Re: [PATCH 5/5] commands: dmsetup: Basic command set for dm device management

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 08.09.25 11:27, Tobias Waldekranz wrote:
> On fre, sep 05, 2025 at 18:54, Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>>> +static struct dm_device *dmsetup_find(const char *name)
>>> +{
>>> +	struct dm_device *dm;
>>> +
>>> +	dm = dm_find_by_name(name);
>>> +	if (IS_ERR_OR_NULL(dm)) {
>>> +		pr_err("Found no device named \"%s\"\n", name);
>>
>> pr_/dev_ is logged, so will also be shared with Linux if pstore/ramoops
>> is enabled. For commands, just use printf.
> 
> Wow, nice! I will have to look into this more.

The really useful part is saving crash logs from the kernel on next bootup,
but it is highly hardware dependent how survivable a restart is for the RAM's
contents, even with ECC.

Sharing barebox and kernel log in the same boot is no problem however, just add
to the barebox DT:

/ {
        reserved-memory {
                #address-cells = <1>;
                #size-cells = <1>;
                ranges;

                /* Address will be determined by the bootloader */
                ramoops {
                        compatible = "ramoops";
                };
        };
};

and enable the relevant options in Kconfig.

>> Nice. FYI, if selftest is too cumbersome once you start adding more
>> targets, you can also add tests that exercise commands via pytest. See
>> test/py/.
> 
> Right, yes I will read up on this in the future.
> 
> Thanks for reviewing!

Cheers,
Ahmad

> 
>> Cheers,
>> Ahmad
>>
>>> +
>>> +BAREBOX_CMD_START(dmsetup)
>>> +	.cmd = do_dmsetup,
>>> +	BAREBOX_CMD_DESC("low level interface to the device mapper")
>>> +	BAREBOX_CMD_OPTS("<command> [args...]")
>>> +	BAREBOX_CMD_GROUP(CMD_GRP_PART)
>>> +	BAREBOX_CMD_HELP(cmd_dmsetup_help)
>>> +BAREBOX_CMD_END
>>
>> -- 
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> 


-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
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