[v3] tee: optee: rework TA bus scanning code

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@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
---
Changes since v:2
- Fixed typo on driver name ftpm-tee -> ftpm_tee

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(-)

Hi Ilias,

I commented v2 instead of you're latest post.
Please find my few comments below.
Addressed or not, Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>


On Sat, 3 Sept 2022 at 09:54, Ilias Apalodimas
<ilias.apalodimas@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@linaro.org>
> Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
> ---
> Changes since v:2
> - Fixed typo on driver name ftpm-tee -> ftpm_tee
>
> 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..1437ba1b676b 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" },

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);

Could s/&child/NULL/.

Br,
etienne

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

Hi Etienne

On Mon, 5 Sept 2022 at 12:28, Etienne Carriere
<etienne.carriere@linaro.org> wrote:
>
> Hi Ilias,
>
> I commented v2 instead of you're latest post.
> Please find my few comments below.
> Addressed or not, Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

Thanks,
I'll send a v4 with the changes

Cheers
/Ilias
>
>
> On Sat, 3 Sept 2022 at 09:54, Ilias Apalodimas
> <ilias.apalodimas@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@linaro.org>
> > Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
> > ---
> > Changes since v:2
> > - Fixed typo on driver name ftpm-tee -> ftpm_tee
> >
> > 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..1437ba1b676b 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" },
>
> 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);
>
> Could s/&child/NULL/.
>
> Br,
> etienne
>
> >                 if (ret)
> > -                       return ret;
> > +                       dev_warn(dev, "Failed to bind device %s\n",
> > +                                optee_bus_probe[i].dev_name);
> >         }
> >
> >         return 0;
> > --
> > 2.34.1
> >