Add dma_buf export API

Add an API to allow bmm buffers to be exported as dma_buf objects, so
they can be imported into DRM without needing to resort to passing
physical addresses around.

3 files changed, 20 insertions, 0 deletions

diff --git a/bmm_lib.c b/bmm_lib.c
index f9d8e69..1b3a156 100644
--- a/bmm_lib.c
+++ b/bmm_lib.c
@@ -34,6 +34,7 @@
 #define API_COMP_MAX		0x0000
 #define API_FEAT(x)		((x) >> 16)
 #define API_COMP(x)		((x) & 0xffff)
+#define API_FEAT_GET_DMABUF_FD	0x0001
 
 static unsigned bmm_api;
 static int bmm_fd = -1;
@@ -207,6 +208,23 @@ unsigned long bmm_get_paddr(void *vaddr)
 	return io.output;
 }
 
+int bmm_get_dmabuf_fd(void *vaddr)
+{
+	int ret;
+	ioctl_arg_t io;
+
+	if (bmm_init() < 0 || API_FEAT(bmm_api) < API_FEAT_GET_DMABUF_FD)
+		return -1;
+
+	io.input = (unsigned long)vaddr;
+	io.output = 0;
+	io.arg = 0;
+
+	ret = ioctl(bmm_fd, BMM_GET_DMABUF_FD, &io);
+
+	return ret < 0 ? -1 : io.output;
+}
+
 unsigned long bmm_get_mem_size(void *vaddr)
 {
 	int ret;
diff --git a/bmm_lib.h b/bmm_lib.h
index 14af196..1c4bbec 100644
--- a/bmm_lib.h
+++ b/bmm_lib.h
@@ -47,6 +47,7 @@ void *bmm_attach(unsigned long paddr, unsigned long len);
 void bmm_detach(void *vaddr, unsigned long len);
 void *bmm_get_vaddr(unsigned long paddr);
 unsigned long bmm_get_paddr(void *vaddr);
+int bmm_get_dmabuf_fd(void *vaddr);
 int bmm_get_mem_attr(void *vaddr);
 int bmm_set_mem_attr(void *vaddr, int attr);	/* Not supported yet */
 unsigned long bmm_get_mem_size(void *vaddr);
diff --git a/bmm_lib_priv.h b/bmm_lib_priv.h
index 41cb680..a93db78 100644
--- a/bmm_lib_priv.h
+++ b/bmm_lib_priv.h
@@ -42,6 +42,7 @@ typedef struct {
 #define BMM_SYNC_USER		_IOWR(BMEM_IOCTL_MAGIC, 16, ioctl_arg_t)
 #define BMM_MALLOC_ALIGNED	_IOWR(BMEM_IOCTL_MAGIC, 17, ioctl_arg_t)
 #define BMM_API_VERSION		_IOWR(BMEM_IOCTL_MAGIC, 18, ioctl_arg_t)
+#define BMM_GET_DMABUF_FD	_IOWR(BMEM_IOCTL_MAGIC, 19, ioctl_arg_t)
 
 #define BMM_DEVICE_FILE	"/dev/bmm"