USB: at91_udc can prefetch data

The at91sam9 chip are ARMv5 so they support preload instructions.
Use preloading to load the FIFO a bit faster.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
index fd15ced899d8..5d352c900d2c 100644
--- a/drivers/usb/gadget/at91_udc.c
+++ b/drivers/usb/gadget/at91_udc.c
@@ -389,6 +389,7 @@ static int write_fifo(struct at91_ep *ep, struct at91_request *req)
         u32             csr = __raw_readl(creg);
         u8 __iomem      *dreg = ep->creg + (AT91_UDP_FDR(0) - AT91_UDP_CSR(0));
         unsigned        total, count, is_last;
+        u8              *buf;
 
         /*
          * TODO: allow for writing two packets to the fifo ... that'll
@@ -413,6 +414,8 @@ static int write_fifo(struct at91_ep *ep, struct at91_request *req)
                         return 0;
         }
 
+        buf = req->req.buf + req->req.actual;
+        prefetch(buf);
         total = req->req.length - req->req.actual;
         if (ep->ep.maxpacket < total) {
                 count = ep->ep.maxpacket;
@@ -435,7 +438,7 @@ static int write_fifo(struct at91_ep *ep, struct at91_request *req)
          * recover when the actual bytecount matters (e.g. for USB Test
          * and Measurement Class devices).
          */
-        __raw_writesb(dreg, req->req.buf + req->req.actual, count);
+        __raw_writesb(dreg, buf, count);
         csr &= ~SET_FX;
         csr |= CLR_FX | AT91_UDP_TXPKTRDY;
         __raw_writel(csr, creg);