common: Move random-number functions into their own header

Create a new rand.h header file and move functions into it, to reduce
the size of common.h

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

include/common.h

@@ -325,12 +325,6 @@ char *	strmhz(char *buf, unsigned long hz);
 /* lib/crc32.c */
 #include <u-boot/crc.h>
 
-/* lib/rand.c */
-#define RAND_MAX -1U
-void srand(unsigned int seed);
-unsigned int rand(void);
-unsigned int rand_r(unsigned int *seedp);
-
 /*
  * STDIO based functions (can always be used)
  */

include/net.h

@@ -16,6 +16,7 @@
 #include <asm/byteorder.h>	/* for nton* / ntoh* stuff */
 #include <env.h>
 #include <linux/if_ether.h>
+#include <rand.h>
 
 #define DEBUG_LL_STATE 0	/* Link local state machine changes */
 #define DEBUG_DEV_PKT 0		/* Packets or info directed to the device */

include/rand.h

@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2000-2009
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ */
+
+#ifndef __RAND_H
+#define __RAND_H
+
+#define RAND_MAX -1U
+
+/**
+ * srand() - Set the random-number seed value
+ *
+ * This can be used to restart the pseudo-random-number sequence from a known
+ * point. This affects future calls to rand() to start from that point
+ *
+ * @seed: New seed
+ */
+void srand(unsigned int seed);
+
+/**
+ * rand() - Get a 32-bit pseudo-random number
+ *
+ * @returns next random number in the sequence
+ */
+unsigned int rand(void);
+
+/**
+ * rand_r() - Get a 32-bit pseudo-random number
+ *
+ * This version of the function allows multiple sequences to be used at the
+ * same time, since it requires the caller to store the seed value.
+ *
+ * @seed value to use, updated on exit
+ * @returns next random number in the sequence
+ */
+unsigned int rand_r(unsigned int *seedp);
+
+#endif

lib/rand.c

@@ -8,6 +8,7 @@
  */
 
 #include <common.h>
+#include <rand.h>
 
 static unsigned int y = 1U;
 

net/link_local.c

@@ -14,6 +14,7 @@
 #include <common.h>
 #include <env.h>
 #include <net.h>
+#include <rand.h>
 #include "arp.h"
 #include "net_rand.h"