linux-kernel - [PATCH v5 2/6] dma-buf: udmabuf: Implement .{begin,end}

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Date: Fri, 19 Jan 2024 15:13:58 +0100
From: Paul Cercueil <paul@...pouillou.net>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jonathan Corbet <corbet@....net>,
	Sumit Semwal <sumit.semwal@...aro.org>,
	Christian König <christian.koenig@....com>
Cc: Jonathan Cameron <jic23@...nel.org>,
	Nuno Sá <noname.nuno@...il.com>,
	Michael Hennerich <Michael.Hennerich@...log.com>,
	linux-usb@...r.kernel.org,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linaro-mm-sig@...ts.linaro.org,
	Paul Cercueil <paul@...pouillou.net>
Subject: [PATCH v5 2/6] dma-buf: udmabuf: Implement .{begin,end}_access

Implement .begin_access() and .end_access() callbacks.

For now these functions will simply sync/flush the CPU cache when
needed.

Signed-off-by: Paul Cercueil <paul@...pouillou.net>

---
v5: New patch
---
 drivers/dma-buf/udmabuf.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index c40645999648..a87d89b58816 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -179,6 +179,31 @@ static int end_cpu_udmabuf(struct dma_buf *buf,
 	return 0;
 }
 
+static int begin_udmabuf(struct dma_buf_attachment *attach,
+			 struct sg_table *sgt,
+			 enum dma_data_direction dir)
+{
+	struct dma_buf *buf = attach->dmabuf;
+	struct udmabuf *ubuf = buf->priv;
+	struct device *dev = ubuf->device->this_device;
+
+	dma_sync_sg_for_device(dev, sgt->sgl, sg_nents(sgt->sgl), dir);
+	return 0;
+}
+
+static int end_udmabuf(struct dma_buf_attachment *attach,
+		       struct sg_table *sgt,
+		       enum dma_data_direction dir)
+{
+	struct dma_buf *buf = attach->dmabuf;
+	struct udmabuf *ubuf = buf->priv;
+	struct device *dev = ubuf->device->this_device;
+
+	if (dir != DMA_TO_DEVICE)
+		dma_sync_sg_for_cpu(dev, sgt->sgl, sg_nents(sgt->sgl), dir);
+	return 0;
+}
+
 static const struct dma_buf_ops udmabuf_ops = {
 	.cache_sgt_mapping = true,
 	.map_dma_buf	   = map_udmabuf,
@@ -189,6 +214,8 @@ static const struct dma_buf_ops udmabuf_ops = {
 	.vunmap		   = vunmap_udmabuf,
 	.begin_cpu_access  = begin_cpu_udmabuf,
 	.end_cpu_access    = end_cpu_udmabuf,
+	.begin_access      = begin_udmabuf,
+	.end_access        = end_udmabuf,
 };
 
 #define SEALS_WANTED (F_SEAL_SHRINK)
-- 
2.43.0