On 10-11-16 13:26, Michal Simek wrote:
On 10.11.2016 13:08, Olliver Schinagl wrote:
Hi Michal,
On 10-11-16 12:37, Michal Simek wrote:
On 8.11.2016 16:54, Olliver Schinagl wrote:
This patch-series introduces methods to retrieve the MAC address from an
onboard EEPROM using the read_rom_hwaddr hook.
The reason we might want to read the MAC address from an EEPROM
instead of
storing the entire environment is mostly a size thing. Our default
environment
already is bigger then the EEPROM so it is understandable that
someone might
not give up the entire eeprom just for the u-boot environment.
Especially if
only board specific things might be stored in the eeprom (MAC,
serial, product
number etc). Additionally it is a board thing and a MAC address might be
programmed at the factory before ever seeing any software.
The current idea of the eeprom layout, is to skip the first 8 bytes,
so that
other information can be stored there if needed, for example a header
with some
magic to identify the EEPROM. Or equivalent purposes.
After those 8 bytes the MAC address follows the first macaddress. The
macaddress
is appended by a CRC8 byte and then padded to make for nice 8 bytes.
Following
the first macaddress one can store a second, or a third etc etc mac
addresses.
The CRC8 is optional (via a define) but is strongly recommended to
have. It
helps preventing user error and more importantly, checks if the bytes
read are
actually a user inserted address. E.g. only writing 1 macaddress into
the eeprom
but trying to consume 2.
Hans de Goede and I talked about retrieving the MAC from the EEPROM
for sunxi
based boards a while ago, but hopefully this patch makes possible to
have
something slightly more generic, even if only the configuration options.
Additionally the EEPROM layout could be recommended by u-boot as well.
Since the Olimex OLinuXino sunxi boards all seem to have an eeprom, I
started
my work on one of these and tested the implementation with one of our
own real
MAC addresses.
What still needs disussing I think, is the patches that remove the
'setup_environment' function in board.c. I think we have put
functionality in
boards.c which does not belong. Injecting ethernet addresses into the
environment instead of using the net_op hooks as well as parsing the
fdt to get
overrides from. I think especially this last point should be done at
a higher
level, if possible at all.
I explicitly did not use the wiser eth_validate_ethaddr_str(),
eth_parse_enetaddr() and the ARP_HLEN define as it was quite painful
(dependancies) to get these functions into the tools. I would suggest
to merge
as is, and if someone wants to improve these simple tools to use
these functions
to happily do so.
These patches where tested on Olimex OLinuXino Lime1 (A10/A20), Lime2
(NAND
and eMMC) and A20-OLinuXino-MICRO-4G variants and have been in use
internally on our production systems since v2 of this patch set.
As a recommendation, I would suggest for the zynq to adopt the config
defines,
as they are nice and generic and suggest to also implement the 8 byte
offset,
crc8 and pad bytes.
Yes, Zynq and ZynqMP is using this feature. I am also aware about using
qspi OTP region for storing information like this.
I saw, which triggered me here. What the Znyq currently does it uses its
own private CONFIG setting:
+int zynq_board_read_rom_ethaddr(unsigned char *ethaddr)
+{
+#if defined(CONFIG_ZYNQ_GEM_EEPROM_ADDR) && \
+ defined(CONFIG_ZYNQ_GEM_I2C_MAC_OFFSET) && \
+ defined(CONFIG_ZYNQ_EEPROM_BUS)
+ i2c_set_bus_num(CONFIG_ZYNQ_EEPROM_BUS);
+
+ if (eeprom_read(CONFIG_ZYNQ_GEM_EEPROM_ADDR,
+ CONFIG_ZYNQ_GEM_I2C_MAC_OFFSET,
+ ethaddr, 6))
+ printf("I2C EEPROM MAC address read failed\n");
+#endif
+
+ return 0;
+}
which are ZNYQ specific. In my patchset I give them very generic names
as they can be used by anybody really.
Once Maxime's patches have merged and stabilized, i'd even say to switch
over to the eeprom framework.
Can you give me that link to these patches?
Well [0] is your own patch, so that is easy :) [1] is Maxime's work. But
with your generic comment, this entire function probably can simply go
then. The only thing I haven't figured out/thought through yet, if
eeprom reading fails, we want to fall back to the old board specific
method. But I think I know what might do there ...
Olliver
[0] http://git.denx.de/?p=u-boot.git;a=commit;h=6919b4bf363574
[1] https://www.mail-archive.com/u-boot@lists.denx.de/msg230179.html
Thanks,
Michal
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