From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: mm: define NET_IP_ALIGN to 0
Date: Wed, 28 Nov 2018 12:04:56 +0000 [thread overview]
Message-ID: <20181128120455.GB24868@arm.com> (raw)
In-Reply-To: <20181128150225.8D30.4A936039@socionext.com>
Hi Kunihiko,
On Wed, Nov 28, 2018 at 03:02:25PM +0900, Kunihiko Hayashi wrote:
> I found that arm64 board that had AVE controller couldn't receive
> any packets after this change.
>
> AVE controller (hardware) forces to ignore lower 2bits of buffer start address,
> that is, the address is always aligned with 4bytes.
> And more, the controller puts received datas with "2byte headroom" [1].
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/ethernet/socionext/sni_ave.c#n591
Is this "2-byte headroom" a fixed property of the hardware? If so, it seems
like you should just be using 2 instead of NET_IP_ALIGN when calculating the
DMA address of the skb buffer.
Will
next prev parent reply other threads:[~2018-11-28 12:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-07 17:10 [PATCH] arm64: mm: define NET_IP_ALIGN to 0 Ard Biesheuvel
2018-11-07 18:10 ` Mark Rutland
2018-11-07 23:18 ` Ard Biesheuvel
2018-11-08 10:06 ` Mark Rutland
2018-11-08 10:34 ` Ard Biesheuvel
2018-11-07 21:14 ` Will Deacon
2018-11-08 12:22 ` Ilias Apalodimas
2018-11-08 17:51 ` Catalin Marinas
2018-11-28 6:02 ` Kunihiko Hayashi
2018-11-28 11:58 ` Ard Biesheuvel
2018-11-29 1:50 ` Kunihiko Hayashi
2018-11-28 12:04 ` Will Deacon [this message]
2018-11-29 1:51 ` Kunihiko Hayashi
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