From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 RFC 2/8] arm: introduce a global dma_ops pointer
Date: Wed, 31 Jul 2013 21:01:35 +0100 [thread overview]
Message-ID: <20130731200135.GZ24642@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1375300452-12545-2-git-send-email-stefano.stabellini@eu.citrix.com>
On Wed, Jul 31, 2013 at 08:54:06PM +0100, Stefano Stabellini wrote:
> Initially set dma_ops to arm_dma_ops.
> Use dma_ops instead of arm_dma_ops in dmabounce.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> CC: will.deacon at arm.com
> CC: linux at arm.linux.org.uk
If you're using swiotlb, there's little point in converting dmabounce
to be able to use it, because it's basically providing the same
functionality - dmabounce is there to do software buffer bouncing within
the DMA to move streaming buffers from DMA-inaccessible memory into
DMA-accessible memory.
It's original use is with older SoCs with buggy DMA (eg, those which
can only address alternate 1MB chunks of memory for example) but also
got used in situations where alternative solutions would've been better
(like using swiotlb.) I've been discouraging its use as it's suffered
from memory exhaustion problems (there's a number of threads and bug
reports which were never solved about IXP4xx(?) platforms suffering
this due to this bouncing.)
next prev parent reply other threads:[~2013-07-31 20:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-31 19:52 [PATCH v2 RFC 0/8] enable swiotlb-xen on arm and arm64 Stefano Stabellini
2013-07-31 19:54 ` [PATCH v2 RFC 1/8] arm: make SWIOTLB available Stefano Stabellini
2013-07-31 19:54 ` [PATCH v2 RFC 2/8] arm: introduce a global dma_ops pointer Stefano Stabellini
2013-07-31 20:01 ` Russell King - ARM Linux [this message]
2013-08-02 11:42 ` Stefano Stabellini
2013-07-31 19:54 ` [PATCH v2 RFC 3/8] arm64: do not initialize arm64_swiotlb if dma_ops is already set Stefano Stabellini
2013-07-31 19:54 ` [PATCH v2 RFC 4/8] xen/arm,arm64: move Xen initialization earlier Stefano Stabellini
2013-07-31 19:54 ` [PATCH v2 RFC 5/8] xen: introduce XENMEM_get_dma_buf and xen_put_dma_buf Stefano Stabellini
2013-07-31 19:54 ` [PATCH v2 RFC 6/8] xen: make xen_create_contiguous_region return the dma address Stefano Stabellini
2013-07-31 19:54 ` [PATCH v2 RFC 7/8] swiotlb-xen: support autotranslate guests Stefano Stabellini
2013-08-01 12:19 ` David Vrabel
2013-07-31 19:54 ` [PATCH v2 RFC 8/8] xen/arm,arm64: enable SWIOTLB_XEN Stefano Stabellini
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