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

[Joe Hershberger]

On Tue, Jan 26, 2016 at 10:36 AM, Olliver Schinagl
<o.schinagl at ultimaker.com> wrote:
> Hey Joe,
>
>
> On 26-01-16 17:31, Joe Hershberger wrote:
>>
>> 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.
>
> Why not? It just reads a mac address and generates a crc8-appended mac
> address (or just the crc8) everybody that uses a mac address to be stored
> somewhere (even if the env is pre-generated) could use this. I don't think
> it is limited to our platform since it does something very generic.

OK.

>
>>
>>>>> @@ -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
>>>>>
>>>>> _______________________________________________
>>>>> U-Boot mailing list
>>>>> U-Boot at lists.denx.de
>>>>> http://lists.denx.de/mailman/listinfo/u-boot
>>>
>>>
>>> --
>>> Met vriendelijke groeten, Kind regards, 与亲切的问候
>>>
>>> Olliver Schinagl
>>> Software Engineer
>>> Research & Development
>>> Ultimaker B.V.
>>>
>
> --
> Met vriendelijke groeten, Kind regards, 与亲切的问候
>
> Olliver Schinagl
> Software Engineer
> Research & Development
> Ultimaker B.V.
>