diff mbox series

[6/6] media: uvcvideo: Use dma_alloc_noncontiguos API

Message ID 20210301085236.947011-7-hch@lst.de
State New
Headers show
Series [1/6] dma-mapping: add a dma_mmap_pages helper | expand

Commit Message

Christoph Hellwig March 1, 2021, 8:52 a.m. UTC
From: Ricardo Ribalda <ribalda@chromium.org>

On architectures where the is no coherent caching such as ARM use the
dma_alloc_noncontiguos API and handle manually the cache flushing using
dma_sync_sgtable().

With this patch on the affected architectures we can measure up to 20x
performance improvement in uvc_video_copy_data_work().

Eg: aarch64 with an external usb camera

NON_CONTIGUOUS
frames:  999
packets: 999
empty:   0 (0 %)
errors:  0
invalid: 0
pts: 0 early, 0 initial, 999 ok
scr: 0 count ok, 0 diff ok
sof: 2048 <= sof <= 0, freq 0.000 kHz
bytes 67034480 : duration 33303
FPS: 29.99
URB: 523446/4993 uS/qty: 104.836 avg 132.532 std 13.230 min 831.094 max (uS)
header: 76564/4993 uS/qty: 15.334 avg 15.229 std 3.438 min 186.875 max (uS)
latency: 468945/4992 uS/qty: 93.939 avg 132.577 std 9.531 min 824.010 max (uS)
decode: 54161/4993 uS/qty: 10.847 avg 6.313 std 1.614 min 111.458 max (uS)
raw decode speed: 9.931 Gbits/s
raw URB handling speed: 1.025 Gbits/s
throughput: 16.102 Mbits/s
URB decode CPU usage 0.162600 %

COHERENT
frames:  999
packets: 999
empty:   0 (0 %)
errors:  0
invalid: 0
pts: 0 early, 0 initial, 999 ok
scr: 0 count ok, 0 diff ok
sof: 2048 <= sof <= 0, freq 0.000 kHz
bytes 54683536 : duration 33302
FPS: 29.99
URB: 1478135/4000 uS/qty: 369.533 avg 390.357 std 22.968 min 3337.865 max (uS)
header: 79761/4000 uS/qty: 19.940 avg 18.495 std 1.875 min 336.719 max (uS)
latency: 281077/4000 uS/qty: 70.269 avg 83.102 std 5.104 min 735.000 max (uS)
decode: 1197057/4000 uS/qty: 299.264 avg 318.080 std 1.615 min 2806.667 max (uS)
raw decode speed: 365.470 Mbits/s
raw URB handling speed: 295.986 Mbits/s
throughput: 13.136 Mbits/s
URB decode CPU usage 3.594500 %

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/media/usb/uvc/uvc_video.c | 79 ++++++++++++++++++++++---------
 drivers/media/usb/uvc/uvcvideo.h  |  4 +-
 2 files changed, 60 insertions(+), 23 deletions(-)

Comments

Laurent Pinchart March 12, 2021, 1:42 a.m. UTC | #1
Hi Christoph and Ricardo,

Thank you for the patch.

On Mon, Mar 01, 2021 at 09:52:36AM +0100, Christoph Hellwig wrote:
> From: Ricardo Ribalda <ribalda@chromium.org>

> 

> On architectures where the is no coherent caching such as ARM use the


s/the is/there is/

> dma_alloc_noncontiguos API and handle manually the cache flushing using


s/dma_alloc_noncontiguos/dma_alloc_noncontiguous/

(and in the subject line too)

> dma_sync_sgtable().

> 

> With this patch on the affected architectures we can measure up to 20x

> performance improvement in uvc_video_copy_data_work().

> 

> Eg: aarch64 with an external usb camera

> 

> NON_CONTIGUOUS

> frames:  999

> packets: 999

> empty:   0 (0 %)

> errors:  0

> invalid: 0

> pts: 0 early, 0 initial, 999 ok

> scr: 0 count ok, 0 diff ok

> sof: 2048 <= sof <= 0, freq 0.000 kHz

> bytes 67034480 : duration 33303

> FPS: 29.99

> URB: 523446/4993 uS/qty: 104.836 avg 132.532 std 13.230 min 831.094 max (uS)

> header: 76564/4993 uS/qty: 15.334 avg 15.229 std 3.438 min 186.875 max (uS)

> latency: 468945/4992 uS/qty: 93.939 avg 132.577 std 9.531 min 824.010 max (uS)

> decode: 54161/4993 uS/qty: 10.847 avg 6.313 std 1.614 min 111.458 max (uS)

> raw decode speed: 9.931 Gbits/s

> raw URB handling speed: 1.025 Gbits/s

> throughput: 16.102 Mbits/s

> URB decode CPU usage 0.162600 %

> 

> COHERENT

> frames:  999

> packets: 999

> empty:   0 (0 %)

> errors:  0

> invalid: 0

> pts: 0 early, 0 initial, 999 ok

> scr: 0 count ok, 0 diff ok

> sof: 2048 <= sof <= 0, freq 0.000 kHz

> bytes 54683536 : duration 33302

> FPS: 29.99

> URB: 1478135/4000 uS/qty: 369.533 avg 390.357 std 22.968 min 3337.865 max (uS)

> header: 79761/4000 uS/qty: 19.940 avg 18.495 std 1.875 min 336.719 max (uS)

> latency: 281077/4000 uS/qty: 70.269 avg 83.102 std 5.104 min 735.000 max (uS)

> decode: 1197057/4000 uS/qty: 299.264 avg 318.080 std 1.615 min 2806.667 max (uS)

> raw decode speed: 365.470 Mbits/s

> raw URB handling speed: 295.986 Mbits/s

> throughput: 13.136 Mbits/s

> URB decode CPU usage 3.594500 %

> 

> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

> Reviewed-by: Tomasz Figa <tfiga@chromium.org>

> Signed-off-by: Christoph Hellwig <hch@lst.de>

> ---

>  drivers/media/usb/uvc/uvc_video.c | 79 ++++++++++++++++++++++---------

>  drivers/media/usb/uvc/uvcvideo.h  |  4 +-

>  2 files changed, 60 insertions(+), 23 deletions(-)

> 

> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c

> index f2f565281e63ff..d008c68fb6c806 100644

> --- a/drivers/media/usb/uvc/uvc_video.c

> +++ b/drivers/media/usb/uvc/uvc_video.c

> @@ -6,11 +6,13 @@

>   *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)

>   */

>  


Should we include <linux/dma-mapping.h> ?

> +#include <linux/highmem.h>

>  #include <linux/kernel.h>

>  #include <linux/list.h>

>  #include <linux/module.h>

>  #include <linux/slab.h>

>  #include <linux/usb.h>

> +#include <linux/usb/hcd.h>

>  #include <linux/videodev2.h>

>  #include <linux/vmalloc.h>

>  #include <linux/wait.h>

> @@ -1096,6 +1098,26 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,

>  	return data[0];

>  }

>  

> +static inline struct device *stream_to_dmadev(struct uvc_streaming *stream)

> +{

> +	return bus_to_hcd(stream->dev->udev->bus)->self.sysdev;

> +}

> +

> +static void uvc_urb_dma_sync(struct uvc_urb *uvc_urb, bool for_device)

> +{

> +	struct device *dma_dev = stream_to_dmadev(uvc_urb->stream);

> +

> +	if (for_device) {

> +		dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt,

> +					    DMA_FROM_DEVICE);


The uvcvideo driver also supports video output devices (they are fairly
rare, but they exist). We thus need to handle DMA_TO_DEVICE too.

> +	} else {

> +		dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt,

> +					 DMA_FROM_DEVICE);

> +		invalidate_kernel_vmap_range(uvc_urb->buffer,

> +					     uvc_urb->stream->urb_size);

> +	}

> +}

> +

>  /*

>   * uvc_video_decode_data_work: Asynchronous memcpy processing

>   *

> @@ -1117,6 +1139,8 @@ static void uvc_video_copy_data_work(struct work_struct *work)

>  		uvc_queue_buffer_release(op->buf);

>  	}

>  

> +	uvc_urb_dma_sync(uvc_urb, true);

> +

>  	ret = usb_submit_urb(uvc_urb->urb, GFP_KERNEL);

>  	if (ret < 0)

>  		dev_err(&uvc_urb->stream->intf->dev,

> @@ -1541,10 +1565,12 @@ static void uvc_video_complete(struct urb *urb)

>  	 * Process the URB headers, and optionally queue expensive memcpy tasks

>  	 * to be deferred to a work queue.

>  	 */

> +	uvc_urb_dma_sync(uvc_urb, false);

>  	stream->decode(uvc_urb, buf, buf_meta);

>  

>  	/* If no async work is needed, resubmit the URB immediately. */

>  	if (!uvc_urb->async_operations) {

> +		uvc_urb_dma_sync(uvc_urb, true);

>  		ret = usb_submit_urb(uvc_urb->urb, GFP_ATOMIC);

>  		if (ret < 0)

>  			dev_err(&stream->intf->dev,

> @@ -1560,24 +1586,46 @@ static void uvc_video_complete(struct urb *urb)

>   */

>  static void uvc_free_urb_buffers(struct uvc_streaming *stream)

>  {

> +	struct device *dma_dev = stream_to_dmadev(stream);

>  	struct uvc_urb *uvc_urb;

>  

>  	for_each_uvc_urb(uvc_urb, stream) {

>  		if (!uvc_urb->buffer)

>  			continue;

>  

> -#ifndef CONFIG_DMA_NONCOHERENT

> -		usb_free_coherent(stream->dev->udev, stream->urb_size,

> -				  uvc_urb->buffer, uvc_urb->dma);

> -#else

> -		kfree(uvc_urb->buffer);

> -#endif

> +		dma_vunmap_noncontiguous(dma_dev, uvc_urb->buffer);

> +		dma_free_noncontiguous(dma_dev, stream->urb_size, uvc_urb->sgt,

> +				       DMA_FROM_DEVICE);

> +

>  		uvc_urb->buffer = NULL;


Maybe also

		uvc_urb->sgt = NULL;

? It's not strictly mandatory, but may make use-after-free bugs easier
to spot.

>  	}

>  

>  	stream->urb_size = 0;

>  }

>  

> +static bool uvc_alloc_urb_buffer(struct uvc_streaming *stream,

> +				 struct uvc_urb *uvc_urb, gfp_t gfp_flags)

> +{

> +	struct device *dma_dev = stream_to_dmadev(stream);

> +

> +


Extra blank line.

> +	uvc_urb->sgt = dma_alloc_noncontiguous(dma_dev, stream->urb_size,

> +					       DMA_FROM_DEVICE, gfp_flags, 0);

> +	if (!uvc_urb->sgt)

> +		return false;

> +	uvc_urb->dma = uvc_urb->sgt->sgl->dma_address;

> +

> +	uvc_urb->buffer = dma_vmap_noncontiguous(dma_dev, stream->urb_size,

> +						 uvc_urb->sgt);

> +	if (!uvc_urb->buffer) {

> +		dma_free_noncontiguous(dma_dev, stream->urb_size,

> +				       uvc_urb->sgt, DMA_FROM_DEVICE);


Same here,

		uvc_urb->sgt = NULL;

> +		return false;

> +	}

> +

> +	return true;

> +}

> +

>  /*

>   * Allocate transfer buffers. This function can be called with buffers

>   * already allocated when resuming from suspend, in which case it will

> @@ -1608,19 +1656,11 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,

>  

>  	/* Retry allocations until one succeed. */

>  	for (; npackets > 1; npackets /= 2) {

> +		stream->urb_size = psize * npackets;


A blank line here would be nice.

>  		for (i = 0; i < UVC_URBS; ++i) {

>  			struct uvc_urb *uvc_urb = &stream->uvc_urb[i];

>  

> -			stream->urb_size = psize * npackets;

> -#ifndef CONFIG_DMA_NONCOHERENT

> -			uvc_urb->buffer = usb_alloc_coherent(

> -				stream->dev->udev, stream->urb_size,

> -				gfp_flags | __GFP_NOWARN, &uvc_urb->dma);

> -#else

> -			uvc_urb->buffer =

> -			    kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN);

> -#endif

> -			if (!uvc_urb->buffer) {

> +			if (!uvc_alloc_urb_buffer(stream, uvc_urb, gfp_flags)) {

>  				uvc_free_urb_buffers(stream);

>  				break;

>  			}

> @@ -1730,12 +1770,8 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream,

>  		urb->context = uvc_urb;

>  		urb->pipe = usb_rcvisocpipe(stream->dev->udev,

>  				ep->desc.bEndpointAddress);

> -#ifndef CONFIG_DMA_NONCOHERENT

>  		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;

>  		urb->transfer_dma = uvc_urb->dma;

> -#else

> -		urb->transfer_flags = URB_ISO_ASAP;

> -#endif

>  		urb->interval = ep->desc.bInterval;

>  		urb->transfer_buffer = uvc_urb->buffer;

>  		urb->complete = uvc_video_complete;

> @@ -1795,10 +1831,8 @@ static int uvc_init_video_bulk(struct uvc_streaming *stream,

>  

>  		usb_fill_bulk_urb(urb, stream->dev->udev, pipe,	uvc_urb->buffer,

>  				  size, uvc_video_complete, uvc_urb);

> -#ifndef CONFIG_DMA_NONCOHERENT

>  		urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;

>  		urb->transfer_dma = uvc_urb->dma;

> -#endif

>  

>  		uvc_urb->urb = urb;

>  	}

> @@ -1895,6 +1929,7 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,

>  

>  	/* Submit the URBs. */

>  	for_each_uvc_urb(uvc_urb, stream) {

> +		uvc_urb_dma_sync(uvc_urb, true);

>  		ret = usb_submit_urb(uvc_urb->urb, gfp_flags);

>  		if (ret < 0) {

>  			dev_err(&stream->intf->dev,

> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h

> index 97df5ecd66c9a7..fec24f1eca1c96 100644

> --- a/drivers/media/usb/uvc/uvcvideo.h

> +++ b/drivers/media/usb/uvc/uvcvideo.h

> @@ -545,7 +545,8 @@ struct uvc_copy_op {

>   * @urb: the URB described by this context structure

>   * @stream: UVC streaming context

>   * @buffer: memory storage for the URB

> - * @dma: DMA coherent addressing for the urb_buffer

> + * @dma: Allocated DMA handle

> + * @sgt: sgt_table with the urb locations in memory

>   * @async_operations: counter to indicate the number of copy operations

>   * @copy_operations: work descriptors for asynchronous copy operations

>   * @work: work queue entry for asynchronous decode

> @@ -556,6 +557,7 @@ struct uvc_urb {

>  

>  	char *buffer;

>  	dma_addr_t dma;

> +	struct sg_table *sgt;


A forward declaration of struct sg_table with the other forward
declarations would be useful.

>  

>  	unsigned int async_operations;

>  	struct uvc_copy_op copy_operations[UVC_MAX_PACKETS];


-- 
Regards,

Laurent Pinchart
Laurent Pinchart March 12, 2021, 1:43 a.m. UTC | #2
And I forgot to mention:

On Fri, Mar 12, 2021 at 03:42:14AM +0200, Laurent Pinchart wrote:
> Hi Christoph and Ricardo,

> 

> Thank you for the patch.

> 

> On Mon, Mar 01, 2021 at 09:52:36AM +0100, Christoph Hellwig wrote:

> > From: Ricardo Ribalda <ribalda@chromium.org>

> > 

> > On architectures where the is no coherent caching such as ARM use the

> 

> s/the is/there is/

> 

> > dma_alloc_noncontiguos API and handle manually the cache flushing using

> 

> s/dma_alloc_noncontiguos/dma_alloc_noncontiguous/

> 

> (and in the subject line too)

> 

> > dma_sync_sgtable().

> > 

> > With this patch on the affected architectures we can measure up to 20x

> > performance improvement in uvc_video_copy_data_work().


Wow, great work ! :-)

> > 

> > Eg: aarch64 with an external usb camera

> > 

> > NON_CONTIGUOUS

> > frames:  999

> > packets: 999

> > empty:   0 (0 %)

> > errors:  0

> > invalid: 0

> > pts: 0 early, 0 initial, 999 ok

> > scr: 0 count ok, 0 diff ok

> > sof: 2048 <= sof <= 0, freq 0.000 kHz

> > bytes 67034480 : duration 33303

> > FPS: 29.99

> > URB: 523446/4993 uS/qty: 104.836 avg 132.532 std 13.230 min 831.094 max (uS)

> > header: 76564/4993 uS/qty: 15.334 avg 15.229 std 3.438 min 186.875 max (uS)

> > latency: 468945/4992 uS/qty: 93.939 avg 132.577 std 9.531 min 824.010 max (uS)

> > decode: 54161/4993 uS/qty: 10.847 avg 6.313 std 1.614 min 111.458 max (uS)

> > raw decode speed: 9.931 Gbits/s

> > raw URB handling speed: 1.025 Gbits/s

> > throughput: 16.102 Mbits/s

> > URB decode CPU usage 0.162600 %

> > 

> > COHERENT

> > frames:  999

> > packets: 999

> > empty:   0 (0 %)

> > errors:  0

> > invalid: 0

> > pts: 0 early, 0 initial, 999 ok

> > scr: 0 count ok, 0 diff ok

> > sof: 2048 <= sof <= 0, freq 0.000 kHz

> > bytes 54683536 : duration 33302

> > FPS: 29.99

> > URB: 1478135/4000 uS/qty: 369.533 avg 390.357 std 22.968 min 3337.865 max (uS)

> > header: 79761/4000 uS/qty: 19.940 avg 18.495 std 1.875 min 336.719 max (uS)

> > latency: 281077/4000 uS/qty: 70.269 avg 83.102 std 5.104 min 735.000 max (uS)

> > decode: 1197057/4000 uS/qty: 299.264 avg 318.080 std 1.615 min 2806.667 max (uS)

> > raw decode speed: 365.470 Mbits/s

> > raw URB handling speed: 295.986 Mbits/s

> > throughput: 13.136 Mbits/s

> > URB decode CPU usage 3.594500 %

> > 

> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

> > Reviewed-by: Tomasz Figa <tfiga@chromium.org>

> > Signed-off-by: Christoph Hellwig <hch@lst.de>

> > ---

> >  drivers/media/usb/uvc/uvc_video.c | 79 ++++++++++++++++++++++---------

> >  drivers/media/usb/uvc/uvcvideo.h  |  4 +-

> >  2 files changed, 60 insertions(+), 23 deletions(-)

> > 

> > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c

> > index f2f565281e63ff..d008c68fb6c806 100644

> > --- a/drivers/media/usb/uvc/uvc_video.c

> > +++ b/drivers/media/usb/uvc/uvc_video.c

> > @@ -6,11 +6,13 @@

> >   *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)

> >   */

> >  

> 

> Should we include <linux/dma-mapping.h> ?

> 

> > +#include <linux/highmem.h>

> >  #include <linux/kernel.h>

> >  #include <linux/list.h>

> >  #include <linux/module.h>

> >  #include <linux/slab.h>

> >  #include <linux/usb.h>

> > +#include <linux/usb/hcd.h>

> >  #include <linux/videodev2.h>

> >  #include <linux/vmalloc.h>

> >  #include <linux/wait.h>

> > @@ -1096,6 +1098,26 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,

> >  	return data[0];

> >  }

> >  

> > +static inline struct device *stream_to_dmadev(struct uvc_streaming *stream)

> > +{

> > +	return bus_to_hcd(stream->dev->udev->bus)->self.sysdev;

> > +}

> > +

> > +static void uvc_urb_dma_sync(struct uvc_urb *uvc_urb, bool for_device)

> > +{

> > +	struct device *dma_dev = stream_to_dmadev(uvc_urb->stream);

> > +

> > +	if (for_device) {

> > +		dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt,

> > +					    DMA_FROM_DEVICE);

> 

> The uvcvideo driver also supports video output devices (they are fairly

> rare, but they exist). We thus need to handle DMA_TO_DEVICE too.

> 

> > +	} else {

> > +		dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt,

> > +					 DMA_FROM_DEVICE);

> > +		invalidate_kernel_vmap_range(uvc_urb->buffer,

> > +					     uvc_urb->stream->urb_size);

> > +	}

> > +}

> > +

> >  /*

> >   * uvc_video_decode_data_work: Asynchronous memcpy processing

> >   *

> > @@ -1117,6 +1139,8 @@ static void uvc_video_copy_data_work(struct work_struct *work)

> >  		uvc_queue_buffer_release(op->buf);

> >  	}

> >  

> > +	uvc_urb_dma_sync(uvc_urb, true);

> > +

> >  	ret = usb_submit_urb(uvc_urb->urb, GFP_KERNEL);

> >  	if (ret < 0)

> >  		dev_err(&uvc_urb->stream->intf->dev,

> > @@ -1541,10 +1565,12 @@ static void uvc_video_complete(struct urb *urb)

> >  	 * Process the URB headers, and optionally queue expensive memcpy tasks

> >  	 * to be deferred to a work queue.

> >  	 */

> > +	uvc_urb_dma_sync(uvc_urb, false);

> >  	stream->decode(uvc_urb, buf, buf_meta);

> >  

> >  	/* If no async work is needed, resubmit the URB immediately. */

> >  	if (!uvc_urb->async_operations) {

> > +		uvc_urb_dma_sync(uvc_urb, true);

> >  		ret = usb_submit_urb(uvc_urb->urb, GFP_ATOMIC);

> >  		if (ret < 0)

> >  			dev_err(&stream->intf->dev,

> > @@ -1560,24 +1586,46 @@ static void uvc_video_complete(struct urb *urb)

> >   */

> >  static void uvc_free_urb_buffers(struct uvc_streaming *stream)

> >  {

> > +	struct device *dma_dev = stream_to_dmadev(stream);

> >  	struct uvc_urb *uvc_urb;

> >  

> >  	for_each_uvc_urb(uvc_urb, stream) {

> >  		if (!uvc_urb->buffer)

> >  			continue;

> >  

> > -#ifndef CONFIG_DMA_NONCOHERENT

> > -		usb_free_coherent(stream->dev->udev, stream->urb_size,

> > -				  uvc_urb->buffer, uvc_urb->dma);

> > -#else

> > -		kfree(uvc_urb->buffer);

> > -#endif

> > +		dma_vunmap_noncontiguous(dma_dev, uvc_urb->buffer);

> > +		dma_free_noncontiguous(dma_dev, stream->urb_size, uvc_urb->sgt,

> > +				       DMA_FROM_DEVICE);

> > +

> >  		uvc_urb->buffer = NULL;

> 

> Maybe also

> 

> 		uvc_urb->sgt = NULL;

> 

> ? It's not strictly mandatory, but may make use-after-free bugs easier

> to spot.

> 

> >  	}

> >  

> >  	stream->urb_size = 0;

> >  }

> >  

> > +static bool uvc_alloc_urb_buffer(struct uvc_streaming *stream,

> > +				 struct uvc_urb *uvc_urb, gfp_t gfp_flags)

> > +{

> > +	struct device *dma_dev = stream_to_dmadev(stream);

> > +

> > +

> 

> Extra blank line.

> 

> > +	uvc_urb->sgt = dma_alloc_noncontiguous(dma_dev, stream->urb_size,

> > +					       DMA_FROM_DEVICE, gfp_flags, 0);

> > +	if (!uvc_urb->sgt)

> > +		return false;

> > +	uvc_urb->dma = uvc_urb->sgt->sgl->dma_address;

> > +

> > +	uvc_urb->buffer = dma_vmap_noncontiguous(dma_dev, stream->urb_size,

> > +						 uvc_urb->sgt);

> > +	if (!uvc_urb->buffer) {

> > +		dma_free_noncontiguous(dma_dev, stream->urb_size,

> > +				       uvc_urb->sgt, DMA_FROM_DEVICE);

> 

> Same here,

> 

> 		uvc_urb->sgt = NULL;

> 

> > +		return false;

> > +	}

> > +

> > +	return true;

> > +}

> > +

> >  /*

> >   * Allocate transfer buffers. This function can be called with buffers

> >   * already allocated when resuming from suspend, in which case it will

> > @@ -1608,19 +1656,11 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,

> >  

> >  	/* Retry allocations until one succeed. */

> >  	for (; npackets > 1; npackets /= 2) {

> > +		stream->urb_size = psize * npackets;

> 

> A blank line here would be nice.

> 

> >  		for (i = 0; i < UVC_URBS; ++i) {

> >  			struct uvc_urb *uvc_urb = &stream->uvc_urb[i];

> >  

> > -			stream->urb_size = psize * npackets;

> > -#ifndef CONFIG_DMA_NONCOHERENT

> > -			uvc_urb->buffer = usb_alloc_coherent(

> > -				stream->dev->udev, stream->urb_size,

> > -				gfp_flags | __GFP_NOWARN, &uvc_urb->dma);

> > -#else

> > -			uvc_urb->buffer =

> > -			    kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN);

> > -#endif

> > -			if (!uvc_urb->buffer) {

> > +			if (!uvc_alloc_urb_buffer(stream, uvc_urb, gfp_flags)) {

> >  				uvc_free_urb_buffers(stream);

> >  				break;

> >  			}

> > @@ -1730,12 +1770,8 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream,

> >  		urb->context = uvc_urb;

> >  		urb->pipe = usb_rcvisocpipe(stream->dev->udev,

> >  				ep->desc.bEndpointAddress);

> > -#ifndef CONFIG_DMA_NONCOHERENT

> >  		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;

> >  		urb->transfer_dma = uvc_urb->dma;

> > -#else

> > -		urb->transfer_flags = URB_ISO_ASAP;

> > -#endif

> >  		urb->interval = ep->desc.bInterval;

> >  		urb->transfer_buffer = uvc_urb->buffer;

> >  		urb->complete = uvc_video_complete;

> > @@ -1795,10 +1831,8 @@ static int uvc_init_video_bulk(struct uvc_streaming *stream,

> >  

> >  		usb_fill_bulk_urb(urb, stream->dev->udev, pipe,	uvc_urb->buffer,

> >  				  size, uvc_video_complete, uvc_urb);

> > -#ifndef CONFIG_DMA_NONCOHERENT

> >  		urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;

> >  		urb->transfer_dma = uvc_urb->dma;

> > -#endif

> >  

> >  		uvc_urb->urb = urb;

> >  	}

> > @@ -1895,6 +1929,7 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,

> >  

> >  	/* Submit the URBs. */

> >  	for_each_uvc_urb(uvc_urb, stream) {

> > +		uvc_urb_dma_sync(uvc_urb, true);

> >  		ret = usb_submit_urb(uvc_urb->urb, gfp_flags);

> >  		if (ret < 0) {

> >  			dev_err(&stream->intf->dev,

> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h

> > index 97df5ecd66c9a7..fec24f1eca1c96 100644

> > --- a/drivers/media/usb/uvc/uvcvideo.h

> > +++ b/drivers/media/usb/uvc/uvcvideo.h

> > @@ -545,7 +545,8 @@ struct uvc_copy_op {

> >   * @urb: the URB described by this context structure

> >   * @stream: UVC streaming context

> >   * @buffer: memory storage for the URB

> > - * @dma: DMA coherent addressing for the urb_buffer

> > + * @dma: Allocated DMA handle

> > + * @sgt: sgt_table with the urb locations in memory

> >   * @async_operations: counter to indicate the number of copy operations

> >   * @copy_operations: work descriptors for asynchronous copy operations

> >   * @work: work queue entry for asynchronous decode

> > @@ -556,6 +557,7 @@ struct uvc_urb {

> >  

> >  	char *buffer;

> >  	dma_addr_t dma;

> > +	struct sg_table *sgt;

> 

> A forward declaration of struct sg_table with the other forward

> declarations would be useful.

> 

> >  

> >  	unsigned int async_operations;

> >  	struct uvc_copy_op copy_operations[UVC_MAX_PACKETS];


-- 
Regards,

Laurent Pinchart
diff mbox series

Patch

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index f2f565281e63ff..d008c68fb6c806 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -6,11 +6,13 @@ 
  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
  */
 
+#include <linux/highmem.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/usb.h>
+#include <linux/usb/hcd.h>
 #include <linux/videodev2.h>
 #include <linux/vmalloc.h>
 #include <linux/wait.h>
@@ -1096,6 +1098,26 @@  static int uvc_video_decode_start(struct uvc_streaming *stream,
 	return data[0];
 }
 
+static inline struct device *stream_to_dmadev(struct uvc_streaming *stream)
+{
+	return bus_to_hcd(stream->dev->udev->bus)->self.sysdev;
+}
+
+static void uvc_urb_dma_sync(struct uvc_urb *uvc_urb, bool for_device)
+{
+	struct device *dma_dev = stream_to_dmadev(uvc_urb->stream);
+
+	if (for_device) {
+		dma_sync_sgtable_for_device(dma_dev, uvc_urb->sgt,
+					    DMA_FROM_DEVICE);
+	} else {
+		dma_sync_sgtable_for_cpu(dma_dev, uvc_urb->sgt,
+					 DMA_FROM_DEVICE);
+		invalidate_kernel_vmap_range(uvc_urb->buffer,
+					     uvc_urb->stream->urb_size);
+	}
+}
+
 /*
  * uvc_video_decode_data_work: Asynchronous memcpy processing
  *
@@ -1117,6 +1139,8 @@  static void uvc_video_copy_data_work(struct work_struct *work)
 		uvc_queue_buffer_release(op->buf);
 	}
 
+	uvc_urb_dma_sync(uvc_urb, true);
+
 	ret = usb_submit_urb(uvc_urb->urb, GFP_KERNEL);
 	if (ret < 0)
 		dev_err(&uvc_urb->stream->intf->dev,
@@ -1541,10 +1565,12 @@  static void uvc_video_complete(struct urb *urb)
 	 * Process the URB headers, and optionally queue expensive memcpy tasks
 	 * to be deferred to a work queue.
 	 */
+	uvc_urb_dma_sync(uvc_urb, false);
 	stream->decode(uvc_urb, buf, buf_meta);
 
 	/* If no async work is needed, resubmit the URB immediately. */
 	if (!uvc_urb->async_operations) {
+		uvc_urb_dma_sync(uvc_urb, true);
 		ret = usb_submit_urb(uvc_urb->urb, GFP_ATOMIC);
 		if (ret < 0)
 			dev_err(&stream->intf->dev,
@@ -1560,24 +1586,46 @@  static void uvc_video_complete(struct urb *urb)
  */
 static void uvc_free_urb_buffers(struct uvc_streaming *stream)
 {
+	struct device *dma_dev = stream_to_dmadev(stream);
 	struct uvc_urb *uvc_urb;
 
 	for_each_uvc_urb(uvc_urb, stream) {
 		if (!uvc_urb->buffer)
 			continue;
 
-#ifndef CONFIG_DMA_NONCOHERENT
-		usb_free_coherent(stream->dev->udev, stream->urb_size,
-				  uvc_urb->buffer, uvc_urb->dma);
-#else
-		kfree(uvc_urb->buffer);
-#endif
+		dma_vunmap_noncontiguous(dma_dev, uvc_urb->buffer);
+		dma_free_noncontiguous(dma_dev, stream->urb_size, uvc_urb->sgt,
+				       DMA_FROM_DEVICE);
+
 		uvc_urb->buffer = NULL;
 	}
 
 	stream->urb_size = 0;
 }
 
+static bool uvc_alloc_urb_buffer(struct uvc_streaming *stream,
+				 struct uvc_urb *uvc_urb, gfp_t gfp_flags)
+{
+	struct device *dma_dev = stream_to_dmadev(stream);
+
+
+	uvc_urb->sgt = dma_alloc_noncontiguous(dma_dev, stream->urb_size,
+					       DMA_FROM_DEVICE, gfp_flags, 0);
+	if (!uvc_urb->sgt)
+		return false;
+	uvc_urb->dma = uvc_urb->sgt->sgl->dma_address;
+
+	uvc_urb->buffer = dma_vmap_noncontiguous(dma_dev, stream->urb_size,
+						 uvc_urb->sgt);
+	if (!uvc_urb->buffer) {
+		dma_free_noncontiguous(dma_dev, stream->urb_size,
+				       uvc_urb->sgt, DMA_FROM_DEVICE);
+		return false;
+	}
+
+	return true;
+}
+
 /*
  * Allocate transfer buffers. This function can be called with buffers
  * already allocated when resuming from suspend, in which case it will
@@ -1608,19 +1656,11 @@  static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
 
 	/* Retry allocations until one succeed. */
 	for (; npackets > 1; npackets /= 2) {
+		stream->urb_size = psize * npackets;
 		for (i = 0; i < UVC_URBS; ++i) {
 			struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
 
-			stream->urb_size = psize * npackets;
-#ifndef CONFIG_DMA_NONCOHERENT
-			uvc_urb->buffer = usb_alloc_coherent(
-				stream->dev->udev, stream->urb_size,
-				gfp_flags | __GFP_NOWARN, &uvc_urb->dma);
-#else
-			uvc_urb->buffer =
-			    kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN);
-#endif
-			if (!uvc_urb->buffer) {
+			if (!uvc_alloc_urb_buffer(stream, uvc_urb, gfp_flags)) {
 				uvc_free_urb_buffers(stream);
 				break;
 			}
@@ -1730,12 +1770,8 @@  static int uvc_init_video_isoc(struct uvc_streaming *stream,
 		urb->context = uvc_urb;
 		urb->pipe = usb_rcvisocpipe(stream->dev->udev,
 				ep->desc.bEndpointAddress);
-#ifndef CONFIG_DMA_NONCOHERENT
 		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
 		urb->transfer_dma = uvc_urb->dma;
-#else
-		urb->transfer_flags = URB_ISO_ASAP;
-#endif
 		urb->interval = ep->desc.bInterval;
 		urb->transfer_buffer = uvc_urb->buffer;
 		urb->complete = uvc_video_complete;
@@ -1795,10 +1831,8 @@  static int uvc_init_video_bulk(struct uvc_streaming *stream,
 
 		usb_fill_bulk_urb(urb, stream->dev->udev, pipe,	uvc_urb->buffer,
 				  size, uvc_video_complete, uvc_urb);
-#ifndef CONFIG_DMA_NONCOHERENT
 		urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 		urb->transfer_dma = uvc_urb->dma;
-#endif
 
 		uvc_urb->urb = urb;
 	}
@@ -1895,6 +1929,7 @@  static int uvc_video_start_transfer(struct uvc_streaming *stream,
 
 	/* Submit the URBs. */
 	for_each_uvc_urb(uvc_urb, stream) {
+		uvc_urb_dma_sync(uvc_urb, true);
 		ret = usb_submit_urb(uvc_urb->urb, gfp_flags);
 		if (ret < 0) {
 			dev_err(&stream->intf->dev,
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 97df5ecd66c9a7..fec24f1eca1c96 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -545,7 +545,8 @@  struct uvc_copy_op {
  * @urb: the URB described by this context structure
  * @stream: UVC streaming context
  * @buffer: memory storage for the URB
- * @dma: DMA coherent addressing for the urb_buffer
+ * @dma: Allocated DMA handle
+ * @sgt: sgt_table with the urb locations in memory
  * @async_operations: counter to indicate the number of copy operations
  * @copy_operations: work descriptors for asynchronous copy operations
  * @work: work queue entry for asynchronous decode
@@ -556,6 +557,7 @@  struct uvc_urb {
 
 	char *buffer;
 	dma_addr_t dma;
+	struct sg_table *sgt;
 
 	unsigned int async_operations;
 	struct uvc_copy_op copy_operations[UVC_MAX_PACKETS];