include/asm-blackfin/net.h

   1 /*
   2  * net.h - misc Blackfin network helpers
   3  *
   4  * Copyright (c) 2008-2009 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #ifndef __ASM_BFIN_RAND_MAC__
  10 #define __ASM_BFIN_RAND_MAC__
  11
  12 /* If the board does not have a real MAC assigned to it, then generate a
  13  * locally administrated pseudo-random one based on CYCLES and compile date.
  14  */
  15 static inline void bfin_gen_rand_mac(uchar *mac_addr)
  16 {
  17         /* make something up */
  18         const char s[] = __DATE__;
  19         size_t i;
  20         u32 cycles;
  21         for (i = 0; i < 6; ++i) {
  22                 asm("%0 = CYCLES;" : "=r" (cycles));
  23                 mac_addr[i] = cycles ^ s[i];
  24         }
  25         mac_addr[0] = (mac_addr[0] | 0x02) & ~0x01; /* make it local unicast */
  26 }
  27
  28 #endif