Messages in this thread | | | Subject | Re: Strange transmit corruption in jsm driver on geode sc1200 system | From | Alan Cox <> | Date | Fri, 25 Aug 2006 22:20:17 +0100 |
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Ar Gwe, 2006-08-25 am 16:30 -0400, ysgrifennodd Lennart Sorensen: > The driver is doing memcpy_toio to tranfer data to the transmit FIFO > (which is a 64byte memory mapped block of memory on the PCI bus as far > as I can tell). The data in the transmit queue is in the right order
That should be staying in order unless the device memory is mislabelled and prefetchable etc.
> being passed to memcpy_toio, but somehow by the time it is in the uart > and goes out the transmiter, every 4th byte is moved 3 bytes back.
What happens if you swap the memcpy_toio with while() writeb() ?
> I read something about the geodes doing memory write reordering, but > that it is supposed to magically not screw up PCI writes. I have no > idea if it is or not though.
They do a lot of stuff but it should not affect the PCI side and I'd expect it to do other things than byte lane re-ordering.
> Does anyone have any suggestions for something to try?
Is the buffer 32bit aligned ?
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