usb: dwc3: gadget: re-factor dwc3_prepare_trbs()

In order to make it easier to add SG support,
let's split the big loop out to its own function.

Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 78 insertions, 68 deletions

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 580272042a33..317fc7d04694 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -539,6 +539,78 @@ static void dwc3_gadget_ep_free_request(struct usb_ep *ep,
         kfree(req);
 }
 
+/**
+ * dwc3_prepare_one_trb - setup one TRB from one request
+ * @dep: endpoint for which this request is prepared
+ * @req: dwc3_request pointer
+ */
+static int dwc3_prepare_one_trb(struct dwc3_ep *dep,
+                struct dwc3_request *req, unsigned last)
+{
+        struct dwc3_trb_hw      *trb_hw;
+        struct dwc3_trb         trb;
+
+        unsigned int            cur_slot;
+
+        trb_hw = &dep->trb_pool[dep->free_slot & DWC3_TRB_MASK];
+        cur_slot = dep->free_slot;
+        dep->free_slot++;
+
+        /* Skip the LINK-TRB on ISOC */
+        if (((cur_slot & DWC3_TRB_MASK) == DWC3_TRB_NUM - 1) &&
+                        usb_endpoint_xfer_isoc(dep->desc))
+                return 0;
+
+        dwc3_gadget_move_request_queued(req);
+        memset(&trb, 0, sizeof(trb));
+
+        req->trb = trb_hw;
+
+        if (usb_endpoint_xfer_isoc(dep->desc)) {
+                trb.isp_imi = true;
+                trb.csp = true;
+        } else {
+                trb.lst = last;
+        }
+
+        if (usb_endpoint_xfer_bulk(dep->desc) && dep->stream_capable)
+                trb.sid_sofn = req->request.stream_id;
+
+        switch (usb_endpoint_type(dep->desc)) {
+        case USB_ENDPOINT_XFER_CONTROL:
+                trb.trbctl = DWC3_TRBCTL_CONTROL_SETUP;
+                break;
+
+        case USB_ENDPOINT_XFER_ISOC:
+                trb.trbctl = DWC3_TRBCTL_ISOCHRONOUS_FIRST;
+
+                /* IOC every DWC3_TRB_NUM / 4 so we can refill */
+                if (!(cur_slot % (DWC3_TRB_NUM / 4)))
+                        trb.ioc = last;
+                break;
+
+        case USB_ENDPOINT_XFER_BULK:
+        case USB_ENDPOINT_XFER_INT:
+                trb.trbctl = DWC3_TRBCTL_NORMAL;
+                break;
+        default:
+                /*
+                 * This is only possible with faulty memory because we
+                 * checked it already :)
+                 */
+                BUG();
+        }
+
+        trb.length      = req->request.length;
+        trb.bplh        = req->request.dma;
+        trb.hwo         = true;
+
+        dwc3_trb_to_hw(&trb, trb_hw);
+        req->trb_dma = dwc3_trb_dma_offset(dep, trb_hw);
+
+        return 0;
+}
+
 /*
  * dwc3_prepare_trbs - setup TRBs from requests
  * @dep: endpoint for which requests are being prepared
@@ -552,14 +624,14 @@ static struct dwc3_request *dwc3_prepare_trbs(struct dwc3_ep *dep,
                 bool starting)
 {
         struct dwc3_request     *req, *n, *ret = NULL;
-        struct dwc3_trb_hw      *trb_hw;
-        struct dwc3_trb         trb;
         u32                     trbs_left;
+        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;
+
         /*
          * if busy & slot are equal than it is either full or empty. If we are
          * starting to proceed requests then we are empty. Otherwise we ar
@@ -594,25 +666,11 @@ static struct dwc3_request *dwc3_prepare_trbs(struct dwc3_ep *dep,
                 return NULL;
 
         list_for_each_entry_safe(req, n, &dep->request_list, list) {
-                unsigned int last_one = 0;
-                unsigned int cur_slot;
-
-                trb_hw = &dep->trb_pool[dep->free_slot & DWC3_TRB_MASK];
-                cur_slot = dep->free_slot;
-                dep->free_slot++;
-
-                /* Skip the LINK-TRB on ISOC */
-                if (((cur_slot & DWC3_TRB_MASK) == DWC3_TRB_NUM - 1) &&
-                                usb_endpoint_xfer_isoc(dep->desc))
-                        continue;
-
-                dwc3_gadget_move_request_queued(req);
-                memset(&trb, 0, sizeof(trb));
                 trbs_left--;
 
-                /* Is our TRB pool empty? */
                 if (!trbs_left)
                         last_one = 1;
+
                 /* Is this the last request? */
                 if (list_empty(&dep->request_list))
                         last_one = 1;
@@ -625,57 +683,9 @@ static struct dwc3_request *dwc3_prepare_trbs(struct dwc3_ep *dep,
                  * While we're debugging the problem, as a workaround to
                  * multiple TRBs handling, use only one TRB at a time.
                  */
-                last_one = 1;
-
-                req->trb = trb_hw;
-                if (!ret)
-                        ret = req;
-
-                trb.bplh = req->request.dma;
-
-                if (usb_endpoint_xfer_isoc(dep->desc)) {
-                        trb.isp_imi = true;
-                        trb.csp = true;
-                } else {
-                        trb.lst = last_one;
-                }
-
-                if (usb_endpoint_xfer_bulk(dep->desc) && dep->stream_capable)
-                        trb.sid_sofn = req->request.stream_id;
-
-                switch (usb_endpoint_type(dep->desc)) {
-                case USB_ENDPOINT_XFER_CONTROL:
-                        trb.trbctl = DWC3_TRBCTL_CONTROL_SETUP;
-                        break;
-
-                case USB_ENDPOINT_XFER_ISOC:
-                        trb.trbctl = DWC3_TRBCTL_ISOCHRONOUS_FIRST;
-
-                        /* IOC every DWC3_TRB_NUM / 4 so we can refill */
-                        if (!(cur_slot % (DWC3_TRB_NUM / 4)))
-                                trb.ioc = last_one;
-                        break;
-
-                case USB_ENDPOINT_XFER_BULK:
-                case USB_ENDPOINT_XFER_INT:
-                        trb.trbctl = DWC3_TRBCTL_NORMAL;
-                        break;
-                default:
-                        /*
-                         * This is only possible with faulty memory because we
-                         * checked it already :)
-                         */
-                        BUG();
-                }
-
-                trb.length      = req->request.length;
-                trb.hwo = true;
-
-                dwc3_trb_to_hw(&trb, trb_hw);
-                req->trb_dma = dwc3_trb_dma_offset(dep, trb_hw);
-
-                if (last_one)
-                        break;
+                dwc3_prepare_one_trb(dep, req, true);
+                ret = req;
+                break;
         }
 
         return ret;