1 files changed, 27 insertions, 4 deletions

diff --git a/sys/dev/usb/usb_transfer.c b/sys/dev/usb/usb_transfer.c
index 0f02fc8..5650790 100644
--- a/sys/dev/usb/usb_transfer.c
+++ b/sys/dev/usb/usb_transfer.c
@@ -237,7 +237,11 @@ usbd_transfer_setup_sub_malloc(struct usb_setup_params *parm,
 		n_obj = 1;
 	} else {
 		/* compute number of objects per page */
+#ifdef USB_DMA_SINGLE_ALLOC
+		n_obj = 1;
+#else
 		n_obj = (USB_PAGE_SIZE / size);
+#endif
 		/*
 		 * Compute number of DMA chunks, rounded up
 		 * to nearest one:
@@ -273,15 +277,33 @@ usbd_transfer_setup_sub_malloc(struct usb_setup_params *parm,
 		    &parm->curr_xfer->xroot->dma_parent_tag;
 	}
 
-	if (ppc) {
-		*ppc = parm->xfer_page_cache_ptr;
+	if (ppc != NULL) {
+		if (n_obj != 1)
+			*ppc = parm->xfer_page_cache_ptr;
+		else
+			*ppc = parm->dma_page_cache_ptr;
 	}
 	r = count;			/* set remainder count */
 	z = n_obj * size;		/* set allocation size */
 	pc = parm->xfer_page_cache_ptr;
 	pg = parm->dma_page_ptr;
 
-	for (x = 0; x != n_dma_pc; x++) {
+	if (n_obj == 1) {
+	    /*
+	     * Avoid mapping memory twice if only a single object
+	     * should be allocated per page cache:
+	     */
+	    for (x = 0; x != n_dma_pc; x++) {
+		if (usb_pc_alloc_mem(parm->dma_page_cache_ptr,
+		    pg, z, align)) {
+			return (1);	/* failure */
+		}
+		/* Make room for one DMA page cache and "n_dma_pg" pages */
+		parm->dma_page_cache_ptr++;
+		pg += n_dma_pg;
+	    }
+	} else {
+	    for (x = 0; x != n_dma_pc; x++) {
 
 		if (r < n_obj) {
 			/* compute last remainder */
@@ -294,7 +316,7 @@ usbd_transfer_setup_sub_malloc(struct usb_setup_params *parm,
 		}
 		/* Set beginning of current buffer */
 		buf = parm->dma_page_cache_ptr->buffer;
-		/* Make room for one DMA page cache and one page */
+		/* Make room for one DMA page cache and "n_dma_pg" pages */
 		parm->dma_page_cache_ptr++;
 		pg += n_dma_pg;
 
@@ -314,6 +336,7 @@ usbd_transfer_setup_sub_malloc(struct usb_setup_params *parm,
 			}
 			mtx_unlock(pc->tag_parent->mtx);
 		}
+	    }
 	}
 
 	parm->xfer_page_cache_ptr = pc;