usbcore: Add flag for whether a host controller uses DMA
This patch (as770b) introduces a new field to usb_bus: a flag
indicating whether or not the host controller uses DMA. This serves
to encapsulate the computation. It also means we will have only one
spot to update if the DMA API changes.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 2102c4d..0cc1420 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1152,7 +1152,7 @@
/* lower level hcd code should use *_dma exclusively,
* unless it uses pio or talks to another transport.
*/
- if (hcd->self.controller->dma_mask) {
+ if (hcd->self.uses_dma) {
if (usb_pipecontrol (urb->pipe)
&& !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
urb->setup_dma = dma_map_single (
@@ -1585,8 +1585,9 @@
at_root_hub = (urb->dev == hcd->self.root_hub);
urb_unlink (urb);
- /* lower level hcd code should use *_dma exclusively */
- if (hcd->self.controller->dma_mask && !at_root_hub) {
+ /* lower level hcd code should use *_dma exclusively if the
+ * host controller does DMA */
+ if (hcd->self.uses_dma && !at_root_hub) {
if (usb_pipecontrol (urb->pipe)
&& !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
dma_unmap_single (hcd->self.controller, urb->setup_dma,
@@ -1710,6 +1711,7 @@
hcd->self.release = &hcd_release;
hcd->self.controller = dev;
hcd->self.bus_name = bus_name;
+ hcd->self.uses_dma = (dev->dma_mask != NULL);
init_timer(&hcd->rh_timer);
hcd->rh_timer.function = rh_timer_func;
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 4709033..0966175 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -269,6 +269,7 @@
struct device *controller; /* host/master side hardware */
int busnum; /* Bus number (in order of reg) */
char *bus_name; /* stable id (PCI slot_name etc) */
+ u8 uses_dma; /* Does the host controller use DMA? */
u8 otg_port; /* 0, or number of OTG/HNP port */
unsigned is_b_host:1; /* true during some HNP roleswitches */
unsigned b_hnp_enable:1; /* OTG: did A-Host enable HNP? */