linux-kernel - Re: [PATCH net-next v5 5/9] net: dsa: microchip: ksz9477: Add Wake on Magic Packet support

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Message-ID: <f4cfb974-42c6-492c-80fd-85bbeaada9d1@gmail.com>
Date:   Wed, 18 Oct 2023 11:20:50 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Oleksij Rempel <o.rempel@...gutronix.de>,
        "David S. Miller" <davem@...emloft.net>,
        Andrew Lunn <andrew@...n.ch>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Vladimir Oltean <olteanv@...il.com>,
        Woojung Huh <woojung.huh@...rochip.com>,
        Arun Ramadoss <arun.ramadoss@...rochip.com>,
        Conor Dooley <conor+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>
Cc:     kernel@...gutronix.de, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, UNGLinuxDriver@...rochip.com,
        "Russell King (Oracle)" <linux@...linux.org.uk>,
        devicetree@...r.kernel.org
Subject: Re: [PATCH net-next v5 5/9] net: dsa: microchip: ksz9477: Add Wake on
 Magic Packet support

On 10/18/23 04:39, Oleksij Rempel wrote:
> Introduce Wake on Magic Packet (WoL) functionality to the ksz9477
> driver.
> 
> Major changes include:
> 
> 1. Extending the `ksz9477_handle_wake_reason` function to identify Magic
>     Packet wake events alongside existing wake reasons.
> 
> 2. Updating the `ksz9477_get_wol` and `ksz9477_set_wol` functions to
>     handle WAKE_MAGIC alongside the existing WAKE_PHY option, and to
>     program the switch's MAC address register accordingly when Magic
>     Packet wake-up is enabled. This change will prevent WAKE_MAGIC
>     activation if the related port has a different MAC address compared
>     to a MAC address already used by HSR or an already active WAKE_MAGIC
>     on another port.
> 
> 3. Adding a restriction in `ksz_port_set_mac_address` to prevent MAC
>     address changes on ports with active Wake on Magic Packet, as the
>     switch's MAC address register is utilized for this feature.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>

This looks good to me, just one suggestion below

[snip]

> +	if (pme_ctrl_old == pme_ctrl)
> +		return 0;
> +
> +	/* To keep reference count of MAC address, we should do this
> +	 * operation only on change of WOL settings.
> +	 */
> +	if (!(pme_ctrl_old & PME_WOL_MAGICPKT) &&
> +	    (pme_ctrl & PME_WOL_MAGICPKT)) {

Maybe use a temporary variable for that condition since you re-use it 
below in case you failed to perform the write of the pme_ctrl value. It 
would be more readable IMHO, something like:

	bool magicpkt_was_disabled = !(pme_ctrl_old & PME_WOL_MAGICPKT) && 
(pme_ctrl & PME_WOL_MAGICPKT));
-- 
Florian