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

[Simon Glass]

Hi Raymond,

On Wed, Dec 27, 2023 at 4:06 PM Raymond Mao <raymond.mao at linaro.org> wrote:
>
> 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)

That should say 0f_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.

We should fix the spec instead.

Regards,
Simon