From: Cho KyongHo <pullip.cho@samsung.com>
Date: Fri, 2 Mar 2018 14:03:48 +0000 (+0900)
Subject: android: ion: add dmabuf cpu access ops for exynos
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6f51c5003d3dab4291d6b7276d98dcb99ac00024;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

android: ion: add dmabuf cpu access ops for exynos

.begin_cpu_access and .end_cpu_access of dmabuf ops provided by ION
needs scatter-gather list because they rely on dma-mapping api.

After 'commit 8dbbf7b ("android: ion: do not map in dma_map_attach()
for Exynos")', ion_dma_buf_begin_cpu_access() and
ion_dma_buf_end_cpu_access() loose scatter-gather list stored in
the dma-buf attachment that is eliminated by the above commit.

Instead, dma-mapping api can be used with ion_buffer.sg_table and the
miscdevice of ion_device because they are initialized at buffer
allocation and ION initialization, respectively since 'commit 10a41c2
("android: ion: add fixups to ion exynos extension")'.

Uncached buffers are not required to maintain CPU caches for CPU
accesses because dma_buf_kmap() returns the kernel address with the
cacheability attribute of the buffer.

Change-Id: I6656f22b696ae96de9f2766751970b25f17572f6
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
---

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index b726485f5cc3..a30dcbb1ddad 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -368,12 +368,23 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
 		mutex_unlock(&buffer->lock);
 	}
 
-	mutex_lock(&dmabuf->lock);
-	list_for_each_entry(att, &dmabuf->attachments, node) {
-		struct sg_table *table = att->priv;
+	if (!ion_buffer_cached(buffer))
+		return 0;
 
-		dma_sync_sg_for_cpu(att->dev, table->sgl, table->nents,
-				    direction);
+	mutex_lock(&dmabuf->lock);
+	if (IS_ENABLED(CONFIG_ION_EXYNOS)) {
+		if (!list_empty(&dmabuf->attachments))
+			dma_sync_sg_for_cpu(buffer->dev->dev.this_device,
+					    buffer->sg_table->sgl,
+					    buffer->sg_table->orig_nents,
+					    direction);
+	} else {
+		list_for_each_entry(att, &dmabuf->attachments, node) {
+			struct sg_table *table = att->priv;
+
+			dma_sync_sg_for_cpu(att->dev, table->sgl, table->nents,
+					    direction);
+		}
 	}
 	mutex_unlock(&dmabuf->lock);
 
@@ -392,12 +403,23 @@ static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
 		mutex_unlock(&buffer->lock);
 	}
 
-	mutex_lock(&dmabuf->lock);
-	list_for_each_entry(att, &dmabuf->attachments, node) {
-		struct sg_table *table = att->priv;
+	if (!ion_buffer_cached(buffer))
+		return 0;
 
-		dma_sync_sg_for_device(att->dev, table->sgl, table->nents,
-				       direction);
+	mutex_lock(&dmabuf->lock);
+	if (IS_ENABLED(CONFIG_ION_EXYNOS)) {
+		if (!list_empty(&dmabuf->attachments))
+			dma_sync_sg_for_device(buffer->dev->dev.this_device,
+					       buffer->sg_table->sgl,
+					       buffer->sg_table->orig_nents,
+					       direction);
+	} else {
+		list_for_each_entry(att, &dmabuf->attachments, node) {
+			struct sg_table *table = att->priv;
+
+			dma_sync_sg_for_device(att->dev, table->sgl,
+					       table->nents, direction);
+		}
 	}
 	mutex_unlock(&dmabuf->lock);