1 files changed, 139 insertions, 0 deletions
diff --git a/roms/seabios/src/memmap.c b/roms/seabios/src/memmap.c
new file mode 100644
index 000000000..378351890
--- /dev/null
+++ b/roms/seabios/src/memmap.c
@@ -0,0 +1,139 @@
+// Support for building memory maps suitable for int 15 e820 calls.
+//
+// Copyright (C) 2008,2009  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU LGPLv3 license.
+
+#include "memmap.h" // struct e820entry
+#include "config.h" // CONFIG_*
+#include "util.h" // dprintf.h
+
+
+/****************************************************************
+ * e820 memory map
+ ****************************************************************/
+
+// Remove an entry from the e820_list.
+static void
+remove_e820(int i)
+{
+    e820_count--;
+    memmove(&e820_list[i], &e820_list[i+1]
+            , sizeof(e820_list[0]) * (e820_count - i));
+}
+
+// Insert an entry in the e820_list at the given position.
+static void
+insert_e820(int i, u64 start, u64 size, u32 type)
+{
+    if (e820_count >= CONFIG_MAX_E820) {
+        warn_noalloc();
+        return;
+    }
+
+    memmove(&e820_list[i+1], &e820_list[i]
+            , sizeof(e820_list[0]) * (e820_count - i));
+    e820_count++;
+    struct e820entry *e = &e820_list[i];
+    e->start = start;
+    e->size = size;
+    e->type = type;
+}
+
+static const char *
+e820_type_name(u32 type)
+{
+    switch (type) {
+    case E820_RAM:      return "RAM";
+    case E820_RESERVED: return "RESERVED";
+    case E820_ACPI:     return "ACPI";
+    case E820_NVS:      return "NVS";
+    case E820_UNUSABLE: return "UNUSABLE";
+    case E820_HOLE:     return "HOLE";
+    default:            return "UNKNOWN";
+    }
+}
+
+// Show the current e820_list.
+static void
+dump_map(void)
+{
+    dprintf(1, "e820 map has %d items:\n", e820_count);
+    int i;
+    for (i=0; i<e820_count; i++) {
+        struct e820entry *e = &e820_list[i];
+        u64 e_end = e->start + e->size;
+        dprintf(1, "  %d: %016llx - %016llx = %d %s\n", i
+                , e->start, e_end, e->type, e820_type_name(e->type));
+    }
+}
+
+// Add a new entry to the list.  This scans for overlaps and keeps the
+// list sorted.
+void
+add_e820(u64 start, u64 size, u32 type)
+{
+    dprintf(8, "Add to e820 map: %08x %08x %d\n", (u32)start, (u32)size, type);
+
+    if (! size)
+        // Huh?  Nothing to do.
+        return;
+
+    // Find position of new item (splitting existing item if needed).
+    u64 end = start + size;
+    int i;
+    for (i=0; i<e820_count; i++) {
+        struct e820entry *e = &e820_list[i];
+        u64 e_end = e->start + e->size;
+        if (start > e_end)
+            continue;
+        // Found position - check if an existing item needs to be split.
+        if (start > e->start) {
+            if (type == e->type) {
+                // Same type - merge them.
+                size += start - e->start;
+                start = e->start;
+            } else {
+                // Split existing item.
+                e->size = start - e->start;
+                i++;
+                if (e_end > end)
+                    insert_e820(i, end, e_end - end, e->type);
+            }
+        }
+        break;
+    }
+    // Remove/adjust existing items that are overlapping.
+    while (i<e820_count) {
+        struct e820entry *e = &e820_list[i];
+        if (end < e->start)
+            // No overlap - done.
+            break;
+        u64 e_end = e->start + e->size;
+        if (end >= e_end) {
+            // Existing item completely overlapped - remove it.
+            remove_e820(i);
+            continue;
+        }
+        // Not completely overlapped - adjust its start.
+        e->start = end;
+        e->size = e_end - end;
+        if (type == e->type) {
+            // Same type - merge them.
+            size += e->size;
+            remove_e820(i);
+        }
+        break;
+    }
+    // Insert new item.
+    if (type != E820_HOLE)
+        insert_e820(i, start, size, type);
+    //dump_map();
+}
+
+// Report on final memory locations.
+void
+memmap_finalize(void)
+{
+    dump_map();
+}