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From: Jakub Kicinski <kuba@kernel.org>
To: <stefanc@marvell.com>
Cc: <netdev@vger.kernel.org>, <thomas.petazzoni@bootlin.com>,
	<davem@davemloft.net>, <nadavh@marvell.com>,
	<ymarkman@marvell.com>, <linux-kernel@vger.kernel.org>,
	<linux@armlinux.org.uk>, <mw@semihalf.com>, <andrew@lunn.ch>,
	<rmk+kernel@armlinux.org.uk>, <atenart@kernel.org>,
	<rabeeh@solid-run.com>
Subject: Re: [V2 net-next] net: mvpp2: Add reserved port private flag configuration
Date: Thu, 11 Mar 2021 12:33:13 -0800	[thread overview]
Message-ID: <20210311123313.0f5e7f80@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <1615481007-16735-1-git-send-email-stefanc@marvell.com>

On Thu, 11 Mar 2021 18:43:27 +0200 stefanc@marvell.com wrote:
> According to Armada SoC architecture and design, all the PPv2 ports
> which are populated on the same communication processor silicon die
> (CP11x) share the same Classifier and Parser engines.
> 
> Armada is an embedded platform and therefore there is a need to reserve
> some of the PPv2 ports for different use cases.
> 
> For example, a port can be reserved for a CM3 CPU running FreeRTOS for
> management purposes or by user-space data plane application.
> 
> During port reservation all common configurations are preserved and
> only RXQ, TXQ, and interrupt vectors are disabled.
> Since TXQ's are disabled, the Kernel won't transmit any packet
> from this port, and to due the closed RXQ interrupts, the Kernel won't
> receive any packet.
> The port MAC address and administrative UP/DOWN state can still
> be changed.
> The only permitted configuration in this mode is MTU change.
> The driver's .ndo_change_mtu callback has logic that switches between
> percpu_pools and shared pools buffer mode, since the buffer management
> not done by Kernel this should be permitted.

Andrew asks good questions. This looks like a strange construct.

IMO Linux should either not see the port (like it doesn't see NC-SI),
or we need representors for physical and logical ports and explicit
forwarding rules.

      parent reply	other threads:[~2021-03-11 20:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-11 16:43 [V2 net-next] net: mvpp2: Add reserved port private flag configuration stefanc
2021-03-11 16:59 ` Andrew Lunn
2021-03-16 15:28   ` [EXT] " Stefan Chulski
2021-03-16 15:41     ` Russell King - ARM Linux admin
2021-03-16 16:51       ` Stefan Chulski
2021-03-18 20:53     ` Andrew Lunn
2021-03-22 15:59       ` Stefan Chulski
2021-03-22 16:28         ` Andrew Lunn
2021-03-22 18:24           ` Stefan Chulski
2021-03-11 20:33 ` Jakub Kicinski [this message]

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