[src/trunk]: src/sys/arch/x86/pci If mode 1 enable check fails, give mode 1 a...

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

details:   https://anonhg.NetBSD.org/src/rev/f9538bc6ae56
branches:  trunk
changeset: 362746:f9538bc6ae56
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Sat Jun 23 16:05:05 2018 +0000

description:
If mode 1 enable check fails, give mode 1 a second chance by trying to
use it to locate a PCI Host Bridge or device from vendor that produced
a chipset lacking a Host Bridge class device.

Should allow us to remove most all the mode 1 quirks added in the last
two decades.

diffstat:

 sys/arch/x86/pci/pci_machdep.c |  35 +++++++++++++++++++++++++++++++++--
 1 files changed, 33 insertions(+), 2 deletions(-)

diffs (63 lines):

diff -r d7d875f13ba4 -r f9538bc6ae56 sys/arch/x86/pci/pci_machdep.c
--- a/sys/arch/x86/pci/pci_machdep.c    Sat Jun 23 15:53:14 2018 +0000
+++ b/sys/arch/x86/pci/pci_machdep.c    Sat Jun 23 16:05:05 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pci_machdep.c,v 1.80 2018/04/11 10:34:19 nonaka Exp $  */
+/*     $NetBSD: pci_machdep.c,v 1.81 2018/06/23 16:05:05 jakllsch Exp $        */
 
 /*-
  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
@@ -73,7 +73,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pci_machdep.c,v 1.80 2018/04/11 10:34:19 nonaka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pci_machdep.c,v 1.81 2018/06/23 16:05:05 jakllsch Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -433,6 +433,30 @@
        }
 }
 
+static int
+pci_mode_check(void)
+{
+       pcireg_t x;
+       pcitag_t t;
+       int device;
+       const int maxdev = pci_bus_maxdevs(NULL, 0);
+
+       for (device = 0; device < maxdev; device++) {
+               t = pci_make_tag(NULL, 0, device, 0);
+               x = pci_conf_read(NULL, t, PCI_CLASS_REG);
+               if (PCI_CLASS(x) == PCI_CLASS_BRIDGE &&
+                   PCI_SUBCLASS(x) == PCI_SUBCLASS_BRIDGE_HOST)
+                       return 0;
+               x = pci_conf_read(NULL, t, PCI_ID_REG);
+               switch (PCI_VENDOR(x)) {
+               case PCI_VENDOR_COMPAQ:
+               case PCI_VENDOR_INTEL:
+               case PCI_VENDOR_VIATECH:
+                       return 0;
+               }
+       }
+       return -1;
+}
 #ifdef __HAVE_PCI_MSI_MSIX
 static int
 pci_has_msi_quirk(pcireg_t id, int type)
@@ -769,6 +793,13 @@
 #ifdef DEBUG
                printf("%s: mode 1 enable failed (%x)\n", __func__, val);
 #endif
+               /* Try out mode 1 to see if we can find a host bridge. */
+               if (pci_mode_check() == 0) {
+#ifdef DEBUG
+                       printf("%s: mode 1 functional, using\n", __func__);
+#endif
+                       return (pci_mode);
+               }
                goto not1;
        }
        outl(PCI_MODE1_ADDRESS_REG, 0);