net: shell: iface: Add link speed settings command

Add this to set link speed through net_shell.
Current zephyr version doesn't have user interface to change
speed, hence adding this to accomodate it. Full duplex will
be set by default for each link speed.

Able to change link speed using command below:
net iface set_link <iface idx> <speed> <optional:h(half)/f(full)>
eg: net iface set_link 1 100 h
    net iface set_link 1 10 f
    net iface set_link 1 1000

Able to set multiple link speed like below:
net iface set_link <iface idx> <speed1> <speed2> <optional:h/f>
eg: net iface set_link 1 10 100 h
    net iface set_link 1 1000 f 10

Signed-off-by: Ling Pei Lee <pei.lee.ling@intel.com>

Author: peileeli

subsys/net/lib/shell/iface.c

@@ -817,6 +817,83 @@ static int cmd_net_default_iface(const struct shell *sh, size_t argc, char *argv
 	return 0;
 }
 
+#if defined(CONFIG_ETH_PHY_DRIVER)
+static int cmd_net_link_speed(const struct shell *sh, size_t argc, char *argv[])
+{
+	int idx = get_iface_idx(sh, argv[1]);
+	const struct device *phy_dev;
+	bool half_duplex = false;
+	uint16_t user_input_spd;
+	struct net_if *iface;
+	uint16_t speed = 0U;
+	int ret;
+
+	if (argc < 3) {
+		PR_WARNING("Usage: net iface set_link <index> "
+			   "<Speed:10/100/1000/2500/5000> [Duplex]:h/f>\n");
+		return -ENOEXEC;
+	}
+
+	iface = net_if_get_by_index(idx);
+	if (net_if_l2(iface) != &NET_L2_GET_NAME(ETHERNET)) {
+		PR_WARNING("Interface %d is not Ethernet type\n", idx);
+		return -EINVAL;
+	}
+
+	phy_dev = net_eth_get_phy(iface);
+	if (!phy_dev) {
+		PR_WARNING("No PHY device found for interface %d\n", idx);
+		return -ENOEXEC;
+	}
+
+	for (int k = 2; k < argc; k++) {
+		if ((k + 1 < argc) && (argv[k+1][0] == 'h')) {
+			half_duplex = true;
+		} else {
+			half_duplex = false;
+		}
+
+		user_input_spd = shell_strtoul(argv[k], 10, &ret);
+		switch (user_input_spd) {
+		case 0:
+			break;
+		case 10:
+			speed |= half_duplex ? LINK_HALF_10BASE : LINK_FULL_10BASE;
+			break;
+		case 100:
+			speed |= half_duplex ? LINK_HALF_100BASE : LINK_FULL_100BASE;
+			break;
+		case 1000:
+			speed |= half_duplex ? LINK_HALF_1000BASE :  LINK_FULL_1000BASE;
+			break;
+		case 2500:
+			if (half_duplex) {
+				PR_WARNING("2500BASE half-duplex not supported\n");
+				return -ENOTSUP;
+			}
+			speed |= LINK_FULL_2500BASE;
+			break;
+		case 5000:
+			if (half_duplex) {
+				PR_WARNING("5000BASE half-duplex not supported\n");
+				return -ENOTSUP;
+			}
+			speed |= LINK_FULL_5000BASE;
+			break;
+		default:
+			PR_WARNING("Unsupported speed %d\n", user_input_spd);
+			return -ENOTSUP;
+		}
+	}
+
+	if (speed != 0U) {
+		return phy_configure_link(phy_dev, speed);
+	}
+	PR_WARNING("No speed specified\n");
+	return -ENOEXEC;
+}
+#endif /* CONFIG_ETH_PHY_DRIVER */
+
 #if defined(CONFIG_NET_SHELL_DYN_CMD_COMPLETION)
 
 #include "iface_dynamic.h"
@@ -841,6 +918,13 @@ SHELL_STATIC_SUBCMD_SET_CREATE(net_cmd_iface,
 	SHELL_CMD(default, IFACE_DYN_CMD,
 		  "'net iface default [<index>]' displays or sets the default network interface.",
 		  cmd_net_default_iface),
+#if defined(CONFIG_ETH_PHY_DRIVER)
+	SHELL_CMD(set_link, IFACE_DYN_CMD,
+		  "'net iface set_link <index> <Speed 10/100/1000/2500/5000> "
+		  "<Duplex[optional]:h/f>'"
+		  " sets link speed for the network interface.",
+		  cmd_net_link_speed),
+#endif /* CONFIG_ETH_PHY_DRIVER */
 	SHELL_SUBCMD_SET_END
 );