3 files changed, 52 insertions, 24 deletions

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 29130682e547..e4f8b90d9627 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -856,7 +856,6 @@ struct dwc3 {
 	unsigned		pullups_connected:1;
 	unsigned		resize_fifos:1;
 	unsigned		setup_packet_pending:1;
-	unsigned		start_config_issued:1;
 	unsigned		three_stage_setup:1;
 	unsigned		usb3_lpm_capable:1;
 
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 3a9354abcb68..8d6b75c2f53b 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -555,7 +555,6 @@ static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 	int ret;
 	u32 reg;
 
-	dwc->start_config_issued = false;
 	cfg = le16_to_cpu(ctrl->wValue);
 
 	switch (state) {
@@ -737,10 +736,6 @@ static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 		dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_ISOCH_DELAY");
 		ret = dwc3_ep0_set_isoch_delay(dwc, ctrl);
 		break;
-	case USB_REQ_SET_INTERFACE:
-		dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_INTERFACE");
-		dwc->start_config_issued = false;
-		/* Fall through */
 	default:
 		dwc3_trace(trace_dwc3_ep0, "Forwarding to gadget driver");
 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 7d1dd82a95ac..2363bad45af8 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -385,24 +385,66 @@ static void dwc3_free_trb_pool(struct dwc3_ep *dep)
 	dep->trb_pool_dma = 0;
 }
 
+static int dwc3_gadget_set_xfer_resource(struct dwc3 *dwc, struct dwc3_ep *dep);
+
+/**
+ * dwc3_gadget_start_config - Configure EP resources
+ * @dwc: pointer to our controller context structure
+ * @dep: endpoint that is being enabled
+ *
+ * The assignment of transfer resources cannot perfectly follow the
+ * data book due to the fact that the controller driver does not have
+ * all knowledge of the configuration in advance. It is given this
+ * information piecemeal by the composite gadget framework after every
+ * SET_CONFIGURATION and SET_INTERFACE. Trying to follow the databook
+ * programming model in this scenario can cause errors. For two
+ * reasons:
+ *
+ * 1) The databook says to do DEPSTARTCFG for every SET_CONFIGURATION
+ * and SET_INTERFACE (8.1.5). This is incorrect in the scenario of
+ * multiple interfaces.
+ *
+ * 2) The databook does not mention doing more DEPXFERCFG for new
+ * endpoint on alt setting (8.1.6).
+ *
+ * The following simplified method is used instead:
+ *
+ * All hardware endpoints can be assigned a transfer resource and this
+ * setting will stay persistent until either a core reset or
+ * hibernation. So whenever we do a DEPSTARTCFG(0) we can go ahead and
+ * do DEPXFERCFG for every hardware endpoint as well. We are
+ * guaranteed that there are as many transfer resources as endpoints.
+ *
+ * This function is called for each endpoint when it is being enabled
+ * but is triggered only when called for EP0-out, which always happens
+ * first, and which should only happen in one of the above conditions.
+ */
 static int dwc3_gadget_start_config(struct dwc3 *dwc, struct dwc3_ep *dep)
 {
 	struct dwc3_gadget_ep_cmd_params params;
 	u32			cmd;
+	int			i;
+	int			ret;
+
+	if (dep->number)
+		return 0;
 
 	memset(&params, 0x00, sizeof(params));
+	cmd = DWC3_DEPCMD_DEPSTARTCFG;
 
-	if (dep->number != 1) {
-		cmd = DWC3_DEPCMD_DEPSTARTCFG;
-		/* XferRscIdx == 0 for ep0 and 2 for the remaining */
-		if (dep->number > 1) {
-			if (dwc->start_config_issued)
-				return 0;
-			dwc->start_config_issued = true;
-			cmd |= DWC3_DEPCMD_PARAM(2);
-		}
+	ret = dwc3_send_gadget_ep_cmd(dwc, 0, cmd, &params);
+	if (ret)
+		return ret;
 
-		return dwc3_send_gadget_ep_cmd(dwc, 0, cmd, &params);
+	for (i = 0; i < DWC3_ENDPOINTS_NUM; i++) {
+		struct dwc3_ep *dep = dwc->eps[i];
+
+		if (!dep)
+			continue;
+
+		ret = dwc3_gadget_set_xfer_resource(dwc, dep);
+		if (ret)
+			return ret;
 	}
 
 	return 0;
@@ -516,10 +558,6 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep,
 		struct dwc3_trb	*trb_st_hw;
 		struct dwc3_trb	*trb_link;
 
-		ret = dwc3_gadget_set_xfer_resource(dwc, dep);
-		if (ret)
-			return ret;
-
 		dep->endpoint.desc = desc;
 		dep->comp_desc = comp_desc;
 		dep->type = usb_endpoint_type(desc);
@@ -1636,8 +1674,6 @@ static int dwc3_gadget_start(struct usb_gadget *g,
 	}
 	dwc3_writel(dwc->regs, DWC3_DCFG, reg);
 
-	dwc->start_config_issued = false;
-
 	/* Start with SuperSpeed Default */
 	dwc3_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(512);
 
@@ -2237,7 +2273,6 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc)
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 
 	dwc3_disconnect_gadget(dwc);
-	dwc->start_config_issued = false;
 
 	dwc->gadget.speed = USB_SPEED_UNKNOWN;
 	dwc->setup_packet_pending = false;
@@ -2288,7 +2323,6 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
 
 	dwc3_stop_active_transfers(dwc);
 	dwc3_clear_stall_all_ep(dwc);
-	dwc->start_config_issued = false;
 
 	/* Reset device address to zero */
 	reg = dwc3_readl(dwc->regs, DWC3_DCFG);