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 (file)
--- 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 @@ const char *smbios_string(const struct smbios_header *header, int index);
  */
 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_ */

diff --git a/lib/smbios-parser.c b/lib/smbios-parser.c
index b89f988..34203f9 100644 (file)
--- a/lib/smbios-parser.c
+++ b/lib/smbios-parser.c
@@ -3,6 +3,8 @@
  * Copyright (C) 2020, Bachmann electronic GmbH
  */
 
+#define LOG_CATEGORY   LOGC_BOOT
+
 #include <common.h>
 #include <smbios.h>
 
@@ -94,3 +96,39 @@ const char *smbios_string(const struct smbios_header *header, int index)
 
        return string_from_smbios_table(header, index);
 }
+
+int smbios_update_version_full(void *smbios_tab, const char *version)
+{
+       const struct smbios_header *hdr;
+       struct smbios_type0 *bios;
+       uint old_len, len;
+       char *ptr;
+
+       log_info("Updating SMBIOS table at %p\n", smbios_tab);
+       hdr = smbios_header(smbios_tab, SMBIOS_BIOS_INFORMATION);
+       if (!hdr)
+               return log_msg_ret("tab", -ENOENT);
+       bios = (struct smbios_type0 *)hdr;
+       ptr = (char *)smbios_string(hdr, bios->bios_ver);
+       if (!ptr)
+               return log_msg_ret("str", -ENOMEDIUM);
+
+       /*
+        * This string is supposed to have at least enough bytes and is
+        * padded with spaces. Update it, taking care not to move the
+        * \0 terminator, so that other strings in the string table
+        * are not disturbed. See smbios_add_string()
+        */
+       old_len = strnlen(ptr, SMBIOS_STR_MAX);
+       len = strnlen(version, SMBIOS_STR_MAX);
+       if (len > old_len)
+               return log_ret(-ENOSPC);
+
+       log_debug("Replacing SMBIOS type 0 version string '%s'\n", ptr);
+       memcpy(ptr, version, len);
+#ifdef LOG_DEBUG
+       print_buffer((ulong)ptr, ptr, 1, old_len + 1, 0);
+#endif
+
+       return 0;
+}

diff --git a/lib/smbios.c b/lib/smbios.c
index 7d463c8..9eb226e 100644 (file)
--- a/lib/smbios.c
+++ b/lib/smbios.c
@@ -20,10 +20,6 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-enum {
-       SMBIOS_STR_MAX  = 64,   /* Maximum length allowed for a string */
-};
-
 /**
  * struct smbios_ctx - context for writing SMBIOS tables
  *