Re: [PATCH 1/2] drivers: misc: external_state: add a barebox external state.

[anis chali <chalianis1@gmail.com>]

> I didn't quite understand what you are hoping to achieve with this patch
> set, but if the command would serve the purpose, then that would be

Okay, I will come back with something soon.

Thank's for support

Le lun. 3 nov. 2025 à 09:22, Ahmad Fatoum <a.fatoum@pengutronix.de> a écrit :
>
> Hi Anis,
>
> On 11/3/25 3:09 PM, anis chali wrote:
> >>> strlen can't return negative numbers.
> > ack, right it is size_t (unsigned)
> >
> >>> The original function had a number of safety checks that are missing here:
> >>>
> >>> - It only ran the code when in EFI payload mode, as the same barebox
> >>>  binary could be chainloaded without EFI
> >>>
> >>> - It checked that /boot is mounted and gave a useful error message to hint
> >>>  at e.g., EFIFS missing, which we are missing out on here.
> >>>
> >>> I am not yet convinced this is strictly an improvement.
> >
> > Yes you are right but I didn't reintegrate the code in generic driver
> > since it will just use Kconfigs to reference a state dtb file.
> > In case this code was accepted there is no context to do the check,
> > but I ensured that barebox gives a behaves in way that the user
> > will quickly see that there is no /boot directory with the message
> > telling No such file or directory, anyway you suggestion to add -f to
> > state command
> > is more elegant, I will do some experimentations. the aim of this
> > patch is to support a state.dtb given in runtime which permits
> > userspace interaction with
> > native board because I didn't figure out how barebox state command
> > could communicate with a barebox intree state.
>
> I didn't quite understand what you are hoping to achieve with this patch
> set, but if the command would serve the purpose, then that would be
> best, I think.
>
> Cheers,
> Ahmad
>
> >
> >>> If you have the need to customize where your state comes from, how about adding
> >>> a state -f /path/to/state.dtb command option and calling it from your init script?
> > right, more elegant suggestion, I will try it.
> >
> > Thank's for feedback
> >
> > Anis.
> >
> > Le lun. 3 nov. 2025 à 01:46, Ahmad Fatoum <a.fatoum@pengutronix.de> a écrit :
> >>
> >> Hi,
> >>
> >> On 03.11.25 05:38, chalianis1@gmail.com wrote:
> >>> From: Chali Anis <chalianis1@gmail.com>
> >>>
> >>> Add a driver to use an external state dtb, gives the ability to define
> >>> an external state at compile time. useful for yocto or buildroot defining
> >>> a state.dtb that will be passed to barebox at compile time vi a defconfig
> >>> fragment.
> >>
> >> We already had code that did this unconditionally for EFI.
> >> Can you explain why this needs to be customizable?
> >>
> >>> +config EXTERNAL_STATE
> >>> +     tristate "Use external barebox state dtb"
> >>> +     depends on OFDEVICE
> >>> +     depends on STATE
> >>> +     help
> >>> +       This permits the use of an extranl dtb state blob
> >>
> >> external
> >>
> >>> +       which permits to dynamicly at compile time specify
> >>
> >> dynamically
> >>
> >>> +       an external blob vi EXTERNAL_STATE_DTB_PATH
> >>> +
> >>> +config EXTERNAL_STATE_DTB_PATH
> >>> +     string "the external barebox state dtb path"
> >>> +     depends on EXTERNAL_STATE
> >>
> >> Really needs help text as EXTERNAL makes me think of a file on the
> >> build host.
> >>
> >>> +static int state_external_init(void)
> >>> +{
> >>> +     const char *dt_path = CONFIG_EXTERNAL_STATE_DTB_PATH;
> >>> +     struct device_node *state_root = NULL;
> >>> +     size_t size;
> >>> +     void *fdt;
> >>> +     int ret;
> >>> +
> >>> +     if (strlen(dt_path) <= 0)
> >>> +             return -EINVAL;
> >>
> >> strlen can't return negative numbers.
> >>
> >> The original function had a number of safety checks that are missing here:
> >>
> >> - It only ran the code when in EFI payload mode, as the same barebox
> >>   binary could be chainloaded without EFI
> >>
> >> - It checked that /boot is mounted and gave a useful error message to hint
> >>   at e.g., EFIFS missing, which we are missing out on here.
> >>
> >>
> >> I am not yet convinced this is strictly an improvement.
> >>
> >> If you have the need to customize where your state comes from, how about adding
> >> a state -f /path/to/state.dtb command option and calling it from your init script?
> >>
> >> Cheers,
> >> Ahmad
> >>
> >>> +
> >>> +     fdt = read_file(dt_path, &size);
> >>> +     if (!fdt) {
> >>> +             pr_info("unable to read %s: %m\n", dt_path);
> >>> +             return 0;
> >>> +     }
> >>> +
> >>> +     state_root = of_unflatten_dtb(fdt, size);
> >>> +     if (!IS_ERR(state_root)) {
> >>> +             struct device_node *np = NULL;
> >>> +             struct state *state;
> >>> +
> >>> +             ret = barebox_register_of(state_root);
> >>> +             if (ret)
> >>> +                     pr_warn("Failed to register device-tree: %pe\n", ERR_PTR(ret));
> >>> +
> >>> +             np = of_find_node_by_alias(state_root, "state");
> >>> +
> >>> +             state = state_new_from_node(np, false);
> >>> +             if (IS_ERR(state))
> >>> +                     return PTR_ERR(state);
> >>> +
> >>> +             ret = state_load(state);
> >>> +             if (ret != -ENOMEDIUM)
> >>> +                     pr_warn("Failed to load persistent state, continuing with defaults, %d\n",
> >>> +                             ret);
> >>> +
> >>> +             return 0;
> >>> +     }
> >>> +
> >>> +     return -EINVAL;
> >>> +}
> >>> +
> >>> +late_initcall(state_external_init);
> >>
> >>
> >> --
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> >
>
> --
> Pengutronix e.K.                  |                             |
> Steuerwalder Str. 21              | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany         | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686  | Fax:   +49-5121-206917-5555 |
>