[src/trunk]: src/sys/dev/usb Improve the usb_syncmem calls in ohci_reset_std_...

[skrll <skrll%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/dc2b13c3b191
branches:  trunk
changeset: 821277:dc2b13c3b191
user:      skrll <skrll%NetBSD.org@localhost>
date:      Tue Jan 31 07:34:02 2017 +0000

description:
Improve the usb_syncmem calls in ohci_reset_std_chain.

Might help kern/51928: Errors reading a USB pen drive on macppc 7.99.59

diffstat:

 sys/dev/usb/ohci.c |  18 +++++++++++-------
 1 files changed, 11 insertions(+), 7 deletions(-)

diffs (61 lines):

diff -r 9e9de45eb662 -r dc2b13c3b191 sys/dev/usb/ohci.c
--- a/sys/dev/usb/ohci.c        Tue Jan 31 07:00:59 2017 +0000
+++ b/sys/dev/usb/ohci.c        Tue Jan 31 07:34:02 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ohci.c,v 1.271 2017/01/30 21:42:08 skrll Exp $ */
+/*     $NetBSD: ohci.c,v 1.272 2017/01/31 07:34:02 skrll Exp $ */
 
 /*
  * Copyright (c) 1998, 2004, 2005, 2012 The NetBSD Foundation, Inc.
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ohci.c,v 1.271 2017/01/30 21:42:08 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ohci.c,v 1.272 2017/01/31 07:34:02 skrll Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -655,15 +655,15 @@
                cur->xfer = xfer;
                ohci_hash_add_td(sc, cur);
 
-               usb_syncmem(&cur->dma, cur->offs, sizeof(cur->td),
-                   BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
-
                curoffs += curlen;
                len -= curlen;
 
                if (len != 0) {
                        KASSERT(next != NULL);
                        DPRINTFN(10, "extend chain", 0, 0, 0, 0);
+                       usb_syncmem(&cur->dma, cur->offs, sizeof(cur->td),
+                           BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
+
                        cur = next;
                }
        }
@@ -673,6 +673,10 @@
        if (!rd &&
            (flags & USBD_FORCE_SHORT_XFER) &&
            alen % mps == 0) {
+               /* We're adding a ZLP so sync the previous TD */
+               usb_syncmem(&cur->dma, cur->offs, sizeof(cur->td),
+                   BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
+
                /* Force a 0 length transfer at the end. */
 
                KASSERT(next != NULL);
@@ -688,10 +692,10 @@
                cur->xfer = xfer;
                ohci_hash_add_td(sc, cur);
 
-               usb_syncmem(&cur->dma, cur->offs, sizeof(cur->td),
-                   BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD);
                DPRINTFN(2, "add 0 xfer", 0, 0, 0, 0);
        }
+
+       /* Last TD gets usb_syncmem'ed by caller */
        *ep = cur;
 }