[U-Boot] [PATCH 6/8] cpu: Add cpu_print_info function

[Mario Six]

Hi Simon,

On Wed, Apr 18, 2018 at 5:45 PM, Simon Glass <sjg at chromium.org> wrote:
> Hi Mario,
>
> On 18 April 2018 at 02:35, Mario Six <mario.six at gdsys.cc> wrote:
>> Hi Simon,
>>
>> On Thu, Apr 12, 2018 at 6:37 PM, Simon Glass <sjg at chromium.org> wrote:
>>> Hi Mario,
>>>
>>> On 11 April 2018 at 00:39, Mario Six <mario.six at gdsys.cc> wrote:
>>>> Hi Simon,
>>>>
>>>> On Fri, Mar 30, 2018 at 10:41 AM, Simon Glass <sjg at chromium.org> wrote:
>>>>> Hi,
>>>>>
>>>>> On 28 March 2018 at 20:38, Mario Six <mario.six at gdsys.cc> wrote:
>>>>>> Add a cpu_print_info function to the CPU uclass to emulate the behavior
>>>>>> of some current non-DM drivers (e.g. MPC83xx) to print CPU information
>>>>>> during startup.
>>>>>>
>>>>>> Signed-off-by: Mario Six <mario.six at gdsys.cc>
>>>>>> ---
>>>>>>  drivers/cpu/cpu-uclass.c | 10 ++++++++++
>>>>>>  include/cpu.h            | 15 +++++++++++++++
>>>>>>  2 files changed, 25 insertions(+)
>>>>>>
>>>>>
>>>>> I really don't want drivers printing stuff. Can you use the existing
>>>>> get_info() method?
>>>>>
>>>>
>>>> I could, but I'm just emulating the behavior of the legacy code here, which
>>>> prints some information when the CPU is initialized. I think that's pretty
>>>> useful, and I can do that in our board file, but that would mean implementing
>>>> the same routine in every MPC83xx board to get the legacy behavior back.
>>>
>>> Yes, but I don't want the legacy code creeping into the eclass. Can
>>> you convert the board to use the CPU eclass instead?
>>>
>>
>> That's what I did, and I just discovered DISPLAY_CPUINFO, which does exactly
>> what is needed. I'll implement the print_cpuinfo function in the CPU driver, so
>> I can get rid of the print function in the uclass (and still retain the
>> information printing at bootup).
>
> OK I see. Ideally we would have a function (perhaps in board_f) which
> prints out the CPU info after obtaining it from the uclass. So could
> you move your print_cpuinfo() function into board_f? Would it be
> possible to use that if CONFIG_CPU is defined?
>
> At some point print_cpuinfo() could be removed from various board files.
>

The function prints the following (example for our device):

--- >8 ---

Reset Status: External/Internal Soft, External/Internal Hard

CPU:   e300c3, MPC8308, Rev: 1.1 at 400 MHz, CSB: 133.333 MHz

--- >8 ---

So there are some values that are very specific to the platform, such as the
CSB (Coherent System Bus) frequency, or the reset status. While it's probably
possible to put some of that into a generic info printing routine, lots of it
is so MPC83xx-specific that it doesn't make much sense for other CPUs.

Any idea how to tackle this? I don't really want to get rid of the Reset Status
printing especially, since it's pretty useful information for debugging devices
in the field.

> Regards,
> Simon
>

Best regards,
Mario