fix root detection on evbarm when raid is involved

there are several problems solved in this change:
- lots of work was re-done when we already have determined the
  device booted from, so several new early returns introduced
  if booted_device has been set
- due to the lack of cpu_bootconf(), raidframe softroot would
  override "root=xxx" on the boot command line
- in the new cpu_bootconf(), switch the order of the platform
  boot-config with the set_root_device() call.  this avoids a
  problem where "root=xxx" is checked after automated methods,
  and is thus ignored.
- in fdt_detect_root_device(), remove the code to add "root=xxx""
  string to the boot_args[] that would be later parsed by the
  set_root_device() call, and simply set booted_device directly.
  also, for any successful call, perform an early return.
- define __HAVE_CPU_BOOTCONF so early boot calls cpu_bootconf().


Index: arch/evbarm/evbarm/autoconf.c
===================================================================
RCS file: /cvsroot/src/sys/arch/evbarm/evbarm/autoconf.c,v
retrieving revision 1.23
diff -p -u -r1.23 autoconf.c
--- arch/evbarm/evbarm/autoconf.c	19 Dec 2020 21:54:00 -0000	1.23
+++ arch/evbarm/evbarm/autoconf.c	25 Jan 2023 05:23:00 -0000
@@ -108,6 +108,9 @@ set_root_device(void)
 	char *ptr, *end, *buf;
 	size_t len;
 
+	if (booted_device)
+		return;
+
 	if (boot_args == NULL)
 		return;
 
@@ -118,7 +121,7 @@ set_root_device(void)
 		return;
 
 	/* NUL-terminate string, get_bootconf_option doesn't */
-	for (end=ptr; *end != '\0'; ++end) {
+	for (end = ptr; *end != '\0'; ++end) {
 		if (*end == ' ' || *end == '\t') {
 			break;
 		}
@@ -144,16 +147,25 @@ set_root_device(void)
 #endif
 
 /*
- * Set up the root device from the boot args
+ * Set up the root device from the boot args.
+ *
+ * cpu_bootconf() is called before RAIDframe root detection,
+ * and cpu_rootconf() is called after.
  */
 void
-cpu_rootconf(void)
+cpu_bootconf(void)
 {
 #ifndef MEMORY_DISK_IS_ROOT
+	set_root_device();
 	if (evbarm_cpu_rootconf)
 		(*evbarm_cpu_rootconf)();
-	set_root_device();
 #endif
+}
+
+void
+cpu_rootconf(void)
+{
+	cpu_bootconf();
 	aprint_normal("boot device: %s\n",
 	    booted_device != NULL ? device_xname(booted_device) : "<unknown>");
 	rootconf();
Index: arch/evbarm/fdt/fdt_machdep.c
===================================================================
RCS file: /cvsroot/src/sys/arch/evbarm/fdt/fdt_machdep.c,v
retrieving revision 1.99
diff -p -u -r1.99 fdt_machdep.c
--- arch/evbarm/fdt/fdt_machdep.c	4 Nov 2022 10:51:17 -0000	1.99
+++ arch/evbarm/fdt/fdt_machdep.c	25 Jan 2023 05:23:00 -0000
@@ -745,13 +745,15 @@ fdt_detect_root_device(device_t dev)
 	uint8_t buf[DEV_BSIZE];
 	uint8_t hash[16];
 	const uint8_t *rhash;
-	char rootarg[64];
 	struct vnode *vp;
 	MD5_CTX md5ctx;
 	int error, len;
 	size_t resid;
 	u_int part;
 
+	if (booted_device)
+		return;
+
 	const int chosen = OF_finddevice("/chosen");
 	if (chosen < 0)
 		return;
@@ -787,22 +789,19 @@ fdt_detect_root_device(device_t dev)
 		MD5Update(&md5ctx, (void *)&mbr, sizeof(mbr));
 		MD5Final(hash, &md5ctx);
 
-		if (memcmp(rhash, hash, 16) != 0)
-			return;
+		if (memcmp(rhash, hash, 16) == 0)
+			booted_device = dev;
 
-		snprintf(rootarg, sizeof(rootarg), " root=%s%c", device_xname(dev), part + 'a');
-		strcat(boot_args, rootarg);
+		return;
 	}
 
 	if (of_hasprop(chosen, "netbsd,gpt-guid")) {
-		char guidbuf[UUID_STR_LEN];
 		const struct uuid *guid = fdtbus_get_prop(chosen, "netbsd,gpt-guid", &len);
-		if (guid == NULL || len != 16)
-			return;
 
-		uuid_snprintf(guidbuf, sizeof(guidbuf), guid);
-		snprintf(rootarg, sizeof(rootarg), " root=wedge:%s", guidbuf);
-		strcat(boot_args, rootarg);
+		if (guid != NULL && len == 16)
+			booted_device = dev;
+
+		return;
 	}
 
 	if (of_hasprop(chosen, "netbsd,gpt-label")) {
@@ -813,6 +812,8 @@ fdt_detect_root_device(device_t dev)
 		device_t dv = dkwedge_find_by_wname(label);
 		if (dv != NULL)
 			booted_device = dv;
+
+		return;
 	}
 
 	if (of_hasprop(chosen, "netbsd,booted-mac-address")) {
@@ -830,6 +831,8 @@ fdt_detect_root_device(device_t dev)
 			}
 		}
 		pserialize_read_exit(s);
+
+		return;
 	}
 }
 
Index: arch/evbarm/include/types.h
===================================================================
RCS file: /cvsroot/src/sys/arch/evbarm/include/types.h,v
retrieving revision 1.15
diff -p -u -r1.15 types.h
--- arch/evbarm/include/types.h	1 Apr 2021 04:35:45 -0000	1.15
+++ arch/evbarm/include/types.h	25 Jan 2023 05:23:00 -0000
@@ -3,6 +3,8 @@
 #ifndef _EVBARM_TYPES_H_
 #define	_EVBARM_TYPES_H_
 
+#define	__HAVE_CPU_BOOTCONF
+
 #ifdef __aarch64__
 #include <aarch64/types.h>