[U-Boot] [PATCH v2 5/5] tools: Add tool to add crc8 to a mac address

[Joe Hershberger]

On Tue, Jan 26, 2016 at 10:27 AM, Olliver Schinagl
<o.schinagl at ultimaker.com> wrote:
> Hey Joe,
>
>
> On 26-01-16 01:45, Joe Hershberger wrote:
>>
>> On Mon, Dec 14, 2015 at 6:41 AM, Olliver Schinagl
>> <o.schinagl at ultimaker.com> wrote:
>>>
>>> This patch adds a little tool that takes a generic MAC address and
>>> generates a CRC byte for it. The output is the full MAC address without
>>> any separators, ready written into an EEPROM.
>>>
>>> Signed-off-by: Olliver Schinagl <o.schinagl at ultimaker.com>
>>> ---
>>>   tools/Makefile       |  4 ++++
>>>   tools/gen_mac_addr.c | 51
>>> +++++++++++++++++++++++++++++++++++++++++++++++++++
>>>   2 files changed, 55 insertions(+)
>>>   create mode 100644 tools/gen_mac_addr.c
>>>
>>> diff --git a/tools/Makefile b/tools/Makefile
>>> index 4a50744..6191c26 100644
>>> --- a/tools/Makefile
>>> +++ b/tools/Makefile
>>> @@ -43,6 +43,10 @@ envcrc-objs := envcrc.o lib/crc32.o
>>> common/env_embedded.o lib/sha1.o
>>>   hostprogs-$(CONFIG_CMD_NET) += gen_eth_addr
>>>   HOSTCFLAGS_gen_eth_addr.o := -pedantic
>>>
>>> +hostprogs-$(CONFIG_CMD_NET) += gen_mac_addr
>>> +gen_mac_addr-objs := gen_mac_addr.o lib/crc8.o
>>> +HOSTCFLAGS_gen_mac_addr.o := -pedantic
>>> +
>>>   hostprogs-$(CONFIG_CMD_LOADS) += img2srec
>>>   HOSTCFLAGS_img2srec.o := -pedantic
>>>
>>> diff --git a/tools/gen_mac_addr.c b/tools/gen_mac_addr.c
>>> new file mode 100644
>>> index 0000000..bd8688f
>>> --- /dev/null
>>> +++ b/tools/gen_mac_addr.c
>>
>> This is not "generating a mac address", right? Its point is to create
>> a CRC for the user-supplied MAC address.
>>
>> Perhaps a better name would be "gen_ethaddr_rom_crc".
>
> Yes, it takes a mac address as input and generates a macaddress + crc as
> output.
>
> e.g. 11:22:33:44:55:66 -> 0x11 0x22 0x33 0x44 0x55 0x66 0x77 0xcc
>
> But maybe it should get some flags to output either both (as described here)
> or just the crc based on the input, and then a few flags to either output it
> in hex format or as an int?

What ever features you think will be useful for the users of this dev
board I guess. I'm not sure if this is a platform (the included
eeprom) that would carry over into other products.

>>
>>> @@ -0,0 +1,51 @@
>>> +/*
>>> + * (C) Copyright 2016
>>> + * Olliver Schinagl <o.schinagl at ultimaker.com>
>>> + *
>>> + * SPDX-License-Identifier:    GPL-2.0+
>>> + */
>>> +
>>> +#include <ctype.h>
>>> +#include <stdint.h>
>>> +#include <stdio.h>
>>> +#include <stdlib.h>
>>> +#include <string.h>
>>> +#include <u-boot/crc.h>
>>> +
>>> +
>>> +int main(int argc, char *argv[])
>>> +{
>>> +       uint_fast8_t i;
>>> +       uint8_t mac_addr[7] = { 0x00 };
>>> +
>>> +       if (argc < 2) {
>>> +               puts("Please supply a MAC address.");
>>> +               return -1;
>>> +       }
>>> +
>>> +       if (!((strlen(argv[1]) == 12) || (strlen(argv[1]) == 17))) {
>>> +               puts("Please supply a valid MAC address with optionaly\n"
>>> +                    "dashes (-) or colons (:) as seperators.");
>>> +               return -1;
>>> +       }
>>
>> You could use the eth_validate_ethaddr_str() function here instead of this
>> code.
>
> A right, well when I first wrote this, I think this didn't exist there yet.
> I'll replace it and use it instead.
>>
>>
>>> +
>>> +       i = 0;
>>> +       while (*argv[1] != '\0') {
>>> +               char nibble[2] = { 0x00, '\n' }; /* for strtol */
>>> +
>>> +               nibble[0] = *argv[1]++;
>>> +               if (isxdigit(nibble[0])) {
>>> +                       if (isupper(nibble[0]))
>>> +                               nibble[0] = tolower(nibble[0]);
>>> +                       mac_addr[i >> 1] |= strtol(nibble, NULL, 16) <<
>>> ((i % 2) ? 0 : 4) & ((i % 2) ? 0x0f : 0xf0);
>>> +                       i++;
>>> +               }
>>> +       }
>>
>> Instead of all this you could just compile in (maybe it already is?)
>> the eth_parse_enetaddr() function that U-Boot uses for this very
>> purpose.
>
> I'll see if I can have access to this function and then rewrite this to use
> that.
>
>>
>>> +       mac_addr[6] = crc8(mac_addr, 6);
>>> +
>>> +       for (i = 0; i < 7; i++)
>>> +               printf("%.2x", mac_addr[i]);
>>> +       putchar('\n');
>>> +
>>> +       return 0;
>>> +}
>>> --
>>> 2.6.2
>>>
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>
>
> --
> Met vriendelijke groeten, Kind regards, 与亲切的问候
>
> Olliver Schinagl
> Software Engineer
> Research & Development
> Ultimaker B.V.
>