diff mbox series

[v2] usb: cdns3: Optimize DMA request buffer allocation

Message ID 1616008439-15494-1-git-send-email-sparmar@cadence.com
State Superseded
Headers show
Series [v2] usb: cdns3: Optimize DMA request buffer allocation | expand

Commit Message

Sanket Parmar March 17, 2021, 7:13 p.m. UTC
dma_alloc_coherent() might fail on the platform with a small
DMA region.

To avoid such failure in cdns3_prepare_aligned_request_buf(),
dma_alloc_coherent() is replaced with dma_alloc_noncoherent()
to allocate aligned request buffer of dynamic length.

Reported-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Sanket Parmar <sparmar@cadence.com>
---

Changelog:
v2:
- used dma_*_noncoherent() APIs
- changed the commit log

 drivers/usb/cdns3/cdns3-gadget.c | 30 ++++++++++++++++++++++++------
 drivers/usb/cdns3/cdns3-gadget.h |  2 ++
 2 files changed, 26 insertions(+), 6 deletions(-)

Comments

Peter Chen March 20, 2021, 9:07 a.m. UTC | #1
On 21-03-18 07:32:45, Christoph Hellwig wrote:
> On Wed, Mar 17, 2021 at 08:13:59PM +0100, Sanket Parmar wrote:

> > dma_alloc_coherent() might fail on the platform with a small

> > DMA region.

> > 

> > To avoid such failure in cdns3_prepare_aligned_request_buf(),

> > dma_alloc_coherent() is replaced with dma_alloc_noncoherent()

> > to allocate aligned request buffer of dynamic length.

> > 

> > Reported-by: Aswath Govindraju <a-govindraju@ti.com>

> > Signed-off-by: Sanket Parmar <sparmar@cadence.com>

> 

> Looks good to me:

> 

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


Hi Christoph,

I would like to confirm the dma_alloc_noncoherent allocates the memory
less than PAGE_SIZE if buffer size it would like to allocate is small
(eg, 64 bytes)? 

-- 

Thanks,
Peter Chen
Peter Chen March 20, 2021, 9:08 a.m. UTC | #2
On 21-03-17 20:13:59, Sanket Parmar wrote:
> dma_alloc_coherent() might fail on the platform with a small

> DMA region.

> 

> To avoid such failure in cdns3_prepare_aligned_request_buf(),

> dma_alloc_coherent() is replaced with dma_alloc_noncoherent()

> to allocate aligned request buffer of dynamic length.

> 

> Reported-by: Aswath Govindraju <a-govindraju@ti.com>

> Signed-off-by: Sanket Parmar <sparmar@cadence.com>

> ---

> 

> Changelog:

> v2:

> - used dma_*_noncoherent() APIs

> - changed the commit log

> 

>  drivers/usb/cdns3/cdns3-gadget.c | 30 ++++++++++++++++++++++++------

>  drivers/usb/cdns3/cdns3-gadget.h |  2 ++

>  2 files changed, 26 insertions(+), 6 deletions(-)

> 

> diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c

> index 0b892a2..126087b 100644

> --- a/drivers/usb/cdns3/cdns3-gadget.c

> +++ b/drivers/usb/cdns3/cdns3-gadget.c

> @@ -819,9 +819,15 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep,

>  					priv_ep->dir);

>  

>  	if ((priv_req->flags & REQUEST_UNALIGNED) &&

> -	    priv_ep->dir == USB_DIR_OUT && !request->status)

> +	    priv_ep->dir == USB_DIR_OUT && !request->status) {

> +		/* Make DMA buffer CPU accessible */

> +		dma_sync_single_for_cpu(priv_dev->sysdev,

> +			priv_req->aligned_buf->dma,

> +			priv_req->aligned_buf->size,

> +			priv_req->aligned_buf->dir);

>  		memcpy(request->buf, priv_req->aligned_buf->buf,

>  		       request->length);

> +	}

>  

>  	priv_req->flags &= ~(REQUEST_PENDING | REQUEST_UNALIGNED);

>  	/* All TRBs have finished, clear the counter */

> @@ -883,8 +889,8 @@ static void cdns3_free_aligned_request_buf(struct work_struct *work)

>  			 * interrupts.

>  			 */

>  			spin_unlock_irqrestore(&priv_dev->lock, flags);

> -			dma_free_coherent(priv_dev->sysdev, buf->size,

> -					  buf->buf, buf->dma);

> +			dma_free_noncoherent(priv_dev->sysdev, buf->size,

> +					  buf->buf, buf->dma, buf->dir);

>  			kfree(buf);

>  			spin_lock_irqsave(&priv_dev->lock, flags);

>  		}

> @@ -911,10 +917,13 @@ static int cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)

>  			return -ENOMEM;

>  

>  		buf->size = priv_req->request.length;

> +		buf->dir = usb_endpoint_dir_in(priv_ep->endpoint.desc) ?

> +			DMA_TO_DEVICE : DMA_FROM_DEVICE;

>  

> -		buf->buf = dma_alloc_coherent(priv_dev->sysdev,

> +		buf->buf = dma_alloc_noncoherent(priv_dev->sysdev,

>  					      buf->size,

>  					      &buf->dma,

> +					      buf->dir,

>  					      GFP_ATOMIC);

>  		if (!buf->buf) {

>  			kfree(buf);

> @@ -936,10 +945,18 @@ static int cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)

>  	}

>  

>  	if (priv_ep->dir == USB_DIR_IN) {

> +		/* Make DMA buffer CPU accessible */

> +		dma_sync_single_for_cpu(priv_dev->sysdev,

> +			buf->dma, buf->size, buf->dir);

>  		memcpy(buf->buf, priv_req->request.buf,

>  		       priv_req->request.length);

>  	}

>  

> +	/* Transfer DMA buffer ownership back to device */

> +	dma_sync_single_for_device(priv_dev->sysdev,

> +			buf->dma, buf->size, buf->dir);

> +

> +


One more blank line.

Otherwise, it seems OK for me.

>  	priv_req->flags |= REQUEST_UNALIGNED;

>  	trace_cdns3_prepare_aligned_request(priv_req);

>  

> @@ -3088,9 +3105,10 @@ static void cdns3_gadget_exit(struct cdns *cdns)

>  		struct cdns3_aligned_buf *buf;

>  

>  		buf = cdns3_next_align_buf(&priv_dev->aligned_buf_list);

> -		dma_free_coherent(priv_dev->sysdev, buf->size,

> +		dma_free_noncoherent(priv_dev->sysdev, buf->size,

>  				  buf->buf,

> -				  buf->dma);

> +				  buf->dma,

> +				  buf->dir);

>  

>  		list_del(&buf->list);

>  		kfree(buf);

> diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-gadget.h

> index ecf9b91..c5660f2 100644

> --- a/drivers/usb/cdns3/cdns3-gadget.h

> +++ b/drivers/usb/cdns3/cdns3-gadget.h

> @@ -12,6 +12,7 @@

>  #ifndef __LINUX_CDNS3_GADGET

>  #define __LINUX_CDNS3_GADGET

>  #include <linux/usb/gadget.h>

> +#include <linux/dma-direction.h>

>  

>  /*

>   * USBSS-DEV register interface.

> @@ -1205,6 +1206,7 @@ struct cdns3_aligned_buf {

>  	void			*buf;

>  	dma_addr_t		dma;

>  	u32			size;

> +	enum dma_data_direction dir;

>  	unsigned		in_use:1;

>  	struct list_head	list;

>  };

> -- 

> 2.4.5

> 


-- 

Thanks,
Peter Chen
Sanket Parmar March 22, 2021, 10:30 a.m. UTC | #3
Hi Peter,

> On 21-03-17 20:13:59, Sanket Parmar wrote:

> > dma_alloc_coherent() might fail on the platform with a small

> > DMA region.

> >

> > To avoid such failure in cdns3_prepare_aligned_request_buf(),

> > dma_alloc_coherent() is replaced with dma_alloc_noncoherent()

> > to allocate aligned request buffer of dynamic length.

> >

> > Reported-by: Aswath Govindraju <a-govindraju@ti.com>

> > Signed-off-by: Sanket Parmar <sparmar@cadence.com>

> > ---

> >

> > Changelog:

> > v2:

> > - used dma_*_noncoherent() APIs

> > - changed the commit log

> >

> >  drivers/usb/cdns3/cdns3-gadget.c | 30 ++++++++++++++++++++++++-----

> -

> >  drivers/usb/cdns3/cdns3-gadget.h |  2 ++

> >  2 files changed, 26 insertions(+), 6 deletions(-)

> >

> > diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-

> gadget.c

> > index 0b892a2..126087b 100644

> > --- a/drivers/usb/cdns3/cdns3-gadget.c

> > +++ b/drivers/usb/cdns3/cdns3-gadget.c

> > @@ -819,9 +819,15 @@ void cdns3_gadget_giveback(struct

> cdns3_endpoint *priv_ep,

> >  					priv_ep->dir);

> >

> >  	if ((priv_req->flags & REQUEST_UNALIGNED) &&

> > -	    priv_ep->dir == USB_DIR_OUT && !request->status)

> > +	    priv_ep->dir == USB_DIR_OUT && !request->status) {

> > +		/* Make DMA buffer CPU accessible */

> > +		dma_sync_single_for_cpu(priv_dev->sysdev,

> > +			priv_req->aligned_buf->dma,

> > +			priv_req->aligned_buf->size,

> > +			priv_req->aligned_buf->dir);

> >  		memcpy(request->buf, priv_req->aligned_buf->buf,

> >  		       request->length);

> > +	}

> >

> >  	priv_req->flags &= ~(REQUEST_PENDING | REQUEST_UNALIGNED);

> >  	/* All TRBs have finished, clear the counter */

> > @@ -883,8 +889,8 @@ static void cdns3_free_aligned_request_buf(struct

> work_struct *work)

> >  			 * interrupts.

> >  			 */

> >  			spin_unlock_irqrestore(&priv_dev->lock, flags);

> > -			dma_free_coherent(priv_dev->sysdev, buf->size,

> > -					  buf->buf, buf->dma);

> > +			dma_free_noncoherent(priv_dev->sysdev, buf-

> >size,

> > +					  buf->buf, buf->dma, buf->dir);

> >  			kfree(buf);

> >  			spin_lock_irqsave(&priv_dev->lock, flags);

> >  		}

> > @@ -911,10 +917,13 @@ static int

> cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)

> >  			return -ENOMEM;

> >

> >  		buf->size = priv_req->request.length;

> > +		buf->dir = usb_endpoint_dir_in(priv_ep->endpoint.desc) ?

> > +			DMA_TO_DEVICE : DMA_FROM_DEVICE;

> >

> > -		buf->buf = dma_alloc_coherent(priv_dev->sysdev,

> > +		buf->buf = dma_alloc_noncoherent(priv_dev->sysdev,

> >  					      buf->size,

> >  					      &buf->dma,

> > +					      buf->dir,

> >  					      GFP_ATOMIC);

> >  		if (!buf->buf) {

> >  			kfree(buf);

> > @@ -936,10 +945,18 @@ static int

> cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)

> >  	}

> >

> >  	if (priv_ep->dir == USB_DIR_IN) {

> > +		/* Make DMA buffer CPU accessible */

> > +		dma_sync_single_for_cpu(priv_dev->sysdev,

> > +			buf->dma, buf->size, buf->dir);

> >  		memcpy(buf->buf, priv_req->request.buf,

> >  		       priv_req->request.length);

> >  	}

> >

> > +	/* Transfer DMA buffer ownership back to device */

> > +	dma_sync_single_for_device(priv_dev->sysdev,

> > +			buf->dma, buf->size, buf->dir);

> > +

> > +

> 

> One more blank line.

> 

> Otherwise, it seems OK for me.


I have remove this blank line. New patch has been posted already.

> 

> >  	priv_req->flags |= REQUEST_UNALIGNED;

> >  	trace_cdns3_prepare_aligned_request(priv_req);

> >

> > @@ -3088,9 +3105,10 @@ static void cdns3_gadget_exit(struct cdns *cdns)

> >  		struct cdns3_aligned_buf *buf;

> >

> >  		buf = cdns3_next_align_buf(&priv_dev->aligned_buf_list);

> > -		dma_free_coherent(priv_dev->sysdev, buf->size,

> > +		dma_free_noncoherent(priv_dev->sysdev, buf->size,

> >  				  buf->buf,

> > -				  buf->dma);

> > +				  buf->dma,

> > +				  buf->dir);

> >

> >  		list_del(&buf->list);

> >  		kfree(buf);

> > diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-

> gadget.h

> > index ecf9b91..c5660f2 100644

> > --- a/drivers/usb/cdns3/cdns3-gadget.h

> > +++ b/drivers/usb/cdns3/cdns3-gadget.h

> > @@ -12,6 +12,7 @@

> >  #ifndef __LINUX_CDNS3_GADGET

> >  #define __LINUX_CDNS3_GADGET

> >  #include <linux/usb/gadget.h>

> > +#include <linux/dma-direction.h>

> >

> >  /*

> >   * USBSS-DEV register interface.

> > @@ -1205,6 +1206,7 @@ struct cdns3_aligned_buf {

> >  	void			*buf;

> >  	dma_addr_t		dma;

> >  	u32			size;

> > +	enum dma_data_direction dir;

> >  	unsigned		in_use:1;

> >  	struct list_head	list;

> >  };

> > --

> > 2.4.5

> >

> 

> --

> 

> Thanks,

> Peter Chen


Thanks,
Sanket
diff mbox series

Patch

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index 0b892a2..126087b 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -819,9 +819,15 @@  void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep,
 					priv_ep->dir);
 
 	if ((priv_req->flags & REQUEST_UNALIGNED) &&
-	    priv_ep->dir == USB_DIR_OUT && !request->status)
+	    priv_ep->dir == USB_DIR_OUT && !request->status) {
+		/* Make DMA buffer CPU accessible */
+		dma_sync_single_for_cpu(priv_dev->sysdev,
+			priv_req->aligned_buf->dma,
+			priv_req->aligned_buf->size,
+			priv_req->aligned_buf->dir);
 		memcpy(request->buf, priv_req->aligned_buf->buf,
 		       request->length);
+	}
 
 	priv_req->flags &= ~(REQUEST_PENDING | REQUEST_UNALIGNED);
 	/* All TRBs have finished, clear the counter */
@@ -883,8 +889,8 @@  static void cdns3_free_aligned_request_buf(struct work_struct *work)
 			 * interrupts.
 			 */
 			spin_unlock_irqrestore(&priv_dev->lock, flags);
-			dma_free_coherent(priv_dev->sysdev, buf->size,
-					  buf->buf, buf->dma);
+			dma_free_noncoherent(priv_dev->sysdev, buf->size,
+					  buf->buf, buf->dma, buf->dir);
 			kfree(buf);
 			spin_lock_irqsave(&priv_dev->lock, flags);
 		}
@@ -911,10 +917,13 @@  static int cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)
 			return -ENOMEM;
 
 		buf->size = priv_req->request.length;
+		buf->dir = usb_endpoint_dir_in(priv_ep->endpoint.desc) ?
+			DMA_TO_DEVICE : DMA_FROM_DEVICE;
 
-		buf->buf = dma_alloc_coherent(priv_dev->sysdev,
+		buf->buf = dma_alloc_noncoherent(priv_dev->sysdev,
 					      buf->size,
 					      &buf->dma,
+					      buf->dir,
 					      GFP_ATOMIC);
 		if (!buf->buf) {
 			kfree(buf);
@@ -936,10 +945,18 @@  static int cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)
 	}
 
 	if (priv_ep->dir == USB_DIR_IN) {
+		/* Make DMA buffer CPU accessible */
+		dma_sync_single_for_cpu(priv_dev->sysdev,
+			buf->dma, buf->size, buf->dir);
 		memcpy(buf->buf, priv_req->request.buf,
 		       priv_req->request.length);
 	}
 
+	/* Transfer DMA buffer ownership back to device */
+	dma_sync_single_for_device(priv_dev->sysdev,
+			buf->dma, buf->size, buf->dir);
+
+
 	priv_req->flags |= REQUEST_UNALIGNED;
 	trace_cdns3_prepare_aligned_request(priv_req);
 
@@ -3088,9 +3105,10 @@  static void cdns3_gadget_exit(struct cdns *cdns)
 		struct cdns3_aligned_buf *buf;
 
 		buf = cdns3_next_align_buf(&priv_dev->aligned_buf_list);
-		dma_free_coherent(priv_dev->sysdev, buf->size,
+		dma_free_noncoherent(priv_dev->sysdev, buf->size,
 				  buf->buf,
-				  buf->dma);
+				  buf->dma,
+				  buf->dir);
 
 		list_del(&buf->list);
 		kfree(buf);
diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-gadget.h
index ecf9b91..c5660f2 100644
--- a/drivers/usb/cdns3/cdns3-gadget.h
+++ b/drivers/usb/cdns3/cdns3-gadget.h
@@ -12,6 +12,7 @@ 
 #ifndef __LINUX_CDNS3_GADGET
 #define __LINUX_CDNS3_GADGET
 #include <linux/usb/gadget.h>
+#include <linux/dma-direction.h>
 
 /*
  * USBSS-DEV register interface.
@@ -1205,6 +1206,7 @@  struct cdns3_aligned_buf {
 	void			*buf;
 	dma_addr_t		dma;
 	u32			size;
+	enum dma_data_direction dir;
 	unsigned		in_use:1;
 	struct list_head	list;
 };