[PATCH v2 05/11] fdt_support: Implement fdt_ethernet_set_macaddr()

[Alexandru Gagniuc <mr.nuke.me@gmail.com>]

Oftentimes we have MAC address information stored in a ROM or OTP. The
way to add that to the FDT would be through the u-boot environment,
and then fdt_fixup_ethernet(). This is not very useful in SPL.

It would be more helpful to be able to "set interface x to MAC y".
This is where fdt_ethernet_set_macaddr() comes in. It is similar in
function to fdt_fixup_ethernet(), but only updates one interface,
without using the u-boot env, and without string processing.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
---
 common/fdt_support.c  | 30 ++++++++++++++++++++++++++++++
 include/fdt_support.h | 17 +++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/common/fdt_support.c b/common/fdt_support.c
index 8992ac5d3f..1c43640cf7 100644
--- a/common/fdt_support.c
+++ b/common/fdt_support.c
@@ -610,6 +610,36 @@ void fdt_fixup_ethernet(void *fdt)
 	}
 }
 
+int fdt_ethernet_set_macaddr(void *fdt, int ethnum, const uint8_t *mac_addr)
+{
+	const char *path, *name;
+	int prop, aliases_node;
+	char eth_name[16] = "ethernet";
+
+	aliases_node = fdt_path_offset(fdt, "/aliases");
+	if (aliases_node < 0)
+		return aliases_node;
+
+	if (ethnum >= 0)
+		sprintf(eth_name, "ethernet%d", ethnum);
+
+	fdt_for_each_property_offset(prop, fdt, aliases_node) {
+		path = fdt_getprop_by_offset(fdt, prop, &name, NULL);
+		if (!strcmp(name, eth_name))
+			break;
+
+		path = NULL;
+	}
+
+	if (!path)
+		return -FDT_ERR_NOTFOUND;
+
+	do_fixup_by_path(fdt, path, "mac-address", mac_addr, 6, 0);
+	do_fixup_by_path(fdt, path, "local-mac-address", mac_addr, 6, 1);
+
+	return 0;
+}
+
 int fdt_record_loadable(void *blob, u32 index, const char *name,
 			uintptr_t load_addr, u32 size, uintptr_t entry_point,
 			const char *type, const char *os, const char *arch)
diff --git a/include/fdt_support.h b/include/fdt_support.h
index f6f46bb8e9..3f0bcb5a00 100644
--- a/include/fdt_support.h
+++ b/include/fdt_support.h
@@ -119,6 +119,23 @@ static inline int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[],
 #endif
 
 void fdt_fixup_ethernet(void *fdt);
+
+/**
+ * Set the "mac-address" and "local-mac-address" of ethernet node
+ * The ethernet node is located from the "/aliases" section of the fdt. When
+ * 'ethnum' is positive, then the name is matched exactly, e.g "ethernet0".
+ * When ethnum is negative, the first ethernet alias is updated.
+ * Unlike fdt_fixup_ethernet(), this function only updates one ethernet node,
+ * and soes not use the "ethaddr" from the u-boot environment. This is useful,
+ * for example, in SPL, when the environment is not initialized or available.
+ *
+ * @param fdt		FDT blob to update
+ * @param ethnum	Ethernet device index, or negative for any ethernet
+ * @param mac_addr	Pointer to 6-byte array containing the MAC address
+ *
+ * @return 0 if ok, or -FDT_ERR_... on error
+ */
+int fdt_ethernet_set_macaddr(void *fdt, int ethnum, const uint8_t *mac_addr);
 int fdt_find_and_setprop(void *fdt, const char *node, const char *prop,
 			 const void *val, int len, int create);
 void fdt_fixup_qe_firmware(void *fdt);
-- 
2.31.1