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Commit 10209abe authored by Andrzej Pietrasiewicz's avatar Andrzej Pietrasiewicz Committed by Felipe Balbi
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usb: dwc2: gadget: Add scatter-gather mode 



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: default avatarAndrzej Pietrasiewicz <andrzej.p@samsung.com>
[mszyprow: fixed null pointer issue, rewrote commit message]
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent 1ff767bf

drivers/usb/dwc2/gadget.c

+77 −36
Original line number Diff line number Diff line
@@ -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 +789,79 @@ 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,

						 struct usb_request *ureq,

						 unsigned int offset,

						 unsigned int len)

{

	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_fill_nonisoc_xfer_ddma_one(hs_ep, &desc,

			ureq->dma + offset, 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 +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;
@@ -1100,7 +1135,7 @@ static void dwc2_hsotg_start_req(struct dwc2_hsotg *hsotg, 
			offset = ureq->actual;



		/* Fill DDMA chain entries */

		dwc2_gadget_config_nonisoc_xfer_ddma(hs_ep, ureq->dma + offset,

		dwc2_gadget_config_nonisoc_xfer_ddma(hs_ep, ureq, offset,

						     length);



		/* write descriptor chain address to control register */
@@ -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;
@@ -1987,13 +2028,12 @@ static void dwc2_hsotg_program_zlp(struct dwc2_hsotg *hsotg, 
		dev_dbg(hsotg->dev, "Receiving zero-length packet on ep%d\n",

			index);

	if (using_desc_dma(hsotg)) {

		/* Not specific buffer needed for ep0 ZLP */

		dma_addr_t dma = hs_ep->desc_list_dma;



		if (!index)

			dwc2_gadget_set_ep0_desc_chain(hsotg, hs_ep);



		dwc2_gadget_config_nonisoc_xfer_ddma(hs_ep, dma, 0);

		/* Not specific buffer needed for ep0 ZLP */

		dwc2_gadget_fill_nonisoc_xfer_ddma_one(hs_ep, &hs_ep->desc_list,

			hs_ep->desc_list_dma, 0, true);

	} else {

		dwc2_writel(hsotg, DXEPTSIZ_MC(1) | DXEPTSIZ_PKTCNT(1) |

			    DXEPTSIZ_XFERSIZE(0),
@@ -4386,6 +4426,7 @@ 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;