optee: add bidirectional communication support

So far, barebox support for OP-TEE was restricted to loading it either
early in PBL or via bootm and to not step over it when allocating
memory. This was guarded behind CONFIG_HAVE_OPTEE.

This commit imports from Linux the driver behind CONFIG_OPTEE, which
brings actual bidirectional communication with OP-TEE in barebox.
This is useful as trusted applications running in OP-TEE can provide
various services to the normal world, like filtered OTP access, RNG
seeded from normally inaccessible entropy sources, firmware TPM and
management of resources like clocks, resets, power domains and voltage
regulators in the form of SCMI.

We already have SCMI support, but only via the SMC calling convention
for communication with TF-A. For integration with publicly available
STM32MP13 firmware, we need to do SCMI over OP-TEE and this is likewise
interesting for STM32MP1 trusted boot setups.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20231127063559.2205776-7-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 385 insertions, 0 deletions

diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
new file mode 100644
index 0000000000..e5f0344d4d
--- /dev/null
+++ b/include/linux/tee_drv.h
@@ -0,0 +1,385 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2015-2022 Linaro Limited
+ */
+
+#ifndef __TEE_DRV_H
+#define __TEE_DRV_H
+
+#include <linux/device.h>
+#include <linux/idr.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/mod_devicetable.h>
+#include <linux/tee.h>
+#include <linux/types.h>
+#include <linux/uuid.h>
+
+/*
+ * The file describes the API provided by the generic TEE driver to the
+ * specific TEE driver.
+ */
+
+#define TEE_SHM_DYNAMIC		BIT(0)  /* Dynamic shared memory registered */
+					/* in secure world */
+#define TEE_SHM_USER_MAPPED	BIT(1)  /* Memory mapped in user space */
+#define TEE_SHM_POOL		BIT(2)  /* Memory allocated from pool */
+#define TEE_SHM_PRIV		BIT(3)  /* Memory private to TEE driver */
+
+struct device;
+struct tee_device;
+struct tee_shm;
+
+/**
+ * struct tee_context - driver specific context on file pointer data
+ * @teedev:	pointer to this drivers struct tee_device
+ * @list_shm:	List of shared memory object owned by this context
+ * @data:	driver specific context data, managed by the driver
+ * @refcount:	reference counter for this structure
+ * @releasing:  flag that indicates if context is being released right now.
+ *		It is needed to break circular dependency on context during
+ *              shared memory release.
+ * @cap_memref_null: flag indicating if the TEE Client support shared
+ *                   memory buffer with a NULL pointer.
+ */
+struct tee_context {
+	struct tee_device *teedev;
+	struct list_head list_shm;
+	void *data;
+	struct kref refcount;
+	bool releasing;
+	bool cap_memref_null;
+};
+
+struct tee_param_memref {
+	size_t shm_offs;
+	size_t size;
+	struct tee_shm *shm;
+};
+
+struct tee_param_value {
+	u64 a;
+	u64 b;
+	u64 c;
+};
+
+struct tee_param {
+	u64 attr;
+	union {
+		struct tee_param_memref memref;
+		struct tee_param_value value;
+	} u;
+};
+
+/**
+ * struct tee_driver_ops - driver operations vtable
+ * @get_version:	returns version of driver
+ * @open:		called when the device file is opened
+ * @release:		release this open file
+ * @open_session:	open a new session
+ * @close_session:	close a session
+ * @invoke_func:	invoke a trusted function
+ * @shm_register:	register shared memory buffer in TEE
+ * @shm_unregister:	unregister shared memory buffer in TEE
+ */
+struct tee_driver_ops {
+	void (*get_version)(struct tee_device *teedev,
+			    struct tee_ioctl_version_data *vers);
+	int (*open)(struct tee_context *ctx);
+	void (*release)(struct tee_context *ctx);
+	int (*open_session)(struct tee_context *ctx,
+			    struct tee_ioctl_open_session_arg *arg,
+			    struct tee_param *param);
+	int (*close_session)(struct tee_context *ctx, u32 session);
+	int (*invoke_func)(struct tee_context *ctx,
+			   struct tee_ioctl_invoke_arg *arg,
+			   struct tee_param *param);
+	int (*shm_register)(struct tee_context *ctx, struct tee_shm *shm);
+	int (*shm_unregister)(struct tee_context *ctx, struct tee_shm *shm);
+};
+
+/**
+ * struct tee_desc - Describes the TEE driver to the subsystem
+ * @name:	name of driver
+ * @ops:	driver operations vtable
+ * @owner:	module providing the driver
+ * @flags:	Extra properties of driver, defined by TEE_DESC_* below
+ */
+#define TEE_DESC_PRIVILEGED	0x1
+struct tee_desc {
+	const char *name;
+	const struct tee_driver_ops *ops;
+	struct module *owner;
+	u32 flags;
+};
+
+/**
+ * tee_device_alloc() - Allocate a new struct tee_device instance
+ * @teedesc:	Descriptor for this driver
+ * @dev:	Parent device for this device
+ * @driver_data: Private driver data for this device
+ *
+ * Allocates a new struct tee_device instance. The device is
+ * removed by tee_device_unregister().
+ *
+ * @returns a pointer to a 'struct tee_device' or an ERR_PTR on failure
+ */
+struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
+				    struct device *dev,
+				    void *driver_data);
+
+/**
+ * tee_device_release() - Releases new struct tee_device instance
+ * @teedev: Device allocated with tee_device_alloc()
+ *
+ * Frees a struct tee_device.
+ */
+void tee_device_release(struct tee_device *teedev);
+
+/**
+ * tee_device_register() - Registers a TEE device
+ * @teedev:	Device to register
+ *
+ * tee_device_unregister() need to be called to remove the @teedev if
+ * this function fails.
+ *
+ * @returns < 0 on failure
+ */
+int tee_device_register(struct tee_device *teedev);
+
+/**
+ * tee_device_unregister() - Removes a TEE device
+ * @teedev:	Device to unregister
+ *
+ * This function should be called to remove the @teedev even if
+ * tee_device_register() hasn't been called yet. Does nothing if
+ * @teedev is NULL.
+ */
+void tee_device_unregister(struct tee_device *teedev);
+
+/**
+ * tee_session_calc_client_uuid() - Calculates client UUID for session
+ * @uuid:		Resulting UUID
+ * @connection_method:	Connection method for session (TEE_IOCTL_LOGIN_*)
+ * @connectuon_data:	Connection data for opening session
+ *
+ * Based on connection method calculates UUIDv5 based client UUID.
+ *
+ * For group based logins verifies that calling process has specified
+ * credentials.
+ *
+ * @return < 0 on failure
+ */
+int tee_session_calc_client_uuid(uuid_t *uuid, u32 connection_method,
+				 const u8 connection_data[TEE_IOCTL_UUID_LEN]);
+
+/**
+ * struct tee_shm - shared memory object
+ * @ctx:	context using the object
+ * @paddr:	physical address of the shared memory
+ * @kaddr:	virtual address of the shared memory
+ * @size:	size of shared memory
+ * @refcount:	reference counter
+ * @flags:	defined by TEE_SHM_* in tee_drv.h
+ * @link:	list head for registering object globally
+ *
+ * This pool is only supposed to be accessed directly from the TEE
+ * subsystem and from drivers that implements their own shm pool manager.
+ */
+struct tee_shm {
+	struct tee_context *ctx;
+	phys_addr_t paddr;
+	void *kaddr;
+	size_t size;
+	refcount_t refcount;
+	u32 flags;
+	struct list_head link;
+};
+
+/**
+ * tee_get_drvdata() - Return driver_data pointer
+ * @returns the driver_data pointer supplied to tee_register().
+ */
+void *tee_get_drvdata(struct tee_device *teedev);
+
+struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size);
+struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size);
+
+/**
+ * tee_shm_is_dynamic() - Check if shared memory object is of the dynamic kind
+ * @shm:	Shared memory handle
+ * @returns true if object is dynamic shared memory
+ */
+static inline bool tee_shm_is_dynamic(struct tee_shm *shm)
+{
+	return shm && (shm->flags & TEE_SHM_DYNAMIC);
+}
+
+/**
+ * tee_shm_free() - Free shared memory
+ * @shm:	Handle to shared memory to free
+ */
+void tee_shm_free(struct tee_shm *shm);
+
+/**
+ * tee_shm_put() - Decrease reference count on a shared memory handle
+ * @shm:	Shared memory handle
+ */
+void tee_shm_put(struct tee_shm *shm);
+
+/**
+ * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
+ * @shm:	Shared memory handle
+ * @offs:	Offset from start of this shared memory
+ * @returns virtual address of the shared memory + offs if offs is within
+ *	the bounds of this shared memory, else an ERR_PTR
+ */
+void *tee_shm_get_va(struct tee_shm *shm, size_t offs);
+
+/**
+ * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
+ * @shm:	Shared memory handle
+ * @offs:	Offset from start of this shared memory
+ * @pa:		Physical address to return
+ * @returns 0 if offs is within the bounds of this shared memory, else an
+ *	error code.
+ */
+int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa);
+
+/**
+ * tee_shm_get_size() - Get size of shared memory buffer
+ * @shm:	Shared memory handle
+ * @returns size of shared memory
+ */
+static inline size_t tee_shm_get_size(struct tee_shm *shm)
+{
+	return shm->size;
+}
+
+/**
+ * tee_client_open_context() - Open a TEE context
+ * @start:	if not NULL, continue search after this context
+ * @match:	function to check TEE device
+ * @data:	data for match function
+ * @vers:	if not NULL, version data of TEE device of the context returned
+ *
+ * This function does an operation similar to open("/dev/teeX") in user space.
+ * A returned context must be released with tee_client_close_context().
+ *
+ * Returns a TEE context of the first TEE device matched by the match()
+ * callback or an ERR_PTR.
+ */
+struct tee_context *
+tee_client_open_context(struct tee_context *start,
+			int (*match)(struct tee_ioctl_version_data *,
+				     const void *),
+			const void *data, struct tee_ioctl_version_data *vers);
+
+/**
+ * tee_client_close_context() - Close a TEE context
+ * @ctx:	TEE context to close
+ *
+ * Note that all sessions previously opened with this context will be
+ * closed when this function is called.
+ */
+void tee_client_close_context(struct tee_context *ctx);
+
+/**
+ * tee_client_get_version() - Query version of TEE
+ * @ctx:	TEE context to TEE to query
+ * @vers:	Pointer to version data
+ */
+void tee_client_get_version(struct tee_context *ctx,
+			    struct tee_ioctl_version_data *vers);
+
+/**
+ * tee_client_open_session() - Open a session to a Trusted Application
+ * @ctx:	TEE context
+ * @arg:	Open session arguments, see description of
+ *		struct tee_ioctl_open_session_arg
+ * @param:	Parameters passed to the Trusted Application
+ *
+ * Returns < 0 on error else see @arg->ret for result. If @arg->ret
+ * is TEEC_SUCCESS the session identifier is available in @arg->session.
+ */
+int tee_client_open_session(struct tee_context *ctx,
+			    struct tee_ioctl_open_session_arg *arg,
+			    struct tee_param *param);
+
+/**
+ * tee_client_close_session() - Close a session to a Trusted Application
+ * @ctx:	TEE Context
+ * @session:	Session id
+ *
+ * Return < 0 on error else 0, regardless the session will not be
+ * valid after this function has returned.
+ */
+int tee_client_close_session(struct tee_context *ctx, u32 session);
+
+/**
+ * tee_client_invoke_func() - Invoke a function in a Trusted Application
+ * @ctx:	TEE Context
+ * @arg:	Invoke arguments, see description of
+ *		struct tee_ioctl_invoke_arg
+ * @param:	Parameters passed to the Trusted Application
+ *
+ * Returns < 0 on error else see @arg->ret for result.
+ */
+int tee_client_invoke_func(struct tee_context *ctx,
+			   struct tee_ioctl_invoke_arg *arg,
+			   struct tee_param *param);
+
+static inline bool tee_param_is_memref(struct tee_param *param)
+{
+	switch (param->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
+	case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
+	case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
+	case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+extern struct bus_type tee_bus_type;
+
+/**
+ * struct tee_client_device - tee based device
+ * @id:			device identifier
+ * @dev:		device structure
+ */
+struct tee_client_device {
+	struct tee_client_device_id id;
+	struct device dev;
+};
+
+#define to_tee_client_device(d) container_of(d, struct tee_client_device, dev)
+
+/**
+ * struct tee_client_driver - tee client driver
+ * @id_table:		device id table supported by this driver
+ * @driver:		driver structure
+ */
+struct tee_client_driver {
+	const struct tee_client_device_id *id_table;
+	struct device_driver driver;
+};
+
+#define to_tee_client_driver(d) \
+		container_of(d, struct tee_client_driver, driver)
+
+/**
+ * teedev_open() - Open a struct tee_device
+ * @teedev:	Device to open
+ *
+ * @return a pointer to struct tee_context on success or an ERR_PTR on failure.
+ */
+struct tee_context *teedev_open(struct tee_device *teedev);
+
+/**
+ * teedev_close_context() - closes a struct tee_context
+ * @ctx:	The struct tee_context to close
+ */
+void teedev_close_context(struct tee_context *ctx);
+
+#endif /*__TEE_DRV_H*/