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From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
To: David1.Zhou@amd.com, hch@infradead.org, jgg@ziepe.ca,
	daniel@ffwll.ch, dri-devel@lists.freedesktop.org,
	linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org,
	intel-gfx@lists.freedesktop.org
Subject: [Intel-gfx] [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function
Date: Wed, 11 Mar 2020 14:51:53 +0100	[thread overview]
Message-ID: <20200311135158.3310-2-christian.koenig@amd.com> (raw)
In-Reply-To: <20200311135158.3310-1-christian.koenig@amd.com>

This can be used by drivers to setup P2P DMA between device
memory which is not backed by struct pages.

The drivers of the involved devices are responsible for
setting up and tearing down DMA addresses as necessary
using dma_map_resource().

The page pointer is set to NULL and only the DMA address,
length and offset values are valid.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 include/linux/scatterlist.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 6eec50fb36c8..28a477bf0bdf 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -145,6 +145,29 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
 	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
 }
 
+/**
+ * sg_set_dma_addr - Set sg entry to point at specified dma address
+ * @sg:		 SG entry
+ * @address:	 DMA address to set
+ * @len:	 Length of data
+ * @offset:	 Offset into page
+ *
+ * Description:
+ *   Use this function to set an sg entry to point to device resources mapped
+ *   using dma_map_resource(). The page pointer is set to NULL and only the DMA
+ *   address, length and offset values are valid.
+ *
+ **/
+static inline void sg_set_dma_addr(struct scatterlist *sg, dma_addr_t address,
+				   unsigned int len, unsigned int offset)
+{
+	sg_set_page(sg, NULL, len, offset);
+	sg->dma_address = address;
+#ifdef CONFIG_NEED_SG_DMA_LENGTH
+	sg->dma_length = len;
+#endif
+}
+
 /*
  * Loop over each sg element, following the pointer to a new list if necessary
  */
-- 
2.17.1

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  reply	other threads:[~2020-03-11 15:04 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 13:51 [Intel-gfx] P2P for DMA-buf Christian König
2020-03-11 13:51 ` Christian König [this message]
2020-03-11 15:28   ` [Intel-gfx] [PATCH 1/6] lib/scatterlist: add sg_set_dma_addr() function Christoph Hellwig
2020-03-12 10:14     ` Christian König
2020-03-12 10:19       ` Christoph Hellwig
2020-03-12 10:31         ` Christian König
2020-03-12 10:47           ` Christoph Hellwig
2020-03-12 11:02             ` Christian König
     [not found]             ` <20200312141928.GK31668@ziepe.ca>
2020-03-12 15:39               ` Christian König
2020-03-12 16:13               ` Logan Gunthorpe
2020-03-13 11:21               ` Christoph Hellwig
2020-03-13 13:33                 ` Christian König
     [not found]                 ` <20200313121742.GZ31668@ziepe.ca>
2020-03-16  8:56                   ` Christoph Hellwig
2020-03-16  9:41                     ` Christian König
2020-03-16  9:52                       ` Christoph Hellwig
2020-03-11 13:51 ` [Intel-gfx] [PATCH 2/6] dma-buf: add peer2peer flag Christian König
2020-03-11 13:51 ` [Intel-gfx] [PATCH 3/6] drm/amdgpu: note that we can handle peer2peer DMA-buf Christian König
2020-03-11 13:51 ` [Intel-gfx] [PATCH 4/6] drm/amdgpu: add checks if DMA-buf P2P is supported Christian König
     [not found]   ` <20200311140415.GB31668@ziepe.ca>
2020-03-11 14:33     ` Christian König
     [not found]       ` <20200311143835.GD31668@ziepe.ca>
2020-03-11 14:43         ` Christian König
2020-03-11 13:51 ` [Intel-gfx] [PATCH 5/6] drm/amdgpu: add support for exporting VRAM using DMA-buf v2 Christian König
2020-03-11 15:08   ` Alex Deucher
2020-03-11 13:51 ` [Intel-gfx] [PATCH 6/6] drm/amdgpu: improve amdgpu_gem_info debugfs file Christian König
2020-03-11 18:09 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [1/6] lib/scatterlist: add sg_set_dma_addr() function Patchwork
2020-03-11 18:34 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork

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