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: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
This commit is contained in:
Sumit Garg 2019-01-29 11:19:35 +05:30 committed by Jens Wiklander
parent 42bf4152d8
commit 0fc1db9d10
5 changed files with 112 additions and 5 deletions

View File

@ -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");
class_destroy(tee_class);
tee_class = NULL;
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);

View File

@ -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 */

View File

@ -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*/

View File

@ -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;
}

View File

@ -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.