Merge tag 'ffa-notif-for-v6.8' of https://git.linaro.org/people/jens.wiklander/linux-tee into soc/drivers

OP-TEE: asynchronous notifications with FF-A

Add support for asynchronous notifications in the OP-TEE FF-A driver. This
is the FF-A counterpart to the asynchronous notifications already
available in the OP-TEE SMC ABI.

* tag 'ffa-notif-for-v6.8' of https://git.linaro.org/people/jens.wiklander/linux-tee:
  optee: ffa_abi: add asynchronous notifications
  optee: provide optee_do_bottom_half() as a common function

Link: https://lore.kernel.org/r/20231211105249.GA587253@rayden
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/tee/optee/call.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2015-2021, Linaro Limited
+ * Copyright (c) 2015-2021, 2023 Linaro Limited
  */
 #include <linux/device.h>
 #include <linux/err.h>
@@ -640,3 +640,32 @@ int optee_check_mem_type(unsigned long start, size_t num_pages)
 
 	return rc;
 }
+
+static int simple_call_with_arg(struct tee_context *ctx, u32 cmd)
+{
+	struct optee *optee = tee_get_drvdata(ctx->teedev);
+	struct optee_shm_arg_entry *entry;
+	struct optee_msg_arg *msg_arg;
+	struct tee_shm *shm;
+	u_int offs;
+
+	msg_arg = optee_get_msg_arg(ctx, 0, &entry, &shm, &offs);
+	if (IS_ERR(msg_arg))
+		return PTR_ERR(msg_arg);
+
+	msg_arg->cmd = cmd;
+	optee->ops->do_call_with_arg(ctx, shm, offs, false);
+
+	optee_free_msg_arg(ctx, entry, offs);
+	return 0;
+}
+
+int optee_do_bottom_half(struct tee_context *ctx)
+{
+	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_DO_BOTTOM_HALF);
+}
+
+int optee_stop_async_notif(struct tee_context *ctx)
+{
+	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_STOP_ASYNC_NOTIF);
+}

drivers/tee/optee/ffa_abi.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2021, Linaro Limited
+ * Copyright (c) 2021, 2023 Linaro Limited
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -695,7 +695,8 @@ static bool optee_ffa_api_is_compatbile(struct ffa_device *ffa_dev,
 static bool optee_ffa_exchange_caps(struct ffa_device *ffa_dev,
 				    const struct ffa_ops *ops,
 				    u32 *sec_caps,
-				    unsigned int *rpc_param_count)
+				    unsigned int *rpc_param_count,
+				    unsigned int *max_notif_value)
 {
 	struct ffa_send_direct_data data = { OPTEE_FFA_EXCHANGE_CAPABILITIES };
 	int rc;
@@ -712,10 +713,39 @@ static bool optee_ffa_exchange_caps(struct ffa_device *ffa_dev,
 
 	*rpc_param_count = (u8)data.data1;
 	*sec_caps = data.data2;
+	if (data.data3)
+		*max_notif_value = data.data3;
+	else
+		*max_notif_value = OPTEE_DEFAULT_MAX_NOTIF_VALUE;
 
 	return true;
 }
 
+static void notif_callback(int notify_id, void *cb_data)
+{
+	struct optee *optee = cb_data;
+
+	if (notify_id == optee->ffa.bottom_half_value)
+		optee_do_bottom_half(optee->ctx);
+	else
+		optee_notif_send(optee, notify_id);
+}
+
+static int enable_async_notif(struct optee *optee)
+{
+	struct ffa_device *ffa_dev = optee->ffa.ffa_dev;
+	struct ffa_send_direct_data data = {
+		.data0 = OPTEE_FFA_ENABLE_ASYNC_NOTIF,
+		.data1 = optee->ffa.bottom_half_value,
+	};
+	int rc;
+
+	rc = ffa_dev->ops->msg_ops->sync_send_receive(ffa_dev, &data);
+	if (rc)
+		return rc;
+	return data.data0;
+}
+
 static void optee_ffa_get_version(struct tee_device *teedev,
 				  struct tee_ioctl_version_data *vers)
 {
@@ -778,7 +808,11 @@ static const struct optee_ops optee_ffa_ops = {
 static void optee_ffa_remove(struct ffa_device *ffa_dev)
 {
 	struct optee *optee = ffa_dev_get_drvdata(ffa_dev);
+	u32 bottom_half_id = optee->ffa.bottom_half_value;
 
+	if (bottom_half_id != U32_MAX)
+		ffa_dev->ops->notifier_ops->notify_relinquish(ffa_dev,
+							      bottom_half_id);
 	optee_remove_common(optee);
 
 	mutex_destroy(&optee->ffa.mutex);
@@ -787,9 +821,51 @@ static void optee_ffa_remove(struct ffa_device *ffa_dev)
 	kfree(optee);
 }
 
+static int optee_ffa_async_notif_init(struct ffa_device *ffa_dev,
+				      struct optee *optee)
+{
+	bool is_per_vcpu = false;
+	u32 notif_id = 0;
+	int rc;
+
+	while (true) {
+		rc = ffa_dev->ops->notifier_ops->notify_request(ffa_dev,
+								is_per_vcpu,
+								notif_callback,
+								optee,
+								notif_id);
+		if (!rc)
+			break;
+		/*
+		 * -EACCES means that the notification ID was
+		 * already bound, try the next one as long as we
+		 * haven't reached the max. Any other error is a
+		 * permanent error, so skip asynchronous
+		 * notifications in that case.
+		 */
+		if (rc != -EACCES)
+			return rc;
+		notif_id++;
+		if (notif_id >= OPTEE_FFA_MAX_ASYNC_NOTIF_VALUE)
+			return rc;
+	}
+	optee->ffa.bottom_half_value = notif_id;
+
+	rc = enable_async_notif(optee);
+	if (rc < 0) {
+		ffa_dev->ops->notifier_ops->notify_relinquish(ffa_dev,
+							      notif_id);
+		optee->ffa.bottom_half_value = U32_MAX;
+	}
+
+	return rc;
+}
+
 static int optee_ffa_probe(struct ffa_device *ffa_dev)
 {
+	const struct ffa_notifier_ops *notif_ops;
 	const struct ffa_ops *ffa_ops;
+	unsigned int max_notif_value;
 	unsigned int rpc_param_count;
 	struct tee_shm_pool *pool;
 	struct tee_device *teedev;
@@ -800,12 +876,13 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 	int rc;
 
 	ffa_ops = ffa_dev->ops;
+	notif_ops = ffa_ops->notifier_ops;
 
 	if (!optee_ffa_api_is_compatbile(ffa_dev, ffa_ops))
 		return -EINVAL;
 
 	if (!optee_ffa_exchange_caps(ffa_dev, ffa_ops, &sec_caps,
-				     &rpc_param_count))
+				     &rpc_param_count, &max_notif_value))
 		return -EINVAL;
 	if (sec_caps & OPTEE_FFA_SEC_CAP_ARG_OFFSET)
 		arg_cache_flags |= OPTEE_SHM_ARG_SHARED;
@@ -823,6 +900,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 
 	optee->ops = &optee_ffa_ops;
 	optee->ffa.ffa_dev = ffa_dev;
+	optee->ffa.bottom_half_value = U32_MAX;
 	optee->rpc_param_count = rpc_param_count;
 
 	teedev = tee_device_alloc(&optee_ffa_clnt_desc, NULL, optee->pool,
@@ -866,6 +944,12 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 	rc = optee_notif_init(optee, OPTEE_DEFAULT_MAX_NOTIF_VALUE);
 	if (rc)
 		goto err_close_ctx;
+	if (sec_caps & OPTEE_FFA_SEC_CAP_ASYNC_NOTIF) {
+		rc = optee_ffa_async_notif_init(ffa_dev, optee);
+		if (rc < 0)
+			pr_err("Failed to initialize async notifications: %d",
+			       rc);
+	}
 
 	rc = optee_enumerate_devices(PTA_CMD_GET_DEVICES);
 	if (rc)
@@ -876,6 +960,9 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 
 err_unregister_devices:
 	optee_unregister_devices();
+	if (optee->ffa.bottom_half_value != U32_MAX)
+		notif_ops->notify_relinquish(ffa_dev,
+					     optee->ffa.bottom_half_value);
 	optee_notif_uninit(optee);
 err_close_ctx:
 	teedev_close_context(ctx);

drivers/tee/optee/optee_ffa.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: BSD-2-Clause */
 /*
- * Copyright (c) 2019-2021, Linaro Limited
+ * Copyright (c) 2019-2021, 2023 Linaro Limited
  */
 
 /*
@@ -73,7 +73,7 @@
  *
  * Call register usage:
  * w3:    Service ID, OPTEE_FFA_EXCHANGE_CAPABILITIES
- * w4-w7: Note used (MBZ)
+ * w4-w7: Not used (MBZ)
  *
  * Return register usage:
  * w3:    Error code, 0 on success
@@ -82,14 +82,16 @@
  *                   OPTEE_FFA_YIELDING_CALL_WITH_ARG.
  *        Bit[31:8]: Reserved (MBZ)
  * w5:	  Bitfield of secure world capabilities OPTEE_FFA_SEC_CAP_* below,
- *	  unused bits MBZ.
- * w6-w7: Not used (MBZ)
+ * w6:	  The maximum secure world notification number
+ * w7:	  Not used (MBZ)
  */
 /*
  * Secure world supports giving an offset into the argument shared memory
  * object, see also OPTEE_FFA_YIELDING_CALL_WITH_ARG
  */
 #define OPTEE_FFA_SEC_CAP_ARG_OFFSET	BIT(0)
+/* OP-TEE supports asynchronous notification via FF-A */
+#define OPTEE_FFA_SEC_CAP_ASYNC_NOTIF	BIT(1)
 
 #define OPTEE_FFA_EXCHANGE_CAPABILITIES OPTEE_FFA_BLOCKING_CALL(2)
 
@@ -108,6 +110,24 @@
  */
 #define OPTEE_FFA_UNREGISTER_SHM	OPTEE_FFA_BLOCKING_CALL(3)
 
+/*
+ * Inform OP-TEE that the normal world is able to receive asynchronous
+ * notifications.
+ *
+ * Call register usage:
+ * w3:    Service ID, OPTEE_FFA_ENABLE_ASYNC_NOTIF
+ * w4:	  Notification value to request bottom half processing, should be
+ *	  less than OPTEE_FFA_MAX_ASYNC_NOTIF_VALUE.
+ * w5-w7: Not used (MBZ)
+ *
+ * Return register usage:
+ * w3:    Error code, 0 on success
+ * w4-w7: Note used (MBZ)
+ */
+#define OPTEE_FFA_ENABLE_ASYNC_NOTIF	OPTEE_FFA_BLOCKING_CALL(5)
+
+#define OPTEE_FFA_MAX_ASYNC_NOTIF_VALUE 64
+
 /*
  * Call with struct optee_msg_arg as argument in the supplied shared memory
  * with a zero internal offset and normal cached memory attributes.

drivers/tee/optee/optee_private.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * Copyright (c) 2015-2021, Linaro Limited
+ * Copyright (c) 2015-2021, 2023 Linaro Limited
  */
 
 #ifndef OPTEE_PRIVATE_H
@@ -147,12 +147,14 @@ struct optee_smc {
  * struct optee_ffa_data -  FFA communication struct
  * @ffa_dev		FFA device, contains the destination id, the id of
  *			OP-TEE in secure world
- * @ffa_ops		FFA operations
+ * @bottom_half_value	Notification ID used for bottom half signalling or
+ *			U32_MAX if unused
  * @mutex		Serializes access to @global_ids
  * @global_ids		FF-A shared memory global handle translation
  */
 struct optee_ffa {
 	struct ffa_device *ffa_dev;
+	u32 bottom_half_value;
 	/* Serializes access to @global_ids */
 	struct mutex mutex;
 	struct rhashtable global_ids;
@@ -346,6 +348,9 @@ void optee_rpc_cmd_free_suppl(struct tee_context *ctx, struct tee_shm *shm);
 void optee_rpc_cmd(struct tee_context *ctx, struct optee *optee,
 		   struct optee_msg_arg *arg);
 
+int optee_do_bottom_half(struct tee_context *ctx);
+int optee_stop_async_notif(struct tee_context *ctx);
+
 /*
  * Small helpers
  */

drivers/tee/optee/smc_abi.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2015-2021, Linaro Limited
+ * Copyright (c) 2015-2021, 2023 Linaro Limited
  * Copyright (c) 2016, EPAM Systems
  */
 
@@ -967,34 +967,6 @@ static int optee_smc_do_call_with_arg(struct tee_context *ctx,
 	return rc;
 }
 
-static int simple_call_with_arg(struct tee_context *ctx, u32 cmd)
-{
-	struct optee_shm_arg_entry *entry;
-	struct optee_msg_arg *msg_arg;
-	struct tee_shm *shm;
-	u_int offs;
-
-	msg_arg = optee_get_msg_arg(ctx, 0, &entry, &shm, &offs);
-	if (IS_ERR(msg_arg))
-		return PTR_ERR(msg_arg);
-
-	msg_arg->cmd = cmd;
-	optee_smc_do_call_with_arg(ctx, shm, offs, false);
-
-	optee_free_msg_arg(ctx, entry, offs);
-	return 0;
-}
-
-static int optee_smc_do_bottom_half(struct tee_context *ctx)
-{
-	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_DO_BOTTOM_HALF);
-}
-
-static int optee_smc_stop_async_notif(struct tee_context *ctx)
-{
-	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_STOP_ASYNC_NOTIF);
-}
-
 /*
  * 5. Asynchronous notification
  */
@@ -1050,7 +1022,7 @@ static irqreturn_t notif_irq_thread_fn(int irq, void *dev_id)
 {
 	struct optee *optee = dev_id;
 
-	optee_smc_do_bottom_half(optee->ctx);
+	optee_do_bottom_half(optee->ctx);
 
 	return IRQ_HANDLED;
 }
@@ -1088,7 +1060,7 @@ static void notif_pcpu_irq_work_fn(struct work_struct *work)
 						   notif_pcpu_work);
 	struct optee *optee = container_of(optee_smc, struct optee, smc);
 
-	optee_smc_do_bottom_half(optee->ctx);
+	optee_do_bottom_half(optee->ctx);
 }
 
 static int init_pcpu_irq(struct optee *optee, u_int irq)
@@ -1160,7 +1132,7 @@ static void uninit_pcpu_irq(struct optee *optee)
 static void optee_smc_notif_uninit_irq(struct optee *optee)
 {
 	if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_ASYNC_NOTIF) {
-		optee_smc_stop_async_notif(optee->ctx);
+		optee_stop_async_notif(optee->ctx);
 		if (optee->smc.notif_irq) {
 			if (irq_is_percpu_devid(optee->smc.notif_irq))
 				uninit_pcpu_irq(optee);