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

Michal Simek michal.simek at xilinx.com
Wed Apr 10 08:46:47 UTC 2019


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.

Thanks,
Michal


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