1) My analysis: Only the data areas are being flushed/invalidated. No
transfer descriptors are flushed/invalidated. I see no cache operations
happening on any DMA control structures, even though there are calls from
EHCI to xxx_pc_flush() and xxx_pc_invalidate().
This is 100% correct if
. In later versions is bug in ARM pmap
causing segmentation fault in ehci atatch code (for more details loot at
http://www.nabble.com/pmap-problem-in-FreeBSD-current-td24352351.html).
--
Pozdrawiam.
Piotr Zięcik
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Wednesday 08 July 2009 12:30:46 Sebastian Huber napisał(a):
Device to memory DMA transfer of a buffer:
(...)
3. all accesses to the buffer via the cache must wait until the DMA has
finished
And this is the problem in my oppinion - USB stack does not wait.
--
Best Regards.
Piotr Zięcik
Wednesday 08 July 2009 11:03:43 Hans Petter Selasky napisał(a):
And what about my patch suggestion in my previous e-mail having the same
subject. Does it work?
I have tested it and it does not work. By the way Writeback before Writeback
Invalidate did not change cache behaviour too much.
(0xC3A9E480, 0xC3BB8080, [PREREAD
_])
- Writeback Invalidate 0xC3BB2770 (size: 0x000D)
= bus_dmamap_sync(0xC3A9E480, 0xC3BB8080, [PREREAD
_])
- Writeback Invalidate 0xC3BB2770 (size: 0x000D)
--
Best regards,
Piotr Zięcik
Monday 29 June 2009 15:16:56 Hans Petter Selasky napisał(a):
You want to change the flags passed to bus_dmamap_sync() so that the
flush/invalidate mapping gets right. I understand why your patch makes it
work. That's not the problem.
In src/sys/arm/arm/busdma_machdep.c there is a function
Sunday 28 June 2009 11:54:40 Hans Petter Selasky napisał(a):
Hi Piotr and Rafal,
Your patch is not fully correct. It will break support for x86 and more
when bounce pages are uses.
Let's get the definitions right:
man busdma
(...)
My view:
XXX_PREXXX functions should be used prior to
Monday 29 June 2009 13:37:41 Hans Petter Selasky napisał(a):
Look into ehci_check_transfer() function
(http://fxr.watson.org/fxr/source/dev/usb/controller/ehci.c#L1294)
usb_pc_cpu_invalidate() [bus_dmamap_sync()] is not used in this function
correcly. It is not paired with
Monday 29 June 2009 13:37:41 Hans Petter Selasky napisał(a):
if (op BUS_DMASYNC_POSTREAD) {
if (bpage-vaddr_nocache == 0) {
cpu_dcache_inv_range(bpage-vaddr,
bpage-datacount);
is a bit
different thing.
--
Pozdrawiam.
Piotr Zięcik
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While bringing up EHCI (8-CURRENT, new USB stack) on ARM machine we have
found cache-related problem in the USB stack.
The usb_pc_cpu_flush() and usb_pc_cpu_invalidate() functions are used to
flush/invalidate CPU caches in various places in USB code. Internally, the
functions are implemented
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