From: Ulf Hansson <ulf.hansson@linaro.org>
To: Claudiu <claudiu.beznea@tuxon.dev>
Cc: wim@linux-watchdog.org, linux@roeck-us.net, robh@kernel.org,
krzk+dt@kernel.org, conor+dt@kernel.org, p.zabel@pengutronix.de,
geert+renesas@glider.be, magnus.damm@gmail.com,
biju.das.jz@bp.renesas.com, linux-watchdog@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-renesas-soc@vger.kernel.org,
Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Subject: Re: [PATCH RESEND v8 09/10] watchdog: rzg2l_wdt: Power on the PM domain in rzg2l_wdt_restart()
Date: Fri, 12 Apr 2024 13:14:51 +0200 [thread overview]
Message-ID: <CAPDyKFqq+gMDHx_-g-j9rO3nBDcXRSoXRjJK9D51=VaQ5XaGvw@mail.gmail.com> (raw)
In-Reply-To: <20240410134044.2138310-10-claudiu.beznea.uj@bp.renesas.com>
On Wed, 10 Apr 2024 at 16:19, Claudiu <claudiu.beznea@tuxon.dev> wrote:
>
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>
> The rzg2l_wdt_restart() is called from atomic context. Calling
> pm_runtime_{get_sync, resume_and_get}() or any other runtime PM resume
> APIs is not an option as it may lead to issues as described in commit
> e4cf89596c1f ("watchdog: rzg2l_wdt: Fix 'BUG: Invalid wait context'")
> that removed the pm_runtime_get_sync() and used directly the
> clk_prepare_enable() APIs.
>
> Starting with RZ/G3S the watchdog could be part of its own software
> controlled power domain (see the initial implementation in Link section).
> In case the watchdog is not used the power domain is off and accessing
> watchdog registers leads to aborts.
>
> To solve this the patch powers on the power domain using
> dev_pm_genpd_resume() API before enabling its clock. This is not
> sleeping or taking any other locks as the power domain will not be
> registered with GENPD_FLAG_IRQ_SAFE flags.
>
> Link: https://lore.kernel.org/all/20240208124300.2740313-1-claudiu.beznea.uj@bp.renesas.com
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
>
> Changes in v8:
> - none, this patch is new
>
> drivers/watchdog/rzg2l_wdt.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
> index c8c20cfb97a3..98e5e9914a5d 100644
> --- a/drivers/watchdog/rzg2l_wdt.c
> +++ b/drivers/watchdog/rzg2l_wdt.c
> @@ -12,6 +12,7 @@
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> #include <linux/pm_runtime.h>
> #include <linux/reset.h>
> #include <linux/units.h>
> @@ -164,6 +165,17 @@ static int rzg2l_wdt_restart(struct watchdog_device *wdev,
> struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
> int ret;
>
> + /*
> + * The device may be part of a power domain that is currently
> + * powered off. We need to power it up before accessing registers.
> + * We don't undo the dev_pm_genpd_resume() as the device need to
> + * be up for the reboot to happen. Also, as we are in atomic context
> + * here there is no need to increment PM runtime usage counter
> + * (to make sure pm_runtime_active() doesn't return wrong code).
> + */
> + if (!pm_runtime_active(wdev->parent))
> + dev_pm_genpd_resume(wdev->parent);
> +
I doubt this is the correct solution, but I may be wrong. Unless this
is invoked at the syscore stage?
> clk_prepare_enable(priv->pclk);
> clk_prepare_enable(priv->osc_clk);
>
> --
> 2.39.2
>
>
Can you redirectly me to the complete series, so I can have a better
overview of the problem?
Kind regards
Uffe
next prev parent reply other threads:[~2024-04-12 11:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-10 13:40 [PATCH RESEND v8 00/10] watchdog: rzg2l_wdt: Add support for RZ/G3S Claudiu
2024-04-10 13:40 ` [PATCH RESEND v8 01/10] watchdog: rzg2l_wdt: Restrict the driver to ARCH_RZG2L and ARCH_R9A09G011 Claudiu
2024-04-10 16:38 ` Guenter Roeck
2024-04-10 13:40 ` [PATCH RESEND v8 02/10] watchdog: rzg2l_wdt: Make the driver depend on PM Claudiu
2024-04-10 16:39 ` Guenter Roeck
2024-04-10 13:40 ` [PATCH RESEND v8 03/10] watchdog: rzg2l_wdt: Use pm_runtime_resume_and_get() Claudiu
2024-04-10 13:51 ` Biju Das
2024-04-10 14:01 ` claudiu beznea
2024-04-10 14:05 ` Biju Das
2024-04-10 14:13 ` Biju Das
2024-04-10 14:48 ` claudiu beznea
2024-04-10 14:54 ` Biju Das
2024-04-10 16:39 ` Guenter Roeck
2024-04-10 13:40 ` [PATCH RESEND v8 04/10] watchdog: rzg2l_wdt: Check return status of pm_runtime_put() Claudiu
2024-04-10 16:41 ` Guenter Roeck
2024-04-11 14:07 ` claudiu beznea
2024-04-10 13:40 ` [PATCH RESEND v8 05/10] watchdog: rzg2l_wdt: Remove reset de-assert from probe Claudiu
2024-04-10 16:41 ` Guenter Roeck
2024-04-10 13:40 ` [PATCH RESEND v8 06/10] watchdog: rzg2l_wdt: Remove comparison with zero Claudiu
2024-04-10 16:41 ` Guenter Roeck
2024-04-10 13:40 ` [PATCH RESEND v8 07/10] watchdog: rzg2l_wdt: Rely on the reset driver for doing proper reset Claudiu
2024-04-10 16:42 ` Guenter Roeck
2024-04-10 13:40 ` [PATCH RESEND v8 08/10] watchdog: rzg2l_wdt: Add suspend/resume support Claudiu
2024-04-10 16:42 ` Guenter Roeck
2024-04-10 13:40 ` [PATCH RESEND v8 09/10] watchdog: rzg2l_wdt: Power on the PM domain in rzg2l_wdt_restart() Claudiu
2024-04-10 16:43 ` Guenter Roeck
2024-04-11 15:20 ` Geert Uytterhoeven
2024-04-12 11:14 ` Ulf Hansson [this message]
2024-04-12 14:02 ` claudiu beznea
2024-04-24 11:14 ` claudiu beznea
2024-04-29 14:19 ` Ulf Hansson
2024-05-20 11:55 ` claudiu beznea
2024-04-12 11:18 ` Ulf Hansson
2024-04-10 13:40 ` [PATCH RESEND v8 10/10] dt-bindings: watchdog: renesas,wdt: Document RZ/G3S support Claudiu
2024-04-10 16:43 ` Guenter Roeck
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