Re: [PATCH v4 3/3] tpm: tpm_crb_ffa: revert defered_probed when tpm_crb_ffa is built-in

[Yeoreum Yun <yeoreum.yun@arm.com>]

> On Mon, Jun 01, 2026 at 08:17:13AM +0100, Yeoreum Yun wrote:
> > Hi Jarkko,
> > 
> > Sorry for late answer.
> > 
> > > On Mon, May 25, 2026 at 08:54:04AM +0100, Yeoreum Yun wrote:
> > > > commit 746d9e9f62a6 ("tpm: tpm_crb_ffa: try to probe tpm_crb_ffa when it's build_in")
> > > > probe tpm_crb_ffa forcefully when it's built-in to integrate with IMA.
> > > > 
> > > > However, IMA now provides the IMA_INIT_LATE_SYNC build option, which
> > > > initialises IMA at the late_initcall_sync level, so this change is no
> > > > longer required.
> > > > 
> > > > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> > > > ---
> > > >  drivers/char/tpm/tpm_crb_ffa.c | 18 +++---------------
> > > >  1 file changed, 3 insertions(+), 15 deletions(-)
> > > > 
> > > > diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c
> > > > index 99f1c1e5644b..025c4d4b17ca 100644
> > > > --- a/drivers/char/tpm/tpm_crb_ffa.c
> > > > +++ b/drivers/char/tpm/tpm_crb_ffa.c
> > > > @@ -177,23 +177,13 @@ static int tpm_crb_ffa_to_linux_errno(int errno)
> > > >   */
> > > >  int tpm_crb_ffa_init(void)
> > > >  {
> > > > -	int ret = 0;
> > > > -
> > > > -	if (!IS_MODULE(CONFIG_TCG_ARM_CRB_FFA)) {
> > > > -		ret = ffa_register(&tpm_crb_ffa_driver);
> > > > -		if (ret) {
> > > > -			tpm_crb_ffa = ERR_PTR(-ENODEV);
> > > > -			return ret;
> > > > -		}
> > > > -	}
> > > > -
> > > >  	if (!tpm_crb_ffa)
> > > > -		ret = -ENOENT;
> > > > +		return -ENOENT;
> > > >  
> > > >  	if (IS_ERR_VALUE(tpm_crb_ffa))
> > > > -		ret = -ENODEV;
> > > > +		return -ENODEV;
> > > >  
> > > > -	return ret;
> > > > +	return 0;
> > > >  }
> > > >  EXPORT_SYMBOL_GPL(tpm_crb_ffa_init);
> > > >  
> > > > @@ -405,9 +395,7 @@ static struct ffa_driver tpm_crb_ffa_driver = {
> > > >  	.id_table = tpm_crb_ffa_device_id,
> > > >  };
> > > >  
> > > > -#ifdef MODULE
> > > >  module_ffa_driver(tpm_crb_ffa_driver);
> > > > -#endif
> > > >  
> > > >  MODULE_AUTHOR("Arm");
> > > >  MODULE_DESCRIPTION("TPM CRB FFA driver");
> > > > -- 
> > > > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
> > > > 
> > > 
> > > How we would sync up this patch? Through which tree etc.
> > 
> > IMHO, the IMA relevant thing would be into IMA tree,
> > However I think this patch would be much easier to sync into Sudeep's
> > FF-A tree where ff-a initilisation is reverted to device_initcall
> > unless you're uncomfortable.
> > 
> > For this, It might be better to split this patch from this series
> > since by above and defer probe of ff-a would make a register failure
> > of registering tpm_crb_ffa driver which is built-in.
> > 
> > @Sudeep what do you think?
> > 
> 
> IIRC, there is/was no dependency between these and FF-A patches that are
> queued in terms of build. I agree there may be dependency to get all the
> functionality but we can resort to linux-next for that. FF-A is not enabled
> in the defconfig, so anyone working on FF-A + TPM must enable then and can
> rely on -next IMHO.
> 
> That said, I have already sent PR for FF-A to SoC team and it is already
> queued for v7.2. I don't have any other plans unless they are fixes.

Thanks. Then I think it's enough to merge this patch to TPM tree
when this patchset is approved once.

-- 
Sincerely,
Yeoreum Yun