2 files changed, 341 insertions, 2 deletions

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 4e9e8e43f634..63cde269db98 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -28,6 +28,32 @@
  *
  * Issue has been fixed in DEV_VER_V3 version of controller.
  *
+ * Work around 2:
+ * Controller for OUT endpoints has shared on-chip buffers for all incoming
+ * packets, including ep0out. It's FIFO buffer, so packets must be handle by DMA
+ * in correct order. If the first packet in the buffer will not be handled,
+ * then the following packets directed for other endpoints and  functions
+ * will be blocked.
+ * Additionally the packets directed to one endpoint can block entire on-chip
+ * buffers. In this case transfer to other endpoints also will blocked.
+ *
+ * To resolve this issue after raising the descriptor missing interrupt
+ * driver prepares internal usb_request object and use it to arm DMA transfer.
+ *
+ * The problematic situation was observed in case when endpoint has been enabled
+ * but no usb_request were queued. Driver try detects such endpoints and will
+ * use this workaround only for these endpoint.
+ *
+ * Driver use limited number of buffer. This number can be set by macro
+ * CDNS3_WA2_NUM_BUFFERS.
+ *
+ * Such blocking situation was observed on ACM gadget. For this function
+ * host send OUT data packet but ACM function is not prepared for this packet.
+ * It's cause that buffer placed in on chip memory block transfer to other
+ * endpoints.
+ *
+ * Issue has been fixed in DEV_VER_V2 version of controller.
+ *
  */
 
 #include <linux/dma-mapping.h>
@@ -99,6 +125,17 @@ struct cdns3_aligned_buf *cdns3_next_align_buf(struct list_head *list)
 }
 
 /**
+ * cdns3_next_priv_request - returns next request from list
+ * @list: list containing requests
+ *
+ * Returns request or NULL if no requests in list
+ */
+struct cdns3_request *cdns3_next_priv_request(struct list_head *list)
+{
+	return list_first_entry_or_null(list, struct cdns3_request, list);
+}
+
+/**
  * select_ep - selects endpoint
  * @priv_dev:  extended gadget object
  * @ep: endpoint address
@@ -335,6 +372,246 @@ static int cdns3_start_all_request(struct cdns3_device *priv_dev,
 	return ret;
 }
 
+/*
+ * WA2: Set flag for all not ISOC OUT endpoints. If this flag is set
+ * driver try to detect whether endpoint need additional internal
+ * buffer for unblocking on-chip FIFO buffer. This flag will be cleared
+ * if before first DESCMISS interrupt the DMA will be armed.
+ */
+#define cdns3_wa2_enable_detection(priv_dev, ep_priv, reg) do { \
+	if (!priv_ep->dir && priv_ep->type != USB_ENDPOINT_XFER_ISOC) { \
+		priv_ep->flags |= EP_QUIRK_EXTRA_BUF_DET; \
+		(reg) |= EP_STS_EN_DESCMISEN; \
+	} } while (0)
+
+/**
+ * cdns3_wa2_descmiss_copy_data copy data from internal requests to
+ * request queued by class driver.
+ * @priv_ep: extended endpoint object
+ * @request: request object
+ */
+static void cdns3_wa2_descmiss_copy_data(struct cdns3_endpoint *priv_ep,
+					 struct usb_request *request)
+{
+	struct usb_request *descmiss_req;
+	struct cdns3_request *descmiss_priv_req;
+
+	while (!list_empty(&priv_ep->wa2_descmiss_req_list)) {
+		int chunk_end;
+		int length;
+
+		descmiss_priv_req =
+			cdns3_next_priv_request(&priv_ep->wa2_descmiss_req_list);
+		descmiss_req = &descmiss_priv_req->request;
+
+		/* driver can't touch pending request */
+		if (descmiss_priv_req->flags & REQUEST_PENDING)
+			break;
+
+		chunk_end = descmiss_priv_req->flags & REQUEST_INTERNAL_CH;
+		length = request->actual + descmiss_req->actual;
+
+		request->status = descmiss_req->status;
+
+		if (length <= request->length) {
+			memcpy(&((u8 *)request->buf)[request->actual],
+			       descmiss_req->buf,
+			       descmiss_req->actual);
+			request->actual = length;
+		} else {
+			/* It should never occures */
+			request->status = -ENOMEM;
+		}
+
+		list_del_init(&descmiss_priv_req->list);
+
+		kfree(descmiss_req->buf);
+		cdns3_gadget_ep_free_request(&priv_ep->endpoint, descmiss_req);
+		--priv_ep->wa2_counter;
+
+		if (!chunk_end)
+			break;
+	}
+}
+
+struct usb_request *cdns3_wa2_gadget_giveback(struct cdns3_device *priv_dev,
+					      struct cdns3_endpoint *priv_ep,
+					      struct cdns3_request *priv_req)
+{
+	if (priv_ep->flags & EP_QUIRK_EXTRA_BUF_EN &&
+	    priv_req->flags & REQUEST_INTERNAL) {
+		struct usb_request *req;
+
+		req = cdns3_next_request(&priv_ep->deferred_req_list);
+
+		priv_ep->descmis_req = NULL;
+
+		if (!req)
+			return NULL;
+
+		cdns3_wa2_descmiss_copy_data(priv_ep, req);
+		if (!(priv_ep->flags & EP_QUIRK_END_TRANSFER) &&
+		    req->length != req->actual) {
+			/* wait for next part of transfer */
+			return NULL;
+		}
+
+		if (req->status == -EINPROGRESS)
+			req->status = 0;
+
+		list_del_init(&req->list);
+		cdns3_start_all_request(priv_dev, priv_ep);
+		return req;
+	}
+
+	return &priv_req->request;
+}
+
+int cdns3_wa2_gadget_ep_queue(struct cdns3_device *priv_dev,
+			      struct cdns3_endpoint *priv_ep,
+			      struct cdns3_request *priv_req)
+{
+	int deferred = 0;
+
+	/*
+	 * If transfer was queued before DESCMISS appear than we
+	 * can disable handling of DESCMISS interrupt. Driver assumes that it
+	 * can disable special treatment for this endpoint.
+	 */
+	if (priv_ep->flags & EP_QUIRK_EXTRA_BUF_DET) {
+		u32 reg;
+
+		cdns3_select_ep(priv_dev, priv_ep->num | priv_ep->dir);
+		priv_ep->flags &= ~EP_QUIRK_EXTRA_BUF_DET;
+		reg = readl(&priv_dev->regs->ep_sts_en);
+		reg &= ~EP_STS_EN_DESCMISEN;
+		writel(reg, &priv_dev->regs->ep_sts_en);
+	}
+
+	if (priv_ep->flags & EP_QUIRK_EXTRA_BUF_EN) {
+		u8 pending_empty = list_empty(&priv_ep->pending_req_list);
+		u8 descmiss_empty = list_empty(&priv_ep->wa2_descmiss_req_list);
+
+		/*
+		 *  DESCMISS transfer has been finished, so data will be
+		 *  directly copied from internal allocated usb_request
+		 *  objects.
+		 */
+		if (pending_empty && !descmiss_empty &&
+		    !(priv_req->flags & REQUEST_INTERNAL)) {
+			cdns3_wa2_descmiss_copy_data(priv_ep,
+						     &priv_req->request);
+			list_add_tail(&priv_req->request.list,
+				      &priv_ep->pending_req_list);
+			cdns3_gadget_giveback(priv_ep, priv_req,
+					      priv_req->request.status);
+
+			/*
+			 * Intentionally driver returns positive value as
+			 * correct value. It informs that transfer has
+			 * been finished.
+			 */
+			return EINPROGRESS;
+		}
+
+		/*
+		 * Driver will wait for completion DESCMISS transfer,
+		 * before starts new, not DESCMISS transfer.
+		 */
+		if (!pending_empty && !descmiss_empty)
+			deferred = 1;
+
+		if (priv_req->flags & REQUEST_INTERNAL)
+			list_add_tail(&priv_req->list,
+				      &priv_ep->wa2_descmiss_req_list);
+	}
+
+	return deferred;
+}
+
+static void cdsn3_wa2_remove_old_request(struct cdns3_endpoint *priv_ep)
+{
+	struct cdns3_request *priv_req;
+
+	while (!list_empty(&priv_ep->wa2_descmiss_req_list)) {
+		u8 chain;
+
+		priv_req = cdns3_next_priv_request(&priv_ep->wa2_descmiss_req_list);
+		chain = !!(priv_req->flags & REQUEST_INTERNAL_CH);
+
+		kfree(priv_req->request.buf);
+		cdns3_gadget_ep_free_request(&priv_ep->endpoint,
+					     &priv_req->request);
+		list_del_init(&priv_req->list);
+		--priv_ep->wa2_counter;
+
+		if (!chain)
+			break;
+	}
+}
+
+/**
+ * cdns3_wa2_descmissing_packet - handles descriptor missing event.
+ * @priv_dev: extended gadget object
+ *
+ * This function is used only for WA2. For more information see Work around 2
+ * description.
+ */
+static void cdns3_wa2_descmissing_packet(struct cdns3_endpoint *priv_ep)
+{
+	struct cdns3_request *priv_req;
+	struct usb_request *request;
+
+	if (priv_ep->flags & EP_QUIRK_EXTRA_BUF_DET) {
+		priv_ep->flags &= ~EP_QUIRK_EXTRA_BUF_DET;
+		priv_ep->flags |= EP_QUIRK_EXTRA_BUF_EN;
+	}
+
+	cdns3_dbg(priv_ep->cdns3_dev, "WA2: Description Missing detected\n");
+
+	if (priv_ep->wa2_counter >= CDNS3_WA2_NUM_BUFFERS)
+		cdsn3_wa2_remove_old_request(priv_ep);
+
+	request = cdns3_gadget_ep_alloc_request(&priv_ep->endpoint,
+						GFP_ATOMIC);
+	if (!request)
+		goto err;
+
+	priv_req = to_cdns3_request(request);
+	priv_req->flags |= REQUEST_INTERNAL;
+
+	/* if this field is still assigned it indicate that transfer related
+	 * with this request has not been finished yet. Driver in this
+	 * case simply allocate next request and assign flag REQUEST_INTERNAL_CH
+	 * flag to previous one. It will indicate that current request is
+	 * part of the previous one.
+	 */
+	if (priv_ep->descmis_req)
+		priv_ep->descmis_req->flags |= REQUEST_INTERNAL_CH;
+
+	priv_req->request.buf = kzalloc(CDNS3_DESCMIS_BUF_SIZE,
+					GFP_ATOMIC);
+	priv_ep->wa2_counter++;
+
+	if (!priv_req->request.buf) {
+		cdns3_gadget_ep_free_request(&priv_ep->endpoint, request);
+		goto err;
+	}
+
+	priv_req->request.length = CDNS3_DESCMIS_BUF_SIZE;
+	priv_ep->descmis_req = priv_req;
+
+	__cdns3_gadget_ep_queue(&priv_ep->endpoint,
+				&priv_ep->descmis_req->request,
+				GFP_ATOMIC);
+
+	return;
+
+err:
+	dev_err(priv_ep->cdns3_dev->dev,
+		"Failed: No sufficient memory for DESCMIS\n");
+}
+
 /**
  * cdns3_gadget_giveback - call struct usb_request's ->complete callback
  * @priv_ep: The endpoint to whom the request belongs to
@@ -368,6 +645,13 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep,
 	priv_req->flags &= ~(REQUEST_PENDING | REQUEST_UNALIGNED);
 	trace_cdns3_gadget_giveback(priv_req);
 
+	if (priv_dev->dev_ver < DEV_VER_V2) {
+		request = cdns3_wa2_gadget_giveback(priv_dev, priv_ep,
+						    priv_req);
+		if (!request)
+			return;
+	}
+
 	if (request->complete) {
 		spin_unlock(&priv_dev->lock);
 		usb_gadget_giveback_request(&priv_ep->endpoint,
@@ -921,8 +1205,25 @@ static int cdns3_check_ep_interrupt_proceed(struct cdns3_endpoint *priv_ep)
 		}
 	}
 
-	if ((ep_sts_reg & EP_STS_IOC) || (ep_sts_reg & EP_STS_ISP))
+	if ((ep_sts_reg & EP_STS_IOC) || (ep_sts_reg & EP_STS_ISP)) {
+		if (priv_ep->flags & EP_QUIRK_EXTRA_BUF_EN) {
+			if (ep_sts_reg & EP_STS_ISP)
+				priv_ep->flags |= EP_QUIRK_END_TRANSFER;
+			else
+				priv_ep->flags &= ~EP_QUIRK_END_TRANSFER;
+		}
+
 		cdns3_transfer_completed(priv_dev, priv_ep);
+	}
+
+	/*
+	 * WA2: this condition should only be meet when
+	 * priv_ep->flags & EP_QUIRK_EXTRA_BUF_DET or
+	 * priv_ep->flags & EP_QUIRK_EXTRA_BUF_EN.
+	 * In other cases this interrupt will be disabled/
+	 */
+	if (ep_sts_reg & EP_STS_DESCMIS && priv_dev->dev_ver < DEV_VER_V2)
+		cdns3_wa2_descmissing_packet(priv_ep);
 
 	return 0;
 }
@@ -1498,6 +1799,9 @@ static int cdns3_gadget_ep_enable(struct usb_ep *ep,
 	cdns3_set_register_bit(&priv_dev->regs->ep_ien,
 			       BIT(cdns3_ep_addr_to_index(bEndpointAddress)));
 
+	if (priv_dev->dev_ver < DEV_VER_V2)
+		cdns3_wa2_enable_detection(priv_dev, priv_ep, reg);
+
 	writel(reg, &priv_dev->regs->ep_sts_en);
 
 	/*
@@ -1516,7 +1820,7 @@ static int cdns3_gadget_ep_enable(struct usb_ep *ep,
 
 	ep->desc = desc;
 	priv_ep->flags &= ~(EP_PENDING_REQUEST | EP_STALL |
-			    EP_QUIRK_ISO_OUT_EN);
+			    EP_QUIRK_ISO_OUT_EN | EP_QUIRK_EXTRA_BUF_EN);
 	priv_ep->flags |= EP_ENABLED | EP_UPDATE_EP_TRBADDR;
 	priv_ep->wa1_set = 0;
 	priv_ep->enqueue = 0;
@@ -1541,6 +1845,7 @@ exit:
 static int cdns3_gadget_ep_disable(struct usb_ep *ep)
 {
 	struct cdns3_endpoint *priv_ep;
+	struct cdns3_request *priv_req;
 	struct cdns3_device *priv_dev;
 	struct usb_request *request;
 	unsigned long flags;
@@ -1593,6 +1898,16 @@ static int cdns3_gadget_ep_disable(struct usb_ep *ep)
 				      -ESHUTDOWN);
 	}
 
+	while (!list_empty(&priv_ep->wa2_descmiss_req_list)) {
+		priv_req = cdns3_next_priv_request(&priv_ep->wa2_descmiss_req_list);
+
+		kfree(priv_req->request.buf);
+		cdns3_gadget_ep_free_request(&priv_ep->endpoint,
+					     &priv_req->request);
+		list_del_init(&priv_req->list);
+		--priv_ep->wa2_counter;
+	}
+
 	while (!list_empty(&priv_ep->deferred_req_list)) {
 		request = cdns3_next_request(&priv_ep->deferred_req_list);
 
@@ -1600,6 +1915,8 @@ static int cdns3_gadget_ep_disable(struct usb_ep *ep)
 				      -ESHUTDOWN);
 	}
 
+	priv_ep->descmis_req = NULL;
+
 	ep->desc = NULL;
 	priv_ep->flags &= ~EP_ENABLED;
 
@@ -1630,6 +1947,14 @@ static int __cdns3_gadget_ep_queue(struct usb_ep *ep,
 	priv_req = to_cdns3_request(request);
 	trace_cdns3_ep_queue(priv_req);
 
+	if (priv_dev->dev_ver < DEV_VER_V2) {
+		ret = cdns3_wa2_gadget_ep_queue(priv_dev, priv_ep,
+						priv_req);
+
+		if (ret == EINPROGRESS)
+			return 0;
+	}
+
 	ret = cdns3_prepare_aligned_request_buf(priv_req);
 	if (ret < 0)
 		return ret;
@@ -2098,6 +2423,7 @@ static int cdns3_init_eps(struct cdns3_device *priv_dev)
 
 		INIT_LIST_HEAD(&priv_ep->pending_req_list);
 		INIT_LIST_HEAD(&priv_ep->deferred_req_list);
+		INIT_LIST_HEAD(&priv_ep->wa2_descmiss_req_list);
 	}
 
 	return 0;
diff --git a/drivers/usb/cdns3/gadget.h b/drivers/usb/cdns3/gadget.h
index 64cead1aee32..42f58048975f 100644
--- a/drivers/usb/cdns3/gadget.h
+++ b/drivers/usb/cdns3/gadget.h
@@ -1079,6 +1079,7 @@ struct cdns3_trb {
 #define CDNS3_EP_ISO_SS_BURST		3
 #define CDNS3_MAX_NUM_DESCMISS_BUF	32
 #define CDNS3_DESCMIS_BUF_SIZE		2048	/* Bytes */
+#define CDNS3_WA2_NUM_BUFFERS		128
 /*-------------------------------------------------------------------------*/
 /* Used structs */
 
@@ -1089,11 +1090,15 @@ struct cdns3_device;
  * @endpoint: usb endpoint
  * @pending_req_list: list of requests queuing on transfer ring.
  * @deferred_req_list: list of requests waiting for queuing on transfer ring.
+ * @wa2_descmiss_req_list: list of requests internally allocated by driver.
  * @trb_pool: transfer ring - array of transaction buffers
  * @trb_pool_dma: dma address of transfer ring
  * @cdns3_dev: device associated with this endpoint
  * @name: a human readable name e.g. ep1out
  * @flags: specify the current state of endpoint
+ * @descmis_req: internal transfer object used for getting data from on-chip
+ *     buffer. It can happen only if function driver doesn't send usb_request
+ *     object on time.
  * @dir: endpoint direction
  * @num: endpoint number (1 - 15)
  * @type: set to bmAttributes & USB_ENDPOINT_XFERTYPE_MASK
@@ -1110,6 +1115,8 @@ struct cdns3_endpoint {
 	struct usb_ep		endpoint;
 	struct list_head	pending_req_list;
 	struct list_head	deferred_req_list;
+	struct list_head	wa2_descmiss_req_list;
+	int			wa2_counter;
 
 	struct cdns3_trb	*trb_pool;
 	dma_addr_t		trb_pool_dma;
@@ -1127,8 +1134,13 @@ struct cdns3_endpoint {
 #define EP_CLAIMED		BIT(7)
 #define EP_DEFERRED_DRDY	BIT(8)
 #define EP_QUIRK_ISO_OUT_EN	BIT(9)
+#define EP_QUIRK_EXTRA_BUF_DET	BIT(10)
+#define EP_QUIRK_EXTRA_BUF_EN	BIT(11)
+#define EP_QUIRK_END_TRANSFER	BIT(12)
 	u32			flags;
 
+	struct cdns3_request	*descmis_req;
+
 	u8			dir;
 	u8			num;
 	u8			type;
@@ -1176,6 +1188,7 @@ struct cdns3_aligned_buf {
  * @aligned_buf: object holds information about aligned buffer associated whit
  *               this endpoint
  * @flags: flag specifying special usage of request
+ * @list: used by internally allocated request to add to wa2_descmiss_req_list.
  */
 struct cdns3_request {
 	struct usb_request		request;