usb: chipidea: udc: add sg list support

index ffa6caee1f3b..94feaecc6059 100644
@@ -338,7 +338,7 @@ static int hw_usb_reset(struct ci_hdrc *ci)
  *****************************************************************************/
 
 static int add_td_to_list(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq,
-			  unsigned length)
+			unsigned int length, struct scatterlist *s)
 {
 	int i;
 	u32 temp;

@@ -366,7 +366,11 @@ static int add_td_to_list(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq,
 		node->ptr->token |= cpu_to_le32(mul << __ffs(TD_MULTO));
 	}
 
-	temp = (u32) (hwreq->req.dma + hwreq->req.actual);
+	if (s)
+		temp = (u32) (sg_dma_address(s) + hwreq->req.actual);
+	else
+		temp = (u32) (hwreq->req.dma + hwreq->req.actual);
+
 	if (length) {
 		node->ptr->page[0] = cpu_to_le32(temp);
 		for (i = 1; i < TD_PAGE_COUNT; i++) {

@@ -400,6 +404,88 @@ static inline u8 _usb_addr(struct ci_hw_ep *ep)
 	return ((ep->dir == TX) ? USB_ENDPOINT_DIR_MASK : 0) | ep->num;
 }
 
+static int prepare_td_for_non_sg(struct ci_hw_ep *hwep,
+		struct ci_hw_req *hwreq)
+{
+	unsigned int rest = hwreq->req.length;
+	int pages = TD_PAGE_COUNT;
+	int ret = 0;
+
+	if (rest == 0) {
+		ret = add_td_to_list(hwep, hwreq, 0, NULL);
+		if (ret < 0)
+			return ret;
+	}
+
+	/*
+	 * The first buffer could be not page aligned.
+	 * In that case we have to span into one extra td.
+	 */
+	if (hwreq->req.dma % PAGE_SIZE)
+		pages--;
+
+	while (rest > 0) {
+		unsigned int count = min(hwreq->req.length - hwreq->req.actual,
+			(unsigned int)(pages * CI_HDRC_PAGE_SIZE));
+
+		ret = add_td_to_list(hwep, hwreq, count, NULL);
+		if (ret < 0)
+			return ret;
+
+		rest -= count;
+	}
+
+	if (hwreq->req.zero && hwreq->req.length && hwep->dir == TX
+	    && (hwreq->req.length % hwep->ep.maxpacket == 0)) {
+		ret = add_td_to_list(hwep, hwreq, 0, NULL);
+		if (ret < 0)
+			return ret;
+	}
+
+	return ret;
+}
+
+static int prepare_td_per_sg(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq,
+		struct scatterlist *s)
+{
+	unsigned int rest = sg_dma_len(s);
+	int ret = 0;
+
+	hwreq->req.actual = 0;
+	while (rest > 0) {
+		unsigned int count = min(rest,
+			(unsigned int)(TD_PAGE_COUNT * CI_HDRC_PAGE_SIZE));
+
+		ret = add_td_to_list(hwep, hwreq, count, s);
+		if (ret < 0)
+			return ret;
+
+		rest -= count;
+	}
+
+	return ret;
+}
+
+static int prepare_td_for_sg(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
+{
+	struct usb_request *req = &hwreq->req;
+	struct scatterlist *s = req->sg;
+	int ret;
+
+	if (!s || req->zero || req->length == 0) {
+		dev_err(hwep->ci->dev, "not supported operation for sg\n");
+		return -EINVAL;
+	}
+
+	do {
+		ret = prepare_td_per_sg(hwep, hwreq, s);
+		if (ret)
+			return ret;
+	} while ((s = sg_next(s)));
+
+	return ret;
+}
+
 /**
  * _hardware_enqueue: configures a request at hardware level
  * @hwep:   endpoint

@@ -411,8 +497,6 @@ static int _hardware_enqueue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
 {
 	struct ci_hdrc *ci = hwep->ci;
 	int ret = 0;
-	unsigned rest = hwreq->req.length;
-	int pages = TD_PAGE_COUNT;
 	struct td_node *firstnode, *lastnode;
 
 	/* don't queue twice */

@@ -426,35 +510,13 @@ static int _hardware_enqueue(struct ci_hw_ep *hwep, struct ci_hw_req *hwreq)
 	if (ret)
 		return ret;
 
-	/*
-	 * The first buffer could be not page aligned.
-	 * In that case we have to span into one extra td.
-	 */
-	if (hwreq->req.dma % PAGE_SIZE)
-		pages--;
-
-	if (rest == 0) {
-		ret = add_td_to_list(hwep, hwreq, 0);
-		if (ret < 0)
-			goto done;
-	}
-
-	while (rest > 0) {
-		unsigned count = min(hwreq->req.length - hwreq->req.actual,
-					(unsigned)(pages * CI_HDRC_PAGE_SIZE));
-		ret = add_td_to_list(hwep, hwreq, count);
-		if (ret < 0)
-			goto done;
-
-		rest -= count;
-	}
+	if (hwreq->req.num_mapped_sgs)
+		ret = prepare_td_for_sg(hwep, hwreq);
+	else
+		ret = prepare_td_for_non_sg(hwep, hwreq);
 
-	if (hwreq->req.zero && hwreq->req.length && hwep->dir == TX
-	    && (hwreq->req.length % hwep->ep.maxpacket == 0)) {
-		ret = add_td_to_list(hwep, hwreq, 0);
-		if (ret < 0)
-			goto done;
-	}
+	if (ret)
+		return ret;
 
 	firstnode = list_first_entry(&hwreq->tds, struct td_node, td);
 

@@ -1935,6 +1997,7 @@ static int udc_start(struct ci_hdrc *ci)
 	ci->gadget.max_speed    = USB_SPEED_HIGH;
 	ci->gadget.name         = ci->platdata->name;
 	ci->gadget.otg_caps	= otg_caps;
+	ci->gadget.sg_supported = 1;
 
 	if (ci->platdata->flags & CI_HDRC_REQUIRES_ALIGNED_DMA)
 		ci->gadget.quirk_avoids_skb_reserve = 1;