From 0fc1db9d105915021260eb241661b8e96f5c0f1a Mon Sep 17 00:00:00 2001 From: Sumit Garg Date: Tue, 29 Jan 2019 11:19:35 +0530 Subject: [PATCH] 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 Reviewed-by: Daniel Thompson Reviewed-by: Bhupesh Sharma Signed-off-by: Jens Wiklander --- drivers/tee/tee_core.c | 54 ++++++++++++++++++++++++++++--- include/linux/mod_devicetable.h | 9 ++++++ include/linux/tee_drv.h | 32 +++++++++++++++++- scripts/mod/devicetable-offsets.c | 3 ++ scripts/mod/file2alias.c | 19 +++++++++++ 5 files changed, 112 insertions(+), 5 deletions(-) diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index adf2588282fc..25f3b9cc8908 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 -#include #include #include #include @@ -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); diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index f9bd2f34b99f..14eaeeb46f41 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -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 */ diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 5076502c07d7..56d7f1b4516d 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -15,11 +15,14 @@ #ifndef __TEE_DRV_H #define __TEE_DRV_H -#include +#include #include #include #include +#include #include +#include +#include /* * 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*/ diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c index 293004499b4d..160718383a71 100644 --- a/scripts/mod/devicetable-offsets.c +++ b/scripts/mod/devicetable-offsets.c @@ -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; } diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index a37af7d71973..d0e41723627f 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -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.