| Message ID | 1547207251-9372-2-git-send-email-sumit.garg@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Introduce TEE bus driver framework | expand |
On Fri, 11 Jan 2019 at 20:39, Bhupesh Sharma <bhsharma@redhat.com> wrote: > > Hi Sumit, > > Thanks for the patch. Some nitpicks in-line: > Apologies for delay in my response as I was on leave. Please find my comments inline. Will include these nitpicks in v4 but let me wait for any further major comments. > On 01/11/2019 05:17 PM, Sumit Garg wrote: > > 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 | 43 ++++++++++++++++++++++++++++++++++++++++--- > > include/linux/tee_drv.h | 36 ++++++++++++++++++++++++++++++++++++ > > 2 files changed, 76 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c > > index 7b2bb4c..a685940 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) > > +{ > > + struct tee_client_device *tee_device; > > + const struct tee_client_device_id *id_table; > > + > > + tee_device = to_tee_client_device(dev); > > + id_table = to_tee_client_driver(drv)->id_table; > > + > > + while (!uuid_is_null(&id_table->uuid)) { > > + if (uuid_equal(&tee_device->id.uuid, &id_table->uuid)) > > + 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; > > @@ -1040,10 +1063,23 @@ 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 chrdev_err; > > } > > > > + rc = bus_register(&tee_bus_type); > > + if (rc) { > > + pr_err("failed to register tee bus\n"); > > + goto bus_err; > > + } > > + > > + return 0; > > + > > +bus_err: > > + unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES); > > +chrdev_err: > > + class_destroy(tee_class); > > + tee_class = NULL; > > + > > Hmm.. these error paths/labels look out-of-order. > See 'drivers/i2c/i2c-dev.c' for example. > > Normally our error paths in an __init function is of the same order as > the __exit function implementation. So this should be changed to > something like: > > +out_unreg_class: > + class_destroy(tee_class); > + tee_class = NULL; > +out_unreg_chrdev: > + unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES); > It seems that prior to this patch also allocation order in __init function differed from release order in __exit function. Will correct that too along with this. > > return rc; > > } > > > > @@ -1052,6 +1088,7 @@ static void __exit tee_exit(void) > > class_destroy(tee_class); > > tee_class = NULL; > > unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES); > > + bus_unregister(&tee_bus_type); > > Since the __exit function order is the reverse of the __init one, lets > reorder this as: > > + bus_unregister(&tee_bus_type); > class_destroy(tee_class); > tee_class = NULL; > unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES); > Ok. > See 'drivers/i2c/i2c-dev.c' for example. > > > } > > > > subsys_initcall(tee_init); > > diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h > > index 6cfe058..ed16bf1 100644 > > --- a/include/linux/tee_drv.h > > +++ b/include/linux/tee_drv.h > > @@ -20,6 +20,8 @@ > > #include <linux/kref.h> > > #include <linux/list.h> > > #include <linux/tee.h> > > +#include <linux/device.h> > > +#include <linux/uuid.h> > > If possible, let's keep alphabetical order of header files when making > changes in the patch. > Ok. > > > > /* > > * The file describes the API provided by the generic TEE driver to the > > @@ -538,4 +540,38 @@ static inline bool tee_param_is_memref(struct tee_param *param) > > } > > } > > > > +extern struct bus_type tee_bus_type; > > + > > +/** > > + * 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; > > +}; > > Hmm.. Do we really need a struct for a single element, rather lets use a > simple typedef here. > Agree, will rather use typedef here. > > + > > +/** > > + * 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; > > +}; > > Add a blank line here. > Ok. > > +#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; > > +}; > > Add a blank line here. Ok. -Sumit > > +#define to_tee_client_driver(d) \ > > + container_of(d, struct tee_client_driver, driver) > > + > > #endif /*__TEE_DRV_H*/ > > > > Thanks, > Bhupesh
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 7b2bb4c..a685940 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) +{ + struct tee_client_device *tee_device; + const struct tee_client_device_id *id_table; + + tee_device = to_tee_client_device(dev); + id_table = to_tee_client_driver(drv)->id_table; + + while (!uuid_is_null(&id_table->uuid)) { + if (uuid_equal(&tee_device->id.uuid, &id_table->uuid)) + 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; @@ -1040,10 +1063,23 @@ 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 chrdev_err; } + rc = bus_register(&tee_bus_type); + if (rc) { + pr_err("failed to register tee bus\n"); + goto bus_err; + } + + return 0; + +bus_err: + unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES); +chrdev_err: + class_destroy(tee_class); + tee_class = NULL; + return rc; } @@ -1052,6 +1088,7 @@ static void __exit tee_exit(void) class_destroy(tee_class); tee_class = NULL; unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES); + bus_unregister(&tee_bus_type); } subsys_initcall(tee_init); diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 6cfe058..ed16bf1 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -20,6 +20,8 @@ #include <linux/kref.h> #include <linux/list.h> #include <linux/tee.h> +#include <linux/device.h> +#include <linux/uuid.h> /* * The file describes the API provided by the generic TEE driver to the @@ -538,4 +540,38 @@ static inline bool tee_param_is_memref(struct tee_param *param) } } +extern struct bus_type tee_bus_type; + +/** + * 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; +}; + +/** + * 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*/
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 | 43 ++++++++++++++++++++++++++++++++++++++++--- include/linux/tee_drv.h | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 76 insertions(+), 3 deletions(-) -- 2.7.4