Commit 0fc1db9d authored by Sumit Garg's avatar Sumit Garg Committed by Jens Wiklander
Browse files

tee: add bus driver framework for TEE based devices 



Introduce a generic TEE bus driver concept for TEE based kernel drivers
which would like to communicate with TEE based devices/services. Also
add support in module device table for these new TEE based devices.

In this TEE bus concept, devices/services are identified via Universally
Unique Identifier (UUID) and drivers register a table of device UUIDs
which they can support.

So this TEE bus framework registers following apis:
- match(): Iterates over the driver UUID table to find a corresponding
  match for device UUID. If a match is found, then this particular device
  is probed via corresponding probe api registered by the driver. This
  process happens whenever a device or a driver is registered with TEE
  bus.
- uevent(): Notifies user-space (udev) whenever a new device is registered
  on this bus for auto-loading of modularized drivers.

Also this framework allows for device enumeration to be specific to
corresponding TEE implementation like OP-TEE etc.

Signed-off-by: default avatarSumit Garg <sumit.garg@linaro.org>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: default avatarBhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: default avatarJens Wiklander <jens.wiklander@linaro.org>
parent 42bf4152

drivers/tee/tee_core.c

+50 −4
Original line number Diff line number Diff line
@@ -15,7 +15,6 @@ 
#define pr_fmt(fmt) "%s: " fmt, __func__



#include <linux/cdev.h>

#include <linux/device.h>

#include <linux/fs.h>

#include <linux/idr.h>

#include <linux/module.h>
@@ -1040,6 +1039,39 @@ int tee_client_invoke_func(struct tee_context *ctx, 
}

EXPORT_SYMBOL_GPL(tee_client_invoke_func);



static int tee_client_device_match(struct device *dev,

				   struct device_driver *drv)

{

	const struct tee_client_device_id *id_table;

	struct tee_client_device *tee_device;



	id_table = to_tee_client_driver(drv)->id_table;

	tee_device = to_tee_client_device(dev);



	while (!uuid_is_null(&id_table->uuid)) {

		if (uuid_equal(&tee_device->id.uuid, &id_table->uuid))

			return 1;

		id_table++;

	}



	return 0;

}



static int tee_client_device_uevent(struct device *dev,

				    struct kobj_uevent_env *env)

{

	uuid_t *dev_id = &to_tee_client_device(dev)->id.uuid;



	return add_uevent_var(env, "MODALIAS=tee:%pUb", dev_id);

}



struct bus_type tee_bus_type = {

	.name		= "tee",

	.match		= tee_client_device_match,

	.uevent		= tee_client_device_uevent,

};

EXPORT_SYMBOL_GPL(tee_bus_type);



static int __init tee_init(void)

{

	int rc;
@@ -1053,18 +1085,32 @@ static int __init tee_init(void) 
	rc = alloc_chrdev_region(&tee_devt, 0, TEE_NUM_DEVICES, "tee");

	if (rc) {

		pr_err("failed to allocate char dev region\n");

		goto out_unreg_class;

	}



	rc = bus_register(&tee_bus_type);

	if (rc) {

		pr_err("failed to register tee bus\n");

		goto out_unreg_chrdev;

	}



	return 0;



out_unreg_chrdev:

	unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES);

out_unreg_class:

	class_destroy(tee_class);

	tee_class = NULL;

	}



	return rc;

}



static void __exit tee_exit(void)

{

	bus_unregister(&tee_bus_type);

	unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES);

	class_destroy(tee_class);

	tee_class = NULL;

	unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES);

}



subsys_initcall(tee_init);

include/linux/mod_devicetable.h

+9 −0
Original line number Diff line number Diff line
@@ -779,4 +779,13 @@ struct typec_device_id { 
	kernel_ulong_t driver_data;

};



/**

 * struct tee_client_device_id - tee based device identifier

 * @uuid: For TEE based client devices we use the device uuid as

 *        the identifier.

 */

struct tee_client_device_id {

	uuid_t uuid;

};



#endif /* LINUX_MOD_DEVICETABLE_H */

include/linux/tee_drv.h

+31 −1
Original line number Diff line number Diff line
@@ -15,11 +15,14 @@ 
#ifndef __TEE_DRV_H

#define __TEE_DRV_H



#include <linux/types.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
@@ -544,4 +547,31 @@ static inline bool tee_param_is_memref(struct tee_param *param) 
	}

}



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)



#endif /*__TEE_DRV_H*/

scripts/mod/devicetable-offsets.c

+3 −0
Original line number Diff line number Diff line
@@ -225,5 +225,8 @@ int main(void) 
	DEVID_FIELD(typec_device_id, svid);

	DEVID_FIELD(typec_device_id, mode);



	DEVID(tee_client_device_id);

	DEVID_FIELD(tee_client_device_id, uuid);



	return 0;

}

scripts/mod/file2alias.c

+19 −0
Original line number Diff line number Diff line
@@ -37,6 +37,9 @@ typedef unsigned char __u8; 
typedef struct {

	__u8 b[16];

} uuid_le;

typedef struct {

	__u8 b[16];

} uuid_t;



/* Big exception to the "don't include kernel headers into userspace, which

 * even potentially has different endianness and word sizes, since
@@ -1287,6 +1290,21 @@ static int do_typec_entry(const char *filename, void *symval, char *alias) 
	return 1;

}



/* Looks like: tee:uuid */

static int do_tee_entry(const char *filename, void *symval, char *alias)

{

	DEF_FIELD(symval, tee_client_device_id, uuid);



	sprintf(alias, "tee:%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",

		uuid.b[0], uuid.b[1], uuid.b[2], uuid.b[3], uuid.b[4],

		uuid.b[5], uuid.b[6], uuid.b[7], uuid.b[8], uuid.b[9],

		uuid.b[10], uuid.b[11], uuid.b[12], uuid.b[13], uuid.b[14],

		uuid.b[15]);



	add_wildcard(alias);

	return 1;

}



/* Does namelen bytes of name exactly match the symbol? */

static bool sym_is(const char *name, unsigned namelen, const char *symbol)

{
@@ -1357,6 +1375,7 @@ static const struct devtable devtable[] = { 
	{"fslmc", SIZE_fsl_mc_device_id, do_fsl_mc_entry},

	{"tbsvc", SIZE_tb_service_id, do_tbsvc_entry},

	{"typec", SIZE_typec_device_id, do_typec_entry},

	{"tee", SIZE_tee_client_device_id, do_tee_entry},

};



/* Create MODULE_ALIAS() statements.

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