dm: eth: Add support for ethprime env var

The ethprime env var is used to indicate the starting device if none is
specified in ethact. Also support aliases specified in the ethprime var.
Signed-off-by: NJoe Hershberger <joe.hershberger@ni.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

net/eth.c

@@ -360,6 +360,18 @@ int eth_initialize(void)
 		printf("No ethernet found.\n");
 		bootstage_error(BOOTSTAGE_ID_NET_ETH_START);
 	} else {
+		char *ethprime = getenv("ethprime");
+		struct udevice *prime_dev = NULL;
+
+		if (ethprime)
+			prime_dev = eth_get_dev_by_name(ethprime);
+		if (prime_dev) {
+			eth_set_dev(prime_dev);
+			eth_current_changed();
+		} else {
+			eth_set_dev(NULL);
+		}
+
 		bootstage_mark(BOOTSTAGE_ID_NET_ETH_INIT);
 		do {
 			if (num_devices)
@@ -367,6 +379,9 @@ int eth_initialize(void)
 
 			printf("eth%d: %s", dev->seq, dev->name);
 
+			if (ethprime && dev == prime_dev)
+				printf(" [PRIME]");
+
 			eth_write_hwaddr(dev);
 
 			uclass_next_device(&dev);
@@ -915,8 +930,20 @@ void eth_set_current(void)
 		act = getenv("ethact");
 		env_changed_id = env_id;
 	}
-	if (act != NULL)
+
+	if (act == NULL) {
+		char *ethprime = getenv("ethprime");
+		void *dev = NULL;
+
+		if (ethprime)
+			dev = eth_get_dev_by_name(ethprime);
+		if (dev)
+			eth_set_dev(dev);
+		else
+			eth_set_dev(NULL);
+	} else {
 		eth_set_dev(eth_get_dev_by_name(act));
+	}
 
 	eth_current_changed();
 }

test/dm/eth.c

@@ -60,3 +60,23 @@ static int dm_test_eth_alias(struct dm_test_state *dms)
 	return 0;
 }
 DM_TEST(dm_test_eth_alias, DM_TESTF_SCAN_FDT);
+
+static int dm_test_eth_prime(struct dm_test_state *dms)
+{
+	NetPingIP = string_to_ip("1.1.2.2");
+
+	/* Expected to be "eth@10003000" because of ethprime variable */
+	setenv("ethact", NULL);
+	setenv("ethprime", "eth5");
+	ut_assertok(NetLoop(PING));
+	ut_asserteq_str("eth@10003000", getenv("ethact"));
+
+	/* Expected to be "eth@10002000" because it is first */
+	setenv("ethact", NULL);
+	setenv("ethprime", NULL);
+	ut_assertok(NetLoop(PING));
+	ut_asserteq_str("eth@10002000", getenv("ethact"));
+
+	return 0;
+}
+DM_TEST(dm_test_eth_prime, DM_TESTF_SCAN_FDT);