Re: [PATCH 0/6] Enable CONFIG_TIMER for all Kirwood / MVEBU boards

Stefan Roese
2022-08-31T07:22:45Z

Hi Tony,

On 31.08.22 08:30, Tony Dinh wrote:
> Hi Stefan,
>
> On Tue, Aug 30, 2022 at 10:08 PM Stefan Roese <sr@denx.de> wrote:
>>
>> Hi Tony,
>>
>> On 31.08.22 07:02, Stefan Roese wrote:
>>> Hi Tony,
>>>
>>> On 31.08.22 00:15, Tony Dinh wrote:
>>>> Hi Stefan,
>>>>
>>>> On Tue, Aug 30, 2022 at 4:53 AM Stefan Roese <sr@denx.de> wrote:
>>>>>
>>>>> This patchset enhaces the recently added Orion Timer driver to support
>>>>> all other Kirkwood & 32bit MVEBU Armada platforms. Additionally, this
>>>>> timer support is then enabled per default for those platforms, so that
>>>>> the board config files don't need to be changed. Also necessary is
>>>>> some dts hacking, so that the timer DT node is available in early
>>>>> U-Boot stages.
>>>>>
>>>>> I've successfully tested this patchset on an Armada XP board. Additional
>>>>> test on other boards and platforms are very welcome and necessary.
>>>>
>>>> I've run some tests with the following 2 Kirkwood boards: Cloud
>>>> Engines Pogo V4 88F6192 (with CONFIG_DM_RTC and CONFIG_RTC_EMULATION),
>>>> and Marvell Sheevaplug 88F6281 (with CONFIG_DM_RTC and CONFIG_RTC_MV).
>>>>
>>>> It seems that it was either frozen or the timer did not expire at some
>>>> subsequent sleep commands. Sometime it happened at 2nd command, some
>>>> time at a later sleep command. For example,
>>>>
>>>> === Pogo V4 (the 1st sleep command works correctly at 10 seconds on my
>>>> stopwatch)
>>>>
>>>> U-Boot 2022.10-rc3-00048-g66ccd87a9c-dirty (Aug 30 2022 - 13:38:24 -0700)
>>>> Pogoplug V4
>>>>
>>>> Hit any key to stop autoboot: 0
>>>> Pogo_V4> sleep 10
>>>> Pogo_V4> sleep 31.5
>>>> <frozen here>
>>>
>>> Does the cmd interface support fractial numbers? Please test again with
>>> 31 or other integral numbers.
>>>
>>>> === Sheevaplug (RTC battery is old, so the date was not updated, but
>>>> the clock seems OK)
>>>>
>>>> U-Boot 2022.10-rc3-00048-g66ccd87a9c-dirty (Aug 30 2022 - 14:14:24 -0700)
>>>> Marvell-Sheevaplug
>>>> Hit any key to stop autoboot: 0
>>>> => date
>>>> Date: 2000-01-01 (Saturday) Time: 0:02:55
>>>> => sleep 10
>>>> => date
>>>> Date: 2000-01-01 (Saturday) Time: 0:03:18
>>>> => sleep 10
>>>> => sleep 20.1
>>>> <frozen here>
>>>>
>>>> Please let me know what I can do (i.e. perhaps running a debug patch).
>>>
>>> Please see above. I assume that the fractional numbers result in very
>>> long numbers internally, which result in a frozen / hanging system.
>>
>> I just tested fractional numbers on another board and hey, it just
>> works. Learned something new. So we seem to have a problem here. Let
>> me see, if I can find something.
>
> I've added debug printfs and possibly tracked down this issue. Seems
> like in the 2nd call to sleep, get_timer(0) did not reset the start
> number.
>
> cmd/sleep.c
> static int do_sleep(struct cmd_tbl *cmdtp, int flag, int argc,
> char *const argv[])
> {
> ulong start = get_timer(0);
>
> "do_sleep got a timer start = 2015" is the 1st call to sleep 5.
> "do_sleep got a timer start = 16304" is the 2nd call to sleep 10.
>
> <BEGIN log>
> Pogo_V4> sleep 5
> do_sleep got a timer start = 2015
> do_sleep delay = 5000
> do_sleep delay = 5000
> do_sleep sleeping...
> do_sleep start 2015 curent 100
> do_sleep start 2015 curent 200
> do_sleep start 2015 curent 300
> <snip>
> do_sleep start 2015 curent 4900
> do_sleep end of sleep ... current = 5000
> Pogo_V4>
>
> Pogo_V4> sleep 10
> do_sleep got a timer start = 16304
> do_sleep delay = 10000
> do_sleep delay = 10000
> do_sleep sleeping...
> <snip>
>
> <END log>
>
> So somewhere in the DM timer, "start" got accumulated. I think each
> get_timer(0) should be a different timer instance. It looks like the
> same timer instance is used again and again, causing the "start "to
> grow bigger, and at one point it might just overflow.

Frankly I don't really understand the problem you describe above. What
do you mean with "timer instance"? get_timer(0) will return different
values, depending on when you call this function. So where exactly is
the problem with the 2nd "sleep 10" above?

Thanks,
Stefan