Re: port-arm/53216 (sunxi awge is unreliable at gigabit speed)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR port-arm/53216; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: port-arm-maintainer%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost,
        gnats-admin%netbsd.org@localhost, skrll%NetBSD.org@localhost
Subject: Re: port-arm/53216 (sunxi awge is unreliable at gigabit speed)
Date: Mon, 18 Oct 2021 21:04:05 +0200

 On Mon, Oct 18, 2021 at 07:41:26AM +0000, skrll%NetBSD.org@localhost wrote:
 > Synopsis: sunxi awge is unreliable at gigabit speed
 > 
 > State-Changed-From-To: open->feedback
 > State-Changed-By: skrll%NetBSD.org@localhost
 > State-Changed-When: Mon, 18 Oct 2021 07:41:25 +0000
 > State-Changed-Why:
 > Is this still a problem? I see these changes that might help your problem
 
 On netbsd-9 I'm still seeing the strange led behavior but I don't notice
 the packet loss any more (maybe I'm just lucky ?).
 Anyway the change below doens't explain why it would work fine with a cisco
 switch but fail with a dlink ...
 
 > 
 > revision 1.67
 > date: 2019-10-15 18:19:05 +0100;  author: tnn;  state: Exp;  lines: +4 -5;  commitid: eOp1fNcFFCQafZGB;
 > correct pointer arithmetics
 > ----------------------------
 > revision 1.66
 > date: 2019-10-15 17:30:49 +0100;  author: tnn;  state: Exp;  lines: +28 -14;  commitid: t0ylgdxkVARbYYGB;
 > awge: fix issue that caused rx packets to be corrupt with DIAGNOSTIC kernel
 > 
 > It seems the hardware can only reliably do rx DMA to addresses that are
 > dcache size aligned. This is hinted at by some GMAC data sheets but hard to
 > find an authoritative source.
 > 
 > on non-DIAGNOSTIC kernels we always implicitly get MCLBYTES-aligned mbuf
 > data pointers, but with the reintroduction of POOL_REDZONE for DIAGNOSTIC
 > we can get 8-byte alignment due to redzone padding. So align rx pointers to
 > 64 bytes which should be good for both arm32 and aarch64.
 > 
 > While here change some bus_dmamap_load() to bus_dmamap_load_mbuf() and add
 > one missing bus_dmamap_sync(). Also fixes the code to not assume that
 > MCLBYTES == AWGE_MAX_PACKET. User may override MCLSHIFT in kernel config.
 > 
 > 
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --