cb->p = buffer;
        cb->offset_in_common = buffer - (u8 *) common_buffer;
-       cb->phys = common_buffer_phys + cb->offset_in_common;
+       if (common_buffer_phys)
+               cb->phys = common_buffer_phys + cb->offset_in_common;
 
        return cb;
 }
 
        /* alloc common buffer */
        dev->common_buffer_size = params->buffer_size * params->num_buffers;
-       dev->common_buffer = dma_alloc_coherent(NULL, dev->common_buffer_size,
-                                               &dev->common_buffer_phys,
-                                               GFP_KERNEL | GFP_DMA);
-       if (!dev->common_buffer) {
+       if (params->usb_device)
+               buffer = kzalloc(dev->common_buffer_size, GFP_KERNEL);
+       else
+               buffer = dma_alloc_coherent(params->device,
+                                           dev->common_buffer_size,
+                                           &dev->common_buffer_phys,
+                                           GFP_KERNEL | GFP_DMA);
+       if (!buffer) {
                smscore_unregister_device(dev);
                return -ENOMEM;
        }
+       dev->common_buffer = buffer;
 
        /* prepare dma buffers */
-       for (buffer = dev->common_buffer;
-            dev->num_buffers < params->num_buffers;
+       for (; dev->num_buffers < params->num_buffers;
             dev->num_buffers++, buffer += params->buffer_size) {
                struct smscore_buffer_t *cb;
 
        dev->board_id = SMS_BOARD_UNKNOWN;
        dev->context = params->context;
        dev->device = params->device;
+       dev->usb_device = params->usb_device;
        dev->setmode_handler = params->setmode_handler;
        dev->detectmode_handler = params->detectmode_handler;
        dev->sendrequest_handler = params->sendrequest_handler;
 
        pr_debug("freed %d buffers\n", num_buffers);
 
-       if (coredev->common_buffer)
-               dma_free_coherent(NULL, coredev->common_buffer_size,
-                       coredev->common_buffer, coredev->common_buffer_phys);
-
+       if (coredev->common_buffer) {
+               if (coredev->usb_device)
+                       kfree(coredev->common_buffer);
+               else
+                       dma_free_coherent(coredev->device,
+                                         coredev->common_buffer_size,
+                                         coredev->common_buffer,
+                                         coredev->common_buffer_phys);
+       }
        kfree(coredev->fw_buf);
 
        list_del(&coredev->entry);
 
                smsusb_onresponse,
                surb
        );
-       surb->urb.transfer_dma = surb->cb->phys;
-       surb->urb.transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+       surb->urb.transfer_flags |= URB_FREE_BUFFER;
 
        return usb_submit_urb(&surb->urb, GFP_ATOMIC);
 }
                dev->in_ep, dev->out_ep);
 
        params.device = &dev->udev->dev;
+       params.usb_device = dev->udev;
        params.buffer_size = dev->buffer_size;
        params.num_buffers = MAX_BUFFERS;
        params.sendrequest_handler = smsusb_sendrequest;