[PATCH] dma-buf: add DMA_BUF_IOCTL_SYNC_PARTIAL support

[Jianqun Xu <jay.xu@xxxxxxxxxxxxxx>]

Add DMA_BUF_IOCTL_SYNC_PARTIAL support for user to sync dma-buf with
offset and len.

Change-Id: I03d2d2e10e48d32aa83c31abade57e0931e1be49
Signed-off-by: Jianqun Xu <jay.xu@xxxxxxxxxxxxxx>
---
 drivers/dma-buf/dma-buf.c    | 42 ++++++++++++++++++++++++++++++++++++
 include/uapi/linux/dma-buf.h |  8 +++++++
 2 files changed, 50 insertions(+)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index d9948d58b3f4..78f37f7c3462 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -392,6 +392,7 @@ static long dma_buf_ioctl(struct file *file,
 {
 	struct dma_buf *dmabuf;
 	struct dma_buf_sync sync;
+	struct dma_buf_sync_partial sync_p;
 	enum dma_data_direction direction;
 	int ret;
 
@@ -430,6 +431,47 @@ static long dma_buf_ioctl(struct file *file,
 	case DMA_BUF_SET_NAME_B:
 		return dma_buf_set_name(dmabuf, (const char __user *)arg);
 
+	case DMA_BUF_IOCTL_SYNC_PARTIAL:
+		if (copy_from_user(&sync_p, (void __user *) arg, sizeof(sync_p)))
+			return -EFAULT;
+
+		if (sync_p.len == 0)
+			return 0;
+
+		if ((sync_p.offset % cache_line_size()) || (sync_p.len % cache_line_size()))
+			return -EINVAL;
+
+		if (sync_p.len > dmabuf->size || sync_p.offset > dmabuf->size - sync_p.len)
+			return -EINVAL;
+
+		if (sync_p.flags & ~DMA_BUF_SYNC_VALID_FLAGS_MASK)
+			return -EINVAL;
+
+		switch (sync_p.flags & DMA_BUF_SYNC_RW) {
+		case DMA_BUF_SYNC_READ:
+			direction = DMA_FROM_DEVICE;
+			break;
+		case DMA_BUF_SYNC_WRITE:
+			direction = DMA_TO_DEVICE;
+			break;
+		case DMA_BUF_SYNC_RW:
+			direction = DMA_BIDIRECTIONAL;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		if (sync_p.flags & DMA_BUF_SYNC_END)
+			ret = dma_buf_end_cpu_access_partial(dmabuf, direction,
+							     sync_p.offset,
+							     sync_p.len);
+		else
+			ret = dma_buf_begin_cpu_access_partial(dmabuf, direction,
+							       sync_p.offset,
+							       sync_p.len);
+
+		return ret;
+
 	default:
 		return -ENOTTY;
 	}
diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h
index 7f30393b92c3..6236c644624d 100644
--- a/include/uapi/linux/dma-buf.h
+++ b/include/uapi/linux/dma-buf.h
@@ -47,4 +47,12 @@ struct dma_buf_sync {
 #define DMA_BUF_SET_NAME_A	_IOW(DMA_BUF_BASE, 1, u32)
 #define DMA_BUF_SET_NAME_B	_IOW(DMA_BUF_BASE, 1, u64)
 
+struct dma_buf_sync_partial {
+	__u64 flags;
+	__u32 offset;
+	__u32 len;
+};
+
+#define DMA_BUF_IOCTL_SYNC_PARTIAL	_IOW(DMA_BUF_BASE, 2, struct dma_buf_sync_partial)
+
 #endif
-- 
2.25.1