rockchip: misc: protect serial# from getting overwritten

serial# is one of the vendor properties and thus protected from being
overwritten if already set. If env_set is called anyway this result in
some nasty warnings, so check for presence before trying that.

In the same direction check for the presence of cpuid# and compare it
to the actual hardware and emit a warning if they don't match.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

arch/arm/mach-rockchip/misc.c

@@ -92,6 +92,7 @@ int rockchip_cpuid_set(const u8 *cpuid, const u32 cpuid_length)
 	char cpuid_str[cpuid_length * 2 + 1];
 	u64 serialno;
 	char serialno_str[17];
+	const char *oldid;
 	int i;
 
 	memset(cpuid_str, 0, sizeof(cpuid_str));
@@ -113,8 +114,16 @@ int rockchip_cpuid_set(const u8 *cpuid, const u32 cpuid_length)
 	serialno |= (u64)crc32_no_comp(serialno, high, 8) << 32;
 	snprintf(serialno_str, sizeof(serialno_str), "%016llx", serialno);
 
+	oldid = env_get("cpuid#");
+	if (oldid && strcmp(oldid, cpuid_str) != 0)
+		printf("cpuid: value %s present in env does not match hardware %s\n",
+		       oldid, cpuid_str);
+
 	env_set("cpuid#", cpuid_str);
-	env_set("serial#", serialno_str);
+
+	/* Only generate serial# when none is set yet */
+	if (!env_get("serial#"))
+		env_set("serial#", serialno_str);
 
 	return 0;
 }