Add PSF font header definition

src/modules/main/font.h

@@ -0,0 +1,32 @@
+#pragma once
+#include <stdint.h>
+
+/* PSF2 header format
+ * Taken from the Linux KBD documentation
+ * http://www.win.tue.nl/~aeb/linux/kbd/font-formats-1.html
+ */
+
+#define PSF2_MAGIC0     0x72
+#define PSF2_MAGIC1     0xb5
+#define PSF2_MAGIC2     0x4a
+#define PSF2_MAGIC3     0x86
+
+/* bits used in flags */
+#define PSF2_HAS_UNICODE_TABLE 0x01
+
+/* max version recognized so far */
+#define PSF2_MAXVERSION 0
+
+/* UTF8 separators */
+#define PSF2_SEPARATOR  0xFF
+#define PSF2_STARTSEQ   0xFE
+
+struct psf2_header {
+	uint8_t magic[4];
+	uint32_t version;
+	uint32_t headersize;    // offset of bitmaps in file
+	uint32_t flags;
+	uint32_t length;        // number of glyphs
+	uint32_t charsize;      // number of bytes for each character
+	uint32_t height, width; // max dimensions of glyphs
+};