diff mbox

[PATCHv8,01/26] v4l: Add DMABUF as a memory type

Message ID 1344958496-9373-2-git-send-email-t.stanislaws@samsung.com
State New
Headers show

Commit Message

Tomasz Stanislawski Aug. 14, 2012, 3:34 p.m. UTC
From: Sumit Semwal <sumit.semwal@ti.com>

Adds DMABUF memory type to v4l framework. Also adds the related file
descriptor in v4l2_plane and v4l2_buffer.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
   [original work in the PoC for buffer sharing]
Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/video/v4l2-compat-ioctl32.c |   18 ++++++++++++++++++
 drivers/media/video/v4l2-ioctl.c          |    1 +
 include/linux/videodev2.h                 |    7 +++++++
 3 files changed, 26 insertions(+)

Comments

Hans Verkuil Aug. 22, 2012, 10:27 a.m. UTC | #1
On Tue August 14 2012 17:34:31 Tomasz Stanislawski wrote:
> From: Sumit Semwal <sumit.semwal@ti.com>
> 
> Adds DMABUF memory type to v4l framework. Also adds the related file
> descriptor in v4l2_plane and v4l2_buffer.
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
>    [original work in the PoC for buffer sharing]
> Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/media/video/v4l2-compat-ioctl32.c |   18 ++++++++++++++++++
>  drivers/media/video/v4l2-ioctl.c          |    1 +
>  include/linux/videodev2.h                 |    7 +++++++
>  3 files changed, 26 insertions(+)
> 
> diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
> index 9ebd5c5..a2e0549 100644
> --- a/drivers/media/video/v4l2-compat-ioctl32.c
> +++ b/drivers/media/video/v4l2-compat-ioctl32.c
> @@ -304,6 +304,7 @@ struct v4l2_plane32 {
>  	union {
>  		__u32		mem_offset;
>  		compat_long_t	userptr;
> +		__u32		fd;

Shouldn't this be int?

>  	} m;
>  	__u32			data_offset;
>  	__u32			reserved[11];
> @@ -325,6 +326,7 @@ struct v4l2_buffer32 {
>  		__u32           offset;
>  		compat_long_t   userptr;
>  		compat_caddr_t  planes;
> +		__u32		fd;

Ditto.

>  	} m;
>  	__u32			length;
>  	__u32			reserved2;
> @@ -348,6 +350,9 @@ static int get_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
>  		up_pln = compat_ptr(p);
>  		if (put_user((unsigned long)up_pln, &up->m.userptr))
>  			return -EFAULT;
> +	} else if (memory == V4L2_MEMORY_DMABUF) {
> +		if (copy_in_user(&up->m.fd, &up32->m.fd, sizeof(int)))
> +			return -EFAULT;
>  	} else {
>  		if (copy_in_user(&up->m.mem_offset, &up32->m.mem_offset,
>  					sizeof(__u32)))
> @@ -371,6 +376,11 @@ static int put_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
>  		if (copy_in_user(&up32->m.mem_offset, &up->m.mem_offset,
>  					sizeof(__u32)))
>  			return -EFAULT;
> +	/* For DMABUF, driver might've set up the fd, so copy it back. */
> +	if (memory == V4L2_MEMORY_DMABUF)
> +		if (copy_in_user(&up32->m.fd, &up->m.fd,
> +					sizeof(int)))
> +			return -EFAULT;
>  
>  	return 0;
>  }
> @@ -453,6 +463,10 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>  			if (get_user(kp->m.offset, &up->m.offset))
>  				return -EFAULT;
>  			break;
> +		case V4L2_MEMORY_DMABUF:
> +			if (get_user(kp->m.fd, &up->m.fd))
> +				return -EFAULT;
> +			break;
>  		}
>  	}
>  
> @@ -517,6 +531,10 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
>  			if (put_user(kp->m.offset, &up->m.offset))
>  				return -EFAULT;
>  			break;
> +		case V4L2_MEMORY_DMABUF:
> +			if (put_user(kp->m.fd, &up->m.fd))
> +				return -EFAULT;
> +			break;
>  		}
>  	}
>  
> diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
> index 6bc47fc..dffd3c9 100644
> --- a/drivers/media/video/v4l2-ioctl.c
> +++ b/drivers/media/video/v4l2-ioctl.c
> @@ -155,6 +155,7 @@ static const char *v4l2_memory_names[] = {
>  	[V4L2_MEMORY_MMAP]    = "mmap",
>  	[V4L2_MEMORY_USERPTR] = "userptr",
>  	[V4L2_MEMORY_OVERLAY] = "overlay",
> +	[V4L2_MEMORY_DMABUF] = "dmabuf",
>  };
>  
>  #define prt_names(a, arr) ((((a) >= 0) && ((a) < ARRAY_SIZE(arr))) ? \
> diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> index 7a147c8..7f918dc 100644
> --- a/include/linux/videodev2.h
> +++ b/include/linux/videodev2.h
> @@ -186,6 +186,7 @@ enum v4l2_memory {
>  	V4L2_MEMORY_MMAP             = 1,
>  	V4L2_MEMORY_USERPTR          = 2,
>  	V4L2_MEMORY_OVERLAY          = 3,
> +	V4L2_MEMORY_DMABUF           = 4,
>  };
>  
>  /* see also http://vektor.theorem.ca/graphics/ycbcr/ */
> @@ -596,6 +597,8 @@ struct v4l2_requestbuffers {
>   *			should be passed to mmap() called on the video node)
>   * @userptr:		when memory is V4L2_MEMORY_USERPTR, a userspace pointer
>   *			pointing to this plane
> + * @fd:			when memory is V4L2_MEMORY_DMABUF, a userspace file
> + *			descriptor associated with this plane
>   * @data_offset:	offset in the plane to the start of data; usually 0,
>   *			unless there is a header in front of the data
>   *
> @@ -610,6 +613,7 @@ struct v4l2_plane {
>  	union {
>  		__u32		mem_offset;
>  		unsigned long	userptr;
> +		int		fd;
>  	} m;
>  	__u32			data_offset;
>  	__u32			reserved[11];
> @@ -634,6 +638,8 @@ struct v4l2_plane {
>   *		(or a "cookie" that should be passed to mmap() as offset)
>   * @userptr:	for non-multiplanar buffers with memory == V4L2_MEMORY_USERPTR;
>   *		a userspace pointer pointing to this buffer
> + * @fd:		for non-multiplanar buffers with memory == V4L2_MEMORY_DMABUF;
> + *		a userspace file descriptor associated with this buffer
>   * @planes:	for multiplanar buffers; userspace pointer to the array of plane
>   *		info structs for this buffer
>   * @length:	size in bytes of the buffer (NOT its payload) for single-plane
> @@ -660,6 +666,7 @@ struct v4l2_buffer {
>  		__u32           offset;
>  		unsigned long   userptr;
>  		struct v4l2_plane *planes;
> +		int		fd;
>  	} m;
>  	__u32			length;
>  	__u32			reserved2;
> 

Regards,

	Hans
Tomasz Stanislawski Aug. 22, 2012, 12:09 p.m. UTC | #2
Hi Hans,
Thank your for the review.
Please refer to the comments below.

On 08/22/2012 12:27 PM, Hans Verkuil wrote:
> On Tue August 14 2012 17:34:31 Tomasz Stanislawski wrote:
>> From: Sumit Semwal <sumit.semwal@ti.com>
>>
>> Adds DMABUF memory type to v4l framework. Also adds the related file
>> descriptor in v4l2_plane and v4l2_buffer.
>>
>> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
>>    [original work in the PoC for buffer sharing]
>> Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
>> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
>> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>> ---
>>  drivers/media/video/v4l2-compat-ioctl32.c |   18 ++++++++++++++++++
>>  drivers/media/video/v4l2-ioctl.c          |    1 +
>>  include/linux/videodev2.h                 |    7 +++++++
>>  3 files changed, 26 insertions(+)
>>
>> diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
>> index 9ebd5c5..a2e0549 100644
>> --- a/drivers/media/video/v4l2-compat-ioctl32.c
>> +++ b/drivers/media/video/v4l2-compat-ioctl32.c
>> @@ -304,6 +304,7 @@ struct v4l2_plane32 {
>>  	union {
>>  		__u32		mem_offset;
>>  		compat_long_t	userptr;
>> +		__u32		fd;
> 
> Shouldn't this be int?
> 

Notice that this field should be consistent with fd field used in
'struct v4l2_exportbuffer'. Therefore I prefer to use fixed-size types.
One could use __s32 here but notice that file descriptors are defined
as small, nonnegative integers according to POSIX spec. The type __u32
suits well for this purpose. The negative values returned by open
syscall are used only to indicate failures.

On the other hand, using __s32 may help to avoid compiler warning while
building userspace apps due to 'signed-vs-unsigned comparisons'.

However, I do not have any strong opinion about 'int vs __u32' issue :).
Do you think that using __s32 for both QUERYBUF and EXPBUF is a good
compromise?

>>  	} m;
>>  	__u32			data_offset;
>>  	__u32			reserved[11];
>> @@ -325,6 +326,7 @@ struct v4l2_buffer32 {
>>  		__u32           offset;
>>  		compat_long_t   userptr;
>>  		compat_caddr_t  planes;
>> +		__u32		fd;
> 
> Ditto.
> 
>>  	} m;
>>  	__u32			length;
>>  	__u32			reserved2;

> Regards,
> 
> 	Hans
> 

Regards,

	Tomasz
Hans Verkuil Aug. 22, 2012, 12:21 p.m. UTC | #3
On Wed August 22 2012 14:09:18 Tomasz Stanislawski wrote:
> Hi Hans,
> Thank your for the review.
> Please refer to the comments below.
> 
> On 08/22/2012 12:27 PM, Hans Verkuil wrote:
> > On Tue August 14 2012 17:34:31 Tomasz Stanislawski wrote:
> >> From: Sumit Semwal <sumit.semwal@ti.com>
> >>
> >> Adds DMABUF memory type to v4l framework. Also adds the related file
> >> descriptor in v4l2_plane and v4l2_buffer.
> >>
> >> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> >>    [original work in the PoC for buffer sharing]
> >> Signed-off-by: Sumit Semwal <sumit.semwal@ti.com>
> >> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
> >> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >> ---
> >>  drivers/media/video/v4l2-compat-ioctl32.c |   18 ++++++++++++++++++
> >>  drivers/media/video/v4l2-ioctl.c          |    1 +
> >>  include/linux/videodev2.h                 |    7 +++++++
> >>  3 files changed, 26 insertions(+)
> >>
> >> diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
> >> index 9ebd5c5..a2e0549 100644
> >> --- a/drivers/media/video/v4l2-compat-ioctl32.c
> >> +++ b/drivers/media/video/v4l2-compat-ioctl32.c
> >> @@ -304,6 +304,7 @@ struct v4l2_plane32 {
> >>  	union {
> >>  		__u32		mem_offset;
> >>  		compat_long_t	userptr;
> >> +		__u32		fd;
> > 
> > Shouldn't this be int?
> > 
> 
> Notice that this field should be consistent with fd field used in
> 'struct v4l2_exportbuffer'. Therefore I prefer to use fixed-size types.
> One could use __s32 here but notice that file descriptors are defined
> as small, nonnegative integers according to POSIX spec. The type __u32
> suits well for this purpose. The negative values returned by open
> syscall are used only to indicate failures.
> 
> On the other hand, using __s32 may help to avoid compiler warning while
> building userspace apps due to 'signed-vs-unsigned comparisons'.
> 
> However, I do not have any strong opinion about 'int vs __u32' issue :).
> Do you think that using __s32 for both QUERYBUF and EXPBUF is a good
> compromise?

The type of a fd is highly variable in the kernel. Just try this for fun:

	grep [^a-z]fd[^a-z] -rsI include/linux/

'int' or 'unsigned int' are by far the most common types.

But in structs I did see a few __s32 types, so I think __s32 is a decent
type to use. Just make sure it is __s32 everywhere. Right now __u32 and
int are both used.

Regards,

	Hans

> 
> >>  	} m;
> >>  	__u32			data_offset;
> >>  	__u32			reserved[11];
> >> @@ -325,6 +326,7 @@ struct v4l2_buffer32 {
> >>  		__u32           offset;
> >>  		compat_long_t   userptr;
> >>  		compat_caddr_t  planes;
> >> +		__u32		fd;
> > 
> > Ditto.
> > 
> >>  	} m;
> >>  	__u32			length;
> >>  	__u32			reserved2;
> 
> > Regards,
> > 
> > 	Hans
> > 
> 
> Regards,
> 
> 	Tomasz
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
diff mbox

Patch

diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
index 9ebd5c5..a2e0549 100644
--- a/drivers/media/video/v4l2-compat-ioctl32.c
+++ b/drivers/media/video/v4l2-compat-ioctl32.c
@@ -304,6 +304,7 @@  struct v4l2_plane32 {
 	union {
 		__u32		mem_offset;
 		compat_long_t	userptr;
+		__u32		fd;
 	} m;
 	__u32			data_offset;
 	__u32			reserved[11];
@@ -325,6 +326,7 @@  struct v4l2_buffer32 {
 		__u32           offset;
 		compat_long_t   userptr;
 		compat_caddr_t  planes;
+		__u32		fd;
 	} m;
 	__u32			length;
 	__u32			reserved2;
@@ -348,6 +350,9 @@  static int get_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
 		up_pln = compat_ptr(p);
 		if (put_user((unsigned long)up_pln, &up->m.userptr))
 			return -EFAULT;
+	} else if (memory == V4L2_MEMORY_DMABUF) {
+		if (copy_in_user(&up->m.fd, &up32->m.fd, sizeof(int)))
+			return -EFAULT;
 	} else {
 		if (copy_in_user(&up->m.mem_offset, &up32->m.mem_offset,
 					sizeof(__u32)))
@@ -371,6 +376,11 @@  static int put_v4l2_plane32(struct v4l2_plane *up, struct v4l2_plane32 *up32,
 		if (copy_in_user(&up32->m.mem_offset, &up->m.mem_offset,
 					sizeof(__u32)))
 			return -EFAULT;
+	/* For DMABUF, driver might've set up the fd, so copy it back. */
+	if (memory == V4L2_MEMORY_DMABUF)
+		if (copy_in_user(&up32->m.fd, &up->m.fd,
+					sizeof(int)))
+			return -EFAULT;
 
 	return 0;
 }
@@ -453,6 +463,10 @@  static int get_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
 			if (get_user(kp->m.offset, &up->m.offset))
 				return -EFAULT;
 			break;
+		case V4L2_MEMORY_DMABUF:
+			if (get_user(kp->m.fd, &up->m.fd))
+				return -EFAULT;
+			break;
 		}
 	}
 
@@ -517,6 +531,10 @@  static int put_v4l2_buffer32(struct v4l2_buffer *kp, struct v4l2_buffer32 __user
 			if (put_user(kp->m.offset, &up->m.offset))
 				return -EFAULT;
 			break;
+		case V4L2_MEMORY_DMABUF:
+			if (put_user(kp->m.fd, &up->m.fd))
+				return -EFAULT;
+			break;
 		}
 	}
 
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index 6bc47fc..dffd3c9 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -155,6 +155,7 @@  static const char *v4l2_memory_names[] = {
 	[V4L2_MEMORY_MMAP]    = "mmap",
 	[V4L2_MEMORY_USERPTR] = "userptr",
 	[V4L2_MEMORY_OVERLAY] = "overlay",
+	[V4L2_MEMORY_DMABUF] = "dmabuf",
 };
 
 #define prt_names(a, arr) ((((a) >= 0) && ((a) < ARRAY_SIZE(arr))) ? \
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 7a147c8..7f918dc 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -186,6 +186,7 @@  enum v4l2_memory {
 	V4L2_MEMORY_MMAP             = 1,
 	V4L2_MEMORY_USERPTR          = 2,
 	V4L2_MEMORY_OVERLAY          = 3,
+	V4L2_MEMORY_DMABUF           = 4,
 };
 
 /* see also http://vektor.theorem.ca/graphics/ycbcr/ */
@@ -596,6 +597,8 @@  struct v4l2_requestbuffers {
  *			should be passed to mmap() called on the video node)
  * @userptr:		when memory is V4L2_MEMORY_USERPTR, a userspace pointer
  *			pointing to this plane
+ * @fd:			when memory is V4L2_MEMORY_DMABUF, a userspace file
+ *			descriptor associated with this plane
  * @data_offset:	offset in the plane to the start of data; usually 0,
  *			unless there is a header in front of the data
  *
@@ -610,6 +613,7 @@  struct v4l2_plane {
 	union {
 		__u32		mem_offset;
 		unsigned long	userptr;
+		int		fd;
 	} m;
 	__u32			data_offset;
 	__u32			reserved[11];
@@ -634,6 +638,8 @@  struct v4l2_plane {
  *		(or a "cookie" that should be passed to mmap() as offset)
  * @userptr:	for non-multiplanar buffers with memory == V4L2_MEMORY_USERPTR;
  *		a userspace pointer pointing to this buffer
+ * @fd:		for non-multiplanar buffers with memory == V4L2_MEMORY_DMABUF;
+ *		a userspace file descriptor associated with this buffer
  * @planes:	for multiplanar buffers; userspace pointer to the array of plane
  *		info structs for this buffer
  * @length:	size in bytes of the buffer (NOT its payload) for single-plane
@@ -660,6 +666,7 @@  struct v4l2_buffer {
 		__u32           offset;
 		unsigned long   userptr;
 		struct v4l2_plane *planes;
+		int		fd;
 	} m;
 	__u32			length;
 	__u32			reserved2;