board: ti: j721s2: Add support to detect daughtercards

Add support to detect daughtercards (GESI Ethernet card) in-order
to set the MAC address of the main CPSW2G interface.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>

board/ti/j721s2/evm.c

@@ -153,6 +153,135 @@ static void setup_serial(void)
 	snprintf(serial_string, sizeof(serial_string), "%016lx", board_serial);
 	env_set("serial#", serial_string);
 }
+
+/*
+ * Declaration of daughtercards to probe. Note that when adding more
+ * cards they should be grouped by the 'i2c_addr' field to allow for a
+ * more efficient probing process.
+ */
+static const struct {
+	u8 i2c_addr;		/* I2C address of card EEPROM */
+	char *card_name;	/* EEPROM-programmed card name */
+	char *dtbo_name;	/* Device tree overlay to apply */
+	u8 eth_offset;		/* ethXaddr MAC address index offset */
+} ext_cards[] = {
+	{
+		0x52,
+		"J7X-GESI-EXP",
+		"k3-j721s2-gesi-exp-board.dtbo",
+		1,		/* Start populating from eth1addr */
+	},
+};
+
+#define DAUGHTER_CARD_NO_OF_MAC_ADDR	5
+static bool daughter_card_detect_flags[ARRAY_SIZE(ext_cards)];
+
+static int probe_daughtercards(void)
+{
+	char mac_addr[DAUGHTER_CARD_NO_OF_MAC_ADDR][TI_EEPROM_HDR_ETH_ALEN];
+	bool eeprom_read_success;
+	struct ti_am6_eeprom ep;
+	u8 previous_i2c_addr;
+	u8 mac_addr_cnt;
+	int i;
+	int ret;
+
+	/* Mark previous I2C address variable as not populated */
+	previous_i2c_addr = 0xff;
+
+	/* No EEPROM data was read yet */
+	eeprom_read_success = false;
+
+	/* Iterate through list of daughtercards */
+	for (i = 0; i < ARRAY_SIZE(ext_cards); i++) {
+		/* Obtain card-specific I2C address */
+		u8 i2c_addr = ext_cards[i].i2c_addr;
+
+		/* Read card EEPROM if not already read previously */
+		if (i2c_addr != previous_i2c_addr) {
+			/* Store I2C address so we can avoid reading twice */
+			previous_i2c_addr = i2c_addr;
+
+			/* Get and parse the daughter card EEPROM record */
+			ret = ti_i2c_eeprom_am6_get(CONFIG_EEPROM_BUS_ADDRESS,
+						    i2c_addr,
+						    &ep,
+						    (char **)mac_addr,
+						    DAUGHTER_CARD_NO_OF_MAC_ADDR,
+						    &mac_addr_cnt);
+			if (ret) {
+				debug("%s: No daughtercard EEPROM at 0x%02x found %d\n",
+				      __func__, i2c_addr, ret);
+				eeprom_read_success = false;
+				/* Skip to the next daughtercard to probe */
+				continue;
+			}
+
+			/* EEPROM read successful, okay to further process. */
+			eeprom_read_success = true;
+		}
+
+		/* Only continue processing if EEPROM data was read */
+		if (!eeprom_read_success)
+			continue;
+
+		/* Only process the parsed data if we found a match */
+		if (strncmp(ep.name, ext_cards[i].card_name, sizeof(ep.name)))
+			continue;
+
+		printf("Detected: %s rev %s\n", ep.name, ep.version);
+		daughter_card_detect_flags[i] = true;
+
+		if (!IS_ENABLED(CONFIG_SPL_BUILD)) {
+			int j;
+			/*
+			 * Populate any MAC addresses from daughtercard into the U-Boot
+			 * environment, starting with a card-specific offset so we can
+			 * have multiple ext_cards contribute to the MAC pool in a well-
+			 * defined manner.
+			 */
+			for (j = 0; j < mac_addr_cnt; j++) {
+				if (!is_valid_ethaddr((u8 *)mac_addr[j]))
+					continue;
+
+				eth_env_set_enetaddr_by_index("eth", ext_cards[i].eth_offset + j,
+							      (uchar *)mac_addr[j]);
+			}
+		}
+	}
+
+	if (!IS_ENABLED(CONFIG_SPL_BUILD)) {
+		char name_overlays[1024] = { 0 };
+
+		for (i = 0; i < ARRAY_SIZE(ext_cards); i++) {
+			if (!daughter_card_detect_flags[i])
+				continue;
+
+			/* Skip if no overlays are to be added */
+			if (!strlen(ext_cards[i].dtbo_name))
+				continue;
+
+			/*
+			 * Make sure we are not running out of buffer space by checking
+			 * if we can fit the new overlay, a trailing space to be used
+			 * as a separator, plus the terminating zero.
+			 */
+			if (strlen(name_overlays) + strlen(ext_cards[i].dtbo_name) + 2 >
+			    sizeof(name_overlays))
+				return -ENOMEM;
+
+			/* Append to our list of overlays */
+			strcat(name_overlays, ext_cards[i].dtbo_name);
+			strcat(name_overlays, " ");
+		}
+
+		/* Apply device tree overlay(s) to the U-Boot environment, if any */
+		if (strlen(name_overlays))
+			return env_set("name_overlays", name_overlays);
+	}
+
+	return 0;
+}
 #endif
 
 /*
@@ -182,6 +311,7 @@ int board_late_init(void)
 	if (IS_ENABLED(CONFIG_TI_I2C_BOARD_DETECT)) {
 		setup_board_eeprom_env();
 		setup_serial();
+		probe_daughtercards();
 	}
 
 	return 0;