Enable multi-stage OP-TEE bus enumeration

Probes drivers on the OP-TEE bus in two steps. First for drivers which
 do not depend on tee-supplicant. After tee-supplicant has been started
 probe the devices which do depend on tee-supplicant.
 
 Also introduces driver which uses an OP-TEE based fTPM Trusted
 Application depends on tee-supplicant NV RAM implementation based on
 RPMB secure storage.
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Merge tag 'optee-bus-for-v5.9' of git://git.linaro.org/people/jens.wiklander/linux-tee into arm/drivers

Enable multi-stage OP-TEE bus enumeration

Probes drivers on the OP-TEE bus in two steps. First for drivers which
do not depend on tee-supplicant. After tee-supplicant has been started
probe the devices which do depend on tee-supplicant.

Also introduces driver which uses an OP-TEE based fTPM Trusted
Application depends on tee-supplicant NV RAM implementation based on
RPMB secure storage.

* tag 'optee-bus-for-v5.9' of git://git.linaro.org/people/jens.wiklander/linux-tee:
  tpm_ftpm_tee: register driver on TEE bus
  optee: enable support for multi-stage bus enumeration
  optee: use uuid for sysfs driver entry

Link: https://lore.kernel.org/r/20200710085230.GA1312913@jade
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/ABI/testing/sysfs-bus-optee-devices

@@ -0,0 +1,8 @@
+What:		/sys/bus/tee/devices/optee-ta-<uuid>/
+Date:           May 2020
+KernelVersion   5.8
+Contact:        op-tee@lists.trustedfirmware.org
+Description:
+		OP-TEE bus provides reference to registered drivers under this directory. The <uuid>
+		matches Trusted Application (TA) driver and corresponding TA in secure OS. Drivers
+		are free to create needed API under optee-ta-<uuid> directory.

MAINTAINERS

@@ -12697,6 +12697,7 @@ OP-TEE DRIVER
 M:	Jens Wiklander <jens.wiklander@linaro.org>
 L:	tee-dev@lists.linaro.org
 S:	Maintained
+F:	Documentation/ABI/testing/sysfs-bus-optee-devices
 F:	drivers/tee/optee/
 
 OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER

drivers/char/tpm/tpm_ftpm_tee.c

@@ -214,11 +214,10 @@ static int ftpm_tee_match(struct tee_ioctl_version_data *ver, const void *data)
  * Return:
  *	On success, 0. On failure, -errno.
  */
-static int ftpm_tee_probe(struct platform_device *pdev)
+static int ftpm_tee_probe(struct device *dev)
 {
 	int rc;
 	struct tpm_chip *chip;
-	struct device *dev = &pdev->dev;
 	struct ftpm_tee_private *pvt_data = NULL;
 	struct tee_ioctl_open_session_arg sess_arg;
 
@@ -297,6 +296,13 @@ out_tee_session:
 	return rc;
 }
 
+static int ftpm_plat_tee_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	return ftpm_tee_probe(dev);
+}
+
 /**
  * ftpm_tee_remove() - remove the TPM device
  * @pdev: the platform_device description.
@@ -304,9 +310,9 @@ out_tee_session:
  * Return:
  *	0 always.
  */
-static int ftpm_tee_remove(struct platform_device *pdev)
+static int ftpm_tee_remove(struct device *dev)
 {
-	struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev);
+	struct ftpm_tee_private *pvt_data = dev_get_drvdata(dev);
 
 	/* Release the chip */
 	tpm_chip_unregister(pvt_data->chip);
@@ -328,11 +334,18 @@ static int ftpm_tee_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static int ftpm_plat_tee_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	return ftpm_tee_remove(dev);
+}
+
 /**
  * ftpm_tee_shutdown() - shutdown the TPM device
  * @pdev: the platform_device description.
  */
-static void ftpm_tee_shutdown(struct platform_device *pdev)
+static void ftpm_plat_tee_shutdown(struct platform_device *pdev)
 {
 	struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev);
 
@@ -347,17 +360,54 @@ static const struct of_device_id of_ftpm_tee_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, of_ftpm_tee_ids);
 
-static struct platform_driver ftpm_tee_driver = {
+static struct platform_driver ftpm_tee_plat_driver = {
 	.driver = {
 		.name = "ftpm-tee",
 		.of_match_table = of_match_ptr(of_ftpm_tee_ids),
 	},
-	.probe = ftpm_tee_probe,
+	.shutdown = ftpm_plat_tee_shutdown,
-	.remove = ftpm_tee_remove,
+	.probe = ftpm_plat_tee_probe,
-	.shutdown = ftpm_tee_shutdown,
+	.remove = ftpm_plat_tee_remove,
 };
 
-module_platform_driver(ftpm_tee_driver);
+/* UUID of the fTPM TA */
+static const struct tee_client_device_id optee_ftpm_id_table[] = {
+	{UUID_INIT(0xbc50d971, 0xd4c9, 0x42c4,
+		   0x82, 0xcb, 0x34, 0x3f, 0xb7, 0xf3, 0x78, 0x96)},
+	{}
+};
+
+MODULE_DEVICE_TABLE(tee, optee_ftpm_id_table);
+
+static struct tee_client_driver ftpm_tee_driver = {
+	.id_table	= optee_ftpm_id_table,
+	.driver		= {
+		.name		= "optee-ftpm",
+		.bus		= &tee_bus_type,
+		.probe		= ftpm_tee_probe,
+		.remove		= ftpm_tee_remove,
+	},
+};
+
+static int __init ftpm_mod_init(void)
+{
+	int rc;
+
+	rc = platform_driver_register(&ftpm_tee_plat_driver);
+	if (rc)
+		return rc;
+
+	return driver_register(&ftpm_tee_driver.driver);
+}
+
+static void __exit ftpm_mod_exit(void)
+{
+	platform_driver_unregister(&ftpm_tee_plat_driver);
+	driver_unregister(&ftpm_tee_driver.driver);
+}
+
+module_init(ftpm_mod_init);
+module_exit(ftpm_mod_exit);
 
 MODULE_AUTHOR("Thirupathaiah Annapureddy <thiruan@microsoft.com>");
 MODULE_DESCRIPTION("TPM Driver for fTPM TA in TEE");

drivers/tee/optee/core.c

@@ -17,6 +17,7 @@
 #include <linux/tee_drv.h>
 #include <linux/types.h>
 #include <linux/uaccess.h>
+#include <linux/workqueue.h>
 #include "optee_private.h"
 #include "optee_smc.h"
 #include "shm_pool.h"
@@ -218,6 +219,11 @@ static void optee_get_version(struct tee_device *teedev,
 	*vers = v;
 }
 
+static void optee_bus_scan(struct work_struct *work)
+{
+	WARN_ON(optee_enumerate_devices(PTA_CMD_GET_DEVICES_SUPP));
+}
+
 static int optee_open(struct tee_context *ctx)
 {
 	struct optee_context_data *ctxdata;
@@ -241,8 +247,18 @@ static int optee_open(struct tee_context *ctx)
 			kfree(ctxdata);
 			return -EBUSY;
 		}
-	}
 
+		if (!optee->scan_bus_done) {
+			INIT_WORK(&optee->scan_bus_work, optee_bus_scan);
+			optee->scan_bus_wq = create_workqueue("optee_bus_scan");
+			if (!optee->scan_bus_wq) {
+				kfree(ctxdata);
+				return -ECHILD;
+			}
+			queue_work(optee->scan_bus_wq, &optee->scan_bus_work);
+			optee->scan_bus_done = true;
+		}
+	}
 	mutex_init(&ctxdata->mutex);
 	INIT_LIST_HEAD(&ctxdata->sess_list);
 
@@ -296,8 +312,13 @@ static void optee_release(struct tee_context *ctx)
 
 	ctx->data = NULL;
 
-	if (teedev == optee->supp_teedev)
+	if (teedev == optee->supp_teedev) {
+		if (optee->scan_bus_wq) {
+			destroy_workqueue(optee->scan_bus_wq);
+			optee->scan_bus_wq = NULL;
+		}
 		optee_supp_release(&optee->supp);
+	}
 }
 
 static const struct tee_driver_ops optee_ops = {
@@ -675,7 +696,7 @@ static int optee_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, optee);
 
-	rc = optee_enumerate_devices();
+	rc = optee_enumerate_devices(PTA_CMD_GET_DEVICES);
 	if (rc) {
 		optee_remove(pdev);
 		return rc;

drivers/tee/optee/device.c

@@ -11,18 +11,6 @@
 #include <linux/uuid.h>
 #include "optee_private.h"
 
-/*
- * Get device UUIDs
- *
- * [out]     memref[0]        Array of device UUIDs
- *
- * Return codes:
- * TEE_SUCCESS - Invoke command success
- * TEE_ERROR_BAD_PARAMETERS - Incorrect input param
- * TEE_ERROR_SHORT_BUFFER - Output buffer size less than required
- */
-#define PTA_CMD_GET_DEVICES		0x0
-
 static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
 {
 	if (ver->impl_id == TEE_IMPL_ID_OPTEE)
@@ -32,7 +20,8 @@ static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
 }
 
 static int get_devices(struct tee_context *ctx, u32 session,
-		       struct tee_shm *device_shm, u32 *shm_size)
+		       struct tee_shm *device_shm, u32 *shm_size,
+		       u32 func)
 {
 	int ret = 0;
 	struct tee_ioctl_invoke_arg inv_arg;
@@ -41,8 +30,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
 	memset(&inv_arg, 0, sizeof(inv_arg));
 	memset(&param, 0, sizeof(param));
 
-	/* Invoke PTA_CMD_GET_DEVICES function */
+	inv_arg.func = func;
-	inv_arg.func = PTA_CMD_GET_DEVICES;
 	inv_arg.session = session;
 	inv_arg.num_params = 4;
 
@@ -65,7 +53,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
 	return 0;
 }
 
-static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
+static int optee_register_device(const uuid_t *device_uuid)
 {
 	struct tee_client_device *optee_device = NULL;
 	int rc;
@@ -75,7 +63,10 @@ static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
 		return -ENOMEM;
 
 	optee_device->dev.bus = &tee_bus_type;
-	dev_set_name(&optee_device->dev, "optee-clnt%u", device_id);
+	if (dev_set_name(&optee_device->dev, "optee-ta-%pUb", device_uuid)) {
+		kfree(optee_device);
+		return -ENOMEM;
+	}
 	uuid_copy(&optee_device->id.uuid, device_uuid);
 
 	rc = device_register(&optee_device->dev);
@@ -87,7 +78,7 @@ static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
 	return rc;
 }
 
-int optee_enumerate_devices(void)
+static int __optee_enumerate_devices(u32 func)
 {
 	const uuid_t pta_uuid =
 		UUID_INIT(0x7011a688, 0xddde, 0x4053,
@@ -118,7 +109,7 @@ int optee_enumerate_devices(void)
 		goto out_ctx;
 	}
 
-	rc = get_devices(ctx, sess_arg.session, NULL, &shm_size);
+	rc = get_devices(ctx, sess_arg.session, NULL, &shm_size, func);
 	if (rc < 0 || !shm_size)
 		goto out_sess;
 
@@ -130,7 +121,7 @@ int optee_enumerate_devices(void)
 		goto out_sess;
 	}
 
-	rc = get_devices(ctx, sess_arg.session, device_shm, &shm_size);
+	rc = get_devices(ctx, sess_arg.session, device_shm, &shm_size, func);
 	if (rc < 0)
 		goto out_shm;
 
@@ -144,7 +135,7 @@ int optee_enumerate_devices(void)
 	num_devices = shm_size / sizeof(uuid_t);
 
 	for (idx = 0; idx < num_devices; idx++) {
-		rc = optee_register_device(&device_uuid[idx], idx);
+		rc = optee_register_device(&device_uuid[idx]);
 		if (rc)
 			goto out_shm;
 	}
@@ -158,3 +149,8 @@ out_ctx:
 
 	return rc;
 }
+
+int optee_enumerate_devices(u32 func)
+{
+	return  __optee_enumerate_devices(func);
+}

drivers/tee/optee/optee_private.h

@@ -78,6 +78,9 @@ struct optee_supp {
  * @memremaped_shm	virtual address of memory in shared memory pool
  * @sec_caps:		secure world capabilities defined by
  *			OPTEE_SMC_SEC_CAP_* in optee_smc.h
+ * @scan_bus_done	flag if device registation was already done.
+ * @scan_bus_wq		workqueue to scan optee bus and register optee drivers
+ * @scan_bus_work	workq to scan optee bus and register optee drivers
  */
 struct optee {
 	struct tee_device *supp_teedev;
@@ -89,6 +92,9 @@ struct optee {
 	struct tee_shm_pool *pool;
 	void *memremaped_shm;
 	u32 sec_caps;
+	bool   scan_bus_done;
+	struct workqueue_struct *scan_bus_wq;
+	struct work_struct scan_bus_work;
 };
 
 struct optee_session {
@@ -173,7 +179,9 @@ void optee_free_pages_list(void *array, size_t num_entries);
 void optee_fill_pages_list(u64 *dst, struct page **pages, int num_pages,
 			   size_t page_offset);
 
-int optee_enumerate_devices(void);
+#define PTA_CMD_GET_DEVICES		0x0
+#define PTA_CMD_GET_DEVICES_SUPP	0x1
+int optee_enumerate_devices(u32 func);
 
 /*
  * Small helpers