[SeaBIOS] [RFC PATCH 2/9] Implement acpi-dsdt functions for memory hotplug.

[Vasilis Liaskovitis]

Extend the DSDT to include methods for handling memory hot-add and hot-remove
notifications and memory device status requests. These functions are called
from the memory device SSDT methods.

Eject has only been tested with level gpe event, but will be changed to edge gpe
event soon, according to recent master patch for other ACPI hotplug events.

Signed-off-by: Vasilis Liaskovitis 
---
 src/acpi-dsdt.dsl |   68 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/src/acpi-dsdt.dsl b/src/acpi-dsdt.dsl
index 4bdc268..184daf0 100644
--- a/src/acpi-dsdt.dsl
+++ b/src/acpi-dsdt.dsl
@@ -709,9 +709,72 @@ DefinitionBlock (
             }
             Return(One)
         }
-    }

+        /* Objects filled in by run-time generated SSDT */
+        External(MTFY, MethodObj)
+        External(MEON, PkgObj)
+
+        Method (CMST, 1, NotSerialized) {
+            // _STA method - return ON status of memdevice
+            // Local0 = MEON flag for this cpu
+            Store(DerefOf(Index(MEON, Arg0)), Local0)
+            If (Local0) { Return(0xF) } Else { Return(0x0) }
+        }
+        /* Memory eject notify method */
+        OperationRegion(MEMJ, SystemIO, 0xaf40, 32)
+        Field (MEMJ, ByteAcc, NoLock, Preserve)
+        {
+            MPE, 256
+        }
+
+        Method (MPEJ, 2, NotSerialized) {
+            // _EJ0 method - eject callback
+            Store(ShiftLeft(1,Arg0), MPE)
+            Sleep(200)
+        }
+
+        /* Memory hotplug notify method */
+        OperationRegion(MEST, SystemIO, 0xaf20, 32)
+        Field (MEST, ByteAcc, NoLock, Preserve)
+        {
+            MES, 256
+        }
+
+        Method(MESC, 0) {
+            // Local5 = active memdevice bitmap
+            Store (MES, Local5)
+            // Local2 = last read byte from bitmap
+            Store (Zero, Local2)
+            // Local0 = memory device iterator
+            Store (Zero, Local0)
+            While (LLess(Local0, SizeOf(MEON))) {
+                // Local1 = MEON flag for this memory device
+                Store(DerefOf(Index(MEON, Local0)), Local1)
+                If (And(Local0, 0x07)) {
+                    // Shift down previously read bitmap byte
+                    ShiftRight(Local2, 1, Local2)
+                } Else {
+                    // Read next byte from memdevice bitmap
+                    Store(DerefOf(Index(Local5, ShiftRight(Local0, 3))), Local2)
+                }
+                // Local3 = active state for this memory device
+                Store(And(Local2, 1), Local3)

+                If (LNotEqual(Local1, Local3)) {
+                    // State change - update MEON with new state
+                    Store(Local3, Index(MEON, Local0))
+                    // Do MEM notify
+                    If (LEqual(Local3, 1)) {
+                        MTFY(Local0, 1)
+                    } Else {
+                        MTFY(Local0, 3)
+                    }
+                }
+                Increment(Local0)
+            }
+            Return(One)
+        }
+    }
 /****************************************************************
  * General purpose events
  ****************************************************************/
@@ -732,7 +795,8 @@ DefinitionBlock (
             Return(_SB.PRSC())
         }
         Method(_L03) {
-            Return(0x01)
+            // Memory hotplug event
+            Return(_SB.MESC())
         }
         Method(_L04) {
             Return(0x01)