mb/siemens/mc_ehl1: Enable Intel I210 MACPHY driver

This variant uses I210 MACPHYs so enable the I210 driver in order to set
the needed MAC addresses. In addition add the function to retrieve a
valid MAC address for the given MACPHY.

Change-Id: Id1d59349db1b86cfdd71bbe27577c0530e8f0b51
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56567
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/siemens/mc_ehl/mainboard.c

@@ -1,8 +1,87 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <baseboard/variants.h>
+#include <console/console.h>
 #include <device/device.h>
+#include <hwilib.h>
+#include <i210.h>
 #include <soc/gpio.h>
+#include <string.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[MAC_ADDR_LEN])
+{
+	for (size_t i = 0; i < MAC_ADDR_LEN; i++) {
+		if (mac[i] != 0x00 && mac[i] != 0xff)
+			return 1;
+		if (mac[i] != mac[0])
+			return 1;
+	}
+	return 0;
+}
+
+/** \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[MAC_ADDR_LEN])
+{
+	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)
+			continue;
+		if (memcmp(buf, mapping, chain_len + 4))
+			continue;
+		/* There is a matching mapping available, get MAC address. */
+		if (hwilib_get_field(XMac1 + i, mac, MAC_ADDR_LEN) == MAC_ADDR_LEN) {
+			if (is_mac_adr_valid(mac))
+				return CB_SUCCESS;
+		}
+		return CB_ERR;
+	}
+	/* No MAC address found for */
+	return CB_ERR;
+}
 
 static void mainboard_init(void *chip_info)
 {

src/mainboard/siemens/mc_ehl/variants/mc_ehl1/Kconfig

@@ -1,5 +1,9 @@
 if BOARD_SIEMENS_MC_EHL1
 
+config BOARD_SPECIFIC_OPTIONS
+	def_bool y
+	select DRIVER_INTEL_I210
+
 config FMDFILE
 	default "src/mainboard/\$(CONFIG_MAINBOARD_DIR)/mc_ehl.fmd"