On 11/6/21 02:52, Andre Przywara wrote:
On Fri, 5 Nov 2021 18:56:34 -0400
Tom Rini <tr...@konsulko.com> wrote:
On Fri, Nov 05, 2021 at 09:38:50PM +0100, Heinrich Schuchardt wrote:
On 11/5/21 20:17, Tom Rini wrote:
On Fri, Nov 05, 2021 at 07:37:02PM +0100, Heinrich Schuchardt wrote:
On 11/5/21 17:12, Simon Glass wrote:
Hi,
On Fri, 5 Nov 2021 at 08:21, Tom Rini <tr...@konsulko.com> wrote:
On Fri, Nov 05, 2021 at 12:14:47PM +0100, Stefan Roese wrote:
Hi Andre,
Added Tom to Cc.
On 05.11.21 11:04, Andre Przywara wrote:
On Thu, 4 Nov 2021 20:02:41 -0600
Simon Glass <s...@chromium.org> wrote:
Hi,
On Thu, 4 Nov 2021 at 19:22, Stefan Roese <s...@denx.de> wrote:
Hi Andre,
On 05.11.21 00:11, Andre Przywara wrote:
On Thu, 4 Nov 2021 11:37:57 +0100
Stefan Roese <s...@denx.de> wrote:
Hi Stefan,
On 04.11.21 04:55, Samuel Holland wrote:
This series hooks up the watchdog uclass to automatically register
watchdog devices for use with sysreset, doing a bit of minor cleanup
along the way.
The goal is for this to replace the sunxi board-level non-DM reset_cpu()
function. I was surprised to find that the wdt_reboot driver requires
its own undocumented device tree node, which references the watchdog
device by phandle. This is problematic for us, because sunxi-u-boot.dtsi
file covers 20 different SoCs with varying watchdog node phandle names.
So it would have required adding a -u-boot.dtsi file for each board.
Hooking things up automatically makes sense to me; this is what Linux
does. However, I put the code behind a new option to avoid surprises for
other platforms.
Changes in v3:
- Move condition to wdt-uclass.c to fix build errors.
- Include watchdog name in error message.
Changes in v2:
- Extend the "if SYSRESET" block to the end of the file.
- Also make gpio_reboot_probe function static.
- Rebase on top of 492ee6b8d0e7 (now handle all watchdogs).
- Added patches 5-6 as an example of how the new option will be used.
Samuel Holland (6):
sysreset: Add uclass Kconfig dependency to drivers
sysreset: Mark driver probe functions as static
sysreset: watchdog: Move watchdog reference to plat data
watchdog: Automatically register device with sysreset
sunxi: Avoid duplicate reset_cpu with SYSRESET enabled
sunxi: Use sysreset framework for poweroff/reset
arch/arm/Kconfig | 3 +++
arch/arm/mach-sunxi/board.c | 2 ++
drivers/sysreset/Kconfig | 11 ++++++--
drivers/sysreset/sysreset_gpio.c | 2 +-
drivers/sysreset/sysreset_resetctl.c | 2 +-
drivers/sysreset/sysreset_syscon.c | 2 +-
drivers/sysreset/sysreset_watchdog.c | 40 ++++++++++++++++++++++------
drivers/watchdog/wdt-uclass.c | 8 ++++++
include/sysreset.h | 10 +++++++
9 files changed, 67 insertions(+), 13 deletions(-)
Applied to u-boot-marvell
Mmmh, why u-boot-marvell,
Because I'm handling watchdog related changed since a few years and we
did not create a specific subsystem repo for this and I'm usually
using my "marvell" one for this.
And fwiw, there's a few other cases like this. If it's too confusing,
maybe we should just roll out a few more repositories, I think it's
easier to do that now than pre-gitlab?
and why did this end up already in master?
Isn't that material for the next merge window? After all this changes
quite a bit, for a lot of boards, and I did not have a closer look at
the sunxi parts yet.
I was hesitating also a bit. But since this patchset is on the list in
v1 since over 2 months now (2021-08-21) I thought it was "ready" for
inclusion now. We are at -rc1 and I think we still have enough time to
fix any resulting problems in this release cycle.
Why do we have the merge window then? This is clearly not a regression or
general fix.
AFAIU, we are a bit less strict here in U-Boot. Patches that were posted
before the merge-window and skipped the review process (most likely
because of lack of time) are often still integrated in the early rcX
cycles. At least this is how I handle it usually.
Tom, is my understanding here correct?
Yes. We are not as strict as the kernel is about what can come in
between rc1 and rc2 (and to a certain degree, post rc2). I leave things
up to the discretion of the custodians. People tend of have less time
to handle U-Boot changes than other stuff, so I try and be flexible in
picking things up.
Yes I agree, that should be plenty of time for people to review it.
Well, if there would be people to review the sunxi parts :-(
I am totally fine with the generic patches (as they have been reviewed),
but the sunxi integration is somewhat risky.
I was explicitly deprioritising that in my queue, as it really doesn't
change, add or fix anything, it's mere refactoring, from the user's point
of view.
Do you see any specific issues?
Patch 6/6 changes the config for all 157 Allwinner boards, so I think that
deserves at least some testing, *before* merging it.
I expect that Samuel did some testing. But still, I agree that it
would be much better, if these patches - especially the Allwinner parts
got more extensive testing.
I will do as much testing now as possible, but I am not happy about that
situation.
Understood. Should we revert patch 6/6 for now?
FWIW, given Samuel has been doing a number of allwinner changes, I had
also assumed it was sufficiently tested, which is why I didn't raise a
further concern when I saw the widespread nature of the overall changes,
just figured it was a few more ready-to-go cleanups that weren't quite
picked up in time. Please do speak up if you want me to revert the last
part.
Also it is often true that people find problems by testing on master
so applying it helps to shake the tree a bit.
Regards,
Simon
We don't actually have a problem with this series but with a previous
watchdog patch. The culprit according to bisecting is:
b147bd3607f8 ("sunxi: Enable watchdog timer support by default")
When booting the OrangePi PC the watchdog triggers while Linux is booting,
ca. 16 s after leaving the UEFI subsystem. This matches WDT_MAX_TIMEOUT in
drivers/watchdog/sunxi_wdt.c.
If I run
=> wdt dev watchdog@1c20ca0
=> wdt stop
before the bootefi command booting succeeds.
We don't disarm the watchdog and Linux does not do it for us in time.
The UEFI specification requires that the default watchdog reset time is 300
s. We should never arm the Sunxi hardware watchdog except within the
watchdog reset driver.
The solution is to disable CONFIG_WATCHDOG_AUTOSTART on SUNXI. See
[PATCH 1/1] watchdog: don't autostart watchdog on Sunxi boards
https://lists.denx.de/pipermail/u-boot/2021-November/466318.html
This means we never did come up with a satisfactory to everyone solution
to what UEFI thinks a watchdog should do, and what other types of
deployment think a watchdog should do, yes?
Dear Tom,
The issue is *not* UEFI specific.
A watchdog timeout of 16 seconds is too short for Linux to boot no matter
whether you use the EFI stub or the legacy entry point.
I only referred to the UEFI specification as it indicates what can be
considered as a reasonable timeout interval: 300 seconds.
16 seconds from the last time we pet the watchdog in U-Boot to the
kernel being able to take over is quite reasonable.
How do we know that the kernel takes over? What if the kernel/EFI
payload doesn't have a watchdog driver? I was assuming that the
watchdog would be disabled as soon as we boot a kernel or an EFI app
calls ExitBootServices (maybe even earlier).
But this sounds like a generic problem, not sunxi specific. So how do
other platforms solve this?
Cheers,
Andre
The UEFI specification has this requirement in chapter "3.1.2 Load
Option Processing":
"... the boot manager must enable the watchdog timer for 5 minutes by
using the EFI_BOOT_SERVICES.SetWatchdogTimer() boot service prior to
calling EFI_BOOT_SERVICES.StartImage(). If a boot option returns control
to the boot manager, the boot manager must disable the watchdog timer
with an additional call to the SetWatchdogTimer() boot service."
This means that having an armed watchdog when starting the kernel is
correct.
If you start a watchdog in the firmware which is not disabled or reset
by the operating system, you are out of luck and won't be able to boot.
Current Linux has driver drivers/watchdog/sunxi_wdt.c compatible to
"allwinner,sun4i-a10-wdt","allwinner,sun6i-a31-wdt" and enabled by
CONFIG_SUNXI_WATCHDOG. This driver was introduced in Linux v3.12. It
originally had compatible "allwinner,sun4i-wdt" only.
Debian Bullseye has the driver enabled as a module. In the bootlog of
the Orange Pi PC I find:
[ 12.321909] sunxi-wdt 1c20ca0.watchdog: Watchdog enabled (timeout=16
sec, nowayout=0)
This message appears approximately *20 seconds* after the EFI stub hands
over to the main kernel. Adding the driver to initrd shortens this to
*18 seconds*. The message occurs after file system checks which can be a
lengthy operation. In Debian systemd manages the watchdog.
As I said: 16 seconds is way too short for a hardware watchdog timeout.
Best regards
Heinrich
Now, if the Andre
says he's fine just disabling watchdog by default for sunxi, fine. But
yes, we never did come up with a reasonable solution to UEFI saying 5
minute timeout for watchdog servicing vs other platforms using a much
shorter watchdog period.
