usb: dwc2: gadget: add scatter-gather mode

usb: dwc2: gadget: add scatter-gather mode

[Andrzej Pietrasiewicz]

Hi Minas,

W dniu 01.04.2019 o 12:01, Minas Harutyunyan pisze:
>
>> @Minas: can you please test with this patch instead of the original one?
>>
> Tested new version. No issue seen by running USB CV (Ch9, MSC) tests.
> Could you please elaborate which else tests you performed?

Only those reported by you to be failing, that is MSC.

Andrzej

usb: dwc2: gadget: add scatter-gather mode

[Minas Harutyunyan]

Hi Andrzej,

On 3/29/2019 6:05 PM, Andrzej Pietrasiewicz wrote:
> From: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
> 
> NOT FOR MERGING
> 
> @Minas: can you please test with this patch instead of the original one?
> 
Tested new version. No issue seen by running USB CV (Ch9, MSC) tests.
Could you please elaborate which else tests you performed?

> @Marek: can you please verify if null pointer bug exists in this version?
> 
> This patch adds support for transferring requests, which are
> non-contiguous in physical memory, i.e. the data buffer is described by
> a scatter-list. This allows transferring large requests without relying
> on error-prone contiguous buffer allocations. This way of allocating
> requests is already implemented in functionfs and TCM USB functions and
> automatically used if UDC driver advertises scatter-gather suppport.
> 
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
> [mszyprow: fixed null pointer issue, rewrote commit message]
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> [andrzej.p: improved handling zlps]
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
>   drivers/usb/dwc2/gadget.c | 107 +++++++++++++++++++++++++++-----------
>   1 file changed, 76 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
> index e15d8a462085..e76b2e040b4c 100644
> --- a/drivers/usb/dwc2/gadget.c
> +++ b/drivers/usb/dwc2/gadget.c
> @@ -768,22 +768,13 @@ static u32 dwc2_gadget_get_desc_params(struct dwc2_hsotg_ep *hs_ep, u32 *mask)
>   	return desc_size;
>   }
>   
> -/*
> - * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
> - * @hs_ep: The endpoint
> - * @dma_buff: DMA address to use
> - * @len: Length of the transfer
> - *
> - * This function will iterate over descriptor chain and fill its entries
> - * with corresponding information based on transfer data.
> - */
> -static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
> +static void dwc2_gadget_fill_nonisoc_xfer_ddma_one(struct dwc2_hsotg_ep *hs_ep,
> +						 struct dwc2_dma_desc **desc,
>   						 dma_addr_t dma_buff,
> -						 unsigned int len)
> +						 unsigned int len,
> +						 bool true_last)
>   {
> -	struct dwc2_hsotg *hsotg = hs_ep->parent;
>   	int dir_in = hs_ep->dir_in;
> -	struct dwc2_dma_desc *desc = hs_ep->desc_list;
>   	u32 mps = hs_ep->ep.maxpacket;
>   	u32 maxsize = 0;
>   	u32 offset = 0;
> @@ -798,41 +789,82 @@ static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
>   		hs_ep->desc_count = 1;
>   
>   	for (i = 0; i < hs_ep->desc_count; ++i) {
> -		desc->status = 0;
> -		desc->status |= (DEV_DMA_BUFF_STS_HBUSY
> +		(*desc)->status = 0;
> +		(*desc)->status |= (DEV_DMA_BUFF_STS_HBUSY
>   				 << DEV_DMA_BUFF_STS_SHIFT);
>   
>   		if (len > maxsize) {
>   			if (!hs_ep->index && !dir_in)
> -				desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
> +				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
>   
> -			desc->status |= (maxsize <<
> -						DEV_DMA_NBYTES_SHIFT & mask);
> -			desc->buf = dma_buff + offset;
> +			(*desc)->status |=
> +				maxsize << DEV_DMA_NBYTES_SHIFT & mask;
> +			(*desc)->buf = dma_buff + offset;
>   
>   			len -= maxsize;
>   			offset += maxsize;
>   		} else {
> -			desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
> +			if (true_last)
> +				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
>   
>   			if (dir_in)
> -				desc->status |= (len % mps) ? DEV_DMA_SHORT :
> -					((hs_ep->send_zlp) ? DEV_DMA_SHORT : 0);
> -			if (len > maxsize)
> -				dev_err(hsotg->dev, "wrong len %d\n", len);
> +				(*desc)->status |= (len % mps) ? DEV_DMA_SHORT :
> +					((hs_ep->send_zlp && true_last) ?
> +					DEV_DMA_SHORT : 0);
>   
> -			desc->status |=
> +			(*desc)->status |=
>   				len << DEV_DMA_NBYTES_SHIFT & mask;
> -			desc->buf = dma_buff + offset;
> +			(*desc)->buf = dma_buff + offset;
>   		}
>   
> -		desc->status &= ~DEV_DMA_BUFF_STS_MASK;
> -		desc->status |= (DEV_DMA_BUFF_STS_HREADY
> +		(*desc)->status &= ~DEV_DMA_BUFF_STS_MASK;
> +		(*desc)->status |= (DEV_DMA_BUFF_STS_HREADY
>   				 << DEV_DMA_BUFF_STS_SHIFT);
> -		desc++;
> +		(*desc)++;
>   	}
>   }
>   
> +/*
> + * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
> + * @hs_ep: The endpoint
> + * @ureq: Request to transfer
> + * @offset: offset in bytes
> + * @len: Length of the transfer
> + *
> + * This function will iterate over descriptor chain and fill its entries
> + * with corresponding information based on transfer data.
> + */
> +static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
> +						 dma_addr_t dma_buff,
> +						 unsigned int len)
> +{
> +	struct usb_request *ureq = NULL;
> +	struct dwc2_dma_desc *desc = hs_ep->desc_list;
> +	struct scatterlist *sg;
> +	int i;
> +	u8 desc_count = 0;
> +
> +	if (hs_ep->req)
> +		ureq = &hs_ep->req->req;
> +
> +	/* non-DMA sg buffer */
> +	if (!ureq || !ureq->num_sgs) {
> +		dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc,
> +			dma_buff, len, true);
> +		return;
> +	}
> +
> +	/* DMA sg buffer */
> +	for_each_sg(ureq->sg, sg, ureq->num_sgs, i) {
> +		dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc,
> +			sg_dma_address(sg) + sg->offset, sg_dma_len(sg),
> +			sg_is_last(sg));
> +		desc_count += hs_ep->desc_count;
> +	}
> +
> +	hs_ep->desc_count = desc_count;
> +}
> +
>   /*
>    * dwc2_gadget_fill_isoc_desc - fills next isochronous descriptor in chain.
>    * @hs_ep: The isochronous endpoint.
> @@ -944,7 +976,13 @@ static void dwc2_gadget_start_isoc_ddma(struct dwc2_hsotg_ep *hs_ep)
>   
>   	hs_ep->next_desc = 0;
>   	list_for_each_entry_safe(hs_req, treq, &hs_ep->queue, queue) {
> -		ret = dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
> +		dma_addr_t dma_addr = hs_req->req.dma;
> +
> +		if (hs_req->req.num_sgs) {
> +			WARN_ON(hs_req->req.num_sgs > 1);
> +			dma_addr = sg_dma_address(hs_req->req.sg);
> +		}
> +		ret = dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
>   						 hs_req->req.length);
>   		if (ret)
>   			break;
> @@ -1399,7 +1437,13 @@ static int dwc2_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
>   	 */
>   	if (using_desc_dma(hs) && hs_ep->isochronous) {
>   		if (hs_ep->target_frame != TARGET_FRAME_INITIAL) {
> -			dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
> +			dma_addr_t dma_addr = hs_req->req.dma;
> +
> +			if (hs_req->req.num_sgs) {
> +				WARN_ON(hs_req->req.num_sgs > 1);
> +				dma_addr = sg_dma_address(hs_req->req.sg);
> +			}
> +			dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
>   						   hs_req->req.length);
>   		}
>   		return 0;
> @@ -4386,6 +4430,7 @@ static int dwc2_hsotg_udc_start(struct usb_gadget *gadget,
>   	hsotg->enabled = 0;
>   	spin_unlock_irqrestore(&hsotg->lock, flags);
>   
> +	gadget->sg_supported = using_desc_dma(hsotg);
>   	dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
>   
>   	return 0;
>

usb: dwc2: gadget: add scatter-gather mode

[Marek Szyprowski]

Hi Andrzej,

On 2019-03-29 15:05, Andrzej Pietrasiewicz wrote:
> From: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
>
> NOT FOR MERGING
>
> @Minas: can you please test with this patch instead of the original one?
>
> @Marek: can you please verify if null pointer bug exists in this version?

Yes, I've checked it on my test environment and the NULL ptr issue 
observed in v2 is fixed. I think it is a good idea to send incremental 
patch to mainline with a 'Fixes:' tag.

> This patch adds support for transferring requests, which are
> non-contiguous in physical memory, i.e. the data buffer is described by
> a scatter-list. This allows transferring large requests without relying
> on error-prone contiguous buffer allocations. This way of allocating
> requests is already implemented in functionfs and TCM USB functions and
> automatically used if UDC driver advertises scatter-gather suppport.
>
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
> [mszyprow: fixed null pointer issue, rewrote commit message]
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> [andrzej.p: improved handling zlps]
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
>   drivers/usb/dwc2/gadget.c | 107 +++++++++++++++++++++++++++-----------
>   1 file changed, 76 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
> index e15d8a462085..e76b2e040b4c 100644
> --- a/drivers/usb/dwc2/gadget.c
> +++ b/drivers/usb/dwc2/gadget.c
> @@ -768,22 +768,13 @@ static u32 dwc2_gadget_get_desc_params(struct dwc2_hsotg_ep *hs_ep, u32 *mask)
>   	return desc_size;
>   }
>   
> -/*
> - * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
> - * @hs_ep: The endpoint
> - * @dma_buff: DMA address to use
> - * @len: Length of the transfer
> - *
> - * This function will iterate over descriptor chain and fill its entries
> - * with corresponding information based on transfer data.
> - */
> -static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
> +static void dwc2_gadget_fill_nonisoc_xfer_ddma_one(struct dwc2_hsotg_ep *hs_ep,
> +						 struct dwc2_dma_desc **desc,
>   						 dma_addr_t dma_buff,
> -						 unsigned int len)
> +						 unsigned int len,
> +						 bool true_last)
>   {
> -	struct dwc2_hsotg *hsotg = hs_ep->parent;
>   	int dir_in = hs_ep->dir_in;
> -	struct dwc2_dma_desc *desc = hs_ep->desc_list;
>   	u32 mps = hs_ep->ep.maxpacket;
>   	u32 maxsize = 0;
>   	u32 offset = 0;
> @@ -798,41 +789,82 @@ static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
>   		hs_ep->desc_count = 1;
>   
>   	for (i = 0; i < hs_ep->desc_count; ++i) {
> -		desc->status = 0;
> -		desc->status |= (DEV_DMA_BUFF_STS_HBUSY
> +		(*desc)->status = 0;
> +		(*desc)->status |= (DEV_DMA_BUFF_STS_HBUSY
>   				 << DEV_DMA_BUFF_STS_SHIFT);
>   
>   		if (len > maxsize) {
>   			if (!hs_ep->index && !dir_in)
> -				desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
> +				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
>   
> -			desc->status |= (maxsize <<
> -						DEV_DMA_NBYTES_SHIFT & mask);
> -			desc->buf = dma_buff + offset;
> +			(*desc)->status |=
> +				maxsize << DEV_DMA_NBYTES_SHIFT & mask;
> +			(*desc)->buf = dma_buff + offset;
>   
>   			len -= maxsize;
>   			offset += maxsize;
>   		} else {
> -			desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
> +			if (true_last)
> +				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
>   
>   			if (dir_in)
> -				desc->status |= (len % mps) ? DEV_DMA_SHORT :
> -					((hs_ep->send_zlp) ? DEV_DMA_SHORT : 0);
> -			if (len > maxsize)
> -				dev_err(hsotg->dev, "wrong len %d\n", len);
> +				(*desc)->status |= (len % mps) ? DEV_DMA_SHORT :
> +					((hs_ep->send_zlp && true_last) ?
> +					DEV_DMA_SHORT : 0);
>   
> -			desc->status |=
> +			(*desc)->status |=
>   				len << DEV_DMA_NBYTES_SHIFT & mask;
> -			desc->buf = dma_buff + offset;
> +			(*desc)->buf = dma_buff + offset;
>   		}
>   
> -		desc->status &= ~DEV_DMA_BUFF_STS_MASK;
> -		desc->status |= (DEV_DMA_BUFF_STS_HREADY
> +		(*desc)->status &= ~DEV_DMA_BUFF_STS_MASK;
> +		(*desc)->status |= (DEV_DMA_BUFF_STS_HREADY
>   				 << DEV_DMA_BUFF_STS_SHIFT);
> -		desc++;
> +		(*desc)++;
>   	}
>   }
>   
> +/*
> + * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
> + * @hs_ep: The endpoint
> + * @ureq: Request to transfer
> + * @offset: offset in bytes
> + * @len: Length of the transfer
> + *
> + * This function will iterate over descriptor chain and fill its entries
> + * with corresponding information based on transfer data.
> + */
> +static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
> +						 dma_addr_t dma_buff,
> +						 unsigned int len)
> +{
> +	struct usb_request *ureq = NULL;
> +	struct dwc2_dma_desc *desc = hs_ep->desc_list;
> +	struct scatterlist *sg;
> +	int i;
> +	u8 desc_count = 0;
> +
> +	if (hs_ep->req)
> +		ureq = &hs_ep->req->req;
> +
> +	/* non-DMA sg buffer */
> +	if (!ureq || !ureq->num_sgs) {
> +		dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc,
> +			dma_buff, len, true);
> +		return;
> +	}
> +
> +	/* DMA sg buffer */
> +	for_each_sg(ureq->sg, sg, ureq->num_sgs, i) {
> +		dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc,
> +			sg_dma_address(sg) + sg->offset, sg_dma_len(sg),
> +			sg_is_last(sg));
> +		desc_count += hs_ep->desc_count;
> +	}
> +
> +	hs_ep->desc_count = desc_count;
> +}
> +
>   /*
>    * dwc2_gadget_fill_isoc_desc - fills next isochronous descriptor in chain.
>    * @hs_ep: The isochronous endpoint.
> @@ -944,7 +976,13 @@ static void dwc2_gadget_start_isoc_ddma(struct dwc2_hsotg_ep *hs_ep)
>   
>   	hs_ep->next_desc = 0;
>   	list_for_each_entry_safe(hs_req, treq, &hs_ep->queue, queue) {
> -		ret = dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
> +		dma_addr_t dma_addr = hs_req->req.dma;
> +
> +		if (hs_req->req.num_sgs) {
> +			WARN_ON(hs_req->req.num_sgs > 1);
> +			dma_addr = sg_dma_address(hs_req->req.sg);
> +		}
> +		ret = dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
>   						 hs_req->req.length);
>   		if (ret)
>   			break;
> @@ -1399,7 +1437,13 @@ static int dwc2_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
>   	 */
>   	if (using_desc_dma(hs) && hs_ep->isochronous) {
>   		if (hs_ep->target_frame != TARGET_FRAME_INITIAL) {
> -			dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
> +			dma_addr_t dma_addr = hs_req->req.dma;
> +
> +			if (hs_req->req.num_sgs) {
> +				WARN_ON(hs_req->req.num_sgs > 1);
> +				dma_addr = sg_dma_address(hs_req->req.sg);
> +			}
> +			dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
>   						   hs_req->req.length);
>   		}
>   		return 0;
> @@ -4386,6 +4430,7 @@ static int dwc2_hsotg_udc_start(struct usb_gadget *gadget,
>   	hsotg->enabled = 0;
>   	spin_unlock_irqrestore(&hsotg->lock, flags);
>   
> +	gadget->sg_supported = using_desc_dma(hsotg);
>   	dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
>   
>   	return 0;

Best regards

usb: dwc2: gadget: add scatter-gather mode

[Andrzej Pietrasiewicz]

From: Andrzej Pietrasiewicz <andrzej.p@samsung.com>

NOT FOR MERGING

@Minas: can you please test with this patch instead of the original one?

@Marek: can you please verify if null pointer bug exists in this version?

This patch adds support for transferring requests, which are
non-contiguous in physical memory, i.e. the data buffer is described by
a scatter-list. This allows transferring large requests without relying
on error-prone contiguous buffer allocations. This way of allocating
requests is already implemented in functionfs and TCM USB functions and
automatically used if UDC driver advertises scatter-gather suppport.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
[mszyprow: fixed null pointer issue, rewrote commit message]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
[andrzej.p: improved handling zlps]
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
---
 drivers/usb/dwc2/gadget.c | 107 +++++++++++++++++++++++++++-----------
 1 file changed, 76 insertions(+), 31 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index e15d8a462085..e76b2e040b4c 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -768,22 +768,13 @@ static u32 dwc2_gadget_get_desc_params(struct dwc2_hsotg_ep *hs_ep, u32 *mask)
 	return desc_size;
 }
 
-/*
- * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
- * @hs_ep: The endpoint
- * @dma_buff: DMA address to use
- * @len: Length of the transfer
- *
- * This function will iterate over descriptor chain and fill its entries
- * with corresponding information based on transfer data.
- */
-static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
+static void dwc2_gadget_fill_nonisoc_xfer_ddma_one(struct dwc2_hsotg_ep *hs_ep,
+						 struct dwc2_dma_desc **desc,
 						 dma_addr_t dma_buff,
-						 unsigned int len)
+						 unsigned int len,
+						 bool true_last)
 {
-	struct dwc2_hsotg *hsotg = hs_ep->parent;
 	int dir_in = hs_ep->dir_in;
-	struct dwc2_dma_desc *desc = hs_ep->desc_list;
 	u32 mps = hs_ep->ep.maxpacket;
 	u32 maxsize = 0;
 	u32 offset = 0;
@@ -798,41 +789,82 @@ static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
 		hs_ep->desc_count = 1;
 
 	for (i = 0; i < hs_ep->desc_count; ++i) {
-		desc->status = 0;
-		desc->status |= (DEV_DMA_BUFF_STS_HBUSY
+		(*desc)->status = 0;
+		(*desc)->status |= (DEV_DMA_BUFF_STS_HBUSY
 				 << DEV_DMA_BUFF_STS_SHIFT);
 
 		if (len > maxsize) {
 			if (!hs_ep->index && !dir_in)
-				desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
+				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
 
-			desc->status |= (maxsize <<
-						DEV_DMA_NBYTES_SHIFT & mask);
-			desc->buf = dma_buff + offset;
+			(*desc)->status |=
+				maxsize << DEV_DMA_NBYTES_SHIFT & mask;
+			(*desc)->buf = dma_buff + offset;
 
 			len -= maxsize;
 			offset += maxsize;
 		} else {
-			desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
+			if (true_last)
+				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
 
 			if (dir_in)
-				desc->status |= (len % mps) ? DEV_DMA_SHORT :
-					((hs_ep->send_zlp) ? DEV_DMA_SHORT : 0);
-			if (len > maxsize)
-				dev_err(hsotg->dev, "wrong len %d\n", len);
+				(*desc)->status |= (len % mps) ? DEV_DMA_SHORT :
+					((hs_ep->send_zlp && true_last) ?
+					DEV_DMA_SHORT : 0);
 
-			desc->status |=
+			(*desc)->status |=
 				len << DEV_DMA_NBYTES_SHIFT & mask;
-			desc->buf = dma_buff + offset;
+			(*desc)->buf = dma_buff + offset;
 		}
 
-		desc->status &= ~DEV_DMA_BUFF_STS_MASK;
-		desc->status |= (DEV_DMA_BUFF_STS_HREADY
+		(*desc)->status &= ~DEV_DMA_BUFF_STS_MASK;
+		(*desc)->status |= (DEV_DMA_BUFF_STS_HREADY
 				 << DEV_DMA_BUFF_STS_SHIFT);
-		desc++;
+		(*desc)++;
 	}
 }
 
+/*
+ * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
+ * @hs_ep: The endpoint
+ * @ureq: Request to transfer
+ * @offset: offset in bytes
+ * @len: Length of the transfer
+ *
+ * This function will iterate over descriptor chain and fill its entries
+ * with corresponding information based on transfer data.
+ */
+static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
+						 dma_addr_t dma_buff,
+						 unsigned int len)
+{
+	struct usb_request *ureq = NULL;
+	struct dwc2_dma_desc *desc = hs_ep->desc_list;
+	struct scatterlist *sg;
+	int i;
+	u8 desc_count = 0;
+
+	if (hs_ep->req)
+		ureq = &hs_ep->req->req;
+
+	/* non-DMA sg buffer */
+	if (!ureq || !ureq->num_sgs) {
+		dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc,
+			dma_buff, len, true);
+		return;
+	}
+
+	/* DMA sg buffer */
+	for_each_sg(ureq->sg, sg, ureq->num_sgs, i) {
+		dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &desc,
+			sg_dma_address(sg) + sg->offset, sg_dma_len(sg),
+			sg_is_last(sg));
+		desc_count += hs_ep->desc_count;
+	}
+
+	hs_ep->desc_count = desc_count;
+}
+
 /*
  * dwc2_gadget_fill_isoc_desc - fills next isochronous descriptor in chain.
  * @hs_ep: The isochronous endpoint.
@@ -944,7 +976,13 @@ static void dwc2_gadget_start_isoc_ddma(struct dwc2_hsotg_ep *hs_ep)
 
 	hs_ep->next_desc = 0;
 	list_for_each_entry_safe(hs_req, treq, &hs_ep->queue, queue) {
-		ret = dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
+		dma_addr_t dma_addr = hs_req->req.dma;
+
+		if (hs_req->req.num_sgs) {
+			WARN_ON(hs_req->req.num_sgs > 1);
+			dma_addr = sg_dma_address(hs_req->req.sg);
+		}
+		ret = dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
 						 hs_req->req.length);
 		if (ret)
 			break;
@@ -1399,7 +1437,13 @@ static int dwc2_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
 	 */
 	if (using_desc_dma(hs) && hs_ep->isochronous) {
 		if (hs_ep->target_frame != TARGET_FRAME_INITIAL) {
-			dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
+			dma_addr_t dma_addr = hs_req->req.dma;
+
+			if (hs_req->req.num_sgs) {
+				WARN_ON(hs_req->req.num_sgs > 1);
+				dma_addr = sg_dma_address(hs_req->req.sg);
+			}
+			dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
 						   hs_req->req.length);
 		}
 		return 0;
@@ -4386,6 +4430,7 @@ static int dwc2_hsotg_udc_start(struct usb_gadget *gadget,
 	hsotg->enabled = 0;
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 
+	gadget->sg_supported = using_desc_dma(hsotg);
 	dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
 
 	return 0;

usb: dwc2: gadget: Add scatter-gather mode

[Andrzej Pietrasiewicz]

Non-isochronous transfers:

dwc2_gadget_config_nonisoc_xfer_ddma() name is prepended with underscore
and the function is adapted to process descriptors passed from outside
and to handle end of current sg list element differently from handling
the end of the entire buffer. A wrapper for the said function is added
which, for sg mode, iterates over scatterlist elements and for each of
them calls the function mentioned above.

Isochronous transfers:

If the usb request contains a scatterlist, the address from the first
element is used as dma address at dwc2_gadget_fill_isoc_desc() invocations.
Current code for isoc transfers does not allow more than 4096 bytes per
transfer, so it is assumed there is only one element in the scatterlist.
If there are more, a warning is issued. Please see the fragment under
the comment:


	/* In DDMA mode for ISOC's don't queue request if length greater
	 * than descriptor limits.
	 */

in dwc2_hsotg_ep_queue() to see the limits for isoc transfers.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
---

@Minas: I was actually unable to test the isochronous transfers.

 drivers/usb/dwc2/gadget.c | 104 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 73 insertions(+), 31 deletions(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index d9bb6cb..90df8f4 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -768,22 +768,13 @@ static u32 dwc2_gadget_get_desc_params(struct dwc2_hsotg_ep *hs_ep, u32 *mask)
 	return desc_size;
 }
 
-/*
- * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
- * @hs_ep: The endpoint
- * @dma_buff: DMA address to use
- * @len: Length of the transfer
- *
- * This function will iterate over descriptor chain and fill its entries
- * with corresponding information based on transfer data.
- */
-static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
+static void _dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
+						 struct dwc2_dma_desc **desc,
 						 dma_addr_t dma_buff,
-						 unsigned int len)
+						 unsigned int len,
+						 bool true_last)
 {
-	struct dwc2_hsotg *hsotg = hs_ep->parent;
 	int dir_in = hs_ep->dir_in;
-	struct dwc2_dma_desc *desc = hs_ep->desc_list;
 	u32 mps = hs_ep->ep.maxpacket;
 	u32 maxsize = 0;
 	u32 offset = 0;
@@ -798,42 +789,80 @@ static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
 		hs_ep->desc_count = 1;
 
 	for (i = 0; i < hs_ep->desc_count; ++i) {
-		desc->status = 0;
-		desc->status |= (DEV_DMA_BUFF_STS_HBUSY
+		(*desc)->status = 0;
+		(*desc)->status |= (DEV_DMA_BUFF_STS_HBUSY
 				 << DEV_DMA_BUFF_STS_SHIFT);
 
 		if (len > maxsize) {
 			if (!hs_ep->index && !dir_in)
-				desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
+				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
 
-			desc->status |= (maxsize <<
-						DEV_DMA_NBYTES_SHIFT & mask);
-			desc->buf = dma_buff + offset;
+			(*desc)->status |=
+				maxsize << DEV_DMA_NBYTES_SHIFT & mask;
+			(*desc)->buf = dma_buff + offset;
 
 			len -= maxsize;
 			offset += maxsize;
 		} else {
-			desc->status |= (DEV_DMA_L | DEV_DMA_IOC);
+			if (true_last)
+				(*desc)->status |= (DEV_DMA_L | DEV_DMA_IOC);
 
 			if (dir_in)
-				desc->status |= (len % mps) ? DEV_DMA_SHORT :
-					((hs_ep->send_zlp) ? DEV_DMA_SHORT : 0);
-			if (len > maxsize)
-				dev_err(hsotg->dev, "wrong len %d\n", len);
+				(*desc)->status |= (len % mps) ? DEV_DMA_SHORT :
+					((hs_ep->send_zlp && true_last) ?
+					DEV_DMA_SHORT : 0);
 
-			desc->status |=
+			(*desc)->status |=
 				len << DEV_DMA_NBYTES_SHIFT & mask;
-			desc->buf = dma_buff + offset;
+			(*desc)->buf = dma_buff + offset;
 		}
 
-		desc->status &= ~DEV_DMA_BUFF_STS_MASK;
-		desc->status |= (DEV_DMA_BUFF_STS_HREADY
+		(*desc)->status &= ~DEV_DMA_BUFF_STS_MASK;
+		(*desc)->status |= (DEV_DMA_BUFF_STS_HREADY
 				 << DEV_DMA_BUFF_STS_SHIFT);
-		desc++;
+		(*desc)++;
 	}
 }
 
 /*
+ * dwc2_gadget_config_nonisoc_xfer_ddma - prepare non ISOC DMA desc chain.
+ * @hs_ep: The endpoint
+ * @dma_buff: DMA address to use
+ * @len: Length of the transfer
+ *
+ * This function will iterate over descriptor chain and fill its entries
+ * with corresponding information based on transfer data.
+ */
+static void dwc2_gadget_config_nonisoc_xfer_ddma(struct dwc2_hsotg_ep *hs_ep,
+						 dma_addr_t dma_buff,
+						 unsigned int len)
+{
+	struct usb_request *ureq = &hs_ep->req->req;
+	struct dwc2_dma_desc *desc = hs_ep->desc_list;
+	struct scatterlist *sg;
+	int i;
+	u8 desc_count = 0;
+
+	/* non-DMA sg buffer */
+	if (!ureq->num_sgs) {
+		_dwc2_gadget_config_nonisoc_xfer_ddma(hs_ep, &desc,
+			dma_buff, len, true);
+
+		return;
+	}
+
+	/* DMA sg buffer */
+	for_each_sg(ureq->sg, sg, ureq->num_sgs, i) {
+		_dwc2_gadget_config_nonisoc_xfer_ddma(hs_ep, &desc,
+			sg_dma_address(sg) + sg->offset, sg_dma_len(sg),
+			sg_is_last(sg));
+		desc_count += hs_ep->desc_count;
+	}
+
+	hs_ep->desc_count = desc_count;
+}
+
+/*
  * dwc2_gadget_fill_isoc_desc - fills next isochronous descriptor in chain.
  * @hs_ep: The isochronous endpoint.
  * @dma_buff: usb requests dma buffer.
@@ -944,7 +973,13 @@ static void dwc2_gadget_start_isoc_ddma(struct dwc2_hsotg_ep *hs_ep)
 
 	hs_ep->next_desc = 0;
 	list_for_each_entry_safe(hs_req, treq, &hs_ep->queue, queue) {
-		ret = dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
+		dma_addr_t dma_addr = hs_req->req.dma;
+
+		if (hs_req->req.num_sgs) {
+			WARN_ON(hs_req->req.num_sgs > 1);
+			dma_addr = sg_dma_address(hs_req->req.sg);
+		}
+		ret = dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
 						 hs_req->req.length);
 		if (ret)
 			break;
@@ -1399,7 +1434,13 @@ static int dwc2_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
 	 */
 	if (using_desc_dma(hs) && hs_ep->isochronous) {
 		if (hs_ep->target_frame != TARGET_FRAME_INITIAL) {
-			dwc2_gadget_fill_isoc_desc(hs_ep, hs_req->req.dma,
+			dma_addr_t dma_addr = hs_req->req.dma;
+
+			if (hs_req->req.num_sgs) {
+				WARN_ON(hs_req->req.num_sgs > 1);
+				dma_addr = sg_dma_address(hs_req->req.sg);
+			}
+			dwc2_gadget_fill_isoc_desc(hs_ep, dma_addr,
 						   hs_req->req.length);
 		}
 		return 0;
@@ -4364,6 +4405,7 @@ static int dwc2_hsotg_udc_start(struct usb_gadget *gadget,
 	hsotg->enabled = 0;
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 
+	gadget->sg_supported = true;
 	dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
 
 	return 0;