On Thu, Jan 24, 2019 at 3:49 PM Sumit Garg [off-list ref] wrote:

On Thu, 24 Jan 2019 at 15:15, Daniel Thompson
[off-list ref] wrote:

quoted

On Thu, Jan 24, 2019 at 11:24:36AM +0530, Sumit Garg wrote:

quoted

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 out-of-tree drivers.

out-of-tree? Surely it can be used to auto-load any modulized driver.

Agree, will correct.

quoted

quoted

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

Signed-off-by: Sumit Garg <redacted>
---
 drivers/tee/tee_core.c            | 57 ++++++++++++++++++++++++++++++++++++---
 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, 115 insertions(+), 5 deletions(-)

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 7b2bb4c..9f4c8bc 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 +1026,42 @@ 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;
+
+     if (add_uevent_var(env, "MODALIAS=tee:%pUb", dev_id))
+             return -ENOMEM;
+
+     return 0;

Can just return directly here:

        return add_uevent_var(... )

Okay will use this instead.

quoted

Other than these nitpicks then FWIW:
Reviewed-by: Daniel Thompson <redacted>

Thanks.
-Sumit

quoted

quoted

+}
+
+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;

@@ -1040,18 +1075,32 @@ 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 f9bd2f3..14eaeeb 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 6cfe058..ce957ce 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 <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

@@ -538,4 +541,31 @@ 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 2930044..1607183 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 a37af7d..d0e4172 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.
--

2.7.4

With Daniel's inputs addressed, for this patch:
Reviewed-by: Bhupesh Sharma <redacted>

Thanks

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