[src/trunk]: src/sys/dev/pci Use the 64-bit PCI DMA tag if it's available, bu...

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

details:   https://anonhg.NetBSD.org/src/rev/7c12b237e765
branches:  trunk
changeset: 969748:7c12b237e765
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat Feb 29 20:39:09 2020 +0000

description:
Use the 64-bit PCI DMA tag if it's available, but range-limit to
40-bit because that's what the hardware can do.

diffstat:

 sys/dev/pci/if_stge.c |  23 ++++++++++++++++++++---
 1 files changed, 20 insertions(+), 3 deletions(-)

diffs (44 lines):

diff -r 344ce220b9de -r 7c12b237e765 sys/dev/pci/if_stge.c
--- a/sys/dev/pci/if_stge.c     Sat Feb 29 20:17:11 2020 +0000
+++ b/sys/dev/pci/if_stge.c     Sat Feb 29 20:39:09 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_stge.c,v 1.79 2020/02/07 00:04:28 thorpej Exp $     */
+/*     $NetBSD: if_stge.c,v 1.80 2020/02/29 20:39:09 thorpej Exp $     */
 
 /*-
  * Copyright (c) 2001 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_stge.c,v 1.79 2020/02/07 00:04:28 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_stge.c,v 1.80 2020/02/29 20:39:09 thorpej Exp $");
 
 
 #include <sys/param.h>
@@ -442,7 +442,24 @@
                return;
        }
 
-       sc->sc_dmat = pa->pa_dmat;
+       /*
+        * We have a 40-bit limit on our DMA addresses.  This isn't an
+        * issue if we're only using a 32-bit DMA tag, but we have to
+        * account for it if the 64-bit DMA tag is available.
+        */
+       if (pci_dma64_available(pa)) {
+               if (bus_dmatag_subregion(pa->pa_dmat64,
+                                        0,
+                                        FRAG_ADDR_MASK + 1ULL,
+                                        &sc->sc_dmat,
+                                        BUS_DMA_WAITOK) != 0) {
+                       aprint_error_dev(self,
+                           "unable to create 40-bit DMA tag\n");
+                       return;
+               }
+       } else {
+               sc->sc_dmat = pa->pa_dmat;
+       }
 
        /* Enable bus mastering. */
        pci_conf_write(pc, pa->pa_tag, PCI_COMMAND_STATUS_REG,