[U-Boot] [U-Boot, PATCHv1, 1/3] net: Add ability to set MAC address via EEPROM to Kconfig

[Olliver Schinagl <o.schinagl@ultimaker.com>]

Hans, Joe,


On 10-12-15 11:29, Hans de Goede wrote:
> Hi Olliver and Joe,
>
> On 11/30/2015 05:50 PM, Oliver Schinagl wrote:
>> From: Olliver Schinagl <o.schinagl@ultimaker.com>
>>
>> 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>
>
> Thanks, from a sunxi pov this and the other 2 patches look good.
>
> Joe can we have your ack for this one please and/or can you merge this
> one through your tree? Either way I will take care of the other 2
> patches in this set.
I do intend to make a v2 and one of the things I hoped would bring up 
some discussion is wether to do the CRC with or without the interface 
ID. In this patch I calculate the CRC on 7 bytes, MAC + id, but I kinda 
went back on that and do a mac + crc + id.

Since nobody commented before, I haven't sent the v2 just yet (which 
will include a generator tool).

Any thoughts before merging this on that subject?

Olliver
>
> From my pov this is fine as v2016.01 material, but if you would
> rather postpone this to v2016.04 that is fine too.
>
> Thanks & Regards,
>
> Hans
>
>
>> ---
>>   doc/README.enetaddr | 36 +++++++++++++++++++++++++++++++++
>>   net/Kconfig         | 58 
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   2 files changed, 94 insertions(+)
>>
>> diff --git a/doc/README.enetaddr b/doc/README.enetaddr
>> index 50e4899..c53b455 100644
>> --- a/doc/README.enetaddr
>> +++ b/doc/README.enetaddr
>> @@ -47,6 +47,42 @@ 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.
>> +CONFIG_NET_ETHADDR_EEPROM_I2C_BUS I2C bus on which the eeprom is 
>> present and
>> +CONFIG_NET_ETHADDR_EEPROM_I2C_ADDR set 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 some header magic for example.
>> +
>> +After the 6 bytes used for the MAC address, there is an 8 byte field 
>> to indicate
>> +the ID of the network interface this MAC address is for. 0xff here 
>> means 'for
>> +the first available interface' and 0x00 means the first network 
>> interface, 0x01
>> +the second, etc. It is up to the platform however to enforce this.
>> +
>> +Appending the 6 MAC bytes and the 7th interface byte is a CRC8 byte 
>> over the
>> +previous 7 bytes. Whether to check this CRC8 or not is dependent on
>> +CONFIG_NET_ETHADDR_EEPROM_CRC8.
>> +
>> +Layout example:
>> +
>> +00000000  21 4d 61 67 69 63 2e 21  01 23 45 67 89 ab ff c0 
>> |!Magic.!.#Eg....|
>> +
>> +where the Header magic (!Magic.!) is spread over the first 8 bytes, 
>> and the MAC
>> +address '01-23-45-67-89-ab' for the first interface (0xff) with the 
>> CRC8
>> +checksum 0xc0.
>> +
>>   -------
>>    Usage
>>   -------
>> diff --git a/net/Kconfig b/net/Kconfig
>> index a44a783..aced51e 100644
>> --- a/net/Kconfig
>> +++ b/net/Kconfig
>> @@ -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
>>

-- 
Met vriendelijke groeten, Kind regards, ??????

Olliver Schinagl
Software Engineer
Research & Development
Ultimaker B.V.