From: "Niklas S??derlund" <niklas.soderlund@ragnatech.se>
To: Christoph Hellwig <hch@infradead.org>
Cc: vinod.koul@intel.com, linux-renesas-soc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
iommu@lists.linux-foundation.org, robin.murphy@arm.com,
laurent.pinchart@ideasonboard.com, geert+renesas@glider.be,
linus.walleij@linaro.org, dan.j.williams@intel.com,
arnd@arndb.de, linux-arch@vger.kernel.org
Subject: Re: [PATCH v5 3/9] dma-mapping: add dma_{map,unmap}_resource
Date: Thu, 10 Mar 2016 17:05:23 +0100 [thread overview]
Message-ID: <20160310160522.GB1111@bigcity.dyn.berto.se> (raw)
In-Reply-To: <20160308073847.GA15520@infradead.org>
Hi Christoph,
On 2016-03-07 23:38:47 -0800, Christoph Hellwig wrote:
> Please add some documentation on where/how this should be used. It's
> not a very obvious interface.
Good idea, I have added the following to Documentation/DMA-API.txt and
folded it in to this patch. Do you feel it's adequate and do you know
anywhere else I should add documentation?
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 45ef3f2..248556a 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -277,14 +277,29 @@ and <size> parameters are provided to do partial page mapping, it is
recommended that you never use these unless you really know what the
cache width is.
+dma_addr_t
+dma_map_resource(struct device *dev, phys_addr_t phys_addr, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+
+Maps a MMIO region so it can be accessed by the device and returns the
+DMA address of the memory. API should only be used to map device MMIO,
+mapping of RAM is not permitted.
+
+void
+dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+
+Unmaps the IOMMU region previously mapped. All the parameters passed in
+must be identical to those passed in (and returned) by the mapping API.
+
int
dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
-In some circumstances dma_map_single() and dma_map_page() will fail to create
-a mapping. A driver can check for these errors by testing the returned
-DMA address with dma_mapping_error(). A non-zero return value means the mapping
-could not be created and the driver should take appropriate action (e.g.
-reduce current DMA mapping usage or delay and try again later).
+In some circumstances dma_map_single(), dma_map_page() and dma_map_resource()
+will fail to create a mapping. A driver can check for these errors by testing
+the returned DMA address with dma_mapping_error(). A non-zero return value
+means the mapping could not be created and the driver should take appropriate
+action (e.g. reduce current DMA mapping usage or delay and try again later).
--
Regards,
Niklas Söderlund
WARNING: multiple messages have this Message-ID (diff)
From: "Niklas S??derlund" <niklas.soderlund@ragnatech.se>
To: Christoph Hellwig <hch@infradead.org>
Cc: vinod.koul@intel.com, linux-renesas-soc@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
iommu@lists.linux-foundation.org, robin.murphy@arm.com,
laurent.pinchart@ideasonboard.com, geert+renesas@glider.be,
linus.walleij@linaro.org, dan.j.williams@intel.com,
arnd@arndb.de, linux-arch@vger.kernel.org
Subject: Re: [PATCH v5 3/9] dma-mapping: add dma_{map,unmap}_resource
Date: Thu, 10 Mar 2016 17:05:23 +0100 [thread overview]
Message-ID: <20160310160522.GB1111@bigcity.dyn.berto.se> (raw)
In-Reply-To: <20160308073847.GA15520@infradead.org>
Hi Christoph,
On 2016-03-07 23:38:47 -0800, Christoph Hellwig wrote:
> Please add some documentation on where/how this should be used. It's
> not a very obvious interface.
Good idea, I have added the following to Documentation/DMA-API.txt and
folded it in to this patch. Do you feel it's adequate and do you know
anywhere else I should add documentation?
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 45ef3f2..248556a 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -277,14 +277,29 @@ and <size> parameters are provided to do partial page mapping, it is
recommended that you never use these unless you really know what the
cache width is.
+dma_addr_t
+dma_map_resource(struct device *dev, phys_addr_t phys_addr, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+
+Maps a MMIO region so it can be accessed by the device and returns the
+DMA address of the memory. API should only be used to map device MMIO,
+mapping of RAM is not permitted.
+
+void
+dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+
+Unmaps the IOMMU region previously mapped. All the parameters passed in
+must be identical to those passed in (and returned) by the mapping API.
+
int
dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
-In some circumstances dma_map_single() and dma_map_page() will fail to create
-a mapping. A driver can check for these errors by testing the returned
-DMA address with dma_mapping_error(). A non-zero return value means the mapping
-could not be created and the driver should take appropriate action (e.g.
-reduce current DMA mapping usage or delay and try again later).
+In some circumstances dma_map_single(), dma_map_page() and dma_map_resource()
+will fail to create a mapping. A driver can check for these errors by testing
+the returned DMA address with dma_mapping_error(). A non-zero return value
+means the mapping could not be created and the driver should take appropriate
+action (e.g. reduce current DMA mapping usage or delay and try again later).
--
Regards,
Niklas S�derlund
WARNING: multiple messages have this Message-ID (diff)
From: niklas.soderlund@ragnatech.se (Niklas S??derlund)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 3/9] dma-mapping: add dma_{map,unmap}_resource
Date: Thu, 10 Mar 2016 17:05:23 +0100 [thread overview]
Message-ID: <20160310160522.GB1111@bigcity.dyn.berto.se> (raw)
In-Reply-To: <20160308073847.GA15520@infradead.org>
Hi Christoph,
On 2016-03-07 23:38:47 -0800, Christoph Hellwig wrote:
> Please add some documentation on where/how this should be used. It's
> not a very obvious interface.
Good idea, I have added the following to Documentation/DMA-API.txt and
folded it in to this patch. Do you feel it's adequate and do you know
anywhere else I should add documentation?
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 45ef3f2..248556a 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -277,14 +277,29 @@ and <size> parameters are provided to do partial page mapping, it is
recommended that you never use these unless you really know what the
cache width is.
+dma_addr_t
+dma_map_resource(struct device *dev, phys_addr_t phys_addr, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+
+Maps a MMIO region so it can be accessed by the device and returns the
+DMA address of the memory. API should only be used to map device MMIO,
+mapping of RAM is not permitted.
+
+void
+dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+
+Unmaps the IOMMU region previously mapped. All the parameters passed in
+must be identical to those passed in (and returned) by the mapping API.
+
int
dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
-In some circumstances dma_map_single() and dma_map_page() will fail to create
-a mapping. A driver can check for these errors by testing the returned
-DMA address with dma_mapping_error(). A non-zero return value means the mapping
-could not be created and the driver should take appropriate action (e.g.
-reduce current DMA mapping usage or delay and try again later).
+In some circumstances dma_map_single(), dma_map_page() and dma_map_resource()
+will fail to create a mapping. A driver can check for these errors by testing
+the returned DMA address with dma_mapping_error(). A non-zero return value
+means the mapping could not be created and the driver should take appropriate
+action (e.g. reduce current DMA mapping usage or delay and try again later).
--
Regards,
Niklas S?derlund
next prev parent reply other threads:[~2016-03-10 16:05 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 [this message]
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
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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