From: robin.murphy@arm•com (Robin Murphy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3 5/6] iommu/mediatek: Add mt8173 IOMMU driver
Date: Mon, 27 Jul 2015 16:49:30 +0100 [thread overview]
Message-ID: <55B6530A.9050903@arm.com> (raw)
In-Reply-To: <20150727153148.GJ7557@n2100.arm.linux.org.uk>
On 27/07/15 16:31, Russell King - ARM Linux wrote:
> On Mon, Jul 27, 2015 at 02:23:26PM +0100, Robin Murphy wrote:
>> On 16/07/15 10:04, Yong Wu wrote:
>>> This patch adds support for mediatek m4u (MultiMedia Memory Management
>>> Unit).
>>>
>>> Signed-off-by: Yong Wu <yong.wu@mediatek•com>
>> [...]
>>> +static void mtk_iommu_flush_pgtable(void *ptr, size_t size, void *cookie)
>>> +{
>>> + struct mtk_iommu_domain *domain = cookie;
>>> + unsigned long offset = (unsigned long)ptr & ~PAGE_MASK;
>>> +
>>> + dma_map_page(domain->data->dev, virt_to_page(ptr), offset,
>>> + size, DMA_TO_DEVICE);
>>
>> Nit: this looks like it may as well be dma_map_single.
>>
>> It would probably be worth following it with a matching unmap too, just to
>> avoid any possible leakage bugs (especially if this M4U ever appears in a
>> SoC supporting RAM above the 32-bit boundary).
>
> Why not do the job properly? Take a look at how I implemented the
> streaming DMA API on Tegra SMMU (patch set recently sent out earlier
> today).
>
> There's no need for hacks like dma_map_page() (and discarding it's
> return value) or dma_map_page() followed by dma_unmap_page().
Indeed, as it happens I do have a branch where I prototyped that for the
long-descriptor io-pgtable-arm code a while ago; this discussion has
prompted me to dig it up again. Stay tuned, folks...
Robin.
next prev parent reply other threads:[~2015-07-27 15:49 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-16 9:04 [PATCH v3 0/6] MT8173 IOMMU SUPPORT Yong Wu
2015-07-16 9:04 ` [PATCH v3 1/6] dt-bindings: iommu: Add binding for mediatek IOMMU Yong Wu
2015-07-16 9:04 ` [PATCH v3 2/6] dt-bindings: mediatek: Add smi dts binding Yong Wu
2015-07-16 9:04 ` [PATCH v3 3/6] iommu: add ARM short descriptor page table allocator Yong Wu
2015-07-21 17:11 ` Will Deacon
2015-07-24 5:24 ` Yong Wu
2015-07-24 16:53 ` Will Deacon
2015-07-27 4:21 ` Yong Wu
2015-07-27 14:05 ` Robin Murphy
2015-07-27 14:11 ` Will Deacon
2015-07-28 5:08 ` Yong Wu
2015-07-28 11:00 ` Will Deacon
2015-07-28 13:37 ` Yong Wu
2015-07-28 13:47 ` Will Deacon
[not found] ` <1438329337.25925.147.camel@mhfsdcap03>
2015-07-31 11:32 ` Will Deacon
2015-09-14 12:25 ` Yong Wu
2015-09-16 12:55 ` Will Deacon
2015-09-17 2:38 ` Yong Wu
2015-07-16 9:04 ` [PATCH v3 4/6] memory: mediatek: Add SMI driver Yong Wu
2015-07-16 9:04 ` [PATCH v3 5/6] iommu/mediatek: Add mt8173 IOMMU driver Yong Wu
2015-07-21 14:59 ` Will Deacon
2015-07-24 5:43 ` Yong Wu
2015-07-24 16:55 ` Will Deacon
2015-07-27 4:24 ` Yong Wu
2015-07-27 15:48 ` Will Deacon
2015-07-27 13:23 ` Robin Murphy
2015-07-27 15:31 ` Russell King - ARM Linux
2015-07-27 15:49 ` Robin Murphy [this message]
2015-07-29 5:41 ` Yong Wu
2015-07-29 10:31 ` Will Deacon
2015-07-29 6:32 ` Yong Wu
2015-07-16 9:04 ` [PATCH v3 6/6] dts: mt8173: Add iommu/smi nodes for mt8173 Yong Wu
2015-07-23 14:40 ` Daniel Kurtz
2015-07-29 7:29 ` Yong Wu
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