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-rw-r--r--Documentation/usb/dma.txt18
-rw-r--r--drivers/staging/usbip/usbip_common.c2
-rw-r--r--drivers/usb/core/hcd.c3
-rw-r--r--include/linux/usb.h28
4 files changed, 19 insertions, 32 deletions
diff --git a/Documentation/usb/dma.txt b/Documentation/usb/dma.txt
index a37e59cf2786..84ef865237db 100644
--- a/Documentation/usb/dma.txt
+++ b/Documentation/usb/dma.txt
@@ -16,11 +16,11 @@ OR: they can now be DMA-aware.
manage dma mappings for existing dma-ready buffers (see below).
- URBs have an additional "transfer_dma" field, as well as a transfer_flags
- bit saying if it's valid. (Control requests also have "setup_dma" and a
- corresponding transfer_flags bit.)
+ bit saying if it's valid. (Control requests also have "setup_dma", but
+ drivers must not use it.)
-- "usbcore" will map those DMA addresses, if a DMA-aware driver didn't do
- it first and set URB_NO_TRANSFER_DMA_MAP or URB_NO_SETUP_DMA_MAP. HCDs
+- "usbcore" will map this DMA address, if a DMA-aware driver didn't do
+ it first and set URB_NO_TRANSFER_DMA_MAP. HCDs
don't manage dma mappings for URBs.
- There's a new "generic DMA API", parts of which are usable by USB device
@@ -53,12 +53,6 @@ and effects like cache-trashing can impose subtle penalties.
to use this type of memory ("dma-coherent"), and memory returned from
kmalloc() will work just fine.
- For control transfers you can use the buffer primitives or not for each
- of the transfer buffer and setup buffer independently. Set the flag bits
- URB_NO_TRANSFER_DMA_MAP and URB_NO_SETUP_DMA_MAP to indicate which
- buffers you have prepared. For non-control transfers URB_NO_SETUP_DMA_MAP
- is ignored.
-
The memory buffer returned is "dma-coherent"; sometimes you might need to
force a consistent memory access ordering by using memory barriers. It's
not using a streaming DMA mapping, so it's good for small transfers on
@@ -130,8 +124,8 @@ of Documentation/PCI/PCI-DMA-mapping.txt, titled "What memory is DMA-able?")
void usb_buffer_unmap (struct urb *urb);
The calls manage urb->transfer_dma for you, and set URB_NO_TRANSFER_DMA_MAP
- so that usbcore won't map or unmap the buffer. The same goes for
- urb->setup_dma and URB_NO_SETUP_DMA_MAP for control requests.
+ so that usbcore won't map or unmap the buffer. They cannot be used for
+ setup_packet buffers in control requests.
Note that several of those interfaces are currently commented out, since
they don't have current users. See the source code. Other than the dmasync
diff --git a/drivers/staging/usbip/usbip_common.c b/drivers/staging/usbip/usbip_common.c
index e3fa4216c1cd..52408164036f 100644
--- a/drivers/staging/usbip/usbip_common.c
+++ b/drivers/staging/usbip/usbip_common.c
@@ -562,7 +562,7 @@ EXPORT_SYMBOL_GPL(sockfd_to_socket);
/* there may be more cases to tweak the flags. */
static unsigned int tweak_transfer_flags(unsigned int flags)
{
- flags &= ~(URB_NO_TRANSFER_DMA_MAP|URB_NO_SETUP_DMA_MAP);
+ flags &= ~URB_NO_TRANSFER_DMA_MAP;
return flags;
}
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 3aaee2811f01..0abc5c537f39 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1316,8 +1316,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
* or uses the provided scatter gather list for bulk.
*/
- if (usb_endpoint_xfer_control(&urb->ep->desc)
- && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) {
+ if (usb_endpoint_xfer_control(&urb->ep->desc)) {
if (hcd->self.uses_dma) {
urb->setup_dma = dma_map_single(
hcd->self.controller,
diff --git a/include/linux/usb.h b/include/linux/usb.h
index a748815ee629..1eb4762d9ea8 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -953,7 +953,6 @@ extern int usb_disabled(void);
#define URB_ISO_ASAP 0x0002 /* iso-only, urb->start_frame
* ignored */
#define URB_NO_TRANSFER_DMA_MAP 0x0004 /* urb->transfer_dma valid on submit */
-#define URB_NO_SETUP_DMA_MAP 0x0008 /* urb->setup_dma valid on submit */
#define URB_NO_FSBR 0x0020 /* UHCI-specific */
#define URB_ZERO_PACKET 0x0040 /* Finish bulk OUT with short packet */
#define URB_NO_INTERRUPT 0x0080 /* HINT: no non-error interrupt
@@ -1049,12 +1048,8 @@ typedef void (*usb_complete_t)(struct urb *);
* @setup_packet: Only used for control transfers, this points to eight bytes
* of setup data. Control transfers always start by sending this data
* to the device. Then transfer_buffer is read or written, if needed.
- * @setup_dma: For control transfers with URB_NO_SETUP_DMA_MAP set, the
- * device driver has provided this DMA address for the setup packet.
- * The host controller driver should use this in preference to
- * setup_packet, but the HCD may chose to ignore the address if it must
- * copy the setup packet into internal structures. Therefore, setup_packet
- * must always point to a valid buffer.
+ * @setup_dma: DMA pointer for the setup packet. The caller must not use
+ * this field; setup_packet must point to a valid buffer.
* @start_frame: Returns the initial frame for isochronous transfers.
* @number_of_packets: Lists the number of ISO transfer buffers.
* @interval: Specifies the polling interval for interrupt or isochronous
@@ -1086,13 +1081,14 @@ typedef void (*usb_complete_t)(struct urb *);
* bounce buffer or talking to an IOMMU),
* although they're cheap on commodity x86 and ppc hardware.
*
- * Alternatively, drivers may pass the URB_NO_xxx_DMA_MAP transfer flags,
- * which tell the host controller driver that no such mapping is needed since
+ * Alternatively, drivers may pass the URB_NO_TRANSFER_DMA_MAP transfer flag,
+ * which tells the host controller driver that no such mapping is needed for
+ * the transfer_buffer since
* the device driver is DMA-aware. For example, a device driver might
* allocate a DMA buffer with usb_alloc_coherent() or call usb_buffer_map().
- * When these transfer flags are provided, host controller drivers will
- * attempt to use the dma addresses found in the transfer_dma and/or
- * setup_dma fields rather than determining a dma address themselves.
+ * When this transfer flag is provided, host controller drivers will
+ * attempt to use the dma address found in the transfer_dma
+ * field rather than determining a dma address themselves.
*
* Note that transfer_buffer must still be set if the controller
* does not support DMA (as indicated by bus.uses_dma) and when talking
@@ -1115,11 +1111,9 @@ typedef void (*usb_complete_t)(struct urb *);
* should always terminate with a short packet, even if it means adding an
* extra zero length packet.
*
- * Control URBs must provide a setup_packet. The setup_packet and
- * transfer_buffer may each be mapped for DMA or not, independently of
- * the other. The transfer_flags bits URB_NO_TRANSFER_DMA_MAP and
- * URB_NO_SETUP_DMA_MAP indicate which buffers have already been mapped.
- * URB_NO_SETUP_DMA_MAP is ignored for non-control URBs.
+ * Control URBs must provide a valid pointer in the setup_packet field.
+ * Unlike the transfer_buffer, the setup_packet may not be mapped for DMA
+ * beforehand.
*
* Interrupt URBs must provide an interval, saying how often (in milliseconds
* or, for highspeed devices, 125 microsecond units)