Hi Etienne,
[...]
> > > +
> > > +#ifndef CONFIG_OPTEE_SERVICE_DISCOVERY
> > > /*
> > > * in U-Boot, the discovery of TA on the TEE bus is not supported:
> > > * only bind the drivers associated to the supported OP-TEE TA
> > > */
> > > if (IS_ENABLED(CONFIG_RNG_OPTEE)) {
> > > + struct udevice *child;
> > > +
> > > ret = device_bind_driver(dev, "optee-rng", "optee-rng", &child);
> >
> > The same principle applies for fTPM. Moreover the linux kernel supports
> > bus scanning, which creates a conflict when the fTPM is added on the .dts
> > (for u-boot to scan it).
>
> Do you mean you would like fTPM driver to NOT be probed upon its
> related DT compatible node and only probed from the fTPM TA discovery
> (optee so-called devices enumeration)?
That should be a user selected option. If the dt entry is there we
should scan it as we do today. However if the DT entry is not there I
believe we should try to scan the device from the tree bus.
>
> Another issue here is that current fTPM implementation [1] does not
> set flag TA_FLAG_DEVICE_ENUM [2] that makes a built-in TA (so-called
> early TA) to be enumerated by OP-TEE.
>
> [1] https://github.com/microsoft/ms-tpm-20-ref/blob/d638536d0fe01acd5e39ffa1bd100b3da82d92c7/Samples/ARM32-FirmwareTPM/optee_ta/fTPM/user_ta_header_defines.h#L47
> [2] https://github.com/OP-TEE/optee_os/blob/3.17.0/lib/libutee/include/user_ta_header.h#L26-L32
Yea I know there's a PR fixing that but was posted on the initial
fTPM project [1]. We need to refresh that
[1] https://github.com/microsoft/MSRSec/pull/34
>
> >
> > Can we make this a bit more generic, even though only the rng is added on
> > this patch?
> >
> > something like
> > struct devices {
> > const char *drv_name;
> > const char *dev_name;
> > } tee_bus_devices = {
> > {
> > "optee-rng",
> > "optee-rng",
> > },
> > }
> > and add an array of the 'scanable' devices? It would make adding the ftpm
> > and other devices trivial
>
> Assuming fTPM TA is enumerated, i don't think we need to add a device
> name here. fTPM service could be proved straight based on the driver
> name. fTPM driver in u-boot expects there is only 1 TEE firmware,
> hence only 1 fTPM TA instance.
>
> For info, i'll send a patch v3 without changes on fTPM.
Yea don't add the ftpm now. I only wanted to convert this to an
array, so we plug in new devices easier in the future.
Cheers
/Ilias
>
> Best regards,
> etienne
>
> >
> > > if (ret)
> > > return ret;
> > > }
> > > +#endif
> > [...]
> >
> >
> > Thanks!
> > /Ilias