Date: Fri, 30 Jan 2009 09:18:11 -0800 From: Sam Leffler <sam@freebsd.org> To: Andrew Thompson <thompsa@freebsd.org> Cc: arm@freebsd.org Subject: Re: busdma problem Message-ID: <49833653.60509@freebsd.org> In-Reply-To: <20090130072649.GF73709@citylink.fud.org.nz> References: <20090130072649.GF73709@citylink.fud.org.nz>
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Andrew Thompson wrote: > Hi, > > > I am having an issue with busdma when bounce buffers are used. I have > patched _bus_dmamap_sync_bp() to print out the details when a bounce > happens and also print the driver buffer before and after. > > During normal dma everything is fine, > > Before: 0xc7c1ab40 data=c1:4b:a4:80:c0:5d:ed:78:00:00:08:0d:c1:1f:46:78:00:00:20:02:00:00:20:02: > [...do dma...] > After: 0xc7c1ab40 data=2c:03:4e:00:6f:00:76:00:61:00:74:00:65:00:6c:00:20:00:57:00:69:00:72:00: > > The buffer 2c:03:4e:00:... is the correct response from the hardware. > When a bounce buffer is used I see the correct data come in and be > bcopy'd to my memory region but it is not visible when read later. > > Before: 0xc7c29b40 data=c1:50:19:00:c0:5d:ed:f8:00:00:08:0d:c1:1f:46:78:00:00:20:02:00:00:20:02: > dma bounced 0x1271000 -> 0xc7c29b40 len=193 data=2c:03:4e:00:6f:00:76:00:61:00:74:00:65:00:6c:00:20:00:57:00:69:00:72:00: > After: 0xc7c29b40 data=c1:50:19:00:c0:5d:ed:f8:00:00:08:0d:c1:1f:46:78:00:00:20:02:00:00:20:02: > > > This is on an xscale ixp425 with 128m memory, the PCI dma tag is limited > to 64m. > > What device is involved? Is this on HEAD? Sam
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