Documented where to get hold of the datasheet.

src/drivers/net/3c509.h

 
 #define EEPROMSIZE	0x40
 #define MAX_EEPROMBUSY	1000
-#define EP_LAST_TAG	0xd7
-#define EP_MAX_BOARDS	16
-#define EP_ID_PORT_START 0x110
+#define EP_ID_PORT_START 0x110  /* avoid 0x100 to avoid conflict with SB16 */
 #define EP_ID_PORT_INC 0x10
 #define EP_ID_PORT_END 0x200
+#define EP_TAG_MAX		0x7 /* must be 2^n - 1 */
 
 /*
  * Commands to read/write EEPROM trough EEPROM command register (Window 0,
  * Tasking EISA and ISA Technical Reference" "Beta Draft 10/30/92" manual
  * from 3com.
  *
+ * Getting this document out of 3Com is almost impossible.  However,
+ * archived copies are available at
+ * http://www.osdever.net/cottontail/downloads/docs/3c5x9b.zip and
+ * several other places on the web (search for 3c5x9b.pdf).
+ *
  **************************************************************************/
 
 #define EP_COMMAND		0x0e	/* Write. BASE+0x0e is always a
 #define RX_ERROR	0x4000
 #define RX_INCOMPLETE	0x8000
 
-
 /*
  * Misc defines for various things.
  */
-#define ACTIVATE_ADAPTER_TO_CONFIG	0xff /* to the id_port */
 #define MFG_ID				0x6d50 /* in EEPROM and W0 ADDR_CONFIG */
 #define PROD_ID				0x9150