usb: dwc3: gadget: Refactor preparing last TRBs

There are a lot of common codes for preparing SG and linear TRBs.
Refactor them for easier read.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index f091e107d9cbdc17a2f6fd03c6ae9107a1014d65..f75ce10407dd16ee08d54a92c470c9947376e42e 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1094,6 +1094,47 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
                        stream_id, short_not_ok, no_interrupt, is_last);
 }
 
+/**
+ * dwc3_prepare_last_sg - prepare TRBs for the last SG entry
+ * @dep: The endpoint that the request belongs to
+ * @req: The request to prepare
+ * @entry_length: The last SG entry size
+ * @node: Indicates whether this is not the first entry (for isoc only)
+ *
+ * Return the number of TRBs prepared.
+ */
+static int dwc3_prepare_last_sg(struct dwc3_ep *dep,
+               struct dwc3_request *req, unsigned int entry_length,
+               unsigned int node)
+{
+       unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);
+       unsigned int rem = req->request.length % maxp;
+       unsigned int num_trbs = 1;
+
+       if ((req->request.length && req->request.zero && !rem &&
+                       !usb_endpoint_xfer_isoc(dep->endpoint.desc)) ||
+                       (!req->direction && rem))
+               num_trbs++;
+
+       if (dwc3_calc_trbs_left(dep) < num_trbs)
+               return 0;
+
+       req->needs_extra_trb = num_trbs > 1;
+
+       /* Prepare a normal TRB */
+       if (req->direction || req->request.length)
+               dwc3_prepare_one_trb(dep, req, entry_length,
+                               req->needs_extra_trb, node, false);
+
+       /* Prepare extra TRBs for ZLP and MPS OUT transfer alignment */
+       if ((!req->direction && !req->request.length) || req->needs_extra_trb)
+               dwc3_prepare_one_trb(dep, req,
+                               req->direction ? 0 : maxp - rem,
+                               false, 1, true);
+
+       return num_trbs;
+}
+
 static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
                struct dwc3_request *req)
 {
@@ -1101,8 +1142,6 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
        struct scatterlist *s;
        int             i;
        unsigned int length = req->request.length;
-       unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);
-       unsigned int rem = length % maxp;
        unsigned int remaining = req->request.num_mapped_sgs
                - req->num_queued_sgs;
        unsigned int num_trbs = req->num_trbs;
@@ -1116,7 +1155,7 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
 
        for_each_sg(sg, s, remaining, i) {
                unsigned int trb_length;
-               unsigned int chain = true;
+               bool last_sg = false;
 
                trb_length = min_t(unsigned int, length, sg_dma_len(s));
 
@@ -1130,45 +1169,16 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
                 * mapped sg.
                 */
                if ((i == remaining - 1) || !length)
-                       chain = false;
+                       last_sg = true;
 
                if (!dwc3_calc_trbs_left(dep))
                        break;
 
-               if (rem && usb_endpoint_dir_out(dep->endpoint.desc) && !chain) {
-                       /* prepare normal TRB */
-                       if (req->request.length) {
-                               if (dwc3_calc_trbs_left(dep) < 2)
-                                       goto out;
-
-                               req->needs_extra_trb = true;
-                               dwc3_prepare_one_trb(dep, req, trb_length,
-                                       true, i, false);
-                       }
-
-                       /* Now prepare one extra TRB to align transfer size */
-                       dwc3_prepare_one_trb(dep, req, maxp - rem,
-                                       false, 1, true);
-               } else if (req->request.zero && req->request.length &&
-                          !usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
-                          !rem && !chain) {
-
-                       if (dwc3_calc_trbs_left(dep) < 2)
+               if (last_sg) {
+                       if (!dwc3_prepare_last_sg(dep, req, trb_length, i))
                                goto out;
-
-                       req->needs_extra_trb = true;
-
-                       /* Prepare normal TRB */
-                       dwc3_prepare_one_trb(dep, req, trb_length,
-                                       true, i, false);
-
-                       /* Prepare one extra TRB to handle ZLP */
-                       dwc3_prepare_one_trb(dep, req,
-                                       req->direction ? 0 : maxp,
-                                       false, 1, true);
                } else {
-                       dwc3_prepare_one_trb(dep, req, trb_length,
-                                       chain, i, false);
+                       dwc3_prepare_one_trb(dep, req, trb_length, 1, i, false);
                }
 
                /*
@@ -1178,7 +1188,7 @@ static int dwc3_prepare_one_trb_sg(struct dwc3_ep *dep,
                 * we have free trbs we can continue queuing from where we
                 * previously stopped
                 */
-               if (chain)
+               if (!last_sg)
                        req->start_sg = sg_next(s);
 
                req->num_queued_sgs++;
@@ -1224,50 +1234,7 @@ out:
 static int dwc3_prepare_one_trb_linear(struct dwc3_ep *dep,
                struct dwc3_request *req)
 {
-       unsigned int length = req->request.length;
-       unsigned int maxp = usb_endpoint_maxp(dep->endpoint.desc);
-       unsigned int rem = length % maxp;
-       unsigned int num_trbs = req->num_trbs;
-
-       if (!dwc3_calc_trbs_left(dep))
-               goto out;
-
-       if ((!length || rem) && usb_endpoint_dir_out(dep->endpoint.desc)) {
-               /* prepare normal TRB */
-               if (req->request.length) {
-                       if (dwc3_calc_trbs_left(dep) < 2)
-                               goto out;
-
-                       req->needs_extra_trb = true;
-                       dwc3_prepare_one_trb(dep, req, length, true, 0, false);
-               }
-
-               /* Now prepare one extra TRB to align transfer size */
-               dwc3_prepare_one_trb(dep, req, maxp - rem, false, 1, true);
-       } else if (req->request.zero && req->request.length &&
-                  !usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
-                  (IS_ALIGNED(req->request.length, maxp))) {
-
-               if (dwc3_calc_trbs_left(dep) < 2)
-                       goto out;
-
-               req->needs_extra_trb = true;
-
-               /* prepare normal TRB */
-               dwc3_prepare_one_trb(dep, req, length, true, 0, false);
-
-               /* Prepare one extra TRB to handle ZLP */
-               dwc3_prepare_one_trb(dep, req, req->direction ? 0 : maxp,
-                               false, 1, true);
-       } else {
-               if (!dwc3_calc_trbs_left(dep))
-                       goto out;
-
-               dwc3_prepare_one_trb(dep, req, length, false, 0, false);
-       }
-
-out:
-       return req->num_trbs - num_trbs;
+       return dwc3_prepare_last_sg(dep, req, req->request.length, 0);
 }
 
 /*