[PATCH v2] tee: optee: rework TA bus scanning code

[Etienne Carriere]

Hi Ilias,

Reviewed-by: Etienne Carriere <etienne.carriere at linaro.org> with minor comments.

On Fri, 2 Sept 2022 at 21:11, Ilias Apalodimas
<ilias.apalodimas at linaro.org> wrote:
>
> Thanks Jens
>
> On Wed, 31 Aug 2022 at 08:59, Jens Wiklander <jens.wiklander at linaro.org> wrote:
> >
> > On Mon, Aug 29, 2022 at 8:34 AM Ilias Apalodimas
> > <ilias.apalodimas at linaro.org> wrote:
> > >
> > > Late versions of OP-TEE support a pseudo bus.  TAs that behave as
> > > hardware blocks (e.g TPM, RNG etc) present themselves on a bus which we can
> > > scan.  Unfortunately U-Boot doesn't support that yet. It's worth noting
> > > that we already have a workaround for RNG.  The details are in
> > > commit 70812bb83da6 ("tee: optee: bind rng optee driver")
> > >
> > > So let's add a list of devices based on U-Boot Kconfig options that we will
> > > scan until we properly implement the tee-bus functionality.
> > >
> > > While at it change the behaviour of the tee core itself wrt to device
> > > binding.  If some device binding fails, print a warning instead of
> > > disabling OP-TEE.
> > >
> > > Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > > ---
> >
> > Reviewed-by: Jens Wiklander <jens.wiklander at linaro.org>
>
> There's a typo in that patch. For the tpm to work the string needs to
> be ftpm_tee instead of ftpm-tee.  I'll send a v3, shall I keep your
> RB?
>
> Cheers
> /Ilias
> >
> > Cheers,
> > Jens
> >
> > > Changes since v1:
> > > - remove a macro and use ARRAY_SIZE directly
> > > - print a warning instead of disabling op-tee if a driver binding fails
> > >
> > >  drivers/tee/optee/core.c | 23 +++++++++++++++++++----
> > >  1 file changed, 19 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> > > index a89d62aaf0b3..3cc92f09d299 100644
> > > --- a/drivers/tee/optee/core.c
> > > +++ b/drivers/tee/optee/core.c
> > > @@ -31,6 +31,18 @@ struct optee_pdata {
> > >         optee_invoke_fn *invoke_fn;
> > >  };
> > >
> > > +static const struct {
> > > +       const char *drv_name;
> > > +       const char *dev_name;
> > > +} optee_bus_probe[] = {
> > > +#ifdef CONFIG_RNG_OPTEE
> > > +       { "optee-rng", "optee-rng" },

By the way, prefer:
+       { .drv_name = "optee-rng", .dev_name = "optee-rng" },


> > > +#endif
> > > +#ifdef CONFIG_TPM2_FTPM_TEE
> > > +       { "ftpm-tee", "ftpm-tee" },
> > > +#endif
> > > +};
> > > +
> > >  struct rpc_param {
> > >         u32     a0;
> > >         u32     a1;
> > > @@ -643,7 +655,7 @@ static int optee_probe(struct udevice *dev)
> > >         struct optee_pdata *pdata = dev_get_plat(dev);
> > >         u32 sec_caps;
> > >         struct udevice *child;
> > > -       int ret;
> > > +       int ret, i;
> > >
> > >         if (!is_optee_api(pdata->invoke_fn)) {
> > >                 dev_err(dev, "OP-TEE api uid mismatch\n");
> > > @@ -672,10 +684,13 @@ static int optee_probe(struct udevice *dev)
> > >          * 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)) {
> > > -               ret = device_bind_driver(dev, "optee-rng", "optee-rng", &child);
> > > +
> > > +       for (i = 0; i < ARRAY_SIZE(optee_bus_probe); i++) {
> > > +               ret = device_bind_driver(dev, optee_bus_probe[i].drv_name,
> > > +                                        optee_bus_probe[i].dev_name, &child);

Can drop child here. NULL is fine.

> > >                 if (ret)
> > > -                       return ret;
> > > +                       dev_warn(dev, "Failed to bind device %s\n",
> > > +                                optee_bus_probe[i].dev_name);
> > >         }
> > >
> > >         return 0;
> > > --
> > > 2.34.1
> > >