Re: [PATCH v2 13/13] udmabuf: add documentation
From: Randy Dunlap <hidden>
Date: 2018-09-11 15:40:31
Also in:
dri-devel, linux-media, lkml
On 9/11/18 6:42 AM, Gerd Hoffmann wrote:
quoted hunk ↗ jump to hunk
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> --- include/uapi/linux/udmabuf.h | 50 +++++++++++++++++++++++++++++++++--- Documentation/driver-api/dma-buf.rst | 8 ++++++ 2 files changed, 55 insertions(+), 3 deletions(-)diff --git a/include/uapi/linux/udmabuf.h b/include/uapi/linux/udmabuf.h index 46b6532ed8..f30b37cb5c 100644 --- a/include/uapi/linux/udmabuf.h +++ b/include/uapi/linux/udmabuf.h@@ -5,8 +5,38 @@ #include <linux/types.h> #include <linux/ioctl.h> +/** + * DOC: udmabuf + * + * udmabuf is a device driver which allows userspace create dmabufs.
to create
+ * The memory used for these dmabufs must be backed by memfd. The
+ * memfd must have F_SEAL_SHRINK and it must not have F_SEAL_WRITE.
+ *
+ * The driver has two ioctls, one to create a dmabuf from a single
+ * memory block and one to create a dmabuf from a list of memory
+ * blocks.
+ *
+ * UDMABUF_CREATE - _IOW('u', 0x42, udmabuf_create)
+ *
+ * UDMABUF_CREATE_LIST - _IOW('u', 0x43, udmabuf_create_list)
+ */
+
+#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create)
+#define UDMABUF_CREATE_LIST _IOW('u', 0x43, struct udmabuf_create_list)
+
#define UDMABUF_FLAGS_CLOEXEC 0x01
+/**
+ * struct udmabuf_create - create a dmabuf from a single memory block.
+ *
+ * @memfd: The file handle.
+ * @offset: Start of the buffer (from memfd start).
+ * Must be page aligned.
+ * @size: Size of the buffer. Must be rounded to page size.
@flags: ???
quoted hunk ↗ jump to hunk
+ * + * flags: + * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf. + */ struct udmabuf_create { __u32 memfd; __u32 flags;@@ -14,6 +44,14 @@ struct udmabuf_create { __u64 size; }; +/** + * struct udmabuf_create_item - one memory block list item. + * + * @memfd: The file handle. + * @offset: Start of the buffer (from memfd start). + * Must be page aligned. + * @size: Size of the buffer. Must be rounded to page size. + */ struct udmabuf_create_item { __u32 memfd; __u32 __pad;@@ -21,13 +59,19 @@ struct udmabuf_create_item { __u64 size; }; +/** + * struct udmabuf_create_list - create a dmabuf from a memory block list. + * + * @count: The number of list elements. + * @list: The memory block list + * + * flags:
@flags:
+ * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf.
+ */
struct udmabuf_create_list {
__u32 flags;
__u32 count;
struct udmabuf_create_item list[];
};thanks. -- ~Randy