UPSTREAM: usb: dwc3: gadget: simplify __dwc3_gadget_kick_transfer()
[firefly-linux-kernel-4.4.55.git] / drivers / usb / dwc3 / gadget.c
index 3d131b7aae5970a8969b5b3448767cc227551524..887f2c13960010e2cb89aaf6d5365a2329b681de 100644 (file)
@@ -145,90 +145,21 @@ int dwc3_gadget_set_link_state(struct dwc3 *dwc, enum dwc3_link_state state)
        return -ETIMEDOUT;
 }
 
-/**
- * dwc3_gadget_resize_tx_fifos - reallocate fifo spaces for current use-case
- * @dwc: pointer to our context structure
- *
- * This function will a best effort FIFO allocation in order
- * to improve FIFO usage and throughput, while still allowing
- * us to enable as many endpoints as possible.
- *
- * Keep in mind that this operation will be highly dependent
- * on the configured size for RAM1 - which contains TxFifo -,
- * the amount of endpoints enabled on coreConsultant tool, and
- * the width of the Master Bus.
- *
- * In the ideal world, we would always be able to satisfy the
- * following equation:
- *
- * ((512 + 2 * MDWIDTH-Bytes) + (Number of IN Endpoints - 1) * \
- * (3 * (1024 + MDWIDTH-Bytes) + MDWIDTH-Bytes)) / MDWIDTH-Bytes
- *
- * Unfortunately, due to many variables that's not always the case.
- */
-int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc)
+static void dwc3_ep_inc_enq(struct dwc3_ep *dep)
 {
-       int             last_fifo_depth = 0;
-       int             ram1_depth;
-       int             fifo_size;
-       int             mdwidth;
-       int             num;
-
-       if (!dwc->needs_fifo_resize)
-               return 0;
-
-       ram1_depth = DWC3_RAM1_DEPTH(dwc->hwparams.hwparams7);
-       mdwidth = DWC3_MDWIDTH(dwc->hwparams.hwparams0);
-
-       /* MDWIDTH is represented in bits, we need it in bytes */
-       mdwidth >>= 3;
-
-       /*
-        * FIXME For now we will only allocate 1 wMaxPacketSize space
-        * for each enabled endpoint, later patches will come to
-        * improve this algorithm so that we better use the internal
-        * FIFO space
-        */
-       for (num = 0; num < dwc->num_in_eps; num++) {
-               /* bit0 indicates direction; 1 means IN ep */
-               struct dwc3_ep  *dep = dwc->eps[(num << 1) | 1];
-               int             mult = 1;
-               int             tmp;
-
-               if (!(dep->flags & DWC3_EP_ENABLED))
-                       continue;
-
-               if (usb_endpoint_xfer_bulk(dep->endpoint.desc)
-                               || usb_endpoint_xfer_isoc(dep->endpoint.desc))
-                       mult = 3;
-
-               /*
-                * REVISIT: the following assumes we will always have enough
-                * space available on the FIFO RAM for all possible use cases.
-                * Make sure that's true somehow and change FIFO allocation
-                * accordingly.
-                *
-                * If we have Bulk or Isochronous endpoints, we want
-                * them to be able to be very, very fast. So we're giving
-                * those endpoints a fifo_size which is enough for 3 full
-                * packets
-                */
-               tmp = mult * (dep->endpoint.maxpacket + mdwidth);
-               tmp += mdwidth;
-
-               fifo_size = DIV_ROUND_UP(tmp, mdwidth);
-
-               fifo_size |= (last_fifo_depth << 16);
-
-               dwc3_trace(trace_dwc3_gadget, "%s: Fifo Addr %04x Size %d",
-                               dep->name, last_fifo_depth, fifo_size & 0xffff);
-
-               dwc3_writel(dwc->regs, DWC3_GTXFIFOSIZ(num), fifo_size);
+       dep->trb_enqueue++;
+       dep->trb_enqueue %= DWC3_TRB_NUM;
+}
 
-               last_fifo_depth += (fifo_size & 0xffff);
-       }
+static void dwc3_ep_inc_deq(struct dwc3_ep *dep)
+{
+       dep->trb_dequeue++;
+       dep->trb_dequeue %= DWC3_TRB_NUM;
+}
 
-       return 0;
+static int dwc3_ep_is_last_trb(unsigned int index)
+{
+       return index == DWC3_TRB_NUM - 1;
 }
 
 void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
@@ -237,21 +168,19 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
        struct dwc3                     *dwc = dep->dwc;
        int                             i;
 
-       if (req->queued) {
+       if (req->started) {
                i = 0;
                do {
-                       dep->busy_slot++;
+                       dwc3_ep_inc_deq(dep);
                        /*
                         * Skip LINK TRB. We can't use req->trb and check for
                         * DWC3_TRBCTL_LINK_TRB because it points the TRB we
                         * just completed (not the LINK TRB).
                         */
-                       if (((dep->busy_slot & DWC3_TRB_MASK) ==
-                               DWC3_TRB_NUM- 1) &&
-                               usb_endpoint_xfer_isoc(dep->endpoint.desc))
-                               dep->busy_slot++;
+                       if (dwc3_ep_is_last_trb(dep->trb_dequeue))
+                               dwc3_ep_inc_deq(dep);
                } while(++i < req->request.num_mapped_sgs);
-               req->queued = false;
+               req->started = false;
        }
        list_del(&req->list);
        req->trb = NULL;
@@ -307,6 +236,8 @@ int dwc3_send_gadget_generic_command(struct dwc3 *dwc, unsigned cmd, u32 param)
        } while (1);
 }
 
+static int __dwc3_gadget_wakeup(struct dwc3 *dwc);
+
 int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep,
                unsigned cmd, struct dwc3_gadget_ep_cmd_params *params)
 {
@@ -314,8 +245,40 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep,
        u32                     timeout = 500;
        u32                     reg;
 
+       int                     susphy = false;
+       int                     ret = -EINVAL;
+
        trace_dwc3_gadget_ep_cmd(dep, cmd, params);
 
+       /*
+        * Synopsys Databook 2.60a states, on section 6.3.2.5.[1-8], that if
+        * we're issuing an endpoint command, we must check if
+        * GUSB2PHYCFG.SUSPHY bit is set. If it is, then we need to clear it.
+        *
+        * We will also set SUSPHY bit to what it was before returning as stated
+        * by the same section on Synopsys databook.
+        */
+       reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
+       if (unlikely(reg & DWC3_GUSB2PHYCFG_SUSPHY)) {
+               susphy = true;
+               reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
+               dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+       }
+
+       if (cmd == DWC3_DEPCMD_STARTTRANSFER) {
+               int             needs_wakeup;
+
+               needs_wakeup = (dwc->link_state == DWC3_LINK_STATE_U1 ||
+                               dwc->link_state == DWC3_LINK_STATE_U2 ||
+                               dwc->link_state == DWC3_LINK_STATE_U3);
+
+               if (unlikely(needs_wakeup)) {
+                       ret = __dwc3_gadget_wakeup(dwc);
+                       dev_WARN_ONCE(dwc->dev, ret, "wakeup failed --> %d\n",
+                                       ret);
+               }
+       }
+
        dwc3_writel(dwc->regs, DWC3_DEPCMDPAR0(ep), params->param0);
        dwc3_writel(dwc->regs, DWC3_DEPCMDPAR1(ep), params->param1);
        dwc3_writel(dwc->regs, DWC3_DEPCMDPAR2(ep), params->param2);
@@ -324,12 +287,40 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep,
        do {
                reg = dwc3_readl(dwc->regs, DWC3_DEPCMD(ep));
                if (!(reg & DWC3_DEPCMD_CMDACT)) {
+                       int cmd_status = DWC3_DEPCMD_STATUS(reg);
+
                        dwc3_trace(trace_dwc3_gadget,
                                        "Command Complete --> %d",
-                                       DWC3_DEPCMD_STATUS(reg));
-                       if (DWC3_DEPCMD_STATUS(reg))
-                               return -EINVAL;
-                       return 0;
+                                       cmd_status);
+
+                       switch (cmd_status) {
+                       case 0:
+                               ret = 0;
+                               break;
+                       case DEPEVT_TRANSFER_NO_RESOURCE:
+                               dwc3_trace(trace_dwc3_gadget, "%s: no resource available");
+                               ret = -EINVAL;
+                               break;
+                       case DEPEVT_TRANSFER_BUS_EXPIRY:
+                               /*
+                                * SW issues START TRANSFER command to
+                                * isochronous ep with future frame interval. If
+                                * future interval time has already passed when
+                                * core receives the command, it will respond
+                                * with an error status of 'Bus Expiry'.
+                                *
+                                * Instead of always returning -EINVAL, let's
+                                * give a hint to the gadget driver that this is
+                                * the case by returning -EAGAIN.
+                                */
+                               dwc3_trace(trace_dwc3_gadget, "%s: bus expiry");
+                               ret = -EAGAIN;
+                               break;
+                       default:
+                               dev_WARN(dwc->dev, "UNKNOWN cmd status\n");
+                       }
+
+                       break;
                }
 
                /*
@@ -340,11 +331,42 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep,
                if (!timeout) {
                        dwc3_trace(trace_dwc3_gadget,
                                        "Command Timed Out");
-                       return -ETIMEDOUT;
+                       ret = -ETIMEDOUT;
+                       break;
                }
 
                udelay(1);
        } while (1);
+
+       if (unlikely(susphy)) {
+               reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
+               reg |= DWC3_GUSB2PHYCFG_SUSPHY;
+               dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+       }
+
+       return ret;
+}
+
+static int dwc3_send_clear_stall_ep_cmd(struct dwc3_ep *dep)
+{
+       struct dwc3 *dwc = dep->dwc;
+       struct dwc3_gadget_ep_cmd_params params;
+       u32 cmd = DWC3_DEPCMD_CLEARSTALL;
+
+       /*
+        * As of core revision 2.60a the recommended programming model
+        * is to set the ClearPendIN bit when issuing a Clear Stall EP
+        * command for IN endpoints. This is to prevent an issue where
+        * some (non-compliant) hosts may not send ACK TPs for pending
+        * IN transfers due to a mishandled error condition. Synopsys
+        * STAR 9000614252.
+        */
+       if (dep->direction && (dwc->revision >= DWC3_REVISION_260A))
+               cmd |= DWC3_DEPCMD_CLEARPENDIN;
+
+       memset(&params, 0, sizeof(params));
+
+       return dwc3_send_gadget_ep_cmd(dwc, dep->number, cmd, &params);
 }
 
 static dma_addr_t dwc3_trb_dma_offset(struct dwc3_ep *dep,
@@ -385,24 +407,66 @@ 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;
+
+       for (i = 0; i < DWC3_ENDPOINTS_NUM; i++) {
+               struct dwc3_ep *dep = dwc->eps[i];
 
-               return dwc3_send_gadget_ep_cmd(dwc, 0, cmd, &params);
+               if (!dep)
+                       continue;
+
+               ret = dwc3_gadget_set_xfer_resource(dwc, dep);
+               if (ret)
+                       return ret;
        }
 
        return 0;
@@ -421,10 +485,20 @@ static int dwc3_gadget_set_ep_config(struct dwc3 *dwc, struct dwc3_ep *dep,
                | DWC3_DEPCFG_MAX_PACKET_SIZE(usb_endpoint_maxp(desc));
 
        /* Burst size is only needed in SuperSpeed mode */
-       if (dwc->gadget.speed == USB_SPEED_SUPER) {
-               u32 burst = dep->endpoint.maxburst - 1;
+       if (dwc->gadget.speed >= USB_SPEED_SUPER) {
+               u32 burst = dep->endpoint.maxburst;
+               u32 nump;
+               u32 reg;
+
+               /* update NumP */
+               reg = dwc3_readl(dwc->regs, DWC3_DCFG);
+               nump = DWC3_DCFG_NUMP(reg);
+               nump = max(nump, burst);
+               reg &= ~DWC3_DCFG_NUMP_MASK;
+               reg |= nump << DWC3_DCFG_NUMP_SHIFT;
+               dwc3_writel(dwc->regs, DWC3_DCFG, reg);
 
-               params.param0 |= DWC3_DEPCFG_BURST_SIZE(burst);
+               params.param0 |= DWC3_DEPCFG_BURST_SIZE(burst - 1);
        }
 
        if (ignore)
@@ -516,10 +590,6 @@ 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);
@@ -529,10 +599,10 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep,
                reg |= DWC3_DALEPENA_EP(dep->number);
                dwc3_writel(dwc->regs, DWC3_DALEPENA, reg);
 
-               if (!usb_endpoint_xfer_isoc(desc))
-                       return 0;
+               if (usb_endpoint_xfer_control(desc))
+                       goto out;
 
-               /* Link TRB for ISOC. The HWO bit is never reset */
+               /* Link TRB. The HWO bit is never reset */
                trb_st_hw = &dep->trb_pool[0];
 
                trb_link = &dep->trb_pool[DWC3_TRB_NUM - 1];
@@ -544,9 +614,10 @@ static int __dwc3_gadget_ep_enable(struct dwc3_ep *dep,
                trb_link->ctrl |= DWC3_TRB_CTRL_HWO;
        }
 
+out:
        switch (usb_endpoint_type(desc)) {
        case USB_ENDPOINT_XFER_CONTROL:
-               strlcat(dep->name, "-control", sizeof(dep->name));
+               /* don't change name */
                break;
        case USB_ENDPOINT_XFER_ISOC:
                strlcat(dep->name, "-isoc", sizeof(dep->name));
@@ -569,19 +640,19 @@ static void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep)
 {
        struct dwc3_request             *req;
 
-       if (!list_empty(&dep->req_queued)) {
+       if (!list_empty(&dep->started_list)) {
                dwc3_stop_active_transfer(dwc, dep->number, true);
 
                /* - giveback all requests to gadget driver */
-               while (!list_empty(&dep->req_queued)) {
-                       req = next_request(&dep->req_queued);
+               while (!list_empty(&dep->started_list)) {
+                       req = next_request(&dep->started_list);
 
                        dwc3_gadget_giveback(dep, req, -ESHUTDOWN);
                }
        }
 
-       while (!list_empty(&dep->request_list)) {
-               req = next_request(&dep->request_list);
+       while (!list_empty(&dep->pending_list)) {
+               req = next_request(&dep->pending_list);
 
                dwc3_gadget_giveback(dep, req, -ESHUTDOWN);
        }
@@ -661,11 +732,10 @@ static int dwc3_gadget_ep_enable(struct usb_ep *ep,
        dep = to_dwc3_ep(ep);
        dwc = dep->dwc;
 
-       if (dep->flags & DWC3_EP_ENABLED) {
-               dev_WARN_ONCE(dwc->dev, true, "%s is already enabled\n",
-                               dep->name);
+       if (dev_WARN_ONCE(dwc->dev, dep->flags & DWC3_EP_ENABLED,
+                                       "%s is already enabled\n",
+                                       dep->name))
                return 0;
-       }
 
        spin_lock_irqsave(&dwc->lock, flags);
        ret = __dwc3_gadget_ep_enable(dep, desc, ep->comp_desc, false, false);
@@ -689,11 +759,10 @@ static int dwc3_gadget_ep_disable(struct usb_ep *ep)
        dep = to_dwc3_ep(ep);
        dwc = dep->dwc;
 
-       if (!(dep->flags & DWC3_EP_ENABLED)) {
-               dev_WARN_ONCE(dwc->dev, true, "%s is already disabled\n",
-                               dep->name);
+       if (dev_WARN_ONCE(dwc->dev, !(dep->flags & DWC3_EP_ENABLED),
+                                       "%s is already disabled\n",
+                                       dep->name))
                return 0;
-       }
 
        spin_lock_irqsave(&dwc->lock, flags);
        ret = __dwc3_gadget_ep_disable(dep);
@@ -746,20 +815,19 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
                        chain ? " chain" : "");
 
 
-       trb = &dep->trb_pool[dep->free_slot & DWC3_TRB_MASK];
+       trb = &dep->trb_pool[dep->trb_enqueue];
 
        if (!req->trb) {
-               dwc3_gadget_move_request_queued(req);
+               dwc3_gadget_move_started_request(req);
                req->trb = trb;
                req->trb_dma = dwc3_trb_dma_offset(dep, trb);
-               req->start_slot = dep->free_slot & DWC3_TRB_MASK;
+               req->first_trb_index = dep->trb_enqueue;
        }
 
-       dep->free_slot++;
-       /* Skip the LINK-TRB on ISOC */
-       if (((dep->free_slot & DWC3_TRB_MASK) == DWC3_TRB_NUM - 1) &&
-                       usb_endpoint_xfer_isoc(dep->endpoint.desc))
-               dep->free_slot++;
+       dwc3_ep_inc_enq(dep);
+       /* Skip the LINK-TRB */
+       if (dwc3_ep_is_last_trb(dep->trb_enqueue))
+               dwc3_ep_inc_enq(dep);
 
        trb->size = DWC3_TRB_SIZE_LENGTH(length);
        trb->bpl = lower_32_bits(dma);
@@ -775,6 +843,9 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
                        trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS_FIRST;
                else
                        trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS;
+
+               /* always enable Interrupt on Missed ISOC */
+               trb->ctrl |= DWC3_TRB_CTRL_ISP_IMI;
                break;
 
        case USB_ENDPOINT_XFER_BULK:
@@ -789,15 +860,14 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
                BUG();
        }
 
+       /* always enable Continue on Short Packet */
+       trb->ctrl |= DWC3_TRB_CTRL_CSP;
+
        if (!req->request.no_interrupt && !chain)
-               trb->ctrl |= DWC3_TRB_CTRL_IOC;
+               trb->ctrl |= DWC3_TRB_CTRL_IOC | DWC3_TRB_CTRL_ISP_IMI;
 
-       if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-               trb->ctrl |= DWC3_TRB_CTRL_ISP_IMI;
-               trb->ctrl |= DWC3_TRB_CTRL_CSP;
-       } else if (last) {
+       if (last)
                trb->ctrl |= DWC3_TRB_CTRL_LST;
-       }
 
        if (chain)
                trb->ctrl |= DWC3_TRB_CTRL_CHN;
@@ -810,68 +880,50 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
        trace_dwc3_prepare_trb(dep, trb);
 }
 
+static u32 dwc3_calc_trbs_left(struct dwc3_ep *dep)
+{
+       struct dwc3_trb         *tmp;
+
+       /*
+        * If enqueue & dequeue are equal than it is either full or empty.
+        *
+        * One way to know for sure is if the TRB right before us has HWO bit
+        * set or not. If it has, then we're definitely full and can't fit any
+        * more transfers in our ring.
+        */
+       if (dep->trb_enqueue == dep->trb_dequeue) {
+               /* If we're full, enqueue/dequeue are > 0 */
+               if (dep->trb_enqueue) {
+                       tmp = &dep->trb_pool[dep->trb_enqueue - 1];
+                       if (tmp->ctrl & DWC3_TRB_CTRL_HWO)
+                               return 0;
+               }
+
+               return DWC3_TRB_NUM - 1;
+       }
+
+       return dep->trb_dequeue - dep->trb_enqueue;
+}
+
 /*
  * dwc3_prepare_trbs - setup TRBs from requests
  * @dep: endpoint for which requests are being prepared
- * @starting: true if the endpoint is idle and no requests are queued.
  *
  * The function goes through the requests list and sets up TRBs for the
  * transfers. The function returns once there are no more TRBs available or
  * it runs out of requests.
  */
-static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
+static void dwc3_prepare_trbs(struct dwc3_ep *dep)
 {
        struct dwc3_request     *req, *n;
        u32                     trbs_left;
-       u32                     max;
        unsigned int            last_one = 0;
 
        BUILD_BUG_ON_NOT_POWER_OF_2(DWC3_TRB_NUM);
 
-       /* the first request must not be queued */
-       trbs_left = (dep->busy_slot - dep->free_slot) & DWC3_TRB_MASK;
-
-       /* Can't wrap around on a non-isoc EP since there's no link TRB */
-       if (!usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-               max = DWC3_TRB_NUM - (dep->free_slot & DWC3_TRB_MASK);
-               if (trbs_left > max)
-                       trbs_left = max;
-       }
+       trbs_left = dwc3_calc_trbs_left(dep);
 
-       /*
-        * If busy & slot are equal than it is either full or empty. If we are
-        * starting to process requests then we are empty. Otherwise we are
-        * full and don't do anything
-        */
-       if (!trbs_left) {
-               if (!starting)
-                       return;
-               trbs_left = DWC3_TRB_NUM;
-               /*
-                * In case we start from scratch, we queue the ISOC requests
-                * starting from slot 1. This is done because we use ring
-                * buffer and have no LST bit to stop us. Instead, we place
-                * IOC bit every TRB_NUM/4. We try to avoid having an interrupt
-                * after the first request so we start at slot 1 and have
-                * 7 requests proceed before we hit the first IOC.
-                * Other transfer types don't use the ring buffer and are
-                * processed from the first TRB until the last one. Since we
-                * don't wrap around we have to start at the beginning.
-                */
-               if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-                       dep->busy_slot = 1;
-                       dep->free_slot = 1;
-               } else {
-                       dep->busy_slot = 0;
-                       dep->free_slot = 0;
-               }
-       }
-
-       /* The last TRB is a link TRB, not used for xfer */
-       if ((trbs_left <= 1) && usb_endpoint_xfer_isoc(dep->endpoint.desc))
-               return;
-
-       list_for_each_entry_safe(req, n, &dep->request_list, list) {
+       list_for_each_entry_safe(req, n, &dep->pending_list, list) {
                unsigned        length;
                dma_addr_t      dma;
                last_one = false;
@@ -890,7 +942,7 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
 
                                if (i == (request->num_mapped_sgs - 1) ||
                                                sg_is_last(s)) {
-                                       if (list_empty(&dep->request_list))
+                                       if (list_empty(&dep->pending_list))
                                                last_one = true;
                                        chain = false;
                                }
@@ -920,7 +972,7 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
                                last_one = 1;
 
                        /* Is this the last request? */
-                       if (list_is_last(&req->list, &dep->request_list))
+                       if (list_is_last(&req->list, &dep->pending_list))
                                last_one = 1;
 
                        dwc3_prepare_one_trb(dep, req, dma, length,
@@ -932,38 +984,19 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
        }
 }
 
-static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param,
-               int start_new)
+static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param)
 {
        struct dwc3_gadget_ep_cmd_params params;
        struct dwc3_request             *req;
        struct dwc3                     *dwc = dep->dwc;
+       int                             starting;
        int                             ret;
        u32                             cmd;
 
-       if (start_new && (dep->flags & DWC3_EP_BUSY)) {
-               dwc3_trace(trace_dwc3_gadget, "%s: endpoint busy", dep->name);
-               return -EBUSY;
-       }
-
-       /*
-        * If we are getting here after a short-out-packet we don't enqueue any
-        * new requests as we try to set the IOC bit only on the last request.
-        */
-       if (start_new) {
-               if (list_empty(&dep->req_queued))
-                       dwc3_prepare_trbs(dep, start_new);
-
-               /* req points to the first request which will be sent */
-               req = next_request(&dep->req_queued);
-       } else {
-               dwc3_prepare_trbs(dep, start_new);
+       starting = !(dep->flags & DWC3_EP_BUSY);
 
-               /*
-                * req points to the first request where HWO changed from 0 to 1
-                */
-               req = next_request(&dep->req_queued);
-       }
+       dwc3_prepare_trbs(dep);
+       req = next_request(&dep->started_list);
        if (!req) {
                dep->flags |= DWC3_EP_PENDING_REQUEST;
                return 0;
@@ -971,7 +1004,7 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param,
 
        memset(&params, 0, sizeof(params));
 
-       if (start_new) {
+       if (starting) {
                params.param0 = upper_32_bits(req->trb_dma);
                params.param1 = lower_32_bits(req->trb_dma);
                cmd = DWC3_DEPCMD_STARTTRANSFER;
@@ -995,7 +1028,7 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep, u16 cmd_param,
 
        dep->flags |= DWC3_EP_BUSY;
 
-       if (start_new) {
+       if (starting) {
                dep->resource_index = dwc3_gadget_ep_get_transfer_index(dwc,
                                dep->number);
                WARN_ON_ONCE(!dep->resource_index);
@@ -1009,7 +1042,7 @@ static void __dwc3_gadget_start_isoc(struct dwc3 *dwc,
 {
        u32 uf;
 
-       if (list_empty(&dep->request_list)) {
+       if (list_empty(&dep->pending_list)) {
                dwc3_trace(trace_dwc3_gadget,
                                "ISOC ep %s run out for requests",
                                dep->name);
@@ -1020,7 +1053,7 @@ static void __dwc3_gadget_start_isoc(struct dwc3 *dwc,
        /* 4 micro frames in the future */
        uf = cur_uf + dep->interval * 4;
 
-       __dwc3_gadget_kick_transfer(dep, uf, 1);
+       __dwc3_gadget_kick_transfer(dep, uf);
 }
 
 static void dwc3_gadget_start_isoc(struct dwc3 *dwc,
@@ -1060,6 +1093,17 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 
        trace_dwc3_ep_queue(req);
 
+       /*
+        * Per databook, the total size of buffer must be a multiple
+        * of MaxPacketSize for OUT endpoints. And MaxPacketSize is
+        * configed for endpoints in dwc3_gadget_set_ep_config(),
+        * set to usb_endpoint_descriptor->wMaxPacketSize.
+        */
+       if (dep->direction == 0 &&
+           req->request.length % dep->endpoint.desc->wMaxPacketSize)
+               req->request.length = roundup(req->request.length,
+                                       dep->endpoint.desc->wMaxPacketSize);
+
        /*
         * We only add to our list of requests now and
         * start consuming the list once we get XferNotReady
@@ -1077,7 +1121,7 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
        if (ret)
                return ret;
 
-       list_add_tail(&req->list, &dep->request_list);
+       list_add_tail(&req->list, &dep->pending_list);
 
        /*
         * If there are no pending requests and the endpoint isn't already
@@ -1089,7 +1133,7 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
        if (!usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
                        !usb_endpoint_xfer_int(dep->endpoint.desc) &&
                        !(dep->flags & DWC3_EP_BUSY)) {
-               ret = __dwc3_gadget_kick_transfer(dep, 0, true);
+               ret = __dwc3_gadget_kick_transfer(dep, 0);
                goto out;
        }
 
@@ -1112,14 +1156,14 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
                 * notion of current microframe.
                 */
                if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
-                       if (list_empty(&dep->req_queued)) {
+                       if (list_empty(&dep->started_list)) {
                                dwc3_stop_active_transfer(dwc, dep->number, true);
                                dep->flags = DWC3_EP_ENABLED;
                        }
                        return 0;
                }
 
-               ret = __dwc3_gadget_kick_transfer(dep, 0, true);
+               ret = __dwc3_gadget_kick_transfer(dep, 0);
                if (!ret)
                        dep->flags &= ~DWC3_EP_PENDING_REQUEST;
 
@@ -1135,8 +1179,7 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
                        (dep->flags & DWC3_EP_BUSY) &&
                        !(dep->flags & DWC3_EP_MISSED_ISOC)) {
                WARN_ON_ONCE(!dep->resource_index);
-               ret = __dwc3_gadget_kick_transfer(dep, dep->resource_index,
-                               false);
+               ret = __dwc3_gadget_kick_transfer(dep, dep->resource_index);
                goto out;
        }
 
@@ -1146,7 +1189,7 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
         * handled.
         */
        if (dep->stream_capable)
-               ret = __dwc3_gadget_kick_transfer(dep, 0, true);
+               ret = __dwc3_gadget_kick_transfer(dep, 0);
 
 out:
        if (ret && ret != -EBUSY)
@@ -1159,6 +1202,32 @@ out:
        return ret;
 }
 
+static void __dwc3_gadget_ep_zlp_complete(struct usb_ep *ep,
+               struct usb_request *request)
+{
+       dwc3_gadget_ep_free_request(ep, request);
+}
+
+static int __dwc3_gadget_ep_queue_zlp(struct dwc3 *dwc, struct dwc3_ep *dep)
+{
+       struct dwc3_request             *req;
+       struct usb_request              *request;
+       struct usb_ep                   *ep = &dep->endpoint;
+
+       dwc3_trace(trace_dwc3_gadget, "queueing ZLP\n");
+       request = dwc3_gadget_ep_alloc_request(ep, GFP_ATOMIC);
+       if (!request)
+               return -ENOMEM;
+
+       request->length = 0;
+       request->buf = dwc->zlp_buf;
+       request->complete = __dwc3_gadget_ep_zlp_complete;
+
+       req = to_dwc3_request(request);
+
+       return __dwc3_gadget_ep_queue(dep, req);
+}
+
 static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
        gfp_t gfp_flags)
 {
@@ -1172,6 +1241,17 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
 
        spin_lock_irqsave(&dwc->lock, flags);
        ret = __dwc3_gadget_ep_queue(dep, req);
+
+       /*
+        * Okay, here's the thing, if gadget driver has requested for a ZLP by
+        * setting request->zero, instead of doing magic, we will just queue an
+        * extra usb_request ourselves so that it gets handled the same way as
+        * any other request.
+        */
+       if (ret == 0 && request->zero && request->length &&
+           (request->length % ep->desc->wMaxPacketSize == 0))
+               ret = __dwc3_gadget_ep_queue_zlp(dwc, dep);
+
        spin_unlock_irqrestore(&dwc->lock, flags);
 
        return ret;
@@ -1193,13 +1273,13 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
 
        spin_lock_irqsave(&dwc->lock, flags);
 
-       list_for_each_entry(r, &dep->request_list, list) {
+       list_for_each_entry(r, &dep->pending_list, list) {
                if (r == req)
                        break;
        }
 
        if (r != req) {
-               list_for_each_entry(r, &dep->req_queued, list) {
+               list_for_each_entry(r, &dep->started_list, list) {
                        if (r == req)
                                break;
                }
@@ -1239,10 +1319,10 @@ int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol)
 
        if (value) {
                if (!protocol && ((dep->direction && dep->flags & DWC3_EP_BUSY) ||
-                               (!list_empty(&dep->req_queued) ||
-                                !list_empty(&dep->request_list)))) {
+                               (!list_empty(&dep->started_list) ||
+                                !list_empty(&dep->pending_list)))) {
                        dwc3_trace(trace_dwc3_gadget,
-                                       "%s: pending request, cannot halt\n",
+                                       "%s: pending request, cannot halt",
                                        dep->name);
                        return -EAGAIN;
                }
@@ -1255,8 +1335,7 @@ int __dwc3_gadget_ep_set_halt(struct dwc3_ep *dep, int value, int protocol)
                else
                        dep->flags |= DWC3_EP_STALL;
        } else {
-               ret = dwc3_send_gadget_ep_cmd(dwc, dep->number,
-                       DWC3_DEPCMD_CLEARSTALL, &params);
+               ret = dwc3_send_clear_stall_ep_cmd(dep);
                if (ret)
                        dev_err(dwc->dev, "failed to clear STALL on %s\n",
                                        dep->name);
@@ -1343,22 +1422,16 @@ static int dwc3_gadget_get_frame(struct usb_gadget *g)
        return DWC3_DSTS_SOFFN(reg);
 }
 
-static int dwc3_gadget_wakeup(struct usb_gadget *g)
+static int __dwc3_gadget_wakeup(struct dwc3 *dwc)
 {
-       struct dwc3             *dwc = gadget_to_dwc(g);
-
        unsigned long           timeout;
-       unsigned long           flags;
 
+       int                     ret;
        u32                     reg;
 
-       int                     ret = 0;
-
        u8                      link_state;
        u8                      speed;
 
-       spin_lock_irqsave(&dwc->lock, flags);
-
        /*
         * According to the Databook Remote wakeup request should
         * be issued only when the device is in early suspend state.
@@ -1370,8 +1443,7 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
        speed = reg & DWC3_DSTS_CONNECTSPD;
        if (speed == DWC3_DSTS_SUPERSPEED) {
                dwc3_trace(trace_dwc3_gadget, "no wakeup on SuperSpeed\n");
-               ret = -EINVAL;
-               goto out;
+               return -EINVAL;
        }
 
        link_state = DWC3_DSTS_USBLNKST(reg);
@@ -1384,14 +1456,13 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
                dwc3_trace(trace_dwc3_gadget,
                                "can't wakeup from '%s'\n",
                                dwc3_gadget_link_string(link_state));
-               ret = -EINVAL;
-               goto out;
+               return -EINVAL;
        }
 
        ret = dwc3_gadget_set_link_state(dwc, DWC3_LINK_STATE_RECOV);
        if (ret < 0) {
                dev_err(dwc->dev, "failed to put link in Recovery\n");
-               goto out;
+               return ret;
        }
 
        /* Recent versions do this automatically */
@@ -1415,10 +1486,20 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
 
        if (DWC3_DSTS_USBLNKST(reg) != DWC3_LINK_STATE_U0) {
                dev_err(dwc->dev, "failed to send remote wakeup\n");
-               ret = -EINVAL;
+               return -EINVAL;
        }
 
-out:
+       return 0;
+}
+
+static int dwc3_gadget_wakeup(struct usb_gadget *g)
+{
+       struct dwc3             *dwc = gadget_to_dwc(g);
+       unsigned long           flags;
+       int                     ret;
+
+       spin_lock_irqsave(&dwc->lock, flags);
+       ret = __dwc3_gadget_wakeup(dwc);
        spin_unlock_irqrestore(&dwc->lock, flags);
 
        return ret;
@@ -1533,37 +1614,12 @@ static void dwc3_gadget_disable_irq(struct dwc3 *dwc)
 static irqreturn_t dwc3_interrupt(int irq, void *_dwc);
 static irqreturn_t dwc3_thread_interrupt(int irq, void *_dwc);
 
-static int dwc3_gadget_start(struct usb_gadget *g,
-               struct usb_gadget_driver *driver)
+static int __dwc3_gadget_start(struct dwc3 *dwc)
 {
-       struct dwc3             *dwc = gadget_to_dwc(g);
        struct dwc3_ep          *dep;
-       unsigned long           flags;
        int                     ret = 0;
-       int                     irq;
        u32                     reg;
 
-       irq = platform_get_irq(to_platform_device(dwc->dev), 0);
-       ret = request_threaded_irq(irq, dwc3_interrupt, dwc3_thread_interrupt,
-                       IRQF_SHARED, "dwc3", dwc);
-       if (ret) {
-               dev_err(dwc->dev, "failed to request irq #%d --> %d\n",
-                               irq, ret);
-               goto err0;
-       }
-
-       spin_lock_irqsave(&dwc->lock, flags);
-
-       if (dwc->gadget_driver) {
-               dev_err(dwc->dev, "%s is already bound to %s\n",
-                               dwc->gadget.name,
-                               dwc->gadget_driver->driver.name);
-               ret = -EBUSY;
-               goto err1;
-       }
-
-       dwc->gadget_driver      = driver;
-
        reg = dwc3_readl(dwc->regs, DWC3_DCFG);
        reg &= ~(DWC3_DCFG_SPEED_MASK);
 
@@ -1601,7 +1657,16 @@ static int dwc3_gadget_start(struct usb_gadget *g,
        }
        dwc3_writel(dwc->regs, DWC3_DCFG, reg);
 
-       dwc->start_config_issued = false;
+       /*
+        * We are telling dwc3 that we want to use DCFG.NUMP as ACK TP's NUMP
+        * field instead of letting dwc3 itself calculate that automatically.
+        *
+        * This way, we maximize the chances that we'll be able to get several
+        * bursts of data without going through any sort of endpoint throttling.
+        */
+       reg = dwc3_readl(dwc->regs, DWC3_GRXTHRCFG);
+       reg &= ~DWC3_GRXTHRCFG_PKTCNTSEL;
+       dwc3_writel(dwc->regs, DWC3_GRXTHRCFG, reg);
 
        /* Start with SuperSpeed Default */
        dwc3_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(512);
@@ -1611,7 +1676,7 @@ static int dwc3_gadget_start(struct usb_gadget *g,
                        false);
        if (ret) {
                dev_err(dwc->dev, "failed to enable %s\n", dep->name);
-               goto err2;
+               goto err0;
        }
 
        dep = dwc->eps[1];
@@ -1619,7 +1684,7 @@ static int dwc3_gadget_start(struct usb_gadget *g,
                        false);
        if (ret) {
                dev_err(dwc->dev, "failed to enable %s\n", dep->name);
-               goto err3;
+               goto err1;
        }
 
        /* begin to receive SETUP packets */
@@ -1628,25 +1693,63 @@ static int dwc3_gadget_start(struct usb_gadget *g,
 
        dwc3_gadget_enable_irq(dwc);
 
-       spin_unlock_irqrestore(&dwc->lock, flags);
-
        return 0;
 
-err3:
+err1:
        __dwc3_gadget_ep_disable(dwc->eps[0]);
 
-err2:
-       dwc->gadget_driver = NULL;
+err0:
+       return ret;
+}
 
-err1:
+static int dwc3_gadget_start(struct usb_gadget *g,
+               struct usb_gadget_driver *driver)
+{
+       struct dwc3             *dwc = gadget_to_dwc(g);
+       unsigned long           flags;
+       int                     ret = 0;
+       int                     irq;
+
+       irq = platform_get_irq(to_platform_device(dwc->dev), 0);
+       ret = request_threaded_irq(irq, dwc3_interrupt, dwc3_thread_interrupt,
+                       IRQF_SHARED, "dwc3", dwc->ev_buf);
+       if (ret) {
+               dev_err(dwc->dev, "failed to request irq #%d --> %d\n",
+                               irq, ret);
+               goto err0;
+       }
+
+       spin_lock_irqsave(&dwc->lock, flags);
+       if (dwc->gadget_driver) {
+               dev_err(dwc->dev, "%s is already bound to %s\n",
+                               dwc->gadget.name,
+                               dwc->gadget_driver->driver.name);
+               ret = -EBUSY;
+               goto err1;
+       }
+
+       dwc->gadget_driver      = driver;
+
+       __dwc3_gadget_start(dwc);
        spin_unlock_irqrestore(&dwc->lock, flags);
 
+       return 0;
+
+err1:
+       spin_unlock_irqrestore(&dwc->lock, flags);
        free_irq(irq, dwc);
 
 err0:
        return ret;
 }
 
+static void __dwc3_gadget_stop(struct dwc3 *dwc)
+{
+       dwc3_gadget_disable_irq(dwc);
+       __dwc3_gadget_ep_disable(dwc->eps[0]);
+       __dwc3_gadget_ep_disable(dwc->eps[1]);
+}
+
 static int dwc3_gadget_stop(struct usb_gadget *g)
 {
        struct dwc3             *dwc = gadget_to_dwc(g);
@@ -1654,17 +1757,12 @@ static int dwc3_gadget_stop(struct usb_gadget *g)
        int                     irq;
 
        spin_lock_irqsave(&dwc->lock, flags);
-
-       dwc3_gadget_disable_irq(dwc);
-       __dwc3_gadget_ep_disable(dwc->eps[0]);
-       __dwc3_gadget_ep_disable(dwc->eps[1]);
-
+       __dwc3_gadget_stop(dwc);
        dwc->gadget_driver      = NULL;
-
        spin_unlock_irqrestore(&dwc->lock, flags);
 
        irq = platform_get_irq(to_platform_device(dwc->dev), 0);
-       free_irq(irq, dwc);
+       free_irq(irq, dwc->ev_buf);
 
        return 0;
 }
@@ -1736,8 +1834,8 @@ static int dwc3_gadget_init_hw_endpoints(struct dwc3 *dwc,
                dep->endpoint.caps.dir_in = !!direction;
                dep->endpoint.caps.dir_out = !direction;
 
-               INIT_LIST_HEAD(&dep->request_list);
-               INIT_LIST_HEAD(&dep->req_queued);
+               INIT_LIST_HEAD(&dep->pending_list);
+               INIT_LIST_HEAD(&dep->started_list);
        }
 
        return 0;
@@ -1834,11 +1932,11 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
                                 * If there are still queued request
                                 * then wait, do not issue either END
                                 * or UPDATE TRANSFER, just attach next
-                                * request in request_list during
+                                * request in pending_list during
                                 * giveback.If any future queued request
                                 * is successfully transferred then we
                                 * will issue UPDATE TRANSFER for all
-                                * request in the request_list.
+                                * request in the pending_list.
                                 */
                                dep->flags |= DWC3_EP_MISSED_ISOC;
                        } else {
@@ -1884,15 +1982,14 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
        int                     ret;
 
        do {
-               req = next_request(&dep->req_queued);
+               req = next_request(&dep->started_list);
                if (WARN_ON_ONCE(!req))
                        return 1;
 
                i = 0;
                do {
-                       slot = req->start_slot + i;
-                       if ((slot == DWC3_TRB_NUM - 1) &&
-                               usb_endpoint_xfer_isoc(dep->endpoint.desc))
+                       slot = req->first_trb_index + i;
+                       if (slot == DWC3_TRB_NUM - 1)
                                slot++;
                        slot %= DWC3_TRB_NUM;
                        trb = &dep->trb_pool[slot];
@@ -1910,8 +2007,8 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
        } while (1);
 
        if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
-                       list_empty(&dep->req_queued)) {
-               if (list_empty(&dep->request_list)) {
+                       list_empty(&dep->started_list)) {
+               if (list_empty(&dep->pending_list)) {
                        /*
                         * If there is no entry in request list then do
                         * not issue END TRANSFER now. Just set PENDING
@@ -1960,7 +2057,7 @@ static void dwc3_endpoint_transfer_complete(struct dwc3 *dwc,
                        if (!(dep->flags & DWC3_EP_ENABLED))
                                continue;
 
-                       if (!list_empty(&dep->req_queued))
+                       if (!list_empty(&dep->started_list))
                                return;
                }
 
@@ -1974,7 +2071,7 @@ static void dwc3_endpoint_transfer_complete(struct dwc3 *dwc,
        if (!usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
                int ret;
 
-               ret = __dwc3_gadget_kick_transfer(dep, 0, is_xfer_complete);
+               ret = __dwc3_gadget_kick_transfer(dep, 0);
                if (!ret || ret == -EBUSY)
                        return;
        }
@@ -2025,7 +2122,7 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
                                        dep->name, active ? "Transfer Active"
                                        : "Transfer Not Active");
 
-                       ret = __dwc3_gadget_kick_transfer(dep, 0, !active);
+                       ret = __dwc3_gadget_kick_transfer(dep, 0);
                        if (!ret || ret == -EBUSY)
                                return;
 
@@ -2171,7 +2268,6 @@ static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)
 
        for (epnum = 1; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
                struct dwc3_ep *dep;
-               struct dwc3_gadget_ep_cmd_params params;
                int ret;
 
                dep = dwc->eps[epnum];
@@ -2183,9 +2279,7 @@ static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)
 
                dep->flags &= ~DWC3_EP_STALL;
 
-               memset(&params, 0, sizeof(params));
-               ret = dwc3_send_gadget_ep_cmd(dwc, dep->number,
-                               DWC3_DEPCMD_CLEARSTALL, &params);
+               ret = dwc3_send_clear_stall_ep_cmd(dep);
                WARN_ON_ONCE(ret);
        }
 }
@@ -2202,7 +2296,6 @@ 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;
@@ -2230,8 +2323,8 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
         *
         * Our suggested workaround is to follow the Disconnect
         * Event steps here, instead, based on a setup_packet_pending
-        * flag. Such flag gets set whenever we have a XferNotReady
-        * event on EP0 and gets cleared on XferComplete for the
+        * flag. Such flag gets set whenever we have a SETUP_PENDING
+        * status for EP0 TRBs and gets cleared on XferComplete for the
         * same endpoint.
         *
         * Refers to:
@@ -2253,7 +2346,6 @@ 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);
@@ -2404,7 +2496,11 @@ static void dwc3_gadget_wakeup_interrupt(struct dwc3 *dwc)
         * implemented.
         */
 
-       dwc->gadget_driver->resume(&dwc->gadget);
+       if (dwc->gadget_driver && dwc->gadget_driver->resume) {
+               spin_unlock(&dwc->lock);
+               dwc->gadget_driver->resume(&dwc->gadget);
+               spin_lock(&dwc->lock);
+       }
 }
 
 static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
@@ -2598,14 +2694,13 @@ static void dwc3_process_event_entry(struct dwc3 *dwc,
        }
 }
 
-static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc, u32 buf)
+static irqreturn_t dwc3_process_event_buf(struct dwc3_event_buffer *evt)
 {
-       struct dwc3_event_buffer *evt;
+       struct dwc3 *dwc = evt->dwc;
        irqreturn_t ret = IRQ_NONE;
        int left;
        u32 reg;
 
-       evt = dwc->ev_buffs[buf];
        left = evt->count;
 
        if (!(evt->flags & DWC3_EVENT_PENDING))
@@ -2630,7 +2725,7 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc, u32 buf)
                evt->lpos = (evt->lpos + 4) % DWC3_EVENT_BUFFERS_SIZE;
                left -= 4;
 
-               dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(buf), 4);
+               dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), 4);
        }
 
        evt->count = 0;
@@ -2638,39 +2733,34 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc, u32 buf)
        ret = IRQ_HANDLED;
 
        /* Unmask interrupt */
-       reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(buf));
+       reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(0));
        reg &= ~DWC3_GEVNTSIZ_INTMASK;
-       dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(buf), reg);
+       dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), reg);
 
        return ret;
 }
 
-static irqreturn_t dwc3_thread_interrupt(int irq, void *_dwc)
+static irqreturn_t dwc3_thread_interrupt(int irq, void *_evt)
 {
-       struct dwc3 *dwc = _dwc;
+       struct dwc3_event_buffer *evt = _evt;
+       struct dwc3 *dwc = evt->dwc;
        unsigned long flags;
        irqreturn_t ret = IRQ_NONE;
-       int i;
 
        spin_lock_irqsave(&dwc->lock, flags);
-
-       for (i = 0; i < dwc->num_event_buffers; i++)
-               ret |= dwc3_process_event_buf(dwc, i);
-
+       ret = dwc3_process_event_buf(evt);
        spin_unlock_irqrestore(&dwc->lock, flags);
 
        return ret;
 }
 
-static irqreturn_t dwc3_check_event_buf(struct dwc3 *dwc, u32 buf)
+static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 {
-       struct dwc3_event_buffer *evt;
+       struct dwc3 *dwc = evt->dwc;
        u32 count;
        u32 reg;
 
-       evt = dwc->ev_buffs[buf];
-
-       count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(buf));
+       count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0));
        count &= DWC3_GEVNTCOUNT_MASK;
        if (!count)
                return IRQ_NONE;
@@ -2679,28 +2769,18 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3 *dwc, u32 buf)
        evt->flags |= DWC3_EVENT_PENDING;
 
        /* Mask interrupt */
-       reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(buf));
+       reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(0));
        reg |= DWC3_GEVNTSIZ_INTMASK;
-       dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(buf), reg);
+       dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), reg);
 
        return IRQ_WAKE_THREAD;
 }
 
-static irqreturn_t dwc3_interrupt(int irq, void *_dwc)
+static irqreturn_t dwc3_interrupt(int irq, void *_evt)
 {
-       struct dwc3                     *dwc = _dwc;
-       int                             i;
-       irqreturn_t                     ret = IRQ_NONE;
-
-       for (i = 0; i < dwc->num_event_buffers; i++) {
-               irqreturn_t status;
-
-               status = dwc3_check_event_buf(dwc, i);
-               if (status == IRQ_WAKE_THREAD)
-                       ret = status;
-       }
+       struct dwc3_event_buffer        *evt = _evt;
 
-       return ret;
+       return dwc3_check_event_buf(evt);
 }
 
 /**
@@ -2744,10 +2824,17 @@ int dwc3_gadget_init(struct dwc3 *dwc)
                goto err3;
        }
 
+       dwc->zlp_buf = kzalloc(DWC3_ZLP_BUF_SIZE, GFP_KERNEL);
+       if (!dwc->zlp_buf) {
+               ret = -ENOMEM;
+               goto err4;
+       }
+
        dwc->gadget.ops                 = &dwc3_gadget_ops;
        dwc->gadget.speed               = USB_SPEED_UNKNOWN;
        dwc->gadget.sg_supported        = true;
        dwc->gadget.name                = "dwc3-gadget";
+       dwc->gadget.is_otg              = dwc->dr_mode == USB_DR_MODE_OTG;
 
        /*
         * FIXME We might be setting max_speed to <SUPER, however versions
@@ -2785,16 +2872,19 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 
        ret = dwc3_gadget_init_endpoints(dwc);
        if (ret)
-               goto err4;
+               goto err5;
 
        ret = usb_add_gadget_udc(dwc->dev, &dwc->gadget);
        if (ret) {
                dev_err(dwc->dev, "failed to register udc\n");
-               goto err4;
+               goto err5;
        }
 
        return 0;
 
+err5:
+       kfree(dwc->zlp_buf);
+
 err4:
        dwc3_gadget_free_endpoints(dwc);
        dma_free_coherent(dwc->dev, DWC3_EP0_BOUNCE_SIZE,
@@ -2827,6 +2917,7 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
                        dwc->ep0_bounce, dwc->ep0_bounce_addr);
 
        kfree(dwc->setup_buf);
+       kfree(dwc->zlp_buf);
 
        dma_free_coherent(dwc->dev, sizeof(*dwc->ep0_trb),
                        dwc->ep0_trb, dwc->ep0_trb_addr);
@@ -2837,54 +2928,40 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
 
 int dwc3_gadget_suspend(struct dwc3 *dwc)
 {
-       if (dwc->pullups_connected) {
-               dwc3_gadget_disable_irq(dwc);
-               dwc3_gadget_run_stop(dwc, true, true);
-       }
+       int ret;
 
-       __dwc3_gadget_ep_disable(dwc->eps[0]);
-       __dwc3_gadget_ep_disable(dwc->eps[1]);
+       if (!dwc->gadget_driver)
+               return 0;
 
-       dwc->dcfg = dwc3_readl(dwc->regs, DWC3_DCFG);
+       ret = dwc3_gadget_run_stop(dwc, false, false);
+       if (ret < 0)
+               return ret;
+
+       dwc3_disconnect_gadget(dwc);
+       __dwc3_gadget_stop(dwc);
 
        return 0;
 }
 
 int dwc3_gadget_resume(struct dwc3 *dwc)
 {
-       struct dwc3_ep          *dep;
        int                     ret;
 
-       /* Start with SuperSpeed Default */
-       dwc3_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(512);
+       if (!dwc->gadget_driver)
+               return 0;
 
-       dep = dwc->eps[0];
-       ret = __dwc3_gadget_ep_enable(dep, &dwc3_gadget_ep0_desc, NULL, false,
-                       false);
-       if (ret)
+       ret = __dwc3_gadget_start(dwc);
+       if (ret < 0)
                goto err0;
 
-       dep = dwc->eps[1];
-       ret = __dwc3_gadget_ep_enable(dep, &dwc3_gadget_ep0_desc, NULL, false,
-                       false);
-       if (ret)
+       ret = dwc3_gadget_run_stop(dwc, true, false);
+       if (ret < 0)
                goto err1;
 
-       /* begin to receive SETUP packets */
-       dwc->ep0state = EP0_SETUP_PHASE;
-       dwc3_ep0_out_start(dwc);
-
-       dwc3_writel(dwc->regs, DWC3_DCFG, dwc->dcfg);
-
-       if (dwc->pullups_connected) {
-               dwc3_gadget_enable_irq(dwc);
-               dwc3_gadget_run_stop(dwc, true, false);
-       }
-
        return 0;
 
 err1:
-       __dwc3_gadget_ep_disable(dwc->eps[0]);
+       __dwc3_gadget_stop(dwc);
 
 err0:
        return ret;