PERFORCE change 152624 for review

[Hans Petter Selasky]

http://perforce.freebsd.org/chv.cgi?CH=152624

Change 152624 by hselasky at hselasky_laptop001 on 2008/11/07 17:02:49

	
	Fix some problems related to busdma:
	Need to unload DMA maps before re-use!
	Fix a corner case when loading zero bytes.

Affected files ...

.. //depot/projects/usb/src/sys/dev/usb2/core/usb2_busdma.c#10 edit

Differences ...

==== //depot/projects/usb/src/sys/dev/usb2/core/usb2_busdma.c#10 (text+ko) ====

@@ -597,6 +597,12 @@
 			uptag = pc->tag_parent;
 
 			/*
+			 * We have to unload the previous loaded DMA
+			 * pages before trying to load a new one!
+			 */
+			bus_dmamap_unload(pc->tag, pc->map);
+
+			/*
 			 * Try to load memory into DMA.
 			 */
 			err = bus_dmamap_load(
@@ -612,6 +618,12 @@
 		} else {
 
 			/*
+			 * We have to unload the previous loaded DMA
+			 * pages before trying to load a new one!
+			 */
+			bus_dmamap_unload(pc->tag, pc->map);
+
+			/*
 			 * Try to load memory into DMA. The callback
 			 * will be called in all cases:
 			 */
@@ -639,6 +651,10 @@
 void
 usb2_pc_cpu_invalidate(struct usb2_page_cache *pc)
 {
+	if (pc->page_offset_end == pc->page_offset_buf) {
+		/* nothing has been loaded into this page cache! */
+		return;
+	}
 	bus_dmamap_sync(pc->tag, pc->map,
 	    BUS_DMASYNC_POSTWRITE | BUS_DMASYNC_POSTREAD);
 	return;
@@ -650,6 +666,10 @@
 void
 usb2_pc_cpu_flush(struct usb2_page_cache *pc)
 {
+	if (pc->page_offset_end == pc->page_offset_buf) {
+		/* nothing has been loaded into this page cache! */
+		return;
+	}
 	bus_dmamap_sync(pc->tag, pc->map,
 	    BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
 	return;
@@ -953,6 +973,12 @@
 
 	if (size > 0) {
 
+		/*
+		 * We have to unload the previous loaded DMA
+		 * pages before trying to load a new one!
+		 */
+		bus_dmamap_unload(pc->tag, pc->map);
+
 		/* try to load memory into DMA using using no wait option */
 		if (bus_dmamap_load(pc->tag, pc->map, pc->buffer,
 		    size, NULL, BUS_DMA_NOWAIT)) {
@@ -990,6 +1016,10 @@
 
 	len = pc->page_offset_end - pc->page_offset_buf;
 
+	if (len == 0) {
+		/* nothing has been loaded into this page cache */
+		return;
+	}
 	bus_dmamap_sync(pc->tag, pc->map, 0, len,
 	    BUS_DMASYNC_POSTWRITE | BUS_DMASYNC_POSTREAD);
 	return;
@@ -1005,6 +1035,10 @@
 
 	len = pc->page_offset_end - pc->page_offset_buf;
 
+	if (len == 0) {
+		/* nothing has been loaded into this page cache */
+		return;
+	}
 	bus_dmamap_sync(pc->tag, pc->map, 0, len,
 	    BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
 	return;