[src/trunk]: src/sys/dev/acpi In acpi_pci_ignore_boot_config(), use acpi_dsm(...

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

details:   https://anonhg.NetBSD.org/src/rev/689cf4c2b6de
branches:  trunk
changeset: 979844:689cf4c2b6de
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Thu Jan 14 14:37:17 2021 +0000

description:
In acpi_pci_ignore_boot_config(), use acpi_dsm() and add some comments
describing the (somewhat confusing) semantics of the _DSM method used
here.

diffstat:

 sys/dev/acpi/acpi_pci.c |  72 ++++++++++++++++++++++++++----------------------
 1 files changed, 39 insertions(+), 33 deletions(-)

diffs (100 lines):

diff -r 6c1e7c668232 -r 689cf4c2b6de sys/dev/acpi/acpi_pci.c
--- a/sys/dev/acpi/acpi_pci.c   Thu Jan 14 14:35:53 2021 +0000
+++ b/sys/dev/acpi/acpi_pci.c   Thu Jan 14 14:37:17 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: acpi_pci.c,v 1.29 2020/05/08 14:42:38 jmcneill Exp $ */
+/* $NetBSD: acpi_pci.c,v 1.30 2021/01/14 14:37:17 thorpej Exp $ */
 
 /*
  * Copyright (c) 2009, 2010 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_pci.c,v 1.29 2020/05/08 14:42:38 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_pci.c,v 1.30 2021/01/14 14:37:17 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -495,44 +495,50 @@
 ACPI_INTEGER
 acpi_pci_ignore_boot_config(ACPI_HANDLE handle)
 {
-       ACPI_OBJECT_LIST objs;
-       ACPI_OBJECT obj[4], *pobj;
-       ACPI_BUFFER buf;
+       ACPI_OBJECT *pobj = NULL;
        ACPI_INTEGER ret;
 
-       objs.Count = 4;
-       objs.Pointer = obj;
-       obj[0].Type = ACPI_TYPE_BUFFER;
-       obj[0].Buffer.Length = ACPI_UUID_LENGTH;
-       obj[0].Buffer.Pointer = acpi_pci_dsm_uuid;
-       obj[1].Type = ACPI_TYPE_INTEGER;
-       obj[1].Integer.Value = 1;
-       obj[2].Type = ACPI_TYPE_INTEGER;
-       obj[2].Integer.Value = 5;
-       obj[3].Type = ACPI_TYPE_PACKAGE;
-       obj[3].Package.Count = 0;
-       obj[3].Package.Elements = NULL;
+       /*
+        * This one is a little confusing, but the result of
+        * evaluating _DSM #5 is:
+        *
+        * 0: The operating system may not ignore the boot configuration
+        *    of PCI resources.
+        *
+        * 1: The operating system may ignore the boot configuration of
+        *    PCI resources, and reconfigure or rebalance these resources
+        *    in the hierarchy as required.
+        */
 
-       buf.Pointer = NULL;
-       buf.Length = ACPI_ALLOCATE_LOCAL_BUFFER;
+       if (ACPI_FAILURE(acpi_dsm(handle, acpi_pci_dsm_uuid,
+                                 1, 5, NULL, &pobj))) {
+               /*
+                * In the absence of _DSM #5, we may assume that the
+                * boot config can be ignored.
+                */
+               return 1;
+       }
 
-       if (ACPI_FAILURE(AcpiEvaluateObject(handle, "_DSM", &objs, &buf)) || buf.Pointer == NULL)
-               return 1;
-
+       /*
+        * ...and we default to "may ignore" in the event that the
+        * method returns nonsense.
+        */
        ret = 1;
 
-       pobj = buf.Pointer;
-       switch (pobj->Type) {
-       case ACPI_TYPE_INTEGER:
-               ret = pobj->Integer.Value;
-               break;
-       case ACPI_TYPE_PACKAGE:
-               if (pobj->Package.Count == 1 && pobj->Package.Elements[0].Type == ACPI_TYPE_INTEGER)
-                       ret = pobj->Package.Elements[0].Integer.Value;
-               break;
+       if (pobj != NULL) {
+               switch (pobj->Type) {
+               case ACPI_TYPE_INTEGER:
+                       ret = pobj->Integer.Value;
+                       break;
+
+               case ACPI_TYPE_PACKAGE:
+                       if (pobj->Package.Count == 1 &&
+                           pobj->Package.Elements[0].Type == ACPI_TYPE_INTEGER)
+                               ret = pobj->Package.Elements[0].Integer.Value;
+                       break;
+               }
+               ACPI_FREE(pobj);
        }
 
-       ACPI_FREE(buf.Pointer);
-
        return ret;
 }