>>
>>> On Sun, Aug 6, 2017 at 1:16 PM, Simon Glass <sjg at chromium.org> wrote:
>>>> Hi Bin,
>>>>
>>>> On 3 August 2017 at 18:17, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>> Hi Simon,
>>>>>
>>>>> On Thu, Aug 3, 2017 at 11:24 PM, Simon Glass <sjg at chromium.org> wrote:
>>>>>> Hi Bin,
>>>>>>
>>>>>> On 1 August 2017 at 17:33, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>>>>> Convert SANDBOX_BITS_PER_LONG to Kconfig and assign it a correct
>>>>>>> number depending on which host we are going to build and run.
>>>>>>>
>>>>>>> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>>>>>> ---
>>>>>>>
>>>>>>>  arch/sandbox/Kconfig         | 5 +++++
>>>>>>>  board/sandbox/README.sandbox | 7 +++----
>>>>>>>  scripts/config_whitelist.txt | 1 -
>>>>>>>  3 files changed, 8 insertions(+), 5 deletions(-)
>>>>>>
>>>>>> Reviewed-by: Simon Glass <sjg at chromium.org>
>>>>>>
>>>>>> Is it OK to build 64-bit sandbox on a 32-bit machine? Does that actually work?
>>>>>>
>>>>>> If then I think we need a 3-way setting like:
>>>>>>
>>>>>> - 32-bit
>>>>>> - 64-bit
>>>>>> - native (i.e. whatever the host is)
>>>>>
>>>>> That means cross-compiling sandbox. So far this is not working. I will
>>>>> take a look.
>>>>
>>>> Or perhaps we just require it to use the bit size of the host? Does
>>>> compiling 64-bit U-Boot on a 32-bit machine actually work?
>>>>
>>>
>>> I have not looked into that further but I suspect there is more work
>>> than the bit size of the host, for example, linking 64-bit vs. 32-bit
>>> libraries?
>>
>> But does it compile 64-bit sandbox OK on a 32-bit machine? I would
>> have thought it would complain.
>>
>
> No. Compiling 64-bit sandbox never worked on a 32-bit machine. So far
> sandbox build only supports:
>
> 1). build from a 32-bit host and run from a 32-bit host
> 2). build from a 64-bit host and run from a 64-bit host (current
> default setting)
>
>> I'm not really asking for this feature, it's just that I don't
>> understand how your patch works, and don't necessarily want to lose
>> the ability to build a 32-bit sandbox. It is to some extent a helpful
>> build/unit test for 32-bit boards which we still have many of.
>>
>
> This patch does not introduce any functional changes. It just converts
> SANDBOX_BITS_PER_LONG to Kconfig so that this can be changed from
> defconfigs or 'make menuconfig' to make it more user friendly if we
> are building (a 32-bit) sandbox on a 32-bit host. Ideally we should
> add such cross-build functionality to sandbox build.

Then I think this patch is fine.

Regards,
Simon

Applied to u-boot-dm, thanks!