lib: uuid: add functions to generate UUID version 4

This patch adds support to generate UUID (Universally Unique Identifier)
in version 4 based on RFC4122, which is randomly.

Source: https://www.ietf.org/rfc/rfc4122.txt

Changes:
- new configs:
  - CONFIG_LIB_UUID for compile lib/uuid.c
  - CONFIG_RANDOM_UUID for functions gen_rand_uuid() and gen_rand_uuid_str()
- add configs dependency to include/config_fallbacks.h for lib uuid.

lib/uuid.c:
- add gen_rand_uuid() - this function writes 16 bytes len binary representation
  of UUID v4 to the memory at given address.

- add gen_rand_uuid_str() - this function writes 37 bytes len hexadecimal
  ASCII string representation of UUID v4 to the memory at given address.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Lukasz Majewski <l.majewski@samsung.com>
[trini: Add CONFIG_EFI_PARTITION to fallbacks]
Signed-off-by: Tom Rini <trini@ti.com>

2 files changed, 35 insertions, 1 deletions

diff --git a/include/config_fallbacks.h b/include/config_fallbacks.h
index d8339b2..c6b20fd 100644
--- a/include/config_fallbacks.h
+++ b/include/config_fallbacks.h
@@ -55,6 +55,20 @@
 #define HAVE_BLOCK_DEVICE
 #endif
 
+#if (defined(CONFIG_PARTITION_UUIDS) || \
+	defined(CONFIG_EFI_PARTITION) || \
+	defined(CONFIG_RANDOM_UUID) || \
+	defined(CONFIG_BOOTP_PXE)) && \
+	!defined(CONFIG_LIB_UUID)
+#define CONFIG_LIB_UUID
+#endif
+
+#if defined(CONFIG_RANDOM_UUID) && \
+	!defined(CONFIG_LIB_RAND) && \
+	!defined(CONFIG_LIB_HW_RAND)
+#define CONFIG_LIB_RAND
+#endif
+
 #ifndef CONFIG_SYS_PROMPT
 #define CONFIG_SYS_PROMPT	"=> "
 #endif
diff --git a/include/uuid.h b/include/uuid.h
index e8feeed..93027c1 100644
--- a/include/uuid.h
+++ b/include/uuid.h
@@ -7,15 +7,35 @@
 #ifndef __UUID_H__
 #define __UUID_H__
 
+/* This is structure is in big-endian */
+struct uuid {
+	unsigned int time_low;
+	unsigned short time_mid;
+	unsigned short time_hi_and_version;
+	unsigned char clock_seq_hi_and_reserved;
+	unsigned char clock_seq_low;
+	unsigned char node[6];
+} __packed;
+
 enum {
 	UUID_STR_FORMAT_STD,
 	UUID_STR_FORMAT_GUID
 };
 
 #define UUID_STR_LEN		36
-#define UUID_BIN_LEN		16
+#define UUID_BIN_LEN		sizeof(struct uuid)
+
+#define UUID_VERSION_MASK	0xf000
+#define UUID_VERSION_SHIFT	12
+#define UUID_VERSION		0x4
+
+#define UUID_VARIANT_MASK	0xc0
+#define UUID_VARIANT_SHIFT	7
+#define UUID_VARIANT		0x1
 
 int uuid_str_valid(const char *uuid);
 int uuid_str_to_bin(char *uuid_str, unsigned char *uuid_bin, int str_format);
 void uuid_bin_to_str(unsigned char *uuid_bin, char *uuid_str, int str_format);
+void gen_rand_uuid(unsigned char *uuid_bin);
+void gen_rand_uuid_str(char *uuid_str, int str_format);
 #endif