[PATCH v3 1/9] bloblist: add API to check the register conventions

[Raymond Mao]

Hi Simon,

On Tue, 26 Dec 2023 at 04:48, Simon Glass <sjg at chromium.org> wrote:

> Hi Raymond,
>
> On Fri, Dec 22, 2023 at 9:31 PM Raymond Mao <raymond.mao at linaro.org>
> wrote:
> >
> > Add bloblist_check_reg_conv() to check whether the bloblist is compliant
> > to the register conventions defined in Firmware Handoff specification.
> > This API can be used for all Arm platforms.
> >
> > Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
> > ---
> > Changes in v2
> > - Refactor of bloblist_check_reg_conv().
> > Changes in v3
> > - bloblist_check_reg_conv() returns -ENOENT if OF_BOARD is disabled.
> >
> >  common/bloblist.c  | 13 +++++++++++++
> >  include/bloblist.h | 12 ++++++++++++
> >  2 files changed, 25 insertions(+)
> >
> > diff --git a/common/bloblist.c b/common/bloblist.c
> > index 625e480f6b..ba17dd851a 100644
> > --- a/common/bloblist.c
> > +++ b/common/bloblist.c
> > @@ -542,3 +542,16 @@ int bloblist_maybe_init(void)
> >
> >         return 0;
> >  }
> > +
> > +int bloblist_check_reg_conv(ulong rfdt, ulong rzero)
> > +{
> > +       if (!IS_ENABLED(CONFIG_OF_BOARD))
> > +               return -ENOENT;
> > +
> > +       if (rzero || rfdt != (ulong)bloblist_find(BLOBLISTT_CONTROL_FDT,
> 0)) {
> > +               gd->bloblist = NULL;  /* Reset the gd bloblist pointer */
> > +               return -EIO;
> > +       }
>
> Where does the magic 4a0fb10b value get checked?
>
> The magic and version of register conventions cannot be checked now since
there is
a bug in the spec. PSB:
```
X1[23:0]: set to the TL signature (4a0f_b10b)
X1[31:24]: version of the register convention used. Set to 1 for the
AArch64 convention specified in this document.
```
Signature (4a0f_b10b) takes all [31:0] and no space for version of the
register convention.
This needs to be updated on TF-A and OP-TEE as well after the spec is
updated.
For now I will just skip the checking.

[...]

Regards,
Raymond