siemens/mc_apl1: Set MAC address for all available i210 MACs

This mainboard uses two i210 Ethernet controller. Therfore we enable the
usage of the i210 driver and have to provide a function to search for a
valid MAC address for all i210 devices by using Siemens hwilib.

Change-Id: I36246cdef987fcece15a297ebb2f41561fca1f69
Signed-off-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-on: https://review.coreboot.org/18380
Tested-by: build bot (Jenkins)
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>

src/mainboard/siemens/mc_apl1/Kconfig

@@ -5,6 +5,8 @@ config BOARD_SPECIFIC_OPTIONS
 	select SOC_INTEL_APOLLOLAKE
 	select BOARD_ROMSIZE_KB_16384
 	select HAVE_ACPI_TABLES
+	select DRIVER_INTEL_I210
+	select USE_SIEMENS_HWILIB
 
 config MAINBOARD_DIR
 	string

src/mainboard/siemens/mc_apl1/mainboard.c

@@ -2,6 +2,7 @@
  * This file is part of the coreboot project.
  *
  * Copyright 2016 Google Inc.
+ * Copyright (C) 2017 Siemens AG
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -14,6 +15,88 @@
  */
 
 #include <device/device.h>
+#include <console/console.h>
+#include <string.h>
+#include <hwilib.h>
+#include <i210.h>
+
+#define MAX_PATH_DEPTH		12
+#define MAX_NUM_MAPPINGS	10
+
+/** \brief This function can decide if a given MAC address is valid or not.
+ *         Currently, addresses filled with 0xff or 0x00 are not valid.
+ * @param  mac  Buffer to the MAC address to check
+ * @return 0    if address is not valid, otherwise 1
+ */
+static uint8_t is_mac_adr_valid(uint8_t mac[6])
+{
+	uint8_t buf[6];
+
+	memset(buf, 0, sizeof(buf));
+	if (!memcmp(buf, mac, sizeof(buf)))
+		return 0;
+	memset(buf, 0xff, sizeof(buf));
+	if (!memcmp(buf, mac, sizeof(buf)))
+		return 0;
+	return 1;
+}
+
+/** \brief This function will search for a MAC address which can be assigned
+ *         to a MACPHY.
+ * @param  dev     pointer to PCI device
+ * @param  mac     buffer where to store the MAC address
+ * @return cb_err  CB_ERR or CB_SUCCESS
+ */
+enum cb_err mainboard_get_mac_address(struct device *dev, uint8_t mac[6])
+{
+	struct bus *parent = dev->bus;
+	uint8_t buf[16], mapping[16], i = 0, chain_len = 0;
+
+	memset(buf, 0, sizeof(buf));
+	memset(mapping, 0, sizeof(mapping));
+
+	/* The first entry in the tree is the device itself. */
+	buf[0] = dev->path.pci.devfn;
+	chain_len = 1;
+	for (i = 1; i < MAX_PATH_DEPTH && parent->dev->bus->subordinate; i++) {
+		buf[i] = parent->dev->path.pci.devfn;
+		chain_len++;
+		parent = parent->dev->bus;
+	}
+	if (i == MAX_PATH_DEPTH) {
+		/* The path is deeper than MAX_PATH_DEPTH devices, error. */
+		printk(BIOS_ERR, "Too many bridges for %s\n", dev_path(dev));
+		return CB_ERR;
+	}
+	/*
+	 * Now construct the mapping based on the device chain starting from
+	 * root bridge device to the device itself.
+	 */
+	mapping[0] = 1;
+	mapping[1] = chain_len;
+	for (i = 0; i < chain_len; i++)
+		mapping[i + 4] = buf[chain_len - i - 1];
+
+	/* Open main hwinfo block */
+	if (hwilib_find_blocks("hwinfo.hex") != CB_SUCCESS)
+		return CB_ERR;
+	/* Now try to find a valid MAC address in hwinfo for this mapping.*/
+	for (i = 0; i < MAX_NUM_MAPPINGS; i++) {
+		if ((hwilib_get_field(XMac1Mapping + i, buf, 16) == 16) &&
+			!(memcmp(buf, mapping, chain_len + 4))) {
+		/* There is a matching mapping available, get MAC address. */
+			if ((hwilib_get_field(XMac1 + i, mac, 6) == 6) &&
+			    (is_mac_adr_valid(mac))) {
+				return CB_SUCCESS;
+			} else {
+				return CB_ERR;
+			}
+		} else
+			continue;
+	}
+	/* No MAC address found for */
+	return CB_ERR;
+}
 
 static void mainboard_init(void *chip_info)
 {