From: Andrew Jeffery <andrew@codeconstruct.com.au>
To: Zev Weiss <zev@bewilderbeest.net>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Guenter Roeck <linux@roeck-us.net>,
Joel Stanley <joel@jms.id.au>, Andrew Jeffery <andrew@aj.id.au>
Cc: linux-watchdog@vger.kernel.org, linux-aspeed@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org,
"Thomas Weißschuh" <linux@weissschuh.net>,
"Eddie James" <eajames@linux.ibm.com>,
"Ivan Mikhaylov" <i.mikhaylov@yadro.com>
Subject: Re: [PATCH] watchdog: aspeed: Add sysfs attributes for reset mask bits
Date: Fri, 22 Sep 2023 13:46:50 +0930 [thread overview]
Message-ID: <91be26169ebbddf3c05cd19626478246cb72a72a.camel@codeconstruct.com.au> (raw)
In-Reply-To: <20230922013542.29136-2-zev@bewilderbeest.net>
On Thu, 2023-09-21 at 18:35 -0700, Zev Weiss wrote:
> The AST2500 and AST2600 watchdog timers provide the ability to control
> which devices are reset by the watchdog timer via a reset mask
> resgister. Previously the driver ignored that register, leaving
> whatever configuration it found at boot and offering no way of
> altering its settings. Add a 'reset_ctrl' sysfs subdirectory with a
> file per bit so that userspace can determine which devices the reset
> is applied to.
>
> Note that not all bits in the hardware register are exposed -- in
> particular, the ARM CPU and SOC/misc reset bits are left hidden since
> clearing them can render the system unable to reboot.
>
> Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
> ---
>
> I'm porting OpenBMC to a platform that requires that the LPC controller remain
> un-reset by a BMC reboot. With this patch userspace can control the reset
> mask of the Aspeed watchdog timer, with a few bits remaining unexposed so as
> to prevent some almost-certainly undesirable situations. If there are other
> bits that people feel shouldn't be exposed (or conversely if someone feels
> strongly that the "dangerous" bits _should_ be exposed) I can adjust
> accordingly.
Is there a reason this has to be managed by userspace? It sounds a lot
like a property of platform design, in which case exposing this feature
in the devicetree might be a better approach.
Andrew
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next prev parent reply other threads:[~2023-09-22 4:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 1:35 [PATCH] watchdog: aspeed: Add sysfs attributes for reset mask bits Zev Weiss
2023-09-22 4:16 ` Andrew Jeffery [this message]
2023-09-22 4:24 ` Guenter Roeck
2023-09-22 4:33 ` Zev Weiss
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