From: Christoph Hellwig <hch@lst.de>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Linux IOMMU <iommu@lists.linux-foundation.org>,
linux-media@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
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: Re: [PATCH 1/8] dma-mapping: add DMA_ATTR_LOW_ADDRESS attribute
Date: Fri, 25 Sep 2020 18:20:03 +0200 [thread overview]
Message-ID: <20200925162003.GA18879@lst.de> (raw)
In-Reply-To: <20200925141218.13550-2-m.szyprowski@samsung.com>
> #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)
I think we need better comments explaining that this is best effort
and only applies to DMA API implementations that actually have an
allocatable IOVA space.
next prev parent reply other threads:[~2020-09-25 16:20 UTC|newest]
Thread overview: 10+ 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 ` [PATCH 1/8] dma-mapping: add DMA_ATTR_LOW_ADDRESS attribute Marek Szyprowski
2020-09-25 16:20 ` Christoph Hellwig [this message]
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 ` [PATCH 3/8] iommu: iova: add support for 'first-fit' algorithm Marek Szyprowski
2020-09-25 14:12 ` [PATCH 4/8] iommu: dma-iommu: refactor iommu_dma_alloc_iova() Marek Szyprowski
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 ` [PATCH 6/8] media: platform: exynos4-is: remove all references to physicall addresses Marek Szyprowski
2020-09-25 14:12 ` [PATCH 7/8] media: platform: exynos4-is: use DMA_ATTR_LOW_ADDRESS Marek Szyprowski
2020-09-25 14:12 ` [PATCH 8/8] media: platform: s5p-mfc: " Marek Szyprowski
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