[PATCH 2/2] env: point fdt address to the fdt in a bloblist

[Raymond Mao]

Hi Tom,

On Fri, 28 Mar 2025 at 19:51, Tom Rini <trini at konsulko.com> wrote:
>
> On Thu, Mar 27, 2025 at 04:13:17PM -0700, Raymond Mao wrote:
>
> > Point fdt_addr to the fdt embedded in the bloblist since fdt_addr
> > is a default address for bootefi, bootm and booti to look for the
> > device tree when launching the kernel.
> >
> > Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
> > ---
> >  env/common.c | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> >
> > diff --git a/env/common.c b/env/common.c
> > index a58955a4f42..a38e5d107a8 100644
> > --- a/env/common.c
> > +++ b/env/common.c
> > @@ -16,6 +16,7 @@
> >  #include <asm/global_data.h>
> >  #include <linux/printk.h>
> >  #include <linux/stddef.h>
> > +#include <mapmem.h>
> >  #include <search.h>
> >  #include <errno.h>
> >  #include <malloc.h>
> > @@ -368,6 +369,18 @@ int env_get_default_into(const char *name, char *buf, unsigned int len)
> >       return env_get_from_linear(default_environment, name, buf, len);
> >  }
> >
> > +static int env_update_fdt_addr_from_bloblist(void)
> > +{
> > +     /*
> > +      * fdt_addr is by default used by booti, bootm and bootefi,
> > +      * thus set it to point to the fdt embedded in a bloblist if it exists.
> > +      */
> > +     if (!CONFIG_IS_ENABLED(BLOBLIST) || gd->fdt_src != FDTSRC_BLOBLIST)
> > +             return 0;
> > +
> > +     return env_set_hex("fdt_addr", (uintptr_t)map_to_sysmem(gd->fdt_blob));
> > +}
>
> This part is fine with me and makes enough sense, we can't do this
> immediately so we need some check to know to do it later.
>
> >  void env_set_default(const char *s, int flags)
> >  {
> >       if (s) {
> > @@ -392,6 +405,10 @@ void env_set_default(const char *s, int flags)
> >
> >       gd->flags |= GD_FLG_ENV_READY;
> >       gd->flags |= GD_FLG_ENV_DEFAULT;
> > +
> > +     /* This has to be done after GD_FLG_ENV_READY is set */
> > +     if (env_update_fdt_addr_from_bloblist())
> > +             pr_err("Failed to set fdt_addr to point at DTB\n");
> >  }
>
> I don't know this is the right spot. This won't work when for example
> the environment is valid but stored in a file on FAT (or whatever) will
> it?
>

I can add invoking 'env_update_fdt_addr_from_bloblist()' inside
'env_import()'. It should work in all the cases then.

Regards,
Raymond

> --
> Tom