acpi: Add global lock enter and leave routines.

I think this diff is the way to go if we want to have proper locking in
our acpi drivers. This doesn't hook onto anything from the kernel and
is just building framework towards locking.

Okay mlarkin@, kettenis@.

1 files changed, 25 insertions, 1 deletions

diff --git a/sys/dev/acpi/dsdt.c b/sys/dev/acpi/dsdt.c
index fb70fb0e3fa..8bfc1bb255e 100644
--- a/sys/dev/acpi/dsdt.c
+++ b/sys/dev/acpi/dsdt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: dsdt.c,v 1.197 2012/07/16 15:27:11 deraadt Exp $ */
+/* $OpenBSD: dsdt.c,v 1.198 2013/01/18 04:07:06 pirofti Exp $ */
 /*
  * Copyright (c) 2005 Jordan Hargrave <jordan@openbsd.org>
  *
@@ -731,6 +731,30 @@ long acpi_release_global_lock(void*);
 static long global_lock_count = 0;
 #define acpi_acquire_global_lock(x) 1
 #define acpi_release_global_lock(x) 0
+
+void
+acpi_glk_enter(void)
+{
+	acpi_acquire_glk(&acpi_softc->sc_facs->global_lock);
+}
+
+void
+acpi_glk_leave(void)
+{
+	int x;
+
+	if (acpi_release_glk(&acpi_softc->sc_facs->global_lock)) {
+		/*
+		 * If pending, notify the BIOS that the lock was released
+		 * by the OSPM. No locking is needed because nobody outside
+		 * the ACPI thread is touching this register.
+		 */
+		x = acpi_read_pmreg(acpi_softc, ACPIREG_PM1_CNT, 0);
+		x |= ACPI_PM1_GBL_RLS;
+		acpi_write_pmreg(acpi_softc, ACPIREG_PM1_CNT, 0, x);
+	}
+}
+
 void
 aml_lockfield(struct aml_scope *scope, struct aml_value *field)
 {