+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_check_unlink_urb);
+
+/**
+ * usb_hcd_unlink_urb_from_ep - remove an URB from its endpoint queue
+ * @hcd: host controller to which @urb was submitted
+ * @urb: URB being unlinked
+ *
+ * Host controller drivers should call this routine before calling
+ * usb_hcd_giveback_urb(). The HCD's private spinlock must be held and
+ * interrupts must be disabled. The actions carried out here are required
+ * for URB completion.
+ */
+void usb_hcd_unlink_urb_from_ep(struct usb_hcd *hcd, struct urb *urb)
+{
+ /* clear all state linking urb to this dev (and hcd) */
+ spin_lock(&hcd_urb_list_lock);
+ list_del_init(&urb->urb_list);
+ spin_unlock(&hcd_urb_list_lock);
+}
+EXPORT_SYMBOL_GPL(usb_hcd_unlink_urb_from_ep);
+
+/*
+ * Some usb host controllers can only perform dma using a small SRAM area.
+ * The usb core itself is however optimized for host controllers that can dma
+ * using regular system memory - like pci devices doing bus mastering.
+ *
+ * To support host controllers with limited dma capabilites we provide dma
+ * bounce buffers. This feature can be enabled using the HCD_LOCAL_MEM flag.
+ * For this to work properly the host controller code must first use the
+ * function dma_declare_coherent_memory() to point out which memory area
+ * that should be used for dma allocations.
+ *
+ * The HCD_LOCAL_MEM flag then tells the usb code to allocate all data for
+ * dma using dma_alloc_coherent() which in turn allocates from the memory
+ * area pointed out with dma_declare_coherent_memory().
+ *
+ * So, to summarize...
+ *
+ * - We need "local" memory, canonical example being
+ * a small SRAM on a discrete controller being the
+ * only memory that the controller can read ...
+ * (a) "normal" kernel memory is no good, and
+ * (b) there's not enough to share
+ *
+ * - The only *portable* hook for such stuff in the
+ * DMA framework is dma_declare_coherent_memory()
+ *
+ * - So we use that, even though the primary requirement
+ * is that the memory be "local" (hence addressible
+ * by that device), not "coherent".
+ *
+ */
+
+static int hcd_alloc_coherent(struct usb_bus *bus,
+ gfp_t mem_flags, dma_addr_t *dma_handle,
+ void **vaddr_handle, size_t size,
+ enum dma_data_direction dir)
+{
+ unsigned char *vaddr;
+
+ vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
+ mem_flags, dma_handle);
+ if (!vaddr)
+ return -ENOMEM;
+
+ /*
+ * Store the virtual address of the buffer at the end
+ * of the allocated dma buffer. The size of the buffer
+ * may be uneven so use unaligned functions instead
+ * of just rounding up. It makes sense to optimize for
+ * memory footprint over access speed since the amount
+ * of memory available for dma may be limited.
+ */
+ put_unaligned((unsigned long)*vaddr_handle,
+ (unsigned long *)(vaddr + size));
+
+ if (dir == DMA_TO_DEVICE)
+ memcpy(vaddr, *vaddr_handle, size);
+
+ *vaddr_handle = vaddr;
+ return 0;
+}
+
+static void hcd_free_coherent(struct usb_bus *bus, dma_addr_t *dma_handle,
+ void **vaddr_handle, size_t size,
+ enum dma_data_direction dir)
+{
+ unsigned char *vaddr = *vaddr_handle;
+
+ vaddr = (void *)get_unaligned((unsigned long *)(vaddr + size));
+
+ if (dir == DMA_FROM_DEVICE)
+ memcpy(vaddr, *vaddr_handle, size);
+
+ hcd_buffer_free(bus, size + sizeof(vaddr), *vaddr_handle, *dma_handle);
+
+ *vaddr_handle = vaddr;
+ *dma_handle = 0;
+}
+
+static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
+ gfp_t mem_flags)
+{
+ enum dma_data_direction dir;
+ int ret = 0;
+
+ /* Map the URB's buffers for DMA access.
+ * Lower level HCD code should use *_dma exclusively,