This patch adds support for scatter gather transfers. If the underlying
gadgets sg_supported == true, then the videeobuf2-dma-sg is used and the
encode routine maps all scatter entries to separate scatterlists for the
usb gadget.
When streaming 1080p with request size of 1024 times 3 bytes top shows a
difference of about 6.4% CPU load applying this patch:
PID USER PR NI VIRT RES %CPU %MEM TIME+ S COMMAND
64 root 0 -20 0.0m 0.0m 7.7 0.0 0:01.25 I [kworker/u5:0-uvcvideo]
83 root 0 -20 0.0m 0.0m 4.5 0.0 0:03.71 I [kworker/u5:3-uvcvideo]
307 root -51 0 0.0m 0.0m 3.8 0.0 0:01.05 S [irq/51-dwc3]
vs.
64 root 0 -20 0.0m 0.0m 5.8 0.0 0:01.79 I [kworker/u5:0-uvcvideo]
306 root -51 0 0.0m 0.0m 3.2 0.0 0:01.97 S [irq/51-dwc3]
82 root 0 -20 0.0m 0.0m 0.6 0.0 0:01.86 I [kworker/u5:1-uvcvideo]
Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
---
v1 -> v2: - fixed missing VIDEOBUF2_DMA_SG select for legacy webcam found by kbuild-all
- ordered header files alphabetically
- used unsigned int in encode_isoc_sg where possible
- changed function parameter order in uvcg_queue_init
- added and used UVCG_REQUEST_HEADER_LEN for the 2 header bytes
- added use_sg into uvc_video_queue instead of pocking through layers
- added sg_free_table to uvc_video_free_requests
- removed unneeded memset
v2 -> v3: - setting queue->dev directly to udc
- removed setting of alloc_devs in uvc_queue_setup
- added measurement results to patch description
---
drivers/usb/gadget/Kconfig | 1 +
drivers/usb/gadget/function/uvc.h | 2 +
drivers/usb/gadget/function/uvc_queue.c | 22 ++++++-
drivers/usb/gadget/function/uvc_queue.h | 7 ++-
drivers/usb/gadget/function/uvc_video.c | 82 +++++++++++++++++++++++--
drivers/usb/gadget/function/uvc_video.h | 2 +
drivers/usb/gadget/legacy/Kconfig | 1 +
7 files changed, 108 insertions(+), 9 deletions(-)
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 2d152571a7de8..dd58094f0b85b 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -450,6 +450,7 @@ config USB_CONFIGFS_F_UVC
depends on USB_CONFIGFS
depends on VIDEO_V4L2
depends on VIDEO_DEV
+ select VIDEOBUF2_DMA_SG
select VIDEOBUF2_VMALLOC
select USB_F_UVC
help
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index 52f894183ecf0..36b78f8b3cd4c 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -75,6 +75,8 @@ struct uvc_request {
struct usb_request *req;
u8 *req_buffer;
struct uvc_video *video;
+ struct sg_table sgt;
+ u8 header[2];
};
struct uvc_video {
diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c
index ff0cc08531d2b..7d00ad7c154c2 100644
--- a/drivers/usb/gadget/function/uvc_queue.c
+++ b/drivers/usb/gadget/function/uvc_queue.c
@@ -17,6 +17,7 @@
#include <linux/wait.h>
#include <media/v4l2-common.h>
+#include <media/videobuf2-dma-sg.h>
#include <media/videobuf2-vmalloc.h>
#include "uvc.h"
@@ -76,7 +77,12 @@ static int uvc_buffer_prepare(struct vb2_buffer *vb)
return -ENODEV;
buf->state = UVC_BUF_STATE_QUEUED;
- buf->mem = vb2_plane_vaddr(vb, 0);
+ if (queue->use_sg) {
+ buf->sgt = vb2_dma_sg_plane_desc(vb, 0);
+ buf->sg = buf->sgt->sgl;
+ } else {
+ buf->mem = vb2_plane_vaddr(vb, 0);
+ }
buf->length = vb2_plane_size(vb, 0);
if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
buf->bytesused = 0;
@@ -116,9 +122,11 @@ static const struct vb2_ops uvc_queue_qops = {
.wait_finish = vb2_ops_wait_finish,
};
-int uvcg_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
+int uvcg_queue_init(struct uvc_video_queue *queue, struct device *dev, enum v4l2_buf_type type,
struct mutex *lock)
{
+ struct uvc_video *video = container_of(queue, struct uvc_video, queue);
+ struct usb_composite_dev *cdev = video->uvc->func.config->cdev;
int ret;
queue->queue.type = type;
@@ -127,9 +135,17 @@ int uvcg_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
queue->queue.buf_struct_size = sizeof(struct uvc_buffer);
queue->queue.ops = &uvc_queue_qops;
queue->queue.lock = lock;
- queue->queue.mem_ops = &vb2_vmalloc_memops;
+ if (cdev->gadget->sg_supported) {
+ queue->queue.mem_ops = &vb2_dma_sg_memops;
+ queue->use_sg = 1;
+ } else {
+ queue->queue.mem_ops = &vb2_vmalloc_memops;
+ }
+
queue->queue.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC
| V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
+ queue->queue.dev = dev;
+
ret = vb2_queue_init(&queue->queue);
if (ret)
return ret;
diff --git a/drivers/usb/gadget/function/uvc_queue.h b/drivers/usb/gadget/function/uvc_queue.h
index 2f0fff7698430..05360a0767f61 100644
--- a/drivers/usb/gadget/function/uvc_queue.h
+++ b/drivers/usb/gadget/function/uvc_queue.h
@@ -34,6 +34,9 @@ struct uvc_buffer {
enum uvc_buffer_state state;
void *mem;
+ struct sg_table *sgt;
+ struct scatterlist *sg;
+ unsigned int offset;
unsigned int length;
unsigned int bytesused;
};
@@ -50,6 +53,8 @@ struct uvc_video_queue {
unsigned int buf_used;
+ bool use_sg;
+
spinlock_t irqlock; /* Protects flags and irqqueue */
struct list_head irqqueue;
};
@@ -59,7 +64,7 @@ static inline int uvc_queue_streaming(struct uvc_video_queue *queue)
return vb2_is_streaming(&queue->queue);
}
-int uvcg_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
+int uvcg_queue_init(struct uvc_video_queue *queue, struct device *dev, enum v4l2_buf_type type,
struct mutex *lock);
void uvcg_free_buffers(struct uvc_video_queue *queue);
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 303cb427f687e..2cefb8bd4f15b 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -27,10 +27,10 @@ static int
uvc_video_encode_header(struct uvc_video *video, struct uvc_buffer *buf,
u8 *data, int len)
{
- data[0] = 2;
+ data[0] = UVCG_REQUEST_HEADER_LEN;
data[1] = UVC_STREAM_EOH | video->fid;
- if (buf->bytesused - video->queue.buf_used <= len - 2)
+ if (buf->bytesused - video->queue.buf_used <= len - UVCG_REQUEST_HEADER_LEN)
data[1] |= UVC_STREAM_EOF;
return 2;
@@ -94,6 +94,71 @@ uvc_video_encode_bulk(struct usb_request *req, struct uvc_video *video,
video->payload_size = 0;
}
+static void
+uvc_video_encode_isoc_sg(struct usb_request *req, struct uvc_video *video,
+ struct uvc_buffer *buf)
+{
+ unsigned int pending = buf->bytesused - video->queue.buf_used;
+ struct uvc_request *ureq = req->context;
+ struct scatterlist *sg, *iter;
+ unsigned int len = video->req_size;
+ unsigned int sg_left, part = 0;
+ unsigned int i;
+ int ret;
+
+ sg = ureq->sgt.sgl;
+ sg_init_table(sg, ureq->sgt.nents);
+
+ /* Init the header. */
+ ret = uvc_video_encode_header(video, buf, ureq->header,
+ video->req_size);
+ sg_set_buf(sg, ureq->header, UVCG_REQUEST_HEADER_LEN);
+ len -= ret;
+
+ if (pending <= len)
+ len = pending;
+
+ req->length = (len == pending) ?
+ len + UVCG_REQUEST_HEADER_LEN : video->req_size;
+
+ /* Init the pending sgs with payload */
+ sg = sg_next(sg);
+
+ for_each_sg(sg, iter, ureq->sgt.nents - 1, i) {
+ if (!len || !buf->sg)
+ break;
+
+ sg_left = sg_dma_len(buf->sg) - buf->offset;
+ part = min_t(unsigned int, len, sg_left);
+
+ sg_set_page(iter, sg_page(buf->sg), part, buf->offset);
+
+ if (part == sg_left) {
+ buf->offset = 0;
+ buf->sg = sg_next(buf->sg);
+ } else {
+ buf->offset += part;
+ }
+ len -= part;
+ }
+
+ /* Assign the video data with header. */
+ req->buf = NULL;
+ req->sg = ureq->sgt.sgl;
+ req->num_sgs = i + 1;
+
+ req->length -= len;
+ video->queue.buf_used += req->length - UVCG_REQUEST_HEADER_LEN;
+
+ if (buf->bytesused == video->queue.buf_used || !buf->sg) {
+ video->queue.buf_used = 0;
+ buf->state = UVC_BUF_STATE_DONE;
+ buf->offset = 0;
+ uvcg_queue_next_buffer(&video->queue, buf);
+ video->fid ^= UVC_STREAM_FID;
+ }
+}
+
static void
uvc_video_encode_isoc(struct usb_request *req, struct uvc_video *video,
struct uvc_buffer *buf)
@@ -180,6 +245,8 @@ uvc_video_free_requests(struct uvc_video *video)
if (video->ureq) {
for (i = 0; i < video->uvc_num_requests; ++i) {
+ sg_free_table(&video->ureq[i].sgt);
+
if (video->ureq[i].req) {
usb_ep_free_request(video->ep, video->ureq[i].req);
video->ureq[i].req = NULL;
@@ -233,6 +300,10 @@ uvc_video_alloc_requests(struct uvc_video *video)
video->ureq[i].video = video;
list_add_tail(&video->ureq[i].req->list, &video->req_free);
+ /* req_size/PAGE_SIZE + 1 for overruns and + 1 for header */
+ sg_alloc_table(&video->ureq[i].sgt,
+ DIV_ROUND_UP(req_size - 2, PAGE_SIZE) + 2,
+ GFP_KERNEL);
}
video->req_size = req_size;
@@ -342,7 +413,8 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
video->encode = uvc_video_encode_bulk;
video->payload_size = 0;
} else
- video->encode = uvc_video_encode_isoc;
+ video->encode = video->queue.use_sg ?
+ uvc_video_encode_isoc_sg : uvc_video_encode_isoc;
schedule_work(&video->pump);
@@ -366,8 +438,8 @@ int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
video->imagesize = 320 * 240 * 2;
/* Initialize the video buffers queue. */
- uvcg_queue_init(&video->queue, V4L2_BUF_TYPE_VIDEO_OUTPUT,
- &video->mutex);
+ uvcg_queue_init(&video->queue, uvc->v4l2_dev.dev->parent,
+ V4L2_BUF_TYPE_VIDEO_OUTPUT, &video->mutex);
return 0;
}
diff --git a/drivers/usb/gadget/function/uvc_video.h b/drivers/usb/gadget/function/uvc_video.h
index 03adeefa343b7..9bf19475f6f9a 100644
--- a/drivers/usb/gadget/function/uvc_video.h
+++ b/drivers/usb/gadget/function/uvc_video.h
@@ -12,6 +12,8 @@
#ifndef __UVC_VIDEO_H__
#define __UVC_VIDEO_H__
+#define UVCG_REQUEST_HEADER_LEN 2
+
struct uvc_video;
int uvcg_video_enable(struct uvc_video *video, int enable);
diff --git a/drivers/usb/gadget/legacy/Kconfig b/drivers/usb/gadget/legacy/Kconfig
index 11dd6e8adc8a7..de6668e584815 100644
--- a/drivers/usb/gadget/legacy/Kconfig
+++ b/drivers/usb/gadget/legacy/Kconfig
@@ -502,6 +502,7 @@ config USB_G_WEBCAM
tristate "USB Webcam Gadget"
depends on VIDEO_V4L2
select USB_LIBCOMPOSITE
+ select VIDEOBUF2_DMA_SG
select VIDEOBUF2_VMALLOC
select USB_F_UVC
help
--
2.30.2
