USB: fix ep_queue request buf dma map and unmap.

1. For 0 length buf, perform dma map with length 4
   to avoid kernel stack dump occurred.
2. Do dma unmap before req->complete to avoid dma
   addr reused after unmapped.

diff --git a/drivers/usb/dwc_otg_310/dwc_otg_pcd_linux.c b/drivers/usb/dwc_otg_310/dwc_otg_pcd_linux.c
index 6a733ddf0117512db0026fde0a13d7f1e5db9324..89261e056770355bb75103b14ce0f1b958c6e0e9 100755 (executable)
--- a/drivers/usb/dwc_otg_310/dwc_otg_pcd_linux.c
+++ b/drivers/usb/dwc_otg_310/dwc_otg_pcd_linux.c
@@ -363,14 +363,21 @@ static int ep_queue(struct usb_ep *usb_ep, struct usb_request *usb_req,
 #else
        if (GET_CORE_IF(pcd)->dma_enable) {
                /* if (usb_req->length != 0) {*/
+               /* In device DMA mode when gadget perform ep_queue request
+                * with buffer length 0, Kernel stack dump occurred. For 0
+                * length buffers perform dma_map_single() with length 4.*/
                if (usb_req->dma == DWC_DMA_ADDR_INVALID) {
                        dma_addr =
                            dma_map_single(gadget_wrapper->gadget.dev.parent,
-                                          usb_req->buf, usb_req->length,
+                                          usb_req->buf,
+                                          usb_req->length !=
+                                          0 ? usb_req->length : 4,
                                           ep->dwc_ep.
                                           is_in ? DMA_TO_DEVICE :
                                           DMA_FROM_DEVICE);
                        usb_req->dma = dma_addr;
+               } else {
+                       dma_addr = usb_req->dma;
                }
 
        }
@@ -920,10 +927,22 @@ static int _complete(dwc_otg_pcd_t *pcd, void *ep_handle,
                     void *req_handle, int32_t status, uint32_t actual)
 {
        struct usb_request *req = (struct usb_request *)req_handle;
-       struct device *dev = NULL;
-#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 27)
        struct dwc_otg_pcd_ep *ep = NULL;
-#endif
+
+       ep = ep_from_handle(pcd, ep_handle);
+
+       if (GET_CORE_IF(pcd)->dma_enable) {
+               /* if (req->length != 0) */
+               if (req->dma != DWC_DMA_ADDR_INVALID) {
+                       dma_unmap_single(gadget_wrapper->gadget.dev.parent,
+                                        req->dma,
+                                        req->length !=
+                                        0 ? req->length : 4,
+                                        ep->dwc_ep.is_in
+                                        ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+                       req->dma = DWC_DMA_ADDR_INVALID;
+               }
+       }
 
        if (req && req->complete) {
                switch (status) {
@@ -950,19 +969,7 @@ static int _complete(dwc_otg_pcd_t *pcd, void *ep_handle,
                DWC_SPINLOCK(pcd->lock);
        }
 
-       dev = &gadget_wrapper->pcd->otg_dev->os_dep.pdev->dev;
-       ep = ep_from_handle(pcd, ep_handle);
 
-       if (GET_CORE_IF(pcd)->dma_enable) {
-               /* if (req->length != 0) */
-               if (req->dma != DWC_DMA_ADDR_INVALID) {
-                       dma_unmap_single(gadget_wrapper->gadget.dev.parent,
-                                        req->dma, req->length,
-                                        ep->dwc_ep.is_in
-                                        ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
-                       req->dma = DWC_DMA_ADDR_INVALID;
-               }
-       }
        return 0;
 }