smbios: Allow writing to the coreboot version string

When U-Boot is booted from coreboot the SMBIOS tables are written by
coreboot, not U-Boot. The existing method of updating the BIOS version
string does not work in that case, since gd->smbios_version is only set
when U-Boot writes the tables.

Add a new function which allows the version to be updated by parsing the
tables and writing the string in the correct place. Since coreboot
provides a pointer to the SMBIOS tables in its sysinfo structure, this
makes it easy to do the update.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/smbios.h b/include/smbios.h
index ecc4fd1..ffeefb4 100644
--- a/include/smbios.h
+++ b/include/smbios.h
@@ -14,6 +14,10 @@
 #define SMBIOS_MAJOR_VER	3
 #define SMBIOS_MINOR_VER	0
 
+enum {
+	SMBIOS_STR_MAX	= 64,	/* Maximum length allowed for a string */
+};
+
 /* SMBIOS structure types */
 enum {
 	SMBIOS_BIOS_INFORMATION = 0,
@@ -269,4 +273,20 @@
  */
 int smbios_update_version(const char *version);
 
+/**
+ * smbios_update_version_full() - Update the version string
+ *
+ * This can be called after the SMBIOS tables are written (e.g. after the U-Boot
+ * main loop has started) to update the BIOS version string (SMBIOS table 0).
+ * It scans for the correct place to put the version, so does not need U-Boot
+ * to have actually written the tables itself (e.g. if a previous bootloader
+ * did it).
+ *
+ * @smbios_tab: Start of SMBIOS tables
+ * @version: New version string to use
+ * @return 0 if OK, -ENOENT if no version string was previously written,
+ *	-ENOSPC if the new string is too large to fit
+ */
+int smbios_update_version_full(void *smbios_tab, const char *version);
+
 #endif /* _SMBIOS_H_ */