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From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Linux IOMMU <iommu@lists.linux-foundation.org>,
	linux-media@vger.kernel.org, linux-samsung-soc@vger.kernel.org
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>, Christoph Hellwig <hch@lst.de>,
	Sylwester Nawrocki <snawrocki@kernel.org>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Tomasz Figa <tfiga@chromium.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/8] dma-mapping: add DMA_ATTR_LOW_ADDRESS attribute
Date: Fri, 25 Sep 2020 16:12:11 +0200	[thread overview]
Message-ID: <20200925141218.13550-2-m.szyprowski@samsung.com> (raw)
In-Reply-To: <20200925141218.13550-1-m.szyprowski@samsung.com>

Some devices require to allocate a special buffer (usually for the
firmware) just at the beginning of the address space to ensure that all
further allocations can be expressed as a positive offset from that
special buffer. When IOMMU is used for managing the DMA address space,
such requirement can be easily fulfilled, simply by enforcing the
'first-fit' IOVA allocation algorithm.

This patch adds a DMA attribute for such case.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 include/linux/dma-mapping.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index bb138ac6f5e6..c8c568ba375b 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -66,6 +66,12 @@
  * at least read-only at lesser-privileged levels).
  */
 #define DMA_ATTR_PRIVILEGED		(1UL << 9)
+/*
+ * DMA_ATTR_LOW_ADDRESS: used to indicate that the buffer should be allocated
+ * at the lowest possible DMA address, usually just at the beginning of the
+ * DMA/IOVA address space ('first-fit' allocation algorithm).
+ */
+#define DMA_ATTR_LOW_ADDRESS		(1UL << 10)
 
 /*
  * A dma_addr_t can hold any valid DMA or bus address for the platform.
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Linux IOMMU <iommu@lists.linux-foundation.org>,
	linux-media@vger.kernel.org, linux-samsung-soc@vger.kernel.org
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Sylwester Nawrocki <snawrocki@kernel.org>,
	linux-kernel@vger.kernel.org,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Christoph Hellwig <hch@lst.de>
Subject: [PATCH 1/8] dma-mapping: add DMA_ATTR_LOW_ADDRESS attribute
Date: Fri, 25 Sep 2020 16:12:11 +0200	[thread overview]
Message-ID: <20200925141218.13550-2-m.szyprowski@samsung.com> (raw)
In-Reply-To: <20200925141218.13550-1-m.szyprowski@samsung.com>

Some devices require to allocate a special buffer (usually for the
firmware) just at the beginning of the address space to ensure that all
further allocations can be expressed as a positive offset from that
special buffer. When IOMMU is used for managing the DMA address space,
such requirement can be easily fulfilled, simply by enforcing the
'first-fit' IOVA allocation algorithm.

This patch adds a DMA attribute for such case.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 include/linux/dma-mapping.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index bb138ac6f5e6..c8c568ba375b 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -66,6 +66,12 @@
  * at least read-only at lesser-privileged levels).
  */
 #define DMA_ATTR_PRIVILEGED		(1UL << 9)
+/*
+ * DMA_ATTR_LOW_ADDRESS: used to indicate that the buffer should be allocated
+ * at the lowest possible DMA address, usually just at the beginning of the
+ * DMA/IOVA address space ('first-fit' allocation algorithm).
+ */
+#define DMA_ATTR_LOW_ADDRESS		(1UL << 10)
 
 /*
  * A dma_addr_t can hold any valid DMA or bus address for the platform.
-- 
2.17.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  parent reply	other threads:[~2020-09-25 14:12 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200925141230eucas1p1b4bb8a7e17a887c6ca6a7b8caa7cf9c7@eucas1p1.samsung.com>
2020-09-25 14:12 ` [PATCH 0/8] IOMMU-DMA - support old allocation algorithm used on ARM Marek Szyprowski
2020-09-25 14:12   ` Marek Szyprowski
     [not found]   ` <CGME20200925141231eucas1p223c342cc989df23e4fc28d97fe3010c5@eucas1p2.samsung.com>
2020-09-25 14:12     ` Marek Szyprowski [this message]
2020-09-25 14:12       ` [PATCH 1/8] dma-mapping: add DMA_ATTR_LOW_ADDRESS attribute Marek Szyprowski
2020-09-25 16:20       ` Christoph Hellwig
2020-09-25 16:20         ` Christoph Hellwig
     [not found]   ` <CGME20200925141231eucas1p22043424ba07b99f7727f750487a55b6d@eucas1p2.samsung.com>
2020-09-25 14:12     ` [PATCH 2/8] iommu: iova: properly handle 0 as a valid IOVA address Marek Szyprowski
2020-09-25 14:12       ` Marek Szyprowski
     [not found]   ` <CGME20200925141232eucas1p1c021913b0c2505e6c77e5078cf2be74f@eucas1p1.samsung.com>
2020-09-25 14:12     ` [PATCH 3/8] iommu: iova: add support for 'first-fit' algorithm Marek Szyprowski
2020-09-25 14:12       ` Marek Szyprowski
     [not found]   ` <CGME20200925141232eucas1p29ad64ca3bc90bb3cbfad9b385cb3d9ef@eucas1p2.samsung.com>
2020-09-25 14:12     ` [PATCH 4/8] iommu: dma-iommu: refactor iommu_dma_alloc_iova() Marek Szyprowski
2020-09-25 14:12       ` Marek Szyprowski
     [not found]   ` <CGME20200925141233eucas1p2148ace93f157bd631edd8db4e8df664b@eucas1p2.samsung.com>
2020-09-25 14:12     ` [PATCH 5/8] iommu: dma-iommu: add support for DMA_ATTR_LOW_ADDRESS Marek Szyprowski
2020-09-25 14:12       ` Marek Szyprowski
     [not found]   ` <CGME20200925141234eucas1p13ab5a15da95185dcc99300772d0d72ce@eucas1p1.samsung.com>
2020-09-25 14:12     ` [PATCH 6/8] media: platform: exynos4-is: remove all references to physicall addresses Marek Szyprowski
2020-09-25 14:12       ` Marek Szyprowski
     [not found]   ` <CGME20200925141234eucas1p2876321230b7f0910242e0e28b3a8388b@eucas1p2.samsung.com>
2020-09-25 14:12     ` [PATCH 7/8] media: platform: exynos4-is: use DMA_ATTR_LOW_ADDRESS Marek Szyprowski
2020-09-25 14:12       ` Marek Szyprowski
     [not found]   ` <CGME20200925141235eucas1p17c6aceae82acfc424cdc7521938c1510@eucas1p1.samsung.com>
2020-09-25 14:12     ` [PATCH 8/8] media: platform: s5p-mfc: " Marek Szyprowski
2020-09-25 14:12       ` Marek Szyprowski

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