Move ACRN Device Model code in a devicemodel/ folder

This is part of the short series of commits that will lead
to a unified repository for the ACRN hypervisor, device model
and the associated documentation.

Signed-off-by: Geoffroy Van Cutsem <geoffroy.vancutsem@intel.com>

devicemodel/core/gc.c

@@ -0,0 +1,76 @@
+#include <sys/cdefs.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "gc.h"
+
+struct gfx_ctx {
+	struct gfx_ctx_image	*gc_image;
+	int raw;
+};
+
+struct gfx_ctx *
+gc_init(int width, int height, void *fbaddr)
+{
+	struct gfx_ctx *gc;
+	struct gfx_ctx_image *gc_image;
+
+	gc = calloc(1, sizeof(struct gfx_ctx));
+	assert(gc != NULL);
+
+	gc_image = calloc(1, sizeof(struct gfx_ctx_image));
+	assert(gc_image != NULL);
+
+	gc_image->width = width;
+	gc_image->height = height;
+	if (fbaddr) {
+		gc_image->data = fbaddr;
+		gc->raw = 1;
+	} else {
+		gc_image->data = calloc(width * height, sizeof(uint32_t));
+		gc->raw = 0;
+	}
+
+	gc->gc_image = gc_image;
+
+	return gc;
+}
+
+void
+gc_set_fbaddr(struct gfx_ctx *gc, void *fbaddr)
+{
+	gc->raw = 1;
+	if (gc->gc_image->data && gc->gc_image->data != fbaddr)
+		free(gc->gc_image->data);
+	gc->gc_image->data = fbaddr;
+}
+
+void
+gc_resize(struct gfx_ctx *gc, int width, int height)
+{
+	struct gfx_ctx_image *gc_image;
+
+	gc_image = gc->gc_image;
+
+	gc_image->width = width;
+	gc_image->height = height;
+	if (!gc->raw) {
+		gc_image->data = realloc(gc_image->data,
+			   width * height * sizeof(uint32_t));
+		if (gc_image->data != NULL)
+			memset(gc_image->data, 0, width * height *
+			    sizeof(uint32_t));
+	}
+}
+
+struct gfx_ctx_image *
+gc_get_image(struct gfx_ctx *gc)
+{
+	if (gc == NULL)
+		return NULL;
+
+	return gc->gc_image;
+}