ACPI patch for systems with multiple pchb

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

Hi all,
if you have more than one PCI host bridge, please take special attention
to test this patch. Tests on other systems are nice as well, but I don't
expect problems with that.

It deals with broken ACPI tables where the bus number is missing or
0 for some bridges.

Joerg

Index: x86/mpacpi.c
===================================================================
RCS file: /data/repo/netbsd/src/sys/arch/x86/x86/mpacpi.c,v
retrieving revision 1.58
diff -u -p -r1.58 mpacpi.c
--- x86/mpacpi.c        26 Apr 2008 15:13:00 -0000      1.58
+++ x86/mpacpi.c        29 May 2008 17:05:59 -0000
@@ -42,6 +42,7 @@ __KERNEL_RCSID(0, "$NetBSD: mpacpi.c,v 1
 #include "opt_acpi.h"
 #include "opt_mpbios.h"
 #include "opt_multiprocessor.h"
+#include "pchb.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -463,6 +464,58 @@ static const char * const pciroot_hid[] 
 };
 
 /*
+ * mpacpi_get_bbn:
+ *
+ * Get or guess the Base Bus Number and sanity check it.
+ */
+static ACPI_STATUS
+mpacpi_get_bbn(struct acpi_softc *acpi, ACPI_HANDLE handle, int *bus)
+{
+       ACPI_STATUS rv;
+       ACPI_INTEGER val;
+       pcireg_t class, dvid;
+       pcitag_t tag;
+
+       rv = acpi_eval_integer(handle, METHOD_NAME__BBN, &val);
+       if (ACPI_SUCCESS(rv))
+               *bus = ACPI_LOWORD(val);
+       else
+               *bus = 0;
+
+       /* If the _BBN is not 0, assume it is valid. */
+       if (*bus != 0)
+               return AE_OK;
+
+       rv = acpi_eval_integer(handle, METHOD_NAME__ADR, &val);
+       if (ACPI_FAILURE(rv) || val == 0xffffffff)
+               return AE_ERROR;
+
+       /* If the _ADR is also 0, assume the _BBN is valid. */
+       if (val == 0)
+               return AE_OK;
+
+#if NPCHB > 0
+       tag = pci_make_tag(acpi->sc_pc, 0,
+           ACPI_HIWORD(val), ACPI_LOWORD(val));
+
+       dvid = pci_conf_read(acpi->sc_pc, tag, PCI_ID_REG);
+       if (PCI_VENDOR(dvid) == PCI_VENDOR_INVALID || PCI_VENDOR(dvid) == 0)
+               return AE_ERROR;
+
+       /* Check if this is a host bridge device. */
+       class = pci_conf_read(acpi->sc_pc, tag, PCI_CLASS_REG);
+       if (PCI_CLASS(class) != PCI_CLASS_BRIDGE ||
+           PCI_SUBCLASS(class) != PCI_SUBCLASS_BRIDGE_HOST)
+               return AE_ERROR;
+
+       *bus = pchb_get_bus_number(acpi->sc_pc, tag);
+       return *bus != -1 ? AE_OK : AE_ERROR;
+#else
+       return AE_ERROR;
+#endif
+}
+
+/*
  * mpacpi_derive_bus:
  *
  * Derive PCI bus number for the ACPI handle.
@@ -528,13 +581,11 @@ mpacpi_derive_bus(ACPI_HANDLE handle, st
                devinfo = buf.Pointer;
 
                if (acpi_match_hid(devinfo, pciroot_hid)) {
-                       rv = acpi_eval_integer(parent, METHOD_NAME__BBN, &val);
-                       AcpiOsFree(buf.Pointer);
-                       if (ACPI_SUCCESS(rv))
-                               bus = ACPI_LOWORD(val);
-                       else
-                               /* assume bus = 0 */
-                               bus = 0;
+                       rv = mpacpi_get_bbn(acpi, parent, &bus);
+                       if (ACPI_FAILURE(rv)) {
+                               AcpiOsFree(buf.Pointer);
+                               return -1;
+                       }
                        break;
                }
 
@@ -590,7 +641,6 @@ mpacpi_pcibus_cb(ACPI_HANDLE handle, UIN
 {
        ACPI_STATUS rv;
        ACPI_BUFFER buf;
-       ACPI_INTEGER val;
        ACPI_DEVICE_INFO *devinfo;
        struct mpacpi_pcibus *mpr;
        struct acpi_softc *acpi = p;
@@ -626,27 +676,10 @@ mpacpi_pcibus_cb(ACPI_HANDLE handle, UIN
        /* check whether this is PCI root bridge or not */
        if (acpi_match_hid(devinfo, pciroot_hid)) {
                /* this is PCI root bridge */
+               rv = mpacpi_get_bbn(acpi, handle, &mpr->mpr_bus);
+               if (ACPI_FAILURE(rv))
+                       panic("mpacpi: PCI root bridge with broken _BBN");
 
-               /* get the bus number */
-               rv = acpi_eval_integer(handle, METHOD_NAME__BBN, &val);
-               if (ACPI_SUCCESS(rv)) {
-                       mpr->mpr_bus = ACPI_LOWORD(val);
-               } else {
-                       /*
-                        * This often happens on systems which have only
-                        * one PCI root bus, assuming 0 will be ok.
-                        *
-                        * If there is a system that have multiple PCI
-                        * root but doesn't describe _BBN for every root,
-                        * the ASL is *broken*.
-                        */
-                       if (mpacpi_npciroots != 0)
-                               panic("mpacpi: ASL is broken");
-
-                       aprint_normal("mpacpi: could not get bus number, "
-                                   "assuming bus 0\n");
-                       mpr->mpr_bus = 0;
-               }
                if (mp_verbose)
                        printf("mpacpi: found root PCI bus %d at level %u\n",
                            mpr->mpr_bus, level);