Introduce a generic TEE bus driver concept for TEE based kernel drivers which would like to communicate with TEE based devices/services.
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 a match() callback function which 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.
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 --- drivers/tee/tee_core.c | 45 +++++++++++++++++++++++++++++++++++++++++---- include/linux/tee_drv.h | 37 ++++++++++++++++++++++++++++++++++++- 2 files changed, 77 insertions(+), 5 deletions(-)
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 7b2bb4c..55370d5 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -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> @@ -1027,6 +1026,30 @@ 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 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)) { + if (uuid_equal(&tee_device->id, id_table)) + return 1; + id_table++; + } + + return 0; +} + +struct bus_type tee_bus_type = { + .name = "tee", + .match = tee_client_device_match, +}; +EXPORT_SYMBOL_GPL(tee_bus_type); + static int __init tee_init(void) { int rc; @@ -1040,18 +1063,32 @@ 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); diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 6cfe058..ba985d8 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -15,11 +15,13 @@ #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/tee.h> +#include <linux/types.h> +#include <linux/uuid.h>
/* * The file describes the API provided by the generic TEE driver to the @@ -538,4 +540,37 @@ static inline bool tee_param_is_memref(struct tee_param *param) } }
+extern struct bus_type tee_bus_type; + +/* + * For TEE based client devices we use the device uuid as the + * identifier. + */ +typedef uuid_t tee_client_device_id; + +/** + * struct tee_client_device - tee based device + * @id: device identifier + * @dev: device structure + */ +struct tee_client_device { + 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 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*/