usb: dwc3: ep0: handle non maxpacket aligned transfers > 512

Use chained TRB mechanism to handle non maxpacket aligned transfers
greater than bounce buffer size. With this the first TRB will be programmed
to receive 'ALIGN(ur->length - maxp, maxp)' data and the second TRB
will be programmed to receive the remaining data using bounce buffer.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index ebf2621fae5d0b4627c507b839b8edc1bb616753..5320e939e0902647edb21a5e55d7e537c1b03b33 100644 (file)
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -834,13 +834,26 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
        maxp = ep0->endpoint.maxpacket;
 
        if (dwc->ep0_bounced) {
+               /*
+                * Handle the first TRB before handling the bounce buffer if
+                * the request length is greater than the bounce buffer size
+                */
+               if (ur->length > DWC3_EP0_BOUNCE_SIZE) {
+                       transfer_size = ALIGN(ur->length - maxp, maxp);
+                       transferred = transfer_size - length;
+                       buf = (u8 *)buf + transferred;
+                       ur->actual += transferred;
+                       remaining_ur_length -= transferred;
+
+                       trb++;
+                       length = trb->size & DWC3_TRB_SIZE_MASK;
+
+                       ep0->free_slot = 0;
+               }
+
                transfer_size = roundup((ur->length - transfer_size),
                                        maxp);
 
-               /* Maximum of DWC3_EP0_BOUNCE_SIZE can only be received */
-               if (transfer_size > DWC3_EP0_BOUNCE_SIZE)
-                       transfer_size = DWC3_EP0_BOUNCE_SIZE;
-
                transferred = min_t(u32, remaining_ur_length,
                                    transfer_size - length);
                memcpy(buf, dwc->ep0_bounce, transferred);
@@ -963,21 +976,22 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
                }
 
                maxpacket = dep->endpoint.maxpacket;
-               transfer_size = roundup((req->request.length - transfer_size),
-                                       maxpacket);
 
-               if (transfer_size > DWC3_EP0_BOUNCE_SIZE) {
-                       dev_WARN(dwc->dev, "bounce buf can't handle req len\n");
-                       transfer_size = DWC3_EP0_BOUNCE_SIZE;
+               if (req->request.length > DWC3_EP0_BOUNCE_SIZE) {
+                       transfer_size = ALIGN(req->request.length - maxpacket,
+                                             maxpacket);
+                       ret = dwc3_ep0_start_trans(dwc, dep->number,
+                                                  req->request.dma,
+                                                  transfer_size,
+                                                  DWC3_TRBCTL_CONTROL_DATA,
+                                                  true);
                }
 
+               transfer_size = roundup((req->request.length - transfer_size),
+                                       maxpacket);
+
                dwc->ep0_bounced = true;
 
-               /*
-                * REVISIT in case request length is bigger than
-                * DWC3_EP0_BOUNCE_SIZE we will need two chained
-                * TRBs to handle the transfer.
-                */
                ret = dwc3_ep0_start_trans(dwc, dep->number,
                                dwc->ep0_bounce_addr, transfer_size,
                                DWC3_TRBCTL_CONTROL_DATA, false);