Program net device MAC addresses after initializing

Add a new function to the eth_device struct for programming a network
controller's hardware address.

After all network devices have been initialized and the proper MAC address
for each has been determined, make a device driver call to program the
address into the device.  Only device instances with valid unicast addresses
will be programmed.

Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
Acked-by: Detlev Zundel <dzu@denx.de>
Tested-by: Prafulla Wadaskar <prafulla@marvell.com>
Tested-by: Heiko Schocher <hs@denx.de>
Tested-by: Thomas Chou <thomas@wytron.com.tw>

README

@@ -3303,6 +3303,11 @@ o If both the SROM and the environment contain a MAC address, and the
 o If neither SROM nor the environment contain a MAC address, an error
   is raised.
 
+If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
+will be programmed into hardware as part of the initialization process.  This
+may be skipped by setting the appropriate 'ethmacskip' environment variable.
+The naming convention is as follows:
+"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
 
 Image Formats:
 ==============

doc/README.drivers.eth

@@ -70,6 +70,7 @@ int ape_register(bd_t *bis, int iobase)
 	dev->halt = ape_halt;
 	dev->send = ape_send;
 	dev->recv = ape_recv;
+	dev->write_hwaddr = ape_write_hwaddr;
 
 	eth_register(dev);
 
@@ -102,11 +103,12 @@ not checking its state or doing random probing.
  -----------
 
 Now that we've registered with the ethernet layer, we can start getting some
-real work done.  You will need four functions:
+real work done.  You will need five functions:
 	int ape_init(struct eth_device *dev, bd_t *bis);
 	int ape_send(struct eth_device *dev, volatile void *packet, int length);
 	int ape_recv(struct eth_device *dev);
 	int ape_halt(struct eth_device *dev);
+	int ape_write_hwaddr(struct eth_device *dev);
 
 The init function checks the hardware (probing/identifying) and gets it ready
 for send/recv operations.  You often do things here such as resetting the MAC
@@ -150,6 +152,9 @@ The halt function should turn off / disable the hardware and place it back in
 its reset state.  It can be called at any time (before any call to the related
 init function), so make sure it can handle this sort of thing.
 
+The write_hwaddr function should program the MAC address stored in dev->enetaddr
+into the Ethernet controller.
+
 So the call graph at this stage would look something like:
 some net operation (ping / tftp / whatever...)
 	eth_init()

doc/README.enetaddr

@@ -33,11 +33,13 @@ Correct flow of setting up the MAC address (summarized):
 1. Read from hardware in initialize() function
 2. Read from environment in net/eth.c after initialize()
 3. Give priority to the value in the environment if a conflict
-4. Program hardware in the device's init() function.
+4. Program the address into hardware if the following conditions are met:
+	a) The relevant driver has a 'write_addr' function
+	b) The user hasn't set an 'ethmacskip' environment variable
+	c) The address is valid (unicast, not all-zeros)
 
-If somebody wants to subvert the design philosophy, this can be done
-in the board-specific board_eth_init() function by calling eth_init()
-after all the NICs have been registered.
+Previous behavior had the MAC address always being programmed into hardware
+in the device's init() function.
 
 -------
  Usage

include/net.h

@@ -105,6 +105,7 @@ struct eth_device {
 #ifdef CONFIG_MCAST_TFTP
 	int (*mcast) (struct eth_device*, u32 ip, u8 set);
 #endif
+	int  (*write_hwaddr) (struct eth_device*);
 	struct eth_device *next;
 	void *priv;
 };

net/eth.c

@@ -60,6 +60,14 @@ int eth_getenv_enetaddr_by_index(int index, uchar *enetaddr)
 	return eth_getenv_enetaddr(enetvar, enetaddr);
 }
 
+static int eth_mac_skip(int index)
+{
+	char enetvar[15];
+	char *skip_state;
+	sprintf(enetvar, index ? "eth%dmacskip" : "ethmacskip", index);
+	return ((skip_state = getenv(enetvar)) != NULL);
+}
+
 #ifdef CONFIG_NET_MULTI
 
 /*
@@ -242,6 +250,11 @@ int eth_initialize(bd_t *bis)
 
 				memcpy(dev->enetaddr, env_enetaddr, 6);
 			}
+			if (dev->write_hwaddr &&
+				!eth_mac_skip(eth_number) &&
+				is_valid_ether_addr(dev->enetaddr)) {
+				dev->write_hwaddr(dev);
+			}
 
 			eth_number++;
 			dev = dev->next;