OvmfPkg: PlatformDxe: introduce state for the main form

We'll need a C language (ie. structure) representation for the state of
the visual elements on the form. We choose the Buffer Storage kind (see
29.2.5.6 "Storage" in UEFI 2.4A), because it's easy to work with.

Note that the structure added in this patch has nothing to do with UEFI
non-volatile variables.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15368 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/PlatformDxe/Platform.h

@@ -19,6 +19,18 @@
 //
 // Macro and type definitions that connect the form with the HII driver code.
 //
+#define FORMSTATEID_MAIN_FORM  1
 #define FORMID_MAIN_FORM       1
 
+#define MAXSIZE_RES_CUR       16
+
+//
+// This structure describes the form state. Its fields relate strictly to the
+// visual widgets on the form.
+//
+typedef struct {
+  UINT16 CurrentPreferredResolution[MAXSIZE_RES_CUR];
+  UINT32 NextPreferredResolution;
+} MAIN_FORM_STATE;
+
 #endif // _PLATFORM_H_

OvmfPkg/PlatformDxe/PlatformForms.vfr

@@ -30,6 +30,11 @@ formset
   title = STRING_TOKEN(STR_FORMSET_TITLE),
   help  = STRING_TOKEN(STR_FORMSET_HELP),
 
+  varstore MAIN_FORM_STATE,
+    varid = FORMSTATEID_MAIN_FORM,
+    name  = MainFormState,
+    guid  = OVMF_PLATFORM_CONFIG_GUID;
+
   form
     formid = FORMID_MAIN_FORM,
     title  = STRING_TOKEN(STR_MAIN_FORM_TITLE);