[PATCH v2 4/5] watchdog: rti_wdt: Add support for loading firmware

[Simon Glass]

Hi,

On Fri, 11 Jun 2021 at 08:08, Tom Rini <trini at konsulko.com> wrote:
>
> On Fri, Jun 11, 2021 at 07:14:21PM +0530, Lokesh Vutla wrote:
> > Hi Tom,
> >
> > On 09/06/21 6:47 pm, Jan Kiszka wrote:
> > > On 07.06.21 13:44, Jan Kiszka wrote:
> > >> On 07.06.21 13:40, Tom Rini wrote:
> > >>> On Mon, Jun 07, 2021 at 03:33:52PM +0530, Lokesh Vutla wrote:
> > >>>> +Tom,
> > >>>>
> > >>>> Hi Tom,
> > >>>>
> > >>>> On 02/06/21 3:07 pm, Jan Kiszka wrote:
> > >>>>> From: Jan Kiszka <jan.kiszka at siemens.com>
> > >>>>>
> > >>>>> To avoid the need of extra boot scripting on AM65x for loading a
> > >>>>> watchdog firmware, add the required rproc init and loading logic for the
> > >>>>> first R5F core to the watchdog start handler. In case the R5F cluster is
> > >>>>> in lock-step mode, also initialize the second core. The firmware itself
> > >>>>> is embedded into U-Boot binary to ease access to it and ensure it is
> > >>>>> properly hashed in case of secure boot.
> > >>>>>
> > >>>>> One possible firmware source is https://github.com/siemens/k3-rti-wdt.
> > >>>>>
> > >>>>> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
> > >>>>> ---
> > >>>>>  drivers/watchdog/Kconfig      | 20 ++++++++++++
> > >>>>>  drivers/watchdog/Makefile     |  5 +++
> > >>>>>  drivers/watchdog/rti_wdt.c    | 58 ++++++++++++++++++++++++++++++++++-
> > >>>>>  drivers/watchdog/rti_wdt_fw.S | 20 ++++++++++++
> > >>>>>  4 files changed, 102 insertions(+), 1 deletion(-)
> > >>>>>  create mode 100644 drivers/watchdog/rti_wdt_fw.S
> > >>>>>
> > >>>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > >>>>> index f0ff2612a6..1a1fddfe9f 100644
> > >>>>> --- a/drivers/watchdog/Kconfig
> > >>>>> +++ b/drivers/watchdog/Kconfig
> > >>>>> @@ -209,6 +209,26 @@ config WDT_K3_RTI
> > >>>>>           Say Y here if you want to include support for the K3 watchdog
> > >>>>>           timer (RTI module) available in the K3 generation of processors.
> > >>>>>
> > >>>>> +if WDT_K3_RTI
> > >>>>> +
> > >>>>> +config WDT_K3_RTI_LOAD_FW
> > >>>>> +       bool "Load watchdog firmware"
> > >>>>> +       depends on REMOTEPROC
> > >>>>> +       help
> > >>>>> +         Automatically load the specified firmware image into the MCU R5F
> > >>>>> +         core 0. On the AM65x, this firmware is supposed to handle the expiry
> > >>>>> +         of the watchdog timer, typically by resetting the system.
> > >>>>> +
> > >>>>> +config WDT_K3_RTI_FW_FILE
> > >>>>> +       string "Watchdog firmware image file"
> > >>>>> +       default "k3-rti-wdt.fw"
> > >>>>> +       depends on WDT_K3_RTI_LOAD_FW
> > >>>>> +       help
> > >>>>> +         Firmware image to be embedded into U-Boot and loaded on watchdog
> > >>>>> +         start.
> > >>>>
> > >>>> I need your input on this proach. Is it okay to include the linker file unders
> > >>>> drivers?
> > >>>
> > >>> Maybe?  I suppose the first thing that springs to mind is why aren't we
> > >>> using binman and including this blob (which I happily see is GPLv2)
> > >>> similar to how we do things with x86 for one example.
> > >>>
> > >>
> > >> See https://www.mail-archive.com/u-boot@lists.denx.de/msg377894.html
> > >>
> > >> Jan
> > >>
> > >
> > > Did this help to answer open questions? Otherwise, please let me know.
> > >
> > > I'd also like to avoid that his patch alone blocks 1-3 of the series
> > > needless - but I would also not mind getting everything in at once.
> >
> > Can you provide your reviewed-by if you are okay with this approach?
>
> I was kind of hoping Simon would chime in here on binman usage.  So,
> re-re-reading the above URL, yes, fsloader wouldn't be the right choice
> for watchdog firmware.  But I think binman_entry_find() and related
> could work, in general, for this case of "need firmware blob embedded in
> to image".  That said, this isn't just any firmware blob, it's the
> watchdog firmware.  The less reliance on other things the safer it is.
> That means this would be an exception to the general firmware blob
> loading rule and yeah, OK, we can do it this way.  Sorry for the delay.

Yes I've been a little tied up recently. But I think this should use
binman. We really don't want to be building binary firmware into
U-Boot itself!

Also Tom says, see x86 for a load of binaries of different types and
how they are accessed at runttime. This is what binman is for.

>
> Reviewed-by: Tom Rini <trini at konsulko.com>
>
> --
> Tom

Regards,
Simon