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From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Eric Nelson <eric@nelint.com>, Eric Dumazet <edumazet@google.com>,
	Fugang Duan <fugang.duan@nxp.com>,
	Otavio Salvador <otavio@ossystems.com.br>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Troy Kisky <troy.kisky@boundarydevices.com>,
	Simone <cjb.sw.nospam@gmail.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: Alignment issues with freescale FEC driver
Date: Fri, 23 Sep 2016 19:30:11 +0100	[thread overview]
Message-ID: <20160923183010.GB1041@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20160923181301.GD22965@lunn.ch>

On Fri, Sep 23, 2016 at 08:13:01PM +0200, Andrew Lunn wrote:
> > Since the hardware requires longword alignment for its' DMA transfers,
> > aligning the IP header will require a memcpy, right?
> 
> The vf610 FEC has an SHIFT16 bit in register ENETx_TACC, which inserts
> two padding bits on transmit. ENETx_RACC has the same.
> 
> What about your hardware?

The iMX6 FEC also has that ability - as part of my FEC patch stack from
ages ago, I implemented support for it.

  "net:fec: implement almost zero-copy receive path"

in my public fec-testing branch.

That patch stack is sadly now totally dead and I've no interest in
reviving it myself.  There was some interest from others in taking my
patch stack over, but that went quiet.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

WARNING: multiple messages have this Message-ID (diff)
From: linux@armlinux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: Alignment issues with freescale FEC driver
Date: Fri, 23 Sep 2016 19:30:11 +0100	[thread overview]
Message-ID: <20160923183010.GB1041@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20160923181301.GD22965@lunn.ch>

On Fri, Sep 23, 2016 at 08:13:01PM +0200, Andrew Lunn wrote:
> > Since the hardware requires longword alignment for its' DMA transfers,
> > aligning the IP header will require a memcpy, right?
> 
> The vf610 FEC has an SHIFT16 bit in register ENETx_TACC, which inserts
> two padding bits on transmit. ENETx_RACC has the same.
> 
> What about your hardware?

The iMX6 FEC also has that ability - as part of my FEC patch stack from
ages ago, I implemented support for it.

  "net:fec: implement almost zero-copy receive path"

in my public fec-testing branch.

That patch stack is sadly now totally dead and I've no interest in
reviving it myself.  There was some interest from others in taking my
patch stack over, but that went quiet.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

  reply	other threads:[~2016-09-23 18:30 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-23 16:43 Alignment issues with freescale FEC driver Eric Nelson
2016-09-23 16:43 ` Eric Nelson
2016-09-23 16:54 ` Eric Dumazet
2016-09-23 16:54   ` Eric Dumazet
2016-09-23 17:19   ` Eric Nelson
2016-09-23 17:19     ` Eric Nelson
2016-09-23 17:33     ` Eric Nelson
2016-09-23 17:33       ` Eric Nelson
2016-09-23 18:13       ` Andrew Lunn
2016-09-23 18:13         ` Andrew Lunn
2016-09-23 18:30         ` Russell King - ARM Linux [this message]
2016-09-23 18:30           ` Russell King - ARM Linux
2016-09-23 18:39           ` Eric Nelson
2016-09-23 18:39             ` Eric Nelson
2016-09-23 18:35         ` Eric Nelson
2016-09-23 18:35           ` Eric Nelson
2016-09-24  2:45           ` David Miller
2016-09-24  2:45             ` David Miller
2016-09-24  5:13             ` Andy Duan
2016-09-24  5:13               ` Andy Duan
2016-09-24 14:42               ` [PATCH 0/3] net: fec: updates to align IP header Eric Nelson
2016-09-24 14:42                 ` [PATCH 1/3] net: fec: remove QUIRK_HAS_RACC from i.mx25 Eric Nelson
2016-09-24 14:42                 ` [PATCH 2/3] net: fec: remove QUIRK_HAS_RACC from i.mx27 Eric Nelson
2016-09-24 14:42                 ` [PATCH 3/3] net: fec: align IP header in hardware Eric Nelson
2016-09-26  9:26                   ` David Laight
2016-09-26 18:39                     ` Eric Nelson
2016-09-28 16:42                       ` David Laight
2016-09-28 17:14                         ` Eric Nelson
2016-09-28 17:25                           ` Russell King - ARM Linux
2016-09-28 18:01                             ` Eric Nelson
2016-09-29 11:07                           ` David Laight
2016-09-30 13:27                             ` Eric Nelson
2016-09-30 13:49                               ` David Laight
2016-09-30 14:16                                 ` Eric Nelson
2016-10-01 19:52                                   ` Russell King - ARM Linux
2016-10-03 16:42                                     ` David Laight
2016-10-03 18:48                                     ` Eric Nelson
2016-10-08  2:44                               ` Andy Duan
2016-09-24 15:09                 ` [PATCH 0/3] net: fec: updates to align IP header Andy Duan
2016-09-24 15:29                   ` Eric Nelson
2016-09-27 11:40                 ` David Miller
2016-09-24  2:43       ` Alignment issues with freescale FEC driver David Miller
2016-09-24  2:43         ` David Miller
2016-09-24 12:27         ` Eric Nelson
2016-09-24 12:27           ` Eric Nelson
2016-09-23 17:37     ` Russell King - ARM Linux
2016-09-23 17:37       ` Russell King - ARM Linux
2016-09-23 18:26       ` Eric Nelson
2016-09-23 18:26         ` Eric Nelson
2016-09-23 18:37         ` Russell King - ARM Linux
2016-09-23 18:37           ` Russell King - ARM Linux
2016-09-23 18:49           ` Eric Nelson
2016-09-23 18:49             ` Eric Nelson
2016-09-23 20:22           ` Uwe Kleine-König
2016-09-23 20:22             ` Uwe Kleine-König

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