smbios: Add more options for the BIOS version string

At present the version string is obtained from PLAIN_VERSION. Some boards
may want to configure this using the device tree, since the build system
can more easily insert things there after U-Boot itself is built. Add this
option to the code.

Also in some cases the version needs to be generated programmatically,
such as when it is stored elsewhere in the ROM and must be read first.
To handle this, keep a pointer around so that it can be updated later.
This works by storing the last string in the context, since it is easier
than passing out a little-used extra parameter.

Provide a function to update the version string.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

include/asm-generic/global_data.h

@@ -447,6 +447,12 @@ struct global_data {
 	 */
 	struct acpi_ctx *acpi_ctx;
 #endif
+#if CONFIG_IS_ENABLED(GENERATE_SMBIOS_TABLE)
+	/**
+	 * @smbios_version: Points to SMBIOS type 0 version
+	 */
+	char *smbios_version;
+#endif
 };
 
 /**

include/smbios.h

@@ -257,4 +257,16 @@ const struct smbios_header *smbios_header(const struct smbios_entry *entry, int
  */
 const char *smbios_string(const struct smbios_header *header, int index);
 
+/**
+ * smbios_update_version() - 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).
+ *
+ * @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(const char *version);
+
 #endif /* _SMBIOS_H_ */

lib/smbios.c

@@ -17,6 +17,12 @@
 #include <dm/uclass-internal.h>
 #endif
 
+DECLARE_GLOBAL_DATA_PTR;
+
+enum {
+	SMBIOS_STR_MAX	= 64,	/* Maximum length allowed for a string */
+};
+
 /**
  * struct smbios_ctx - context for writing SMBIOS tables
  *
@@ -27,12 +33,15 @@
  * @next_ptr:	pointer to the start of the next string to be added. When the
  *		table is nopt empty, this points to the byte after the \0 of the
  *		previous string.
+ * @last_str:	points to the last string that was written to the table, or NULL
+ *		if none
  */
 struct smbios_ctx {
 	ofnode node;
 	struct udevice *dev;
 	char *eos;
 	char *next_ptr;
+	char *last_str;
 };
 
 /**
@@ -78,6 +87,7 @@ static int smbios_add_string(struct smbios_ctx *ctx, const char *str)
 
 	for (;;) {
 		if (!*p) {
+			ctx->last_str = p;
 			strcpy(p, str);
 			p += strlen(str);
 			*p++ = '\0';
@@ -87,8 +97,10 @@ static int smbios_add_string(struct smbios_ctx *ctx, const char *str)
 			return i;
 		}
 
-		if (!strcmp(p, str))
+		if (!strcmp(p, str)) {
+			ctx->last_str = p;
 			return i;
+		}
 
 		p += strlen(p) + 1;
 		i++;
@@ -119,6 +131,35 @@ static void smbios_set_eos(struct smbios_ctx *ctx, char *eos)
 {
 	ctx->eos = eos;
 	ctx->next_ptr = eos;
+	ctx->last_str = NULL;
+}
+
+int smbios_update_version(const char *version)
+{
+	char *ptr = gd->smbios_version;
+	uint old_len, len;
+
+	if (!ptr)
+		return log_ret(-ENOENT);
+
+	/*
+	 * 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;
 }
 
 /**
@@ -146,7 +187,18 @@ static int smbios_write_type0(ulong *current, int handle,
 	fill_smbios_header(t, SMBIOS_BIOS_INFORMATION, len, handle);
 	smbios_set_eos(ctx, t->eos);
 	t->vendor = smbios_add_string(ctx, "U-Boot");
+
+	t->bios_ver = smbios_add_prop(ctx, "version");
+	if (!t->bios_ver)
 		t->bios_ver = smbios_add_string(ctx, PLAIN_VERSION);
+	if (t->bios_ver)
+		gd->smbios_version = ctx->last_str;
+	log_debug("smbios_version = %p: '%s'\n", gd->smbios_version,
+		  gd->smbios_version);
+#ifdef LOG_DEBUG
+	print_buffer((ulong)gd->smbios_version, gd->smbios_version,
+		     1, strlen(gd->smbios_version) + 1, 0);
+#endif
 	t->bios_release_date = smbios_add_string(ctx, U_BOOT_DMI_DATE);
 #ifdef CONFIG_ROM_SIZE
 	t->bios_rom_size = (CONFIG_ROM_SIZE / 65536) - 1;
@@ -345,7 +397,7 @@ static int smbios_write_type127(ulong *current, int handle,
 }
 
 static struct smbios_write_method smbios_write_funcs[] = {
-	{ smbios_write_type0, },
+	{ smbios_write_type0, "bios", },
 	{ smbios_write_type1, "system", },
 	{ smbios_write_type2, "baseboard", },
 	{ smbios_write_type3, "chassis", },