[v2,05/15] Add UCLASS_TEE for Trusted Execution Environment

Message ID 20180823104334.16083-6-jens.wiklander@linaro.org
State New
Headers show
Series
  • AVB using OP-TEE
Related show

Commit Message

Jens Wiklander Aug. 23, 2018, 10:43 a.m.
Adds a uclass to interface with a TEE (Trusted Execution Environment).

A TEE driver is a driver that interfaces with a trusted OS running in
some secure environment, for example, TrustZone on ARM cpus, or a
separate secure co-processor etc.

The TEE subsystem can serve a TEE driver for a Global Platform compliant
TEE, but it's not limited to only Global Platform TEEs.

The over all design is based on the TEE subsystem in the Linux kernel,
tailored for U-boot.

Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org>

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

---
 MAINTAINERS              |   6 +
 drivers/Kconfig          |   2 +
 drivers/Makefile         |   1 +
 drivers/tee/Kconfig      |   8 ++
 drivers/tee/Makefile     |   3 +
 drivers/tee/tee-uclass.c | 192 ++++++++++++++++++++++++++
 include/dm/uclass-id.h   |   1 +
 include/tee.h            | 290 +++++++++++++++++++++++++++++++++++++++
 8 files changed, 503 insertions(+)
 create mode 100644 drivers/tee/Kconfig
 create mode 100644 drivers/tee/Makefile
 create mode 100644 drivers/tee/tee-uclass.c
 create mode 100644 include/tee.h

-- 
2.17.1

Comments

Simon Glass Aug. 30, 2018, 12:28 a.m. | #1
Hi Jens,

On 23 August 2018 at 04:43, Jens Wiklander <jens.wiklander@linaro.org> wrote:
> Adds a uclass to interface with a TEE (Trusted Execution Environment).
>
> A TEE driver is a driver that interfaces with a trusted OS running in
> some secure environment, for example, TrustZone on ARM cpus, or a
> separate secure co-processor etc.
>
> The TEE subsystem can serve a TEE driver for a Global Platform compliant
> TEE, but it's not limited to only Global Platform TEEs.
>
> The over all design is based on the TEE subsystem in the Linux kernel,
> tailored for U-boot.

U-Boot

>
> Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org>
> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
> ---
>  MAINTAINERS              |   6 +
>  drivers/Kconfig          |   2 +
>  drivers/Makefile         |   1 +
>  drivers/tee/Kconfig      |   8 ++
>  drivers/tee/Makefile     |   3 +
>  drivers/tee/tee-uclass.c | 192 ++++++++++++++++++++++++++
>  include/dm/uclass-id.h   |   1 +
>  include/tee.h            | 290 +++++++++++++++++++++++++++++++++++++++
>  8 files changed, 503 insertions(+)
>  create mode 100644 drivers/tee/Kconfig
>  create mode 100644 drivers/tee/Makefile
>  create mode 100644 drivers/tee/tee-uclass.c
>  create mode 100644 include/tee.h

Reviewed-by: Simon Glass <sjg@chromium.org>

Various nits below.

>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 58b61ac05882..7458c606ee92 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -571,6 +571,12 @@ TQ GROUP
>  S:     Orphaned (Since 2016-02)
>  T:     git git://git.denx.de/u-boot-tq-group.git
>
> +TEE
> +M:     Jens Wiklander <jens.wiklander@linaro.org>
> +S:     Maintained
> +F:     drivers/tee/
> +F:     include/tee.h
> +
>  UBI
>  M:     Kyungmin Park <kmpark@infradead.org>
>  M:     Heiko Schocher <hs@denx.de>
> diff --git a/drivers/Kconfig b/drivers/Kconfig
> index c72abf893297..f3249ab1d143 100644
> --- a/drivers/Kconfig
> +++ b/drivers/Kconfig
> @@ -94,6 +94,8 @@ source "drivers/spmi/Kconfig"
>
>  source "drivers/sysreset/Kconfig"
>
> +source "drivers/tee/Kconfig"
> +
>  source "drivers/thermal/Kconfig"
>
>  source "drivers/timer/Kconfig"
> diff --git a/drivers/Makefile b/drivers/Makefile
> index d53208540ea6..0fcae36f50f7 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -103,6 +103,7 @@ obj-y += smem/
>  obj-y += soc/
>  obj-$(CONFIG_REMOTEPROC) += remoteproc/
>  obj-y += thermal/
> +obj-$(CONFIG_TEE) += tee/
>
>  obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
>  endif
> diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
> new file mode 100644
> index 000000000000..817ab331b0f8
> --- /dev/null
> +++ b/drivers/tee/Kconfig
> @@ -0,0 +1,8 @@
> +# Generic Trusted Execution Environment Configuration
> +config TEE
> +       bool "Trusted Execution Environment support"
> +       depends on ARM && (ARM64 || CPU_V7A)
> +       select ARM_SMCCC
> +       help
> +         This implements a generic interface towards a Trusted Execution
> +         Environment (TEE).

Please expand this. What is it? Why would I use it? Also perhaps add a web link?

> diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
> new file mode 100644
> index 000000000000..b6d8e16e6211
> --- /dev/null
> +++ b/drivers/tee/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0+
> +
> +obj-y += tee-uclass.o
> diff --git a/drivers/tee/tee-uclass.c b/drivers/tee/tee-uclass.c
> new file mode 100644
> index 000000000000..0209983491a0
> --- /dev/null
> +++ b/drivers/tee/tee-uclass.c
> @@ -0,0 +1,192 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2018 Linaro Limited
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <tee.h>
> +
> +/**
> + * struct tee_uclass_priv - information of a TEE, stored by the uclass
> + *
> + * @list_shm:  list of structe tee_shm representing memory blocks shared
> + *             with the TEE.
> + */
> +struct tee_uclass_priv {
> +       struct list_head list_shm;
> +};
> +
> +static const struct tee_driver_ops *tee_get_ops(struct udevice *dev)
> +{
> +       return device_get_ops(dev);
> +}
> +
> +void tee_get_version(struct udevice *dev, struct tee_version_data *vers)
> +{
> +       tee_get_ops(dev)->get_version(dev, vers);
> +}
> +
> +int tee_open_session(struct udevice *dev, struct tee_open_session_arg *arg,
> +                    ulong num_param, struct tee_param *param)
> +{
> +       return tee_get_ops(dev)->open_session(dev, arg, num_param, param);
> +}
> +
> +int tee_close_session(struct udevice *dev, u32 session)
> +{
> +       return tee_get_ops(dev)->close_session(dev, session);
> +}
> +
> +int tee_invoke_func(struct udevice *dev, struct tee_invoke_arg *arg,
> +                   ulong num_param, struct tee_param *param)
> +{
> +       return tee_get_ops(dev)->invoke_func(dev, arg, num_param, param);
> +}
> +
> +struct tee_shm *__tee_shm_add(struct udevice *dev, ulong align, void *addr,
> +                             ulong size, u32 flags)
> +{
> +       struct tee_shm *shm;
> +       void *p = addr;
> +
> +       if (flags & TEE_SHM_ALLOC) {
> +               if (align)
> +                       p = memalign(align, size);
> +               else
> +                       p = malloc(size);
> +       }
> +       if (!p)
> +               return NULL;
> +
> +       shm = calloc(1, sizeof(*shm));
> +       if (!shm)
> +               goto err;
> +
> +       shm->dev = dev;
> +       shm->addr = p;
> +       shm->size = size;
> +       shm->flags = flags;
> +
> +       if ((flags & TEE_SHM_SEC_REGISTER) &&
> +           tee_get_ops(dev)->shm_register(dev, shm))
> +               goto err;
> +
> +       if (flags & TEE_SHM_REGISTER) {
> +               struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> +
> +               list_add(&shm->link, &priv->list_shm);
> +       }
> +       return shm;
> +err:
> +       free(shm);
> +       if (flags & TEE_SHM_ALLOC)
> +               free(p);
> +       return NULL;
> +}
> +
> +struct tee_shm *tee_shm_alloc(struct udevice *dev, ulong size,
> +                             u32 flags)
> +{
> +       u32 f = flags;
> +
> +       f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER | TEE_SHM_ALLOC;

blank line here

> +       return __tee_shm_add(dev, 0, NULL, size, f);
> +}
> +
> +struct tee_shm *tee_shm_register(struct udevice *dev, void *addr,
> +                                ulong size, u32 flags)
> +{
> +       u32 f = flags & ~TEE_SHM_ALLOC;
> +
> +       f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER;

and here

> +       return __tee_shm_add(dev, 0, addr, size, f);
> +}
> +
> +void tee_shm_free(struct tee_shm *shm)
> +{
> +       if (!shm)
> +               return;
> +
> +       if (shm->flags & TEE_SHM_SEC_REGISTER)
> +               tee_get_ops(shm->dev)->shm_unregister(shm->dev, shm);
> +
> +       if (shm->flags & TEE_SHM_REGISTER)
> +               list_del(&shm->link);
> +
> +       if (shm->flags & TEE_SHM_ALLOC)
> +               free(shm->addr);
> +
> +       free(shm);
> +}
> +
> +bool tee_shm_is_registered(struct tee_shm *shm, struct udevice *dev)
> +{
> +       struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> +       struct tee_shm *s;
> +
> +       list_for_each_entry(s, &priv->list_shm, link)
> +               if (s == shm)
> +                       return true;
> +
> +       return false;
> +}
> +
> +struct udevice *tee_find_device(struct udevice *start,
> +                               int (*match)(struct tee_version_data *vers,
> +                                            const void *data),
> +                               const void *data,
> +                               struct tee_version_data *vers)

Please add function comment

> +{
> +       struct udevice *dev = start;
> +       struct tee_version_data lv;
> +       struct tee_version_data *v = vers ? vers : &lv;
> +
> +       if (!dev)
> +               uclass_first_device(UCLASS_TEE, &dev);

This can return an error if it finds a device but it tails to probe.
If you don't care about that, I suppose it is OK.

> +
> +       for (; dev; uclass_next_device(&dev)) {
> +               tee_get_ops(dev)->get_version(dev, v);
> +               if (!match || match(v, data))
> +                       return dev;
> +       }
> +
> +       return NULL;
> +}
> +
> +static int tee_pre_probe(struct udevice *dev)
> +{
> +       struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> +
> +       INIT_LIST_HEAD(&priv->list_shm);
> +
> +       return 0;
> +}
> +
> +static int tee_pre_remove(struct udevice *dev)
> +{
> +       struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> +       struct tee_shm *shm;
> +
> +       /*
> +        * Any remaining shared memory must be unregistered now as U-boot

U-Boot

> +        * is about to hand over to the next stage and that memory will be
> +        * reused.
> +        */
> +       while (!list_empty(&priv->list_shm)) {
> +               shm = list_first_entry(&priv->list_shm, struct tee_shm, link);
> +               debug("%s: freeing leftover shm %p (size %lu, flags %#x)\n",
> +                     __func__, (void *)shm, shm->size, shm->flags);
> +               tee_shm_free(shm);
> +       }
> +
> +       return 0;
> +}
> +
> +UCLASS_DRIVER(tee) = {
> +       .id = UCLASS_TEE,
> +       .name = "tee",
> +       .per_device_auto_alloc_size = sizeof(struct tee_uclass_priv),
> +       .pre_probe = tee_pre_probe,
> +       .pre_remove = tee_pre_remove,
> +};
> diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> index a39643ec5eef..955e0a915b87 100644
> --- a/include/dm/uclass-id.h
> +++ b/include/dm/uclass-id.h
> @@ -81,6 +81,7 @@ enum uclass_id {
>         UCLASS_SPI_GENERIC,     /* Generic SPI flash target */
>         UCLASS_SYSCON,          /* System configuration device */
>         UCLASS_SYSRESET,        /* System reset device */
> +       UCLASS_TEE,             /* Trusted Execution Environment device */
>         UCLASS_THERMAL,         /* Thermal sensor */
>         UCLASS_TIMER,           /* Timer device */
>         UCLASS_TPM,             /* Trusted Platform Module TIS interface */
> diff --git a/include/tee.h b/include/tee.h
> new file mode 100644
> index 000000000000..3e6771123ef0
> --- /dev/null
> +++ b/include/tee.h
> @@ -0,0 +1,290 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (c) 2018 Linaro Limited
> + */
> +
> +#ifndef __TEE_H
> +#define __TEE_H
> +
> +#include <common.h>
> +#include <dm.h>

Please drop both of those.

> +
> +#define TEE_UUID_LEN           16
> +
> +#define TEE_GEN_CAP_GP          BIT(0) /* GlobalPlatform compliant TEE */
> +#define TEE_GEN_CAP_REG_MEM     BIT(1) /* Supports registering shared memory */
> +
> +#define TEE_SHM_REGISTER       BIT(0)  /* In list of shared memory */
> +#define TEE_SHM_SEC_REGISTER   BIT(1)  /* TEE notified of this memory */
> +#define TEE_SHM_ALLOC          BIT(2)  /* The memory is malloced() and must */
> +                                       /* be freed() */
> +
> +#define TEE_PARAM_ATTR_TYPE_NONE               0       /* parameter not used */
> +#define TEE_PARAM_ATTR_TYPE_VALUE_INPUT                1
> +#define TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT       2
> +#define TEE_PARAM_ATTR_TYPE_VALUE_INOUT                3       /* input and output */
> +#define TEE_PARAM_ATTR_TYPE_MEMREF_INPUT       5
> +#define TEE_PARAM_ATTR_TYPE_MEMREF_OUTPUT      6
> +#define TEE_PARAM_ATTR_TYPE_MEMREF_INOUT       7       /* input and output */
> +#define TEE_PARAM_ATTR_TYPE_MASK               0xff
> +#define TEE_PARAM_ATTR_META                    0x100
> +#define TEE_PARAM_ATTR_MASK                    (TEE_PARAM_ATTR_TYPE_MASK | \
> +                                                TEE_PARAM_ATTR_META)
> +
> +/*
> + * Some Global Platform error codes which has a meaning if the
> + * TEE_GEN_CAP_GP bit is returned by the driver in
> + * struct tee_version_data::gen_caps
> + */
> +#define TEE_SUCCESS                    0x00000000
> +#define TEE_ERROR_GENERIC              0xffff0000
> +#define TEE_ERROR_BAD_PARAMETERS       0xffff0006
> +#define TEE_ERROR_ITEM_NOT_FOUND       0xffff0008
> +#define TEE_ERROR_NOT_IMPLEMENTED      0xffff0009
> +#define TEE_ERROR_NOT_SUPPORTED                0xffff000a
> +#define TEE_ERROR_COMMUNICATION                0xffff000e
> +#define TEE_ERROR_OUT_OF_MEMORY                0xffff000c
> +#define TEE_ERROR_TARGET_DEAD          0xffff3024
> +
> +#define TEE_ORIGIN_COMMS               0x00000002
> +
> +/**
> + * struct tee_shm - memory shared with the TEE
> + * @dev:       The TEE device
> + * @link:      List node in the list in struct struct tee_uclass_priv
> + * @addr:      Pointer to the shared memory
> + * @size:      Size of the the shared memory
> + * @flags:     TEE_SHM_* above
> + */
> +struct tee_shm {
> +       struct udevice *dev;
> +       struct list_head link;
> +       void *addr;
> +       ulong size;
> +       u32 flags;
> +};
> +
> +/**
> + * struct tee_param_memref - parameter memory reference

Used for ...?

> + * @shm_offs:  Offset in bytes into the shared memory object @shm
> + * @size:      Size in bytes of the memory reference
> + * @shm:       Pointer to a shared memory object for the buffer
> + */
> +struct tee_param_memref {
> +       ulong shm_offs;
> +       ulong size;
> +       struct tee_shm *shm;
> +};
> +
> +/**
> + * struct tee_param_value - value parameter

??

This doesn't really explain anything. What is it for?

> + * @a, @b, @c: Parameters passed by value
> + */
> +struct tee_param_value {
> +       u64 a;
> +       u64 b;
> +       u64 c;
> +};
> +
> +/**
> + * struct tee_param - invoke parameter
> + * @attr:      Attributes
> + * @u.memref:  Memref parameter if (@attr & TEE_PARAM_ATTR_MASK) is one of
> + *             TEE_PARAM_ATTR_TYPE_MEMREF_* above
> + * @u.value:   Value parameter if (@attr & TEE_PARAM_ATTR_MASK) is one of
> + *             TEE_PARAM_ATTR_TYPE_VALUE_* above
> + */
> +struct tee_param {
> +       u64 attr;
> +       union {
> +               struct tee_param_memref memref;
> +               struct tee_param_value value;
> +       } u;
> +};
> +
> +/**
> + * struct tee_open_session_arg - extra arguments for tee_open_session()
> + * @uuid:      [in] UUID of the Trusted Application
> + * @clnt_uuid: [in] Normally zeroes
> + * @clnt_login:        [in] Normally 0
> + * @session:   [out] Session id
> + * @ret:       [out] return value
> + * @ret_origin:        [out] origin of the return value
> + */
> +struct tee_open_session_arg {
> +       u8 uuid[TEE_UUID_LEN];
> +       u8 clnt_uuid[TEE_UUID_LEN];
> +       u32 clnt_login;
> +       u32 session;
> +       u32 ret;
> +       u32 ret_origin;

Do these use the sized u32 type because it is an API of some sort?
Otherwise, why not uint?

> +};
> +
> +/**
> + * struct tee_invoke_arg - extra arguments for tee_invoke_func()
> + * @func:      [in] Trusted Application function, specific to the TA
> + * @session:   [in] Session id, from open session
> + * @ret:       [out] return value
> + * @ret_origin:        [out] origin of the return value
> + */
> +struct tee_invoke_arg {
> +       u32 func;
> +       u32 session;
> +       u32 ret;
> +       u32 ret_origin;
> +};
> +
> +/**
> + * struct tee_version_data - description of TEE
> + * @gen_caps:  Generic capabilities, TEE_GEN_CAP_* above
> + */
> +struct tee_version_data {
> +       u32 gen_caps;
> +};
> +
> +/**
> + * struct tee_driver_ops - TEE driver operations
> + * @get_version:       Query capabilities of TEE device,
> +                       see tee_get_version()
> + * @open_session:      Opens a session to a Trusted Application in the TEE,
> + *                     see tee_open_session().
> + * @close_session:     Closes a session to Trusted Application,
> + *                     see tee_close_session()
> + * @invoke_func:       Invokes a function in a Trusted Application,
> +                       see tee_invoke_func()

These comments should be against each function in the struct below.
You should repeat the comment from the exported functions there too.

> + */
> +struct tee_driver_ops {
> +       void (*get_version)(struct udevice *dev, struct tee_version_data *vers);
> +       int (*open_session)(struct udevice *dev,
> +                           struct tee_open_session_arg *arg, ulong num_param,
> +                           struct tee_param *param);
> +       int (*close_session)(struct udevice *dev, u32 session);
> +       int (*invoke_func)(struct udevice *dev, struct tee_invoke_arg *arg,
> +                          ulong num_param, struct tee_param *param);
> +       /**
> +        * shm_register() - Registers memory shared with the TEE
> +        * @dev:        The TEE device
> +        * @shm:        Pointer to a shared memory object
> +        * Returns 0 on success or < 0 on failure.
> +        */
> +       int (*shm_register)(struct udevice *dev, struct tee_shm *shm);
> +       /**
> +        * shm_unregister() - Unregisters memory shared with the TEE
> +        * @dev:        The TEE device
> +        * @shm:        Pointer to a shared memory object
> +        * Returns 0 on success or < 0 on failure.
> +        */
> +       int (*shm_unregister)(struct udevice *dev, struct tee_shm *shm);
> +};
> +
[...]

Regards,
Simon
Jens Wiklander Aug. 30, 2018, 1:16 p.m. | #2
On Wed, Aug 29, 2018 at 06:28:48PM -0600, Simon Glass wrote:
> Hi Jens,
> 
> On 23 August 2018 at 04:43, Jens Wiklander <jens.wiklander@linaro.org> wrote:
> > Adds a uclass to interface with a TEE (Trusted Execution Environment).
> >
> > A TEE driver is a driver that interfaces with a trusted OS running in
> > some secure environment, for example, TrustZone on ARM cpus, or a
> > separate secure co-processor etc.
> >
> > The TEE subsystem can serve a TEE driver for a Global Platform compliant
> > TEE, but it's not limited to only Global Platform TEEs.
> >
> > The over all design is based on the TEE subsystem in the Linux kernel,
> > tailored for U-boot.
> 
> U-Boot
> 
> >
> > Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org>
> > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
> > ---
> >  MAINTAINERS              |   6 +
> >  drivers/Kconfig          |   2 +
> >  drivers/Makefile         |   1 +
> >  drivers/tee/Kconfig      |   8 ++
> >  drivers/tee/Makefile     |   3 +
> >  drivers/tee/tee-uclass.c | 192 ++++++++++++++++++++++++++
> >  include/dm/uclass-id.h   |   1 +
> >  include/tee.h            | 290 +++++++++++++++++++++++++++++++++++++++
> >  8 files changed, 503 insertions(+)
> >  create mode 100644 drivers/tee/Kconfig
> >  create mode 100644 drivers/tee/Makefile
> >  create mode 100644 drivers/tee/tee-uclass.c
> >  create mode 100644 include/tee.h
> 
> Reviewed-by: Simon Glass <sjg@chromium.org>
> 
> Various nits below.
> 
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 58b61ac05882..7458c606ee92 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -571,6 +571,12 @@ TQ GROUP
> >  S:     Orphaned (Since 2016-02)
> >  T:     git git://git.denx.de/u-boot-tq-group.git
> >
> > +TEE
> > +M:     Jens Wiklander <jens.wiklander@linaro.org>
> > +S:     Maintained
> > +F:     drivers/tee/
> > +F:     include/tee.h
> > +
> >  UBI
> >  M:     Kyungmin Park <kmpark@infradead.org>
> >  M:     Heiko Schocher <hs@denx.de>
> > diff --git a/drivers/Kconfig b/drivers/Kconfig
> > index c72abf893297..f3249ab1d143 100644
> > --- a/drivers/Kconfig
> > +++ b/drivers/Kconfig
> > @@ -94,6 +94,8 @@ source "drivers/spmi/Kconfig"
> >
> >  source "drivers/sysreset/Kconfig"
> >
> > +source "drivers/tee/Kconfig"
> > +
> >  source "drivers/thermal/Kconfig"
> >
> >  source "drivers/timer/Kconfig"
> > diff --git a/drivers/Makefile b/drivers/Makefile
> > index d53208540ea6..0fcae36f50f7 100644
> > --- a/drivers/Makefile
> > +++ b/drivers/Makefile
> > @@ -103,6 +103,7 @@ obj-y += smem/
> >  obj-y += soc/
> >  obj-$(CONFIG_REMOTEPROC) += remoteproc/
> >  obj-y += thermal/
> > +obj-$(CONFIG_TEE) += tee/
> >
> >  obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
> >  endif
> > diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
> > new file mode 100644
> > index 000000000000..817ab331b0f8
> > --- /dev/null
> > +++ b/drivers/tee/Kconfig
> > @@ -0,0 +1,8 @@
> > +# Generic Trusted Execution Environment Configuration
> > +config TEE
> > +       bool "Trusted Execution Environment support"
> > +       depends on ARM && (ARM64 || CPU_V7A)
> > +       select ARM_SMCCC
> > +       help
> > +         This implements a generic interface towards a Trusted Execution
> > +         Environment (TEE).
> 
> Please expand this. What is it? Why would I use it? Also perhaps add a
> web link?

I'll expand it. I'll skip the why part though.

> 
> > diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
> > new file mode 100644
> > index 000000000000..b6d8e16e6211
> > --- /dev/null
> > +++ b/drivers/tee/Makefile
> > @@ -0,0 +1,3 @@
> > +# SPDX-License-Identifier: GPL-2.0+
> > +
> > +obj-y += tee-uclass.o
> > diff --git a/drivers/tee/tee-uclass.c b/drivers/tee/tee-uclass.c
> > new file mode 100644
> > index 000000000000..0209983491a0
> > --- /dev/null
> > +++ b/drivers/tee/tee-uclass.c
> > @@ -0,0 +1,192 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (c) 2018 Linaro Limited
> > + */
> > +
> > +#include <common.h>
> > +#include <dm.h>
> > +#include <tee.h>
> > +
> > +/**
> > + * struct tee_uclass_priv - information of a TEE, stored by the uclass
> > + *
> > + * @list_shm:  list of structe tee_shm representing memory blocks shared
> > + *             with the TEE.
> > + */
> > +struct tee_uclass_priv {
> > +       struct list_head list_shm;
> > +};
> > +
> > +static const struct tee_driver_ops *tee_get_ops(struct udevice *dev)
> > +{
> > +       return device_get_ops(dev);
> > +}
> > +
> > +void tee_get_version(struct udevice *dev, struct tee_version_data *vers)
> > +{
> > +       tee_get_ops(dev)->get_version(dev, vers);
> > +}
> > +
> > +int tee_open_session(struct udevice *dev, struct tee_open_session_arg *arg,
> > +                    ulong num_param, struct tee_param *param)
> > +{
> > +       return tee_get_ops(dev)->open_session(dev, arg, num_param, param);
> > +}
> > +
> > +int tee_close_session(struct udevice *dev, u32 session)
> > +{
> > +       return tee_get_ops(dev)->close_session(dev, session);
> > +}
> > +
> > +int tee_invoke_func(struct udevice *dev, struct tee_invoke_arg *arg,
> > +                   ulong num_param, struct tee_param *param)
> > +{
> > +       return tee_get_ops(dev)->invoke_func(dev, arg, num_param, param);
> > +}
> > +
> > +struct tee_shm *__tee_shm_add(struct udevice *dev, ulong align, void *addr,
> > +                             ulong size, u32 flags)
> > +{
> > +       struct tee_shm *shm;
> > +       void *p = addr;
> > +
> > +       if (flags & TEE_SHM_ALLOC) {
> > +               if (align)
> > +                       p = memalign(align, size);
> > +               else
> > +                       p = malloc(size);
> > +       }
> > +       if (!p)
> > +               return NULL;
> > +
> > +       shm = calloc(1, sizeof(*shm));
> > +       if (!shm)
> > +               goto err;
> > +
> > +       shm->dev = dev;
> > +       shm->addr = p;
> > +       shm->size = size;
> > +       shm->flags = flags;
> > +
> > +       if ((flags & TEE_SHM_SEC_REGISTER) &&
> > +           tee_get_ops(dev)->shm_register(dev, shm))
> > +               goto err;
> > +
> > +       if (flags & TEE_SHM_REGISTER) {
> > +               struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> > +
> > +               list_add(&shm->link, &priv->list_shm);
> > +       }
> > +       return shm;
> > +err:
> > +       free(shm);
> > +       if (flags & TEE_SHM_ALLOC)
> > +               free(p);
> > +       return NULL;
> > +}
> > +
> > +struct tee_shm *tee_shm_alloc(struct udevice *dev, ulong size,
> > +                             u32 flags)
> > +{
> > +       u32 f = flags;
> > +
> > +       f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER | TEE_SHM_ALLOC;
> 
> blank line here
> 
> > +       return __tee_shm_add(dev, 0, NULL, size, f);
> > +}
> > +
> > +struct tee_shm *tee_shm_register(struct udevice *dev, void *addr,
> > +                                ulong size, u32 flags)
> > +{
> > +       u32 f = flags & ~TEE_SHM_ALLOC;
> > +
> > +       f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER;
> 
> and here
> 
> > +       return __tee_shm_add(dev, 0, addr, size, f);
> > +}
> > +
> > +void tee_shm_free(struct tee_shm *shm)
> > +{
> > +       if (!shm)
> > +               return;
> > +
> > +       if (shm->flags & TEE_SHM_SEC_REGISTER)
> > +               tee_get_ops(shm->dev)->shm_unregister(shm->dev, shm);
> > +
> > +       if (shm->flags & TEE_SHM_REGISTER)
> > +               list_del(&shm->link);
> > +
> > +       if (shm->flags & TEE_SHM_ALLOC)
> > +               free(shm->addr);
> > +
> > +       free(shm);
> > +}
> > +
> > +bool tee_shm_is_registered(struct tee_shm *shm, struct udevice *dev)
> > +{
> > +       struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> > +       struct tee_shm *s;
> > +
> > +       list_for_each_entry(s, &priv->list_shm, link)
> > +               if (s == shm)
> > +                       return true;
> > +
> > +       return false;
> > +}
> > +
> > +struct udevice *tee_find_device(struct udevice *start,
> > +                               int (*match)(struct tee_version_data *vers,
> > +                                            const void *data),
> > +                               const void *data,
> > +                               struct tee_version_data *vers)
> 
> Please add function comment

There is one in include/tee.h

> > +{
> > +       struct udevice *dev = start;
> > +       struct tee_version_data lv;
> > +       struct tee_version_data *v = vers ? vers : &lv;
> > +
> > +       if (!dev)
> > +               uclass_first_device(UCLASS_TEE, &dev);
> 
> This can return an error if it finds a device but it tails to probe.
> If you don't care about that, I suppose it is OK.

Thanks. I need the first device that probes OK and then the next devices
that probes OK and so on. I'll need to make some small changes here.

> > +
> > +       for (; dev; uclass_next_device(&dev)) {
> > +               tee_get_ops(dev)->get_version(dev, v);
> > +               if (!match || match(v, data))
> > +                       return dev;
> > +       }
> > +
> > +       return NULL;
> > +}
> > +
> > +static int tee_pre_probe(struct udevice *dev)
> > +{
> > +       struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> > +
> > +       INIT_LIST_HEAD(&priv->list_shm);
> > +
> > +       return 0;
> > +}
> > +
> > +static int tee_pre_remove(struct udevice *dev)
> > +{
> > +       struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
> > +       struct tee_shm *shm;
> > +
> > +       /*
> > +        * Any remaining shared memory must be unregistered now as U-boot
> 
> U-Boot
> 
> > +        * is about to hand over to the next stage and that memory will be
> > +        * reused.
> > +        */
> > +       while (!list_empty(&priv->list_shm)) {
> > +               shm = list_first_entry(&priv->list_shm, struct tee_shm, link);
> > +               debug("%s: freeing leftover shm %p (size %lu, flags %#x)\n",
> > +                     __func__, (void *)shm, shm->size, shm->flags);
> > +               tee_shm_free(shm);
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +UCLASS_DRIVER(tee) = {
> > +       .id = UCLASS_TEE,
> > +       .name = "tee",
> > +       .per_device_auto_alloc_size = sizeof(struct tee_uclass_priv),
> > +       .pre_probe = tee_pre_probe,
> > +       .pre_remove = tee_pre_remove,
> > +};
> > diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> > index a39643ec5eef..955e0a915b87 100644
> > --- a/include/dm/uclass-id.h
> > +++ b/include/dm/uclass-id.h
> > @@ -81,6 +81,7 @@ enum uclass_id {
> >         UCLASS_SPI_GENERIC,     /* Generic SPI flash target */
> >         UCLASS_SYSCON,          /* System configuration device */
> >         UCLASS_SYSRESET,        /* System reset device */
> > +       UCLASS_TEE,             /* Trusted Execution Environment device */
> >         UCLASS_THERMAL,         /* Thermal sensor */
> >         UCLASS_TIMER,           /* Timer device */
> >         UCLASS_TPM,             /* Trusted Platform Module TIS interface */
> > diff --git a/include/tee.h b/include/tee.h
> > new file mode 100644
> > index 000000000000..3e6771123ef0
> > --- /dev/null
> > +++ b/include/tee.h
> > @@ -0,0 +1,290 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
> > +/*
> > + * Copyright (c) 2018 Linaro Limited
> > + */
> > +
> > +#ifndef __TEE_H
> > +#define __TEE_H
> > +
> > +#include <common.h>
> > +#include <dm.h>
> 
> Please drop both of those.
> 
> > +
> > +#define TEE_UUID_LEN           16
> > +
> > +#define TEE_GEN_CAP_GP          BIT(0) /* GlobalPlatform compliant TEE */
> > +#define TEE_GEN_CAP_REG_MEM     BIT(1) /* Supports registering shared memory */
> > +
> > +#define TEE_SHM_REGISTER       BIT(0)  /* In list of shared memory */
> > +#define TEE_SHM_SEC_REGISTER   BIT(1)  /* TEE notified of this memory */
> > +#define TEE_SHM_ALLOC          BIT(2)  /* The memory is malloced() and must */
> > +                                       /* be freed() */
> > +
> > +#define TEE_PARAM_ATTR_TYPE_NONE               0       /* parameter not used */
> > +#define TEE_PARAM_ATTR_TYPE_VALUE_INPUT                1
> > +#define TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT       2
> > +#define TEE_PARAM_ATTR_TYPE_VALUE_INOUT                3       /* input and output */
> > +#define TEE_PARAM_ATTR_TYPE_MEMREF_INPUT       5
> > +#define TEE_PARAM_ATTR_TYPE_MEMREF_OUTPUT      6
> > +#define TEE_PARAM_ATTR_TYPE_MEMREF_INOUT       7       /* input and output */
> > +#define TEE_PARAM_ATTR_TYPE_MASK               0xff
> > +#define TEE_PARAM_ATTR_META                    0x100
> > +#define TEE_PARAM_ATTR_MASK                    (TEE_PARAM_ATTR_TYPE_MASK | \
> > +                                                TEE_PARAM_ATTR_META)
> > +
> > +/*
> > + * Some Global Platform error codes which has a meaning if the
> > + * TEE_GEN_CAP_GP bit is returned by the driver in
> > + * struct tee_version_data::gen_caps
> > + */
> > +#define TEE_SUCCESS                    0x00000000
> > +#define TEE_ERROR_GENERIC              0xffff0000
> > +#define TEE_ERROR_BAD_PARAMETERS       0xffff0006
> > +#define TEE_ERROR_ITEM_NOT_FOUND       0xffff0008
> > +#define TEE_ERROR_NOT_IMPLEMENTED      0xffff0009
> > +#define TEE_ERROR_NOT_SUPPORTED                0xffff000a
> > +#define TEE_ERROR_COMMUNICATION                0xffff000e
> > +#define TEE_ERROR_OUT_OF_MEMORY                0xffff000c
> > +#define TEE_ERROR_TARGET_DEAD          0xffff3024
> > +
> > +#define TEE_ORIGIN_COMMS               0x00000002
> > +
> > +/**
> > + * struct tee_shm - memory shared with the TEE
> > + * @dev:       The TEE device
> > + * @link:      List node in the list in struct struct tee_uclass_priv
> > + * @addr:      Pointer to the shared memory
> > + * @size:      Size of the the shared memory
> > + * @flags:     TEE_SHM_* above
> > + */
> > +struct tee_shm {
> > +       struct udevice *dev;
> > +       struct list_head link;
> > +       void *addr;
> > +       ulong size;
> > +       u32 flags;
> > +};
> > +
> > +/**
> > + * struct tee_param_memref - parameter memory reference
> 
> Used for ...?
> 
> > + * @shm_offs:  Offset in bytes into the shared memory object @shm
> > + * @size:      Size in bytes of the memory reference
> > + * @shm:       Pointer to a shared memory object for the buffer
> > + */
> > +struct tee_param_memref {
> > +       ulong shm_offs;
> > +       ulong size;
> > +       struct tee_shm *shm;
> > +};
> > +
> > +/**
> > + * struct tee_param_value - value parameter
> 
> ??
> 
> This doesn't really explain anything. What is it for?

I'll expand and refer to struct tee_param below.

> 
> > + * @a, @b, @c: Parameters passed by value
> > + */
> > +struct tee_param_value {
> > +       u64 a;
> > +       u64 b;
> > +       u64 c;
> > +};
> > +
> > +/**
> > + * struct tee_param - invoke parameter
> > + * @attr:      Attributes
> > + * @u.memref:  Memref parameter if (@attr & TEE_PARAM_ATTR_MASK) is one of
> > + *             TEE_PARAM_ATTR_TYPE_MEMREF_* above
> > + * @u.value:   Value parameter if (@attr & TEE_PARAM_ATTR_MASK) is one of
> > + *             TEE_PARAM_ATTR_TYPE_VALUE_* above
> > + */
> > +struct tee_param {
> > +       u64 attr;
> > +       union {
> > +               struct tee_param_memref memref;
> > +               struct tee_param_value value;
> > +       } u;
> > +};
> > +
> > +/**
> > + * struct tee_open_session_arg - extra arguments for tee_open_session()
> > + * @uuid:      [in] UUID of the Trusted Application
> > + * @clnt_uuid: [in] Normally zeroes
> > + * @clnt_login:        [in] Normally 0
> > + * @session:   [out] Session id
> > + * @ret:       [out] return value
> > + * @ret_origin:        [out] origin of the return value
> > + */
> > +struct tee_open_session_arg {
> > +       u8 uuid[TEE_UUID_LEN];
> > +       u8 clnt_uuid[TEE_UUID_LEN];
> > +       u32 clnt_login;
> > +       u32 session;
> > +       u32 ret;
> > +       u32 ret_origin;
> 
> Do these use the sized u32 type because it is an API of some sort?
> Otherwise, why not uint?

Yes, the minimum width is 32-bits and wider than that is waste.

> 
> > +};
> > +
> > +/**
> > + * struct tee_invoke_arg - extra arguments for tee_invoke_func()
> > + * @func:      [in] Trusted Application function, specific to the TA
> > + * @session:   [in] Session id, from open session
> > + * @ret:       [out] return value
> > + * @ret_origin:        [out] origin of the return value
> > + */
> > +struct tee_invoke_arg {
> > +       u32 func;
> > +       u32 session;
> > +       u32 ret;
> > +       u32 ret_origin;
> > +};
> > +
> > +/**
> > + * struct tee_version_data - description of TEE
> > + * @gen_caps:  Generic capabilities, TEE_GEN_CAP_* above
> > + */
> > +struct tee_version_data {
> > +       u32 gen_caps;
> > +};
> > +
> > +/**
> > + * struct tee_driver_ops - TEE driver operations
> > + * @get_version:       Query capabilities of TEE device,
> > +                       see tee_get_version()
> > + * @open_session:      Opens a session to a Trusted Application in the TEE,
> > + *                     see tee_open_session().
> > + * @close_session:     Closes a session to Trusted Application,
> > + *                     see tee_close_session()
> > + * @invoke_func:       Invokes a function in a Trusted Application,
> > +                       see tee_invoke_func()
> 
> These comments should be against each function in the struct below.
> You should repeat the comment from the exported functions there too.

I'll fix.

> 
> > + */
> > +struct tee_driver_ops {
> > +       void (*get_version)(struct udevice *dev, struct tee_version_data *vers);
> > +       int (*open_session)(struct udevice *dev,
> > +                           struct tee_open_session_arg *arg, ulong num_param,
> > +                           struct tee_param *param);
> > +       int (*close_session)(struct udevice *dev, u32 session);
> > +       int (*invoke_func)(struct udevice *dev, struct tee_invoke_arg *arg,
> > +                          ulong num_param, struct tee_param *param);
> > +       /**
> > +        * shm_register() - Registers memory shared with the TEE
> > +        * @dev:        The TEE device
> > +        * @shm:        Pointer to a shared memory object
> > +        * Returns 0 on success or < 0 on failure.
> > +        */
> > +       int (*shm_register)(struct udevice *dev, struct tee_shm *shm);
> > +       /**
> > +        * shm_unregister() - Unregisters memory shared with the TEE
> > +        * @dev:        The TEE device
> > +        * @shm:        Pointer to a shared memory object
> > +        * Returns 0 on success or < 0 on failure.
> > +        */
> > +       int (*shm_unregister)(struct udevice *dev, struct tee_shm *shm);
> > +};
> > +
> [...]

Thanks for the review.
--
Jens

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 58b61ac05882..7458c606ee92 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -571,6 +571,12 @@  TQ GROUP
 S:	Orphaned (Since 2016-02)
 T:	git git://git.denx.de/u-boot-tq-group.git
 
+TEE
+M:	Jens Wiklander <jens.wiklander@linaro.org>
+S:	Maintained
+F:	drivers/tee/
+F:	include/tee.h
+
 UBI
 M:	Kyungmin Park <kmpark@infradead.org>
 M:	Heiko Schocher <hs@denx.de>
diff --git a/drivers/Kconfig b/drivers/Kconfig
index c72abf893297..f3249ab1d143 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -94,6 +94,8 @@  source "drivers/spmi/Kconfig"
 
 source "drivers/sysreset/Kconfig"
 
+source "drivers/tee/Kconfig"
+
 source "drivers/thermal/Kconfig"
 
 source "drivers/timer/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index d53208540ea6..0fcae36f50f7 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -103,6 +103,7 @@  obj-y += smem/
 obj-y += soc/
 obj-$(CONFIG_REMOTEPROC) += remoteproc/
 obj-y += thermal/
+obj-$(CONFIG_TEE) += tee/
 
 obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
 endif
diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
new file mode 100644
index 000000000000..817ab331b0f8
--- /dev/null
+++ b/drivers/tee/Kconfig
@@ -0,0 +1,8 @@ 
+# Generic Trusted Execution Environment Configuration
+config TEE
+	bool "Trusted Execution Environment support"
+	depends on ARM && (ARM64 || CPU_V7A)
+	select ARM_SMCCC
+	help
+	  This implements a generic interface towards a Trusted Execution
+	  Environment (TEE).
diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
new file mode 100644
index 000000000000..b6d8e16e6211
--- /dev/null
+++ b/drivers/tee/Makefile
@@ -0,0 +1,3 @@ 
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-y += tee-uclass.o
diff --git a/drivers/tee/tee-uclass.c b/drivers/tee/tee-uclass.c
new file mode 100644
index 000000000000..0209983491a0
--- /dev/null
+++ b/drivers/tee/tee-uclass.c
@@ -0,0 +1,192 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2018 Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <tee.h>
+
+/**
+ * struct tee_uclass_priv - information of a TEE, stored by the uclass
+ *
+ * @list_shm:	list of structe tee_shm representing memory blocks shared
+ *		with the TEE.
+ */
+struct tee_uclass_priv {
+	struct list_head list_shm;
+};
+
+static const struct tee_driver_ops *tee_get_ops(struct udevice *dev)
+{
+	return device_get_ops(dev);
+}
+
+void tee_get_version(struct udevice *dev, struct tee_version_data *vers)
+{
+	tee_get_ops(dev)->get_version(dev, vers);
+}
+
+int tee_open_session(struct udevice *dev, struct tee_open_session_arg *arg,
+		     ulong num_param, struct tee_param *param)
+{
+	return tee_get_ops(dev)->open_session(dev, arg, num_param, param);
+}
+
+int tee_close_session(struct udevice *dev, u32 session)
+{
+	return tee_get_ops(dev)->close_session(dev, session);
+}
+
+int tee_invoke_func(struct udevice *dev, struct tee_invoke_arg *arg,
+		    ulong num_param, struct tee_param *param)
+{
+	return tee_get_ops(dev)->invoke_func(dev, arg, num_param, param);
+}
+
+struct tee_shm *__tee_shm_add(struct udevice *dev, ulong align, void *addr,
+			      ulong size, u32 flags)
+{
+	struct tee_shm *shm;
+	void *p = addr;
+
+	if (flags & TEE_SHM_ALLOC) {
+		if (align)
+			p = memalign(align, size);
+		else
+			p = malloc(size);
+	}
+	if (!p)
+		return NULL;
+
+	shm = calloc(1, sizeof(*shm));
+	if (!shm)
+		goto err;
+
+	shm->dev = dev;
+	shm->addr = p;
+	shm->size = size;
+	shm->flags = flags;
+
+	if ((flags & TEE_SHM_SEC_REGISTER) &&
+	    tee_get_ops(dev)->shm_register(dev, shm))
+		goto err;
+
+	if (flags & TEE_SHM_REGISTER) {
+		struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
+
+		list_add(&shm->link, &priv->list_shm);
+	}
+	return shm;
+err:
+	free(shm);
+	if (flags & TEE_SHM_ALLOC)
+		free(p);
+	return NULL;
+}
+
+struct tee_shm *tee_shm_alloc(struct udevice *dev, ulong size,
+			      u32 flags)
+{
+	u32 f = flags;
+
+	f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER | TEE_SHM_ALLOC;
+	return __tee_shm_add(dev, 0, NULL, size, f);
+}
+
+struct tee_shm *tee_shm_register(struct udevice *dev, void *addr,
+				 ulong size, u32 flags)
+{
+	u32 f = flags & ~TEE_SHM_ALLOC;
+
+	f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER;
+	return __tee_shm_add(dev, 0, addr, size, f);
+}
+
+void tee_shm_free(struct tee_shm *shm)
+{
+	if (!shm)
+		return;
+
+	if (shm->flags & TEE_SHM_SEC_REGISTER)
+		tee_get_ops(shm->dev)->shm_unregister(shm->dev, shm);
+
+	if (shm->flags & TEE_SHM_REGISTER)
+		list_del(&shm->link);
+
+	if (shm->flags & TEE_SHM_ALLOC)
+		free(shm->addr);
+
+	free(shm);
+}
+
+bool tee_shm_is_registered(struct tee_shm *shm, struct udevice *dev)
+{
+	struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
+	struct tee_shm *s;
+
+	list_for_each_entry(s, &priv->list_shm, link)
+		if (s == shm)
+			return true;
+
+	return false;
+}
+
+struct udevice *tee_find_device(struct udevice *start,
+				int (*match)(struct tee_version_data *vers,
+					     const void *data),
+				const void *data,
+				struct tee_version_data *vers)
+{
+	struct udevice *dev = start;
+	struct tee_version_data lv;
+	struct tee_version_data *v = vers ? vers : &lv;
+
+	if (!dev)
+		uclass_first_device(UCLASS_TEE, &dev);
+
+	for (; dev; uclass_next_device(&dev)) {
+		tee_get_ops(dev)->get_version(dev, v);
+		if (!match || match(v, data))
+			return dev;
+	}
+
+	return NULL;
+}
+
+static int tee_pre_probe(struct udevice *dev)
+{
+	struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
+
+	INIT_LIST_HEAD(&priv->list_shm);
+
+	return 0;
+}
+
+static int tee_pre_remove(struct udevice *dev)
+{
+	struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
+	struct tee_shm *shm;
+
+	/*
+	 * Any remaining shared memory must be unregistered now as U-boot
+	 * is about to hand over to the next stage and that memory will be
+	 * reused.
+	 */
+	while (!list_empty(&priv->list_shm)) {
+		shm = list_first_entry(&priv->list_shm, struct tee_shm, link);
+		debug("%s: freeing leftover shm %p (size %lu, flags %#x)\n",
+		      __func__, (void *)shm, shm->size, shm->flags);
+		tee_shm_free(shm);
+	}
+
+	return 0;
+}
+
+UCLASS_DRIVER(tee) = {
+	.id = UCLASS_TEE,
+	.name = "tee",
+	.per_device_auto_alloc_size = sizeof(struct tee_uclass_priv),
+	.pre_probe = tee_pre_probe,
+	.pre_remove = tee_pre_remove,
+};
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index a39643ec5eef..955e0a915b87 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -81,6 +81,7 @@  enum uclass_id {
 	UCLASS_SPI_GENERIC,	/* Generic SPI flash target */
 	UCLASS_SYSCON,		/* System configuration device */
 	UCLASS_SYSRESET,	/* System reset device */
+	UCLASS_TEE,		/* Trusted Execution Environment device */
 	UCLASS_THERMAL,		/* Thermal sensor */
 	UCLASS_TIMER,		/* Timer device */
 	UCLASS_TPM,		/* Trusted Platform Module TIS interface */
diff --git a/include/tee.h b/include/tee.h
new file mode 100644
index 000000000000..3e6771123ef0
--- /dev/null
+++ b/include/tee.h
@@ -0,0 +1,290 @@ 
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2018 Linaro Limited
+ */
+
+#ifndef __TEE_H
+#define __TEE_H
+
+#include <common.h>
+#include <dm.h>
+
+#define TEE_UUID_LEN		16
+
+#define TEE_GEN_CAP_GP          BIT(0)	/* GlobalPlatform compliant TEE */
+#define TEE_GEN_CAP_REG_MEM     BIT(1)	/* Supports registering shared memory */
+
+#define TEE_SHM_REGISTER	BIT(0)	/* In list of shared memory */
+#define TEE_SHM_SEC_REGISTER	BIT(1)	/* TEE notified of this memory */
+#define TEE_SHM_ALLOC		BIT(2)	/* The memory is malloced() and must */
+					/* be freed() */
+
+#define TEE_PARAM_ATTR_TYPE_NONE		0	/* parameter not used */
+#define TEE_PARAM_ATTR_TYPE_VALUE_INPUT		1
+#define TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT	2
+#define TEE_PARAM_ATTR_TYPE_VALUE_INOUT		3	/* input and output */
+#define TEE_PARAM_ATTR_TYPE_MEMREF_INPUT	5
+#define TEE_PARAM_ATTR_TYPE_MEMREF_OUTPUT	6
+#define TEE_PARAM_ATTR_TYPE_MEMREF_INOUT	7	/* input and output */
+#define TEE_PARAM_ATTR_TYPE_MASK		0xff
+#define TEE_PARAM_ATTR_META			0x100
+#define TEE_PARAM_ATTR_MASK			(TEE_PARAM_ATTR_TYPE_MASK | \
+						 TEE_PARAM_ATTR_META)
+
+/*
+ * Some Global Platform error codes which has a meaning if the
+ * TEE_GEN_CAP_GP bit is returned by the driver in
+ * struct tee_version_data::gen_caps
+ */
+#define TEE_SUCCESS			0x00000000
+#define TEE_ERROR_GENERIC		0xffff0000
+#define TEE_ERROR_BAD_PARAMETERS	0xffff0006
+#define TEE_ERROR_ITEM_NOT_FOUND	0xffff0008
+#define TEE_ERROR_NOT_IMPLEMENTED	0xffff0009
+#define TEE_ERROR_NOT_SUPPORTED		0xffff000a
+#define TEE_ERROR_COMMUNICATION		0xffff000e
+#define TEE_ERROR_OUT_OF_MEMORY		0xffff000c
+#define TEE_ERROR_TARGET_DEAD		0xffff3024
+
+#define TEE_ORIGIN_COMMS		0x00000002
+
+/**
+ * struct tee_shm - memory shared with the TEE
+ * @dev:	The TEE device
+ * @link:	List node in the list in struct struct tee_uclass_priv
+ * @addr:	Pointer to the shared memory
+ * @size:	Size of the the shared memory
+ * @flags:	TEE_SHM_* above
+ */
+struct tee_shm {
+	struct udevice *dev;
+	struct list_head link;
+	void *addr;
+	ulong size;
+	u32 flags;
+};
+
+/**
+ * struct tee_param_memref - parameter memory reference
+ * @shm_offs:	Offset in bytes into the shared memory object @shm
+ * @size:	Size in bytes of the memory reference
+ * @shm:	Pointer to a shared memory object for the buffer
+ */
+struct tee_param_memref {
+	ulong shm_offs;
+	ulong size;
+	struct tee_shm *shm;
+};
+
+/**
+ * struct tee_param_value - value parameter
+ * @a, @b, @c:	Parameters passed by value
+ */
+struct tee_param_value {
+	u64 a;
+	u64 b;
+	u64 c;
+};
+
+/**
+ * struct tee_param - invoke parameter
+ * @attr:	Attributes
+ * @u.memref:	Memref parameter if (@attr & TEE_PARAM_ATTR_MASK) is one of
+ *		TEE_PARAM_ATTR_TYPE_MEMREF_* above
+ * @u.value:	Value parameter if (@attr & TEE_PARAM_ATTR_MASK) is one of
+ *		TEE_PARAM_ATTR_TYPE_VALUE_* above
+ */
+struct tee_param {
+	u64 attr;
+	union {
+		struct tee_param_memref memref;
+		struct tee_param_value value;
+	} u;
+};
+
+/**
+ * struct tee_open_session_arg - extra arguments for tee_open_session()
+ * @uuid:	[in] UUID of the Trusted Application
+ * @clnt_uuid:	[in] Normally zeroes
+ * @clnt_login:	[in] Normally 0
+ * @session:	[out] Session id
+ * @ret:	[out] return value
+ * @ret_origin:	[out] origin of the return value
+ */
+struct tee_open_session_arg {
+	u8 uuid[TEE_UUID_LEN];
+	u8 clnt_uuid[TEE_UUID_LEN];
+	u32 clnt_login;
+	u32 session;
+	u32 ret;
+	u32 ret_origin;
+};
+
+/**
+ * struct tee_invoke_arg - extra arguments for tee_invoke_func()
+ * @func:	[in] Trusted Application function, specific to the TA
+ * @session:	[in] Session id, from open session
+ * @ret:	[out] return value
+ * @ret_origin:	[out] origin of the return value
+ */
+struct tee_invoke_arg {
+	u32 func;
+	u32 session;
+	u32 ret;
+	u32 ret_origin;
+};
+
+/**
+ * struct tee_version_data - description of TEE
+ * @gen_caps:	Generic capabilities, TEE_GEN_CAP_* above
+ */
+struct tee_version_data {
+	u32 gen_caps;
+};
+
+/**
+ * struct tee_driver_ops - TEE driver operations
+ * @get_version:	Query capabilities of TEE device,
+			see tee_get_version()
+ * @open_session:	Opens a session to a Trusted Application in the TEE,
+ *			see tee_open_session().
+ * @close_session:	Closes a session to Trusted Application,
+ *			see tee_close_session()
+ * @invoke_func:	Invokes a function in a Trusted Application,
+			see tee_invoke_func()
+ */
+struct tee_driver_ops {
+	void (*get_version)(struct udevice *dev, struct tee_version_data *vers);
+	int (*open_session)(struct udevice *dev,
+			    struct tee_open_session_arg *arg, ulong num_param,
+			    struct tee_param *param);
+	int (*close_session)(struct udevice *dev, u32 session);
+	int (*invoke_func)(struct udevice *dev, struct tee_invoke_arg *arg,
+			   ulong num_param, struct tee_param *param);
+	/**
+	 * shm_register() - Registers memory shared with the TEE
+	 * @dev:	The TEE device
+	 * @shm:	Pointer to a shared memory object
+	 * Returns 0 on success or < 0 on failure.
+	 */
+	int (*shm_register)(struct udevice *dev, struct tee_shm *shm);
+	/**
+	 * shm_unregister() - Unregisters memory shared with the TEE
+	 * @dev:	The TEE device
+	 * @shm:	Pointer to a shared memory object
+	 * Returns 0 on success or < 0 on failure.
+	 */
+	int (*shm_unregister)(struct udevice *dev, struct tee_shm *shm);
+};
+
+/**
+ * __tee_shm_add() - Internal helper function to register shared memory
+ * @dev:	The TEE device
+ * @align:	Required alignment of allocated memory block if
+ *		(@flags & TEE_SHM_ALLOC)
+ * @addr:	Address of memory block, ignored if (@flags & TEE_SHM_ALLOC)
+ * @size:	Size of memory block
+ * @flags:	TEE_SHM_* above
+ *
+ * returns pointer to struct tee_shm on success or NULL on error
+ */
+struct tee_shm *__tee_shm_add(struct udevice *dev, ulong align, void *addr,
+			      ulong size, u32 flags);
+
+/**
+ * tee_shm_alloc() - Allocate shared memory
+ * @dev:	The TEE device
+ * @size:	Size of memory block
+ * @flags:	TEE_SHM_* above
+ *
+ * returns pointer to struct tee_shm on success or NULL on error
+ */
+struct tee_shm *tee_shm_alloc(struct udevice *dev, ulong size, u32 flags);
+
+/**
+ * tee_shm_register() - Registers shared memory
+ * @dev:	The TEE device
+ * @addr:	Address of memory block
+ * @size:	Size of memory block
+ * @flags:	TEE_SHM_* above
+ *
+ * returns pointer to struct tee_shm on success or NULL on error
+ */
+struct tee_shm *tee_shm_register(struct udevice *dev, void *addr,
+				 ulong length, u32 flags);
+
+/**
+ * tee_shm_free() - Frees shared memory
+ * @shm:	Shared memory object
+ */
+void tee_shm_free(struct tee_shm *shm);
+
+/**
+ * tee_shm_is_registered() - Check register status of shared memory object
+ * @shm:	Pointer to shared memory object
+ * @dev:	The TEE device
+ *
+ * Returns true if the shared memory object is registered for the supplied
+ * TEE device
+ */
+bool tee_shm_is_registered(struct tee_shm *shm, struct udevice *dev);
+
+/**
+ * tee_find_device() - Look up a TEE device
+ * @start:	if not NULL, continue search after this device
+ * @match:	function to check TEE device
+ * @data:	data for match function
+ * @vers:	if not NULL, version data of TEE device of the device returned
+ *
+ * Returns a probed TEE device of the first TEE device matched by the
+ * match() callback or NULL.
+ */
+struct udevice *tee_find_device(struct udevice *start,
+				int (*match)(struct tee_version_data *vers,
+					     const void *data),
+				const void *data,
+				struct tee_version_data *vers);
+
+/**
+ * tee_get_version() - Query capabilities of TEE device
+ * @dev:	The TEE device
+ * @vers:	Pointer to version data
+ */
+void tee_get_version(struct udevice *dev, struct tee_version_data *vers);
+
+/**
+ * tee_open_session() - Open a session to a Trusted Application
+ * @dev:	The TEE device
+ * @arg:	Open session arguments
+ * @num_param:	Number of elements in @param
+ * @param:	Parameters for Trusted Application
+ *
+ * Returns < 0 on error else see @arg->ret for result. If @arg->ret is
+ * TEE_SUCCESS the session identifier is available in @arg->session.
+ */
+int tee_open_session(struct udevice *dev, struct tee_open_session_arg *arg,
+		     ulong num_param, struct tee_param *param);
+
+/**
+ * tee_close_session() - Close a session to a Trusted Application
+ * @dev:	The TEE device
+ * @session:	Session id
+ *
+ * Return < 0 on error else 0, regardless the session will not be valid
+ * after this function has returned.
+ */
+int tee_close_session(struct udevice *dev, u32 session);
+
+/**
+ * tee_invoke_func() - Invoke a function in a Trusted Application
+ * @dev:	The TEE device
+ * @arg:	Invoke arguments
+ * @num_param:	Number of elements in @param
+ * @param:	Parameters for Trusted Application
+ *
+ * Returns < 0 on error else see @arg->ret for result.
+ */
+int tee_invoke_func(struct udevice *dev, struct tee_invoke_arg *arg,
+		    ulong num_param, struct tee_param *param);
+
+#endif /*__TEE_H*/