Hi Jeremy,

On 12/08/15 23:06, Jeremy Linton wrote:
[...]
+static void *device_get_mac_addr(struct device *dev,
+                                const char *name, char *addr,
+                                int alen)
+{
+       int ret = device_property_read_u8_array(dev, name, addr, alen);
+
+       if (ret == 0 && is_valid_ether_addr(addr))
+               return addr;
+       return NULL;
+}

Not sure I understand the logic here - "return the same thing we were given if we updated it, or null if we didn't". It's only indicating success/failure (the caller can perfectly well cast its own buffer to a void * if it needs to), so why wouldn't you just return a normal int error code?

+/**
+ * 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
+ * address. If that isn't set, then 'local-mac-address' is checked next,
+ * because that is the default address.  If that isn't set, then the obsolete
+ * 'address' is checked, just in case we're using an old device tree.
+ *
+ * Note that the 'address' property is supposed to contain a virtual address of
+ * the register set, but some DTS files have redefined that property to be the
+ * MAC address.
+ *
+ * All-zero MAC addresses are rejected, because those could be properties that
+ * exist in the device tree, but were not set by U-Boot.  For example, the
+ * DTS could define 'mac-address' and 'local-mac-address', with zero MAC
+ * addresses.  Some older U-Boots only initialized 'local-mac-address'.  In
+ * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
+ * but is all zeros.
+*/
+void *device_get_mac_address(struct device *dev, char *addr, int alen)
+{
+       addr = device_get_mac_addr(dev, "mac-address", addr, alen);
+       if (addr)
+               return addr;
+
+       addr = device_get_mac_addr(dev, "local-mac-address", addr, alen);
+       if (addr)
+               return addr;
+
+       return device_get_mac_addr(dev, "address", addr, alen);
+}
+EXPORT_SYMBOL(device_get_mac_address);

Same here, it's not at all apparent why this should return a void * instead of an int (or even possibly bool). of_get_mac_address is giving its caller back a _new_ pointer they didn't know about before; this isn't.

Robin.

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