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>

diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
index fd15ced899d8a3f9214590541a6a967327131690..5d352c900d2c9d677e3438223e76d55dde66a5c6 100644 (file)
--- 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);