Re: [PATCH 03/10] ARM: i.MX6: Record reset reason as a part of startup

From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Barebox List <barebox@lists.infradead.org>
Subject: Re: [PATCH 03/10] ARM: i.MX6: Record reset reason as a part of startup
Date: Tue, 17 Apr 2018 08:35:12 -0700	[thread overview]
Message-ID: <CAHQ1cqE+jzfOoFNkXpUX_eqjN=whM9EGYFA1OYo59gFbDiSYWQ@mail.gmail.com> (raw)
In-Reply-To: <20180417064925.4uwscnbqgnw2zu27@pengutronix.de>

On Mon, Apr 16, 2018 at 11:49 PM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> On Mon, Apr 16, 2018 at 06:28:11AM -0700, Andrey Smirnov wrote:
>> On Mon, Apr 16, 2018 at 12:13 AM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
>> > Hi Andrey,
>> >
>> > On Sat, Apr 14, 2018 at 10:50:17AM -0700, Andrey Smirnov wrote:
>> >> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
>> >> ---
>> >>  arch/arm/mach-imx/imx6.c                      | 4 +++-
>> >>  arch/arm/mach-imx/include/mach/reset-reason.h | 2 ++
>> >>  2 files changed, 5 insertions(+), 1 deletion(-)
>> >>
>> >> diff --git a/arch/arm/mach-imx/imx6.c b/arch/arm/mach-imx/imx6.c
>> >> index 14a1cba5a..3d81c2785 100644
>> >> --- a/arch/arm/mach-imx/imx6.c
>> >> +++ b/arch/arm/mach-imx/imx6.c
>> >> @@ -19,6 +19,7 @@
>> >>  #include <mach/imx6.h>
>> >>  #include <mach/generic.h>
>> >>  #include <mach/revision.h>
>> >> +#include <mach/reset-reason.h>
>> >>  #include <mach/imx6-anadig.h>
>> >>  #include <mach/imx6-regs.h>
>> >>  #include <mach/generic.h>
>> >> @@ -151,6 +152,7 @@ int imx6_init(void)
>> >>  {
>> >>       const char *cputypestr;
>> >>       u32 mx6_silicon_revision;
>> >> +     void __iomem *src = IOMEM(MX6_SRC_BASE_ADDR);
>> >>
>> >>       imx6_init_lowlevel();
>> >>
>> >> @@ -195,7 +197,7 @@ int imx6_init(void)
>> >>       }
>> >>
>> >>       imx_set_silicon_revision(cputypestr, mx6_silicon_revision);
>> >> -
>> >> +     imx_set_reset_reason(src + IMX6_SRC_SRSR);
>> >
>> > This will get overwritten by the watchdog driver if enabled.
>> >
>>
>> I am not sure I see how. Imx_watchdog_detect_reset_source() reports
>> reset sources with the same priority as this code, so
>> reset_source_set_priority() should bail out early without changing
>> anything in that case.
>
> I wasn't aware there is a priority mechanism involved. Indeed the
> behaviour seems to be correct. Maybe we should even higher the priority
> of imx_set_reset_reason()? This information seems the more accurate one,
> so it should be used, and we shouldn't depend on the order of execution.
>

I think if I add support for "reset-source-priority" to imxwd.c and
set it up to use the value less then RESET_SOURCE_DEFAULT_PRIORITY by
default we can get both what you describe and allow users to override
the behavior and prioritize reset source provided by watchdog driver.

Let me know if this sounds like a bad idea.

Thanks,
Andrey Smirnov

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