Add UCLASS_TEE for Trusted Execution Environment

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.

Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

8 files changed, 569 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 6b4d00a..dac76e0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -629,6 +629,12 @@ 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 11b88a1..927a2b8 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -100,6 +100,8 @@ 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 e3b9e8c..fb38b67 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -105,6 +105,7 @@ obj-y += input/
 obj-y += smem/
 obj-y += soc/
 obj-y += thermal/
+obj-$(CONFIG_TEE) += tee/
 obj-y += axi/
 obj-$(CONFIG_W1) += w1/
 obj-$(CONFIG_W1_EEPROM) += w1-eeprom/
diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
new file mode 100644
index 0000000..f3fc3c2
--- /dev/null
+++ b/drivers/tee/Kconfig
@@ -0,0 +1,11 @@
+# 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). A TEE is a trusted OS running in some secure
+	  environment, for example, TrustZone on ARM cpus, or a separate
+	  secure co-processor etc. See also:
+	  https://en.wikipedia.org/wiki/Trusted_execution_environment
diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
new file mode 100644
index 0000000..b6d8e16
--- /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 0000000..1bee54e
--- /dev/null
+++ b/drivers/tee/tee-uclass.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2018 Linaro Limited
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/uclass-internal.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,
+		     uint 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,
+		    uint num_param, struct tee_param *param)
+{
+	return tee_get_ops(dev)->invoke_func(dev, arg, num_param, param);
+}
+
+int __tee_shm_add(struct udevice *dev, ulong align, void *addr, ulong size,
+		  u32 flags, struct tee_shm **shmp)
+{
+	struct tee_shm *shm;
+	void *p = addr;
+	int rc;
+
+	if (flags & TEE_SHM_ALLOC) {
+		if (align)
+			p = memalign(align, size);
+		else
+			p = malloc(size);
+	}
+	if (!p)
+		return -ENOMEM;
+
+	shm = calloc(1, sizeof(*shm));
+	if (!shm) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	shm->dev = dev;
+	shm->addr = p;
+	shm->size = size;
+	shm->flags = flags;
+
+	if (flags & TEE_SHM_SEC_REGISTER) {
+		rc = tee_get_ops(dev)->shm_register(dev, shm);
+		if (rc)
+			goto err;
+	}
+
+	if (flags & TEE_SHM_REGISTER) {
+		struct tee_uclass_priv *priv = dev_get_uclass_priv(dev);
+
+		list_add(&shm->link, &priv->list_shm);
+	}
+
+	*shmp = shm;
+
+	return 0;
+err:
+	free(shm);
+	if (flags & TEE_SHM_ALLOC)
+		free(p);
+
+	return rc;
+}
+
+int tee_shm_alloc(struct udevice *dev, ulong size, u32 flags,
+		  struct tee_shm **shmp)
+{
+	u32 f = flags;
+
+	f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER | TEE_SHM_ALLOC;
+
+	return __tee_shm_add(dev, 0, NULL, size, f, shmp);
+}
+
+int tee_shm_register(struct udevice *dev, void *addr, ulong size, u32 flags,
+		     struct tee_shm **shmp)
+{
+	u32 f = flags & ~TEE_SHM_ALLOC;
+
+	f |= TEE_SHM_SEC_REGISTER | TEE_SHM_REGISTER;
+
+	return __tee_shm_add(dev, 0, addr, size, f, shmp);
+}
+
+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_find_first_device(UCLASS_TEE, &dev);
+	else
+		uclass_find_next_device(&dev);
+
+	for (; dev; uclass_find_next_device(&dev)) {
+		if (device_probe(dev))
+			continue;
+		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 79fd300..269a2c6 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -85,6 +85,7 @@ 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 0000000..b86dbec
--- /dev/null
+++ b/include/tee.h
@@ -0,0 +1,336 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2018 Linaro Limited
+ */
+
+#ifndef __TEE_H
+#define __TEE_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_SECURITY		0xffff000f
+#define TEE_ERROR_OUT_OF_MEMORY		0xffff000c
+#define TEE_ERROR_TARGET_DEAD		0xffff3024
+
+#define TEE_ORIGIN_COMMS		0x00000002
+#define TEE_ORIGIN_TEE			0x00000003
+#define TEE_ORIGIN_TRUSTED_APP		0x00000004
+
+struct udevice;
+/**
+ * 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 - memory reference for a Trusted Application
+ * @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
+ *
+ * Used as a part of struct tee_param, see that for more information.
+ */
+struct tee_param_memref {
+	ulong shm_offs;
+	ulong size;
+	struct tee_shm *shm;
+};
+
+/**
+ * struct tee_param_value - value parameter for a Trusted Application
+ * @a, @b, @c:	Parameters passed by value
+ *
+ * Used as a part of struct tee_param, see that for more information.
+ */
+struct tee_param_value {
+	u64 a;
+	u64 b;
+	u64 c;
+};
+
+/**
+ * struct tee_param - invoke parameter for a Trusted Application
+ * @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
+ *
+ * Parameters to TA are passed using an array of this struct, for
+ * flexibility both value parameters and memory refereces can be used.
+ */
+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,
+ * @open_session:	Opens a session to a Trusted Application in the TEE,
+ * @close_session:	Closes a session to Trusted Application,
+ * @invoke_func:	Invokes a function in a Trusted Application,
+ * @shm_register:	Registers memory shared with the TEE
+ * @shm_unregister:	Unregisters memory shared with the TEE
+ */
+struct tee_driver_ops {
+	/**
+	 * get_version() - Query capabilities of TEE device
+	 * @dev:	The TEE device
+	 * @vers:	Pointer to version data
+	 */
+	void (*get_version)(struct udevice *dev, struct tee_version_data *vers);
+	/**
+	 * 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 (*open_session)(struct udevice *dev,
+			    struct tee_open_session_arg *arg, uint num_param,
+			    struct tee_param *param);
+	/**
+	 * 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 (*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 (*invoke_func)(struct udevice *dev, struct tee_invoke_arg *arg,
+			   uint 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
+ * @shmp:	If the function return 0, this holds the allocated
+ *		struct tee_shm
+ *
+ * returns 0 on success or < 0 on failure.
+ */
+int __tee_shm_add(struct udevice *dev, ulong align, void *addr, ulong size,
+		  u32 flags, struct tee_shm **shmp);
+
+/**
+ * tee_shm_alloc() - Allocate shared memory
+ * @dev:	The TEE device
+ * @size:	Size of memory block
+ * @flags:	TEE_SHM_* above
+ * @shmp:	If the function return 0, this holds the allocated
+ *		struct tee_shm
+ *
+ * returns 0 on success or < 0 on failure.
+ */
+int tee_shm_alloc(struct udevice *dev, ulong size, u32 flags,
+		  struct tee_shm **shmp);
+
+/**
+ * tee_shm_register() - Registers shared memory
+ * @dev:	The TEE device
+ * @addr:	Address of memory block
+ * @size:	Size of memory block
+ * @flags:	TEE_SHM_* above
+ * @shmp:	If the function return 0, this holds the allocated
+ *		struct tee_shm
+ *
+ * returns 0 on success or < 0 on failure.
+ */
+int tee_shm_register(struct udevice *dev, void *addr, ulong size, u32 flags,
+		     struct tee_shm **shmp);
+
+/**
+ * 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, returns != 0 if the device
+ *		matches
+ * @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,
+		     uint 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,
+		    uint num_param, struct tee_param *param);
+
+#endif /* __TEE_H */