x86: Add DSDT table for supporting ACPI on QEMU

The DSDT table contains a bytecode that is executed by a driver in the kernel.

Signed-off-by: Saket Sinha <saket.sinha89@gmail.com>
Tested with QEMU '-M q35'
Tested-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/x86/cpu/qemu/acpi/dbug.asl b/arch/x86/cpu/qemu/acpi/dbug.asl
new file mode 100644
index 0000000000..38a65266aa
--- /dev/null
+++ b/arch/x86/cpu/qemu/acpi/dbug.asl
@@ -0,0 +1,25 @@
+/* Debugging */
+
+Scope(\) {
+    /* Debug Output */
+    OperationRegion(DBG, SystemIO, 0x0402, 0x01)
+    Field(DBG, ByteAcc, NoLock, Preserve) {
+        DBGB,   8,
+    }
+	/*
+	 * Debug method - use this method to send output to the QEMU
+	 * BIOS debug port.  This method handles strings, integers,
+	 * and buffers.  For example: DBUG("abc") DBUG(0x123)
+	 */
+    Method(DBUG, 1) {
+        ToHexString(Arg0, Local0)
+        ToBuffer(Local0, Local0)
+        Subtract(SizeOf(Local0), 1, Local1)
+        Store(Zero, Local2)
+        While (LLess(Local2, Local1)) {
+            Store(DerefOf(Index(Local0, Local2)), DBGB)
+            Increment(Local2)
+        }
+        Store(0x0a, dbgb)
+    }
+}