@@ -47,6 +47,91 @@ Correct flow of setting up the MAC address (summarized):
Previous behavior had the MAC address always being programmed into hardware
in the device's init() function.
+--------
+ EEPROM
+--------
+
+When there is an EEPROM available on a board, but the EEPROM is not large enough
+to store the whole environment, it may be desired to store a MAC address in the
+onboard EEPROM. Using CONFIG_NET_ETHADDR_EEPROM enables this feature. Depending
+on the board, the EEPROM may be connected on various methods, but currently,
+only the I2C bus is available via CONFIG_NET_ETHADDR_EEPROM_I2C.
+
+The following config options are available,
+CONFIG_NET_ETHADDR_EEPROM_I2C_BUS is the I2C bus on which the eeprom is present.
+CONFIG_NET_ETHADDR_EEPROM_I2C_ADDR sets the address of the EEPROM, which
+defaults to the very common 0x50. Small size EEPROM's generally use single byte
+addressing but larger EEPROM's may use double byte addressing, which can be
+configured using CONFIG_NET_ETHADDR_EEPROM_ADDRLEN.
+
+Within the EEPROM, the MAC address can be stored on any arbitrary offset,
+CONFIG_NET_ETHADDR_EEPROM_OFFSET sets this to 8 as a default however, allowing
+the first 8 bytes to be used for an optional data, for example a configuration
+struct where the mac address is part of.
+
+Appending the 6 (ARP_HLEN) bytes is a CRC8 byte over the previous ARP_HLEN
+bytes. Whether to check this CRC8 or not is dependent on
+CONFIG_NET_ETHADDR_EEPROM_CRC8.
+
+To keep things nicely aligned, a final 'reserved' byte is added to the mac
+address + crc8 combo.
+
+A board may want to store more information in its eeprom, using the following
+example layout, this can be achieved.
+
+struct mac_addr {
+ uint8_t mac[ARP_HLEN];
+ uint8_t crc8;
+ uint8_t reserved;
+};
+
+struct config_eeprom {
+ uint32_t magic;
+ uint8_t version;
+ uint8_t reserved[2];
+ uint8_t mac_cnt;
+ struct mac_addr[mac_cnt];
+};
+
+Filling this in:
+struct config_eeprom eeprom = {
+ .magic = { 'M', 'g', 'i', 'c' },
+ .reserved = { 0x00, 0x00 },
+ .mac_cnt = 2,
+ .mac_addr = {
+ {
+ .mac = {
+ 0x01, 0x23, 0x45,
+ 0x67, 0x89, 0xab,
+ },
+ .crc8 = 0xbe,
+ .reserved = 0x00,
+ }, {
+ .mac = {
+ 0xba, 0x98, 0x76,
+ 0x54, 0x32, 0x10,
+ },
+ .crc8 = 0x82,
+ .reserved = 0x00,
+ },
+ },
+};
+
+The eeprom content would look like this.
+
+00000000 4d 67 69 63 01 00 00 02 01 23 45 67 89 ab be 00 |Mgic.....#Eg....|
+00000010 ba 98 76 54 32 10 82 00 |..vT2...|
+
+Alternativly the i2c-tools can be used as well.
+
+i2cset I2CBUS 0x50 0x08 0x01
+i2cset I2CBUS 0x50 0x09 0x23
+i2cset I2CBUS 0x50 0x0a 0x45
+i2cset I2CBUS 0x50 0x0b 0x67
+i2cset I2CBUS 0x50 0x0c 0x89
+i2cset I2CBUS 0x50 0x0d 0xab
+i2cset I2CBUS 0x50 0x0e 0xbe
+
-------
Usage
-------
@@ -7,6 +7,64 @@ menuconfig NET
if NET
+config NET_ETHADDR_EEPROM
+ bool "Get ethaddr from eeprom"
+ help
+ Selecting this will try to get the Ethernet address from an onboard
+ EEPROM and set into the environment if and only if the environment
+ does currently not already hold a MAC address. For more information
+ see doc/README.enetaddr.
+
+config NET_ETHADDR_EEPROM_I2C
+ depends on NET_ETHADDR_EEPROM
+ bool "EEPROM on I2C bus"
+ help
+ This switch enables checks for an EEPROM on the I2C bus. Naturally
+ this will only work if there is an actual EEPROM connected on the
+ I2C bus and the bus and device are properly configured via the
+ options below.
+
+config NET_ETHADDR_EEPROM_I2C_BUS
+ depends on NET_ETHADDR_EEPROM_I2C
+ int "I2C bus"
+ default 0
+ help
+ Select the bus on which the EEPROM is present, defaults to bus 0.
+
+config NET_ETHADDR_EEPROM_I2C_ADDR
+ depends on NET_ETHADDR_EEPROM_I2C
+ hex "eeprom address"
+ default 0x50
+ help
+ Select the address of the eeprom, defaults to address 0x50.
+
+config NET_ETHADDR_EEPROM_I2C_ADDRLEN
+ depends on NET_ETHADDR_EEPROM_I2C
+ int "eeprom address length"
+ default 1
+ help
+ Number of bytes to be used for the I2C address length. Typically 1,
+ 2 for large memories, 0 for register type devices with only one
+ register.
+
+config NET_ETHADDR_EEPROM_OFFSET
+ depends on NET_ETHADDR_EEPROM
+ int "EEPROM offset"
+ default 8
+ help
+ Select the byte offset of the MAC address within the page,
+ defaults to byte 8.
+
+config NET_ETHADDR_EEPROM_CRC8
+ depends on NET_ETHADDR_EEPROM
+ bool "Check CRC8 of MAC"
+ default y
+ help
+ Optionally, it is possible to run a CRC-8-CCITT check on the MAC
+ address. To do so, the MAC address is stored with a CRC8 byte append.
+ This option enables the CRC check of the MAC address against the CRC
+ byte.
+
config NET_RANDOM_ETHADDR
bool "Random ethaddr if unset"
select LIB_RAND
This patch allows Kconfig to enable and set parameters to make it possible to read the MAC address from an EEPROM. This patch only sets up some environment variables, it is up to the specific boards to actually use these defines. Besides the various tuneables as to how to access the eeprom (bus, address, addressing mode/length, 2 configurable that are EEPROM generic (e.g. SPI or some other form of access) which are: NET_ETHADDR_EEPROM_OFFSET, indicating where in the EEPROM the start of the MAC address is. The default is 8 allowing for 8 bytes before the MAC for other purposes (header MAGIC for example). NET_ETHADDR_EEPROM_CRC8, indicating the MAC is appended with a CRC8-CCIT checksum that should be verified. Currently only I2C eeproms have been tested and thus only those options are available, but shouldn't be a limit. NET_ETHADDR_EEPROM_SPI can be just as created. Signed-off-by: Olliver Schinagl <o.schinagl@ultimaker.com> --- doc/README.enetaddr | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++ net/Kconfig | 58 ++++++++++++++++++++++++++++++++++++ 2 files changed, 143 insertions(+)