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Message-ID: <20211207161303.bvmuxt5o7m6oeivg@skbuf>
Date: Tue, 7 Dec 2021 16:13:03 +0000
From: Vladimir Oltean <vladimir.oltean@....com>
To: Clément Léger <clement.leger@...tlin.com>
CC: "David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Claudiu Manoil <claudiu.manoil@....com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
"UNGLinuxDriver@...rochip.com" <UNGLinuxDriver@...rochip.com>,
Andrew Lunn <andrew@...n.ch>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Denis Kirjanov <dkirjanov@...e.de>,
Julian Wiedmann <jwi@...ux.ibm.com>
Subject: Re: [PATCH net-next v6 4/4] net: ocelot: add FDMA support
On Tue, Dec 07, 2021 at 04:48:39PM +0100, Clément Léger wrote:
> Ethernet frames can be extracted or injected autonomously to or from
> the device’s DDR3/DDR3L memory and/or PCIe memory space. Linked list
> data structures in memory are used for injecting or extracting Ethernet
> frames. The FDMA generates interrupts when frame extraction or
> injection is done and when the linked lists need updating.
>
> The FDMA is shared between all the ethernet ports of the switch and
> uses a linked list of descriptors (DCB) to inject and extract packets.
> Before adding descriptors, the FDMA channels must be stopped. It would
> be inefficient to do that each time a descriptor would be added so the
> channels are restarted only once they stopped.
>
> Both channels uses ring-like structure to feed the DCBs to the FDMA.
> head and tail are never touched by hardware and are completely handled
> by the driver. On top of that, page recycling has been added and is
> mostly taken from gianfar driver.
>
> Co-developed-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
> Signed-off-by: Clément Léger <clement.leger@...tlin.com>
> ---
Looks good to me, thanks!
Reviewed-by: Vladimir Oltean <vladimir.oltean@....com>
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