Merge branch 'u-boot-microblaze/zynq' into 'u-boot-arm/master'

[karo-tx-uboot.git] / doc / README.enetaddr

diff --git a/doc/README.enetaddr b/doc/README.enetaddr
index 1d75aa3876efc8c47bbe9e6c76963ef0ec105bf0..1eaeaf9416efb5c76a81a202390f4bf110b11adc 100644 (file)
--- a/doc/README.enetaddr
+++ b/doc/README.enetaddr
@@ -28,6 +28,23 @@ Here are the places where MAC addresses might be stored:
              purpose of passing this information to an OS kernel we are about
              to boot
 
+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. The environment variable will be compared to the driver initialized
+   struct eth_device->enetaddr. If they differ, a warning is printed, and the
+   environment variable will be used unchanged.
+   If the environment variable is not set, it will be initialized from
+   eth_device->enetaddr, and a warning will be printed.
+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)
+
+Previous behavior had the MAC address always being programmed into hardware
+in the device's init() function.
+
 -------
  Usage
 -------