From: Stefan Richter <stefanr@s5r6.in-berlin.de>
To: linuxppc-dev@ozlabs.org
Cc: linux-kernel@vger.kernel.org
Subject: dma_alloc_coherent() on PPC32: physical addresses above 2G possible?
Date: Sun, 20 Jul 2008 20:36:23 +0200 [thread overview]
Message-ID: <488385A7.4010509@s5r6.in-berlin.de> (raw)
Hi all,
I have to implement a workaround for a PCI device which gets into
trouble if descriptors are located at 32bit addresses, while 31bit
addresses are fine. I would like to avoid this workaround on machines
on which dma_alloc_coherent() won't ever go at memory above 2 GB.
Is defined(CONFIG_PPC32) a safe test for this? I'm under the impression
that defined(CONFIG_X86_32) is safe.
Are there any other means to detect when the workaround can be omitted,
at compile time or at runtime?
PS: I don't want to set the DMA mask of this device to DMA_31BIT_MASK
because that would be detrimental to other functions of the device. It's
a TI TSB43AB22A FireWire controller.
--
Stefan Richter
-=====-==--- -=== =-=--
http://arcgraph.de/sr/
next reply other threads:[~2008-07-20 18:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-20 18:36 Stefan Richter [this message]
2008-07-20 18:43 ` dma_alloc_coherent() on PPC32: physical addresses above 2G possible? Arjan van de Ven
2008-07-20 19:25 ` Stefan Richter
2008-07-20 19:39 ` Arjan van de Ven
2008-07-20 20:11 ` Stefan Richter
2008-07-20 19:48 ` Arjan van de Ven
2008-07-20 21:35 ` Benjamin Herrenschmidt
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