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

[Olliver Schinagl]

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?
>
>> @@ -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.