lede/target/linux/generic/pending-5.4/681-NET-add-of_get_mac_address_mtd.patch

From: John Crispin <blogic@openwrt.org>
Subject: NET: add mtd-mac-address support to of_get_mac_address()

Many embedded devices have information such as mac addresses stored inside mtd
devices. This patch allows us to add a property inside a node describing a
network interface. The new property points at a mtd partition with an offset
where the mac address can be found.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/of/of_net.c    |   37 +++++++++++++++++++++++++++++++++++++
 include/linux/of_net.h |    1 +
 2 files changed, 38 insertions(+)

--- a/drivers/of/of_net.c
+++ b/drivers/of/of_net.c
@@ -11,6 +11,7 @@
 #include <linux/phy.h>
 #include <linux/export.h>
 #include <linux/device.h>
+#include <linux/mtd/mtd.h>
 
 /**
  * of_get_phy_mode - Get phy mode for given device_node
@@ -39,7 +40,7 @@ int of_get_phy_mode(struct device_node *
 }
 EXPORT_SYMBOL_GPL(of_get_phy_mode);
 
-static const void *of_get_mac_addr(struct device_node *np, const char *name)
+static void *of_get_mac_addr(struct device_node *np, const char *name)
 {
 	struct property *pp = of_find_property(np, name, NULL);
 
@@ -72,6 +73,138 @@ static const void *of_get_mac_addr_nvmem
 	return mac;
 }
 
+typedef int(*mtd_mac_address_read)(struct mtd_info *mtd, loff_t from, u_char *buf);
+
+static int read_mtd_mac_address(struct mtd_info *mtd, loff_t from, u_char *mac)
+{
+	size_t retlen;
+
+	return mtd_read(mtd, from, 6, &retlen, mac);
+}
+
+static int read_mtd_mac_address_ascii(struct mtd_info *mtd, loff_t from, u_char *mac)
+{
+	size_t retlen;
+	char buf[17];
+
+	if (mtd_read(mtd, from, 12, &retlen, buf)) {
+		return -1;
+	}
+	if (sscanf(buf, "%2hhx%2hhx%2hhx%2hhx%2hhx%2hhx",
+			&mac[0], &mac[1], &mac[2], &mac[3],
+			&mac[4], &mac[5]) == 6) {
+		if (mac[0] == '\0' && mac[1] == '\0') { /* First 2 bytes are zero, probably a bug. Trying to re-read */
+			buf[4] = '\0'; /* Make it null-terminated */
+			if (sscanf(buf, "%4hx", mac) == 1)
+				*(uint16_t*)mac = htons(*(uint16_t*)mac);
+		}
+		return 0;
+	}
+	if (mtd_read(mtd, from+12, 5, &retlen, buf+12)) {
+		return -1;
+	}
+	if (sscanf(buf, "%2hhx:%2hhx:%2hhx:%2hhx:%2hhx:%2hhx",
+			&mac[0], &mac[1], &mac[2], &mac[3],
+			&mac[4], &mac[5]) == 6) {
+		return 0;
+	}
+	return -1;
+}
+
+static struct mtd_mac_address_property {
+	char *name;
+	mtd_mac_address_read read;
+} mtd_mac_address_properties[] = {
+	{
+		.name = "mtd-mac-address",
+		.read = read_mtd_mac_address,
+	}, {
+		.name = "mtd-mac-address-ascii",
+		.read = read_mtd_mac_address_ascii,
+	},
+};
+
+static const void *of_get_mac_address_mtd(struct device_node *np)
+{
+#ifdef CONFIG_MTD
+	struct device_node *mtd_np = NULL;
+	struct property *prop;
+	int size, ret = -1;
+	struct mtd_info *mtd;
+	const char *part;
+	const __be32 *list;
+	phandle phandle;
+	u32 mac_inc = 0;
+	u8 mac[ETH_ALEN];
+	void *addr;
+	u32 inc_idx;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mtd_mac_address_properties); i++) {
+		list = of_get_property(np, mtd_mac_address_properties[i].name, &size);
+		if (!list || (size != (2 * sizeof(*list))))
+			continue;
+
+		phandle = be32_to_cpup(list++);
+		if (phandle)
+			mtd_np = of_find_node_by_phandle(phandle);
+
+		if (!mtd_np)
+			continue;
+
+		part = of_get_property(mtd_np, "label", NULL);
+		if (!part)
+			part = mtd_np->name;
+
+		mtd = get_mtd_device_nm(part);
+		if (IS_ERR(mtd))
+			continue;
+
+		ret = mtd_mac_address_properties[i].read(mtd, be32_to_cpup(list), mac);
+		put_mtd_device(mtd);
+		if (!ret) {
+			break;
+		}
+	}
+	if (ret) {
+		return NULL;
+	}
+
+	if (of_property_read_u32(np, "mtd-mac-address-increment-byte", &inc_idx))
+		inc_idx = 5;
+	if (inc_idx > 5)
+		return NULL;
+
+	if (!of_property_read_u32(np, "mtd-mac-address-increment", &mac_inc))
+		mac[inc_idx] += mac_inc;
+
+	if (!is_valid_ether_addr(mac))
+		return NULL;
+
+	addr = of_get_mac_addr(np, "mac-address");
+	if (addr) {
+		memcpy(addr, mac, ETH_ALEN);
+		return addr;
+	}
+
+	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
+	if (!prop)
+		return NULL;
+
+	prop->name = "mac-address";
+	prop->length = ETH_ALEN;
+	prop->value = kmemdup(mac, ETH_ALEN, GFP_KERNEL);
+	if (!prop->value || of_add_property(np, prop))
+		goto free;
+
+	return prop->value;
+free:
+	kfree(prop->value);
+	kfree(prop);
+#endif
+	return NULL;
+}
+
 /**
  * Search the device tree for the best MAC address to use.  'mac-address' is
  * checked first, because that is supposed to contain to "most recent" MAC
@@ -92,12 +225,20 @@ static const void *of_get_mac_addr_nvmem
  * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
  * but is all zeros.
  *
+ *
+ * If a mtd-mac-address property exists, try to fetch the MAC address from the
+ * specified mtd device, and store it as a 'mac-address' property
+ *
  * Return: Will be a valid pointer on success and ERR_PTR in case of error.
 */
 const void *of_get_mac_address(struct device_node *np)
 {
 	const void *addr;
 
+	addr = of_get_mac_address_mtd(np);
+	if (addr)
+		return addr;
+
 	addr = of_get_mac_addr(np, "mac-address");
 	if (addr)
 		return addr;