[U-Boot] [PATCH 1/2 v2] watchdog: Implement generic watchdog_reset() version

Wed Apr 10 08:52:45 UTC 2019

On 10.04.19 10:46, Michal Simek wrote:
> On 10. 04. 19 10:40, Stefan Roese wrote:
>> On 10.04.19 09:44, Michal Simek wrote:
>>> On 09. 04. 19 16:34, Stefan Roese wrote:
>>>> On 09.04.19 16:27, Michal Simek wrote:
>>>>> On 09. 04. 19 16:22, Stefan Roese wrote:
>>>>>> On 09.04.19 12:45, Michal Simek wrote:
>>>>>>> On 08. 04. 19 11:28, Stefan Roese wrote:
>>>>>>>> This patch tries to implement a generic watchdog_reset() function
>>>>>>>> that
>>>>>>>> can be used by all boards that want to service the watchdog
>>>>>>>> device in
>>>>>>>> U-Boot. This watchdog servicing is enabled via CONFIG_WATCHDOG.
>>>>>>>>
>>>>>>>> Without this approach, new boards or platforms needed to implement a
>>>>>>>> board specific version of this functionality, mostly copy'ing the
>>>>>>>> same
>>>>>>>> code over and over again into their board or platforms code base.
>>>>>>>>
>>>>>>>> With this new generic function, the scattered other functions are
>>>>>>>> now
>>>>>>>> removed to be replaced by the generic one. The new version also
>>>>>>>> enables
>>>>>>>> the configuration of the watchdog timeout via the DT "timeout-sec"
>>>>>>>> property (if enabled via CONFIG_OF_CONTROL).
>>>>>>>>
>>>>>>>> This patch also adds a new flag to the GD flags, to flag that the
>>>>>>>> watchdog is ready to use and adds the pointer to the watchdog device
>>>>>>>> to the GD. This enables us to remove the global "watchdog_dev"
>>>>>>>> variable, which was prone to cause problems because of its
>>>>>>>> potentially
>>>>>>>> very early use in watchdog_reset(), even before the BSS is cleared.
>>>>>>>>
>>>>>>>> Signed-off-by: Stefan Roese <sr at denx.de>
>>>>>>>> Cc: Heiko Schocher <hs at denx.de>
>>>>>>>> Cc: Tom Rini <trini at konsulko.com>
>>>>>>>> Cc: Michal Simek <michal.simek at xilinx.com>
>>>>>>>> Cc: "Marek Behún" <marek.behun at nic.cz>
>>>>>>>> Cc: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
>>>>>>>> ---
>>>>>>>> This patch depends on the following patches:
>>>>>>>>
>>>>>>>> [1] watchdog: Move watchdog_dev to data section (BSS may not be
>>>>>>>> cleared)
>>>>>>>> https://patchwork.ozlabs.org/patch/1075500/
>>>>>>>>
>>>>>>>> [2] watchdog: Handle SPL build with watchdog disabled
>>>>>>>> https://patchwork.ozlabs.org/patch/1074098/
>>>>>>>>
>>>>>>>> I would like to see [1] applied in this release, since its a real
>>>>>>>> fix on
>>>>>>>> some of the platforms with minimal chances of breakage.
>>>>>>>>
>>>>>>>> This patch now is a bigger rework and is intended for the next merge
>>>>>>>> window.
>>>>>>>>
>>>>>>>> Please note that I didn't remove the "timeout-sec" handling from the
>>>>>>>> driver already reading it from the DT (cdns & at91) in this patch.
>>>>>>>> The reason for this is, that in the cdns case, the removal also
>>>>>>>> brings
>>>>>>>> a functional change, which I wanted to do in a separate patch. And
>>>>>>>> in the at91 case its because there are updates to this driver
>>>>>>>> already
>>>>>>>> queued in the at91 next git branch which would most likely cause
>>>>>>>> merge
>>>>>>>> conflict. I'll send a cleanup patch for this driver later after
>>>>>>>> these
>>>>>>>> patches have been applied.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Stefan
>>>>>>>>
>>>>>>>> v2:
>>>>>>>> - Rename watchdog_start() to initr_watchdog() and move it to
>>>>>>>> board_r.c.
>>>>>>>>       This way its only called once, after the DM subsystem has bound
>>>>>>>> all
>>>>>>>>       watchdog drivers. This enables the use of the currently
>>>>>>>> implemented
>>>>>>>>       logic of using the correct watchdog in U-Boot (via alias etc).
>>>>>>>>
>>>>>>>>      arch/mips/mach-mt7620/cpu.c                   | 36
>>>>>>>> -----------------
>>>>>>>>      board/CZ.NIC/turris_mox/turris_mox.c          | 30
>>>>>>>> --------------
>>>>>>>>      board/CZ.NIC/turris_omnia/turris_omnia.c      | 35
>>>>>>>> ----------------
>>>>>>>>      .../microblaze-generic/microblaze-generic.c   | 40
>>>>>>>> -------------------
>>>>>>>>      board/xilinx/zynq/board.c                     | 39
>>>>>>>> ------------------
>>>>>>>>      board/xilinx/zynqmp/zynqmp.c                  | 39
>>>>>>>> ------------------
>>>>>>>>      common/board_r.c                              | 40
>>>>>>>> +++++++++++++++++++
>>>>>>>>      drivers/watchdog/wdt-uclass.c                 | 26 ++++++++++++
>>>>>>>>      include/asm-generic/global_data.h             |  4 ++
>>>>>>>>      9 files changed, 70 insertions(+), 219 deletions(-)
>>>>>>
>>>>>> <snip>
>>>>>>
>>>>>>>>      int board_early_init_r(void)
>>>>>>>>      {
>>>>>>>>          u32 val;
>>>>>>>> diff --git a/common/board_r.c b/common/board_r.c
>>>>>>>> index 472987d5d5..d80f16c3ed 100644
>>>>>>>> --- a/common/board_r.c
>>>>>>>> +++ b/common/board_r.c
>>>>>>>> @@ -48,6 +48,7 @@
>>>>>>>>      #include <linux/compiler.h>
>>>>>>>>      #include <linux/err.h>
>>>>>>>>      #include <efi_loader.h>
>>>>>>>> +#include <wdt.h>
>>>>>>>>        DECLARE_GLOBAL_DATA_PTR;
>>>>>>>>      @@ -621,6 +622,42 @@ static int initr_bedbug(void)
>>>>>>>>      }
>>>>>>>>      #endif
>>>>>>>>      +#if defined(CONFIG_WATCHDOG) && defined(CONFIG_WDT)
>>>>>>>
>>>>>>> This is not correct.
>>>>>>> Here should be just CONFIG_WDT.
>>>>>>>
>>>>>>> Because there are cases where you want just start watchdog in u-boot
>>>>>>> but
>>>>>>> never service it by u-boot.
>>>>>>
>>>>>> AFAIK, this would change the current behavior. Currently, only when
>>>>>> CONFIG_WATCHDOG is enabled the watchdog driver is started
>>>>>> automatically
>>>>>> in U-Boot (and serviced). If I make the change you suggest above, all
>>>>>> boards defining CONFIG_WDT (DM watchdog support) will automatically
>>>>>> enable the watchdog. This might make sense, but AFAICT this changes
>>>>>> the current behavior.
>>>>>
>>>>> The question is what default is. Because when I was adding support for
>>>>> Zynq/ZynqMP/Microblaze this logic is used there.
>>>>> I think that WDT should be there and if you think there are boards
>>>>> which
>>>>> want to have both we can cover that by Kconfig.
>>>>
>>>> As mentioned above, I agree that it makes sense to start the watchdog
>>>> automatically, if its enabled / selected via CONFIG_WDT. I suggest
>>>> that I move forward with your suggested change, but it would be fair
>>>> to Cc the maintainers of boards that have CONFIG_WDT set but
>>>> CONFIG_WATCHDOG unset. Do you (or anyone else) know of a tool / script
>>>> to detect such board configurations in U-Boot (one option set and
>>>> another unset)?
>>>
>>> good.
>>> Tom?
>>
>> I've run a Travis job on all boards with an error added for this
>> configuration (CONFIG_WDT set but CONFIG_WATCHDOG unset). Here the
>> list of these boards with their maintainers:
>>
>> taurus: Heiko Schocher <hs at denx.de>
>> smartweb: Heiko Schocher <hs at denx.de>
>> ast2500: Maxim Sloyko <maxims at google.com>
>> picosam9g45: Erik van Luijk <evanluijk at interact.nl>
>> mt7623n_bpir2: Ryder Lee <ryder.lee at mediatek.com> Weijie Gao
>> <weijie.gao at mediatek.com>
>> mt7629_rfb: Ryder Lee <ryder.lee at mediatek.com> Weijie Gao
>> <weijie.gao at mediatek.com>
>> bitmain_antminer_s9: Michal Simek <monstr at monstr.eu>
> 
> On this board disabling watchdog servicing was done by purpose.

And it will stay disabled even with the imply, as the defconfig
currently disables CONFIG_WATCHDOG. So no change here.

BTW: bitmain_antminer_s9_defconfig seems to be the only board that
disables CONFIG_WATCHDOG.

Thanks,
Stefan