From: Christoph Hellwig <hch@infradead.org>
To: Christoph Hellwig <hch@infradead.org>,
Dan Williams <dan.j.williams@intel.com>,
Vinod Koul <vinod.koul@intel.com>,
linux-renesas-soc@vger.kernel.org,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
iommu@lists.linux-foundation.org, robin.murphy@arm.com,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
geert+renesas@glider.be, Linus Walleij <linus.walleij@linaro.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-arch@vger.kernel.org
Subject: Re: [PATCH v5 3/9] dma-mapping: add dma_{map,unmap}_resource
Date: Tue, 15 Mar 2016 01:22:54 -0700 [thread overview]
Message-ID: <20160315082254.GE9136@infradead.org> (raw)
In-Reply-To: <20160311125846.GF1111@bigcity.dyn.berto.se>
On Fri, Mar 11, 2016 at 01:58:46PM +0100, Niklas S?derlund wrote:
> Without an IOMMU this is easy since the phys_addr_t and dma_addr_t are
> the same and no special care is needed. However if you have a IOMMU you
> need to map the DMA slave phys_addr_t to a dma_addr_t using something
> like this. Is it not very similar to dma_map_single() where one maps
> processor virtual memory (instead if MMIO) so that it can be used with
> DMA slaves?
It's similar, but I don't think this actually works as a general case
as there are quite a few places that expect to be able to have a
struct page for a physical address. We'd at least need a very careful
audit for that case.
WARNING: multiple messages have this Message-ID (diff)
From: hch@infradead.org (Christoph Hellwig)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 3/9] dma-mapping: add dma_{map,unmap}_resource
Date: Tue, 15 Mar 2016 01:22:54 -0700 [thread overview]
Message-ID: <20160315082254.GE9136@infradead.org> (raw)
In-Reply-To: <20160311125846.GF1111@bigcity.dyn.berto.se>
On Fri, Mar 11, 2016 at 01:58:46PM +0100, Niklas S?derlund wrote:
> Without an IOMMU this is easy since the phys_addr_t and dma_addr_t are
> the same and no special care is needed. However if you have a IOMMU you
> need to map the DMA slave phys_addr_t to a dma_addr_t using something
> like this. Is it not very similar to dma_map_single() where one maps
> processor virtual memory (instead if MMIO) so that it can be used with
> DMA slaves?
It's similar, but I don't think this actually works as a general case
as there are quite a few places that expect to be able to have a
struct page for a physical address. We'd at least need a very careful
audit for that case.
next prev parent reply other threads:[~2016-03-15 8:23 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-08 2:42 [PATCH v5 0/9] dmaengine: rcar-dmac: add iommu support for slave transfers Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` [PATCH v5 1/9] iommu: Add MMIO mapping type Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-17 11:18 ` Laurent Pinchart
2016-03-17 11:18 ` Laurent Pinchart
2016-03-17 11:18 ` Laurent Pinchart
2016-03-17 11:18 ` Laurent Pinchart
2016-03-08 2:42 ` [PATCH v5 2/9] dma-mapping: add {map,unmap}_resource to dma_map_ops Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` [PATCH v5 3/9] dma-mapping: add dma_{map,unmap}_resource Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 7:38 ` Christoph Hellwig
2016-03-08 7:38 ` Christoph Hellwig
2016-03-10 16:05 ` Niklas S??derlund
2016-03-10 16:05 ` Niklas S??derlund
2016-03-10 16:05 ` Niklas S??derlund
2016-03-11 6:19 ` Vinod Koul
2016-03-11 6:19 ` Vinod Koul
2016-03-11 6:19 ` Vinod Koul
2016-03-11 6:47 ` Dan Williams
2016-03-11 6:47 ` Dan Williams
2016-03-11 6:47 ` Dan Williams
2016-03-11 11:15 ` Christoph Hellwig
2016-03-11 11:15 ` Christoph Hellwig
2016-03-11 11:15 ` Christoph Hellwig
2016-03-11 12:58 ` Niklas Söderlund
2016-03-11 12:58 ` Niklas Söderlund
2016-03-11 12:58 ` Niklas Söderlund
2016-03-11 12:58 ` Niklas Söderlund
2016-03-15 8:22 ` Christoph Hellwig [this message]
2016-03-15 8:22 ` Christoph Hellwig
2016-03-15 8:22 ` Christoph Hellwig
2016-03-17 11:33 ` Laurent Pinchart
2016-03-17 11:33 ` Laurent Pinchart
2016-03-17 11:33 ` Laurent Pinchart
2016-03-17 11:33 ` Laurent Pinchart
2016-03-21 15:26 ` Christoph Hellwig
2016-03-21 15:26 ` Christoph Hellwig
2016-03-21 15:26 ` Christoph Hellwig
2016-04-13 13:29 ` Niklas Söderlund
2016-04-13 13:29 ` Niklas Söderlund
2016-04-13 13:29 ` Niklas Söderlund
2016-04-13 13:29 ` Niklas Söderlund
2016-04-13 13:29 ` Niklas Söderlund
2016-04-21 9:48 ` Niklas Söderlund
2016-04-21 9:48 ` Niklas Söderlund
2016-04-21 9:48 ` Niklas Söderlund
2016-04-21 9:48 ` Niklas Söderlund
2016-04-21 13:49 ` Christoph Hellwig
2016-04-21 13:49 ` Christoph Hellwig
2016-04-21 13:49 ` Christoph Hellwig
2016-04-25 14:26 ` Niklas Söderlund
2016-04-25 14:26 ` Niklas Söderlund
2016-04-25 14:26 ` Niklas Söderlund
2016-04-25 14:26 ` Niklas Söderlund
2016-04-25 19:10 ` Christoph Hellwig
2016-04-25 19:10 ` Christoph Hellwig
2016-04-25 19:10 ` Christoph Hellwig
2016-04-26 13:29 ` Niklas Söderlund
2016-04-26 13:29 ` Niklas Söderlund
2016-04-26 13:29 ` Niklas Söderlund
2016-04-26 13:29 ` Niklas Söderlund
2016-04-26 13:29 ` Niklas Söderlund
2016-03-11 13:46 ` Robin Murphy
2016-03-11 13:46 ` Robin Murphy
2016-03-11 13:46 ` Robin Murphy
2016-03-11 13:46 ` Robin Murphy
2016-03-11 17:51 ` Dan Williams
2016-03-11 17:51 ` Dan Williams
2016-03-11 17:51 ` Dan Williams
2016-03-08 2:42 ` [PATCH v5 4/9] arm: dma-mapping: add {map,unmap}_resource for iommu ops Niklas Söderlund
2016-03-08 2:42 ` [PATCH v5 4/9] arm: dma-mapping: add {map, unmap}_resource " Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` [PATCH v5 5/9] dmaengine: rcar-dmac: slave address are physical Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-17 11:30 ` Laurent Pinchart
2016-03-17 11:30 ` Laurent Pinchart
2016-03-17 11:30 ` Laurent Pinchart
2016-03-17 11:30 ` Laurent Pinchart
2016-03-08 2:42 ` [PATCH v5 6/9] dmaengine: rcar-dmac: group slave configuration Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-17 11:28 ` Laurent Pinchart
2016-03-17 11:28 ` Laurent Pinchart
2016-03-17 11:28 ` Laurent Pinchart
2016-03-17 11:28 ` Laurent Pinchart
2016-03-08 2:42 ` [PATCH v5 7/9] dmaengine: rcar-dmac: add iommu support for slave transfers Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` [PATCH v5 8/9] ARM: dts: r8a7790: add iommus to dmac0 and dmac1 Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
2016-03-08 2:42 ` [PATCH v5 9/9] ARM: dts: r8a7791: " Niklas Söderlund
2016-03-08 2:42 ` Niklas Söderlund
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