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

[Olliver Schinagl]

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.
>
>>>> @@ -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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>>>> 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.