linux-kernel - Re: [PATCH net] net: dsa: mv88e6xxx: Reset mv88e6393x watchdog register

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Message-ID: <20230328120604.zawfeskqs4yhlze6@kandell>
Date:   Tue, 28 Mar 2023 14:06:04 +0200
From:   Marek Behún <marek.behun@....cz>
To:     Gustav Ekelund <gustav.ekelund@...s.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, kernel@...s.com,
        Gustav Ekelund <gustaek@...s.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net] net: dsa: mv88e6xxx: Reset mv88e6393x watchdog
 register

On Tue, Mar 28, 2023 at 01:55:11PM +0200, Gustav Ekelund wrote:
> From: Gustav Ekelund <gustaek@...s.com>
> 
> The watchdog event bits are not cleared during SW reset in the mv88e6393x
> switch. This causes one event to be handled over and over again.
> 
> Explicitly clear the watchdog event register to 0 after the SW reset.
> 
> Signed-off-by: Gustav Ekelund <gustaek@...s.com>
> ---
>  drivers/net/dsa/mv88e6xxx/chip.c    |  2 +-
>  drivers/net/dsa/mv88e6xxx/global2.c | 17 +++++++++++++++++
>  drivers/net/dsa/mv88e6xxx/global2.h |  1 +
>  3 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index 30383c4f8fd0..ee22d4785e9e 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -5596,7 +5596,7 @@ static const struct mv88e6xxx_ops mv88e6393x_ops = {
>  	 * .port_set_upstream_port method.
>  	 */
>  	.set_egress_port = mv88e6393x_set_egress_port,
> -	.watchdog_ops = &mv88e6390_watchdog_ops,
> +	.watchdog_ops = &mv88e6393x_watchdog_ops,
>  	.mgmt_rsvd2cpu = mv88e6393x_port_mgmt_rsvd2cpu,
>  	.pot_clear = mv88e6xxx_g2_pot_clear,
>  	.reset = mv88e6352_g1_reset,
> diff --git a/drivers/net/dsa/mv88e6xxx/global2.c b/drivers/net/dsa/mv88e6xxx/global2.c
> index ed3b2f88e783..bef8297d4f78 100644
> --- a/drivers/net/dsa/mv88e6xxx/global2.c
> +++ b/drivers/net/dsa/mv88e6xxx/global2.c
> @@ -943,6 +943,23 @@ const struct mv88e6xxx_irq_ops mv88e6390_watchdog_ops = {
>  	.irq_free = mv88e6390_watchdog_free,
>  };
>  
> +static int mv88e6393x_watchdog_action(struct mv88e6xxx_chip *chip, int irq)
> +{
> +	mv88e6390_watchdog_action(chip, irq);
> +
> +	mv88e6xxx_g2_write(chip, MV88E6390_G2_WDOG_CTL,
> +			   MV88E6390_G2_WDOG_CTL_UPDATE |
> +			   MV88E6390_G2_WDOG_CTL_PTR_EVENT);
> +
> +	return IRQ_HANDLED;
> +}

Shouldn't this update be in .irq_setup() method? In the commit message
you're saying that the problem is that bits aren't cleared with SW
reset. So I would guess that the change should be in the setup of
watchdog IRQ, not in IRQ action?

(I am not disagreeing, I am just asking because I don't have access to
documentation right now.)

Marek

> +const struct mv88e6xxx_irq_ops mv88e6393x_watchdog_ops = {
> +	.irq_action = mv88e6393x_watchdog_action,
> +	.irq_setup = mv88e6390_watchdog_setup,
> +	.irq_free = mv88e6390_watchdog_free,
> +};
> +
>  static irqreturn_t mv88e6xxx_g2_watchdog_thread_fn(int irq, void *dev_id)
>  {
>  	struct mv88e6xxx_chip *chip = dev_id;
> diff --git a/drivers/net/dsa/mv88e6xxx/global2.h b/drivers/net/dsa/mv88e6xxx/global2.h
> index e973114d6890..7e091965582b 100644
> --- a/drivers/net/dsa/mv88e6xxx/global2.h
> +++ b/drivers/net/dsa/mv88e6xxx/global2.h
> @@ -369,6 +369,7 @@ int mv88e6xxx_g2_device_mapping_write(struct mv88e6xxx_chip *chip, int target,
>  extern const struct mv88e6xxx_irq_ops mv88e6097_watchdog_ops;
>  extern const struct mv88e6xxx_irq_ops mv88e6250_watchdog_ops;
>  extern const struct mv88e6xxx_irq_ops mv88e6390_watchdog_ops;
> +extern const struct mv88e6xxx_irq_ops mv88e6393x_watchdog_ops;
>  
>  extern const struct mv88e6xxx_avb_ops mv88e6165_avb_ops;
>  extern const struct mv88e6xxx_avb_ops mv88e6352_avb_ops;
> -- 
> 2.30.2
>