[PATCH v4 04/22] arm-ffa: add runtime direct-message support

Harsimran Singh Tungal <[email protected]>
Newsgroups gmane.comp.boot-loaders.u-boot
Message-ID <[email protected]> 
Add the FF-A runtime transport implementation needed after
ExitBootServices() so EFI runtime services can continue to exchange
direct messages with secure partitions. The runtime code keeps resident
FF-A private data, tracks whether the runtime context is ready,
translates FF-A error codes, and exposes ffa_sync_send_receive_runtime()
for FFA_MSG_SEND_DIRECT_REQ/RESP.

Add the ARM_FFA_RT_MODE Kconfig option and build arm-ffa-runtime.c when
FF-A transport and EFI loader support are enabled. Move FF-A errno
translation out of arm-ffa-uclass.c so boot-time and runtime callers use
the same mapping.

Tag the runtime code and data with __efi_runtime and __efi_runtime_data
so they remain available after ExitBootServices(). The runtime
direct-message path uses invoke_ffa_fn_runtime() and rejects requests
until the runtime context has been enabled.

Reviewed-by: Simon Glass <[email protected]>
Acked-by: Abdellatif El Khlifi <[email protected]>
Signed-off-by: Harsimran Singh Tungal <[email protected]>
---
 drivers/firmware/arm-ffa/Kconfig           |  11 +
 drivers/firmware/arm-ffa/Makefile          |   4 +-
 drivers/firmware/arm-ffa/arm-ffa-runtime.c | 251 +++++++++++++++++++++
 drivers/firmware/arm-ffa/arm-ffa-uclass.c  |  35 +--
 include/arm_ffa_runtime.h                  | 132 +++++++++++
 5 files changed, 397 insertions(+), 36 deletions(-)
 create mode 100644 drivers/firmware/arm-ffa/arm-ffa-runtime.c

diff --git a/drivers/firmware/arm-ffa/Kconfig b/drivers/firmware/arm-ffa/Kconfig
index 3706a889305..7aaf25fdb58 100644
--- a/drivers/firmware/arm-ffa/Kconfig
+++ b/drivers/firmware/arm-ffa/Kconfig
@@ -18,6 +18,9 @@ config ARM_FFA_TRANSPORT
 	  The FF-A support in U-Boot is based on FF-A specification v1.0 and uses SMC32
 	  calling convention.
 
+	  The FF-A bus also provides a runtime layer to keep a minimal set of FF-A
+	  operations available after ExitBootServices().
+
 	  FF-A specification:
 
 	  https://developer.arm.com/documentation/den0077/a/?lang=en
@@ -41,3 +44,11 @@ config ARM_FFA_TRANSPORT
 	  Secure World (sandbox_ffa.c).
 
 	  For more details about the FF-A support, please refer to doc/arch/arm64.ffa.rst
+
+config ARM_FFA_RT_MODE
+	bool "Enable FF-A runtime support"
+	depends on ARM_FFA_TRANSPORT && EFI_LOADER
+	default y
+	help
+	  Enable the FF-A runtime layer, keeping a minimal set of FF-A
+	  operations available after ExitBootServices().
diff --git a/drivers/firmware/arm-ffa/Makefile b/drivers/firmware/arm-ffa/Makefile
index 318123a7f42..9deb59ba640 100644
--- a/drivers/firmware/arm-ffa/Makefile
+++ b/drivers/firmware/arm-ffa/Makefile
@@ -1,12 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0+
 #
-# Copyright 2022-2023 Arm Limited and/or its affiliates <[email protected]>
+# Copyright 2022-2023, 2026 Arm Limited and/or its affiliates <[email protected]>
 #
 # Authors:
 #   Abdellatif El Khlifi <[email protected]>
 
 # build the generic FF-A methods
-obj-y += arm-ffa-uclass.o
+obj-y += arm-ffa-uclass.o arm-ffa-runtime.o
 ifeq ($(CONFIG_SANDBOX),y)
 # build the FF-A sandbox emulator and driver
 obj-y += ffa-emul-uclass.o sandbox_ffa.o
diff --git a/drivers/firmware/arm-ffa/arm-ffa-runtime.c b/drivers/firmware/arm-ffa/arm-ffa-runtime.c
new file mode 100644
index 00000000000..d761ec9ee07
--- /dev/null
+++ b/drivers/firmware/arm-ffa/arm-ffa-runtime.c
@@ -0,0 +1,251 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Arm Limited and/or its affiliates <[email protected]>
+ *
+ * Authors:
+ *      Harsimran Singh Tungal <[email protected]>
+ *      Abdellatif El Khlifi <[email protected]>
+ */
+
+#include <arm_ffa_runtime.h>
+#include <arm_ffa_priv.h>
+#include <log.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+
+/* Error mapping declarations */
+
+int __ffa_runtime_data ffa_to_std_errmap[MAX_NUMBER_FFA_ERR] = {
+	[NOT_SUPPORTED] = -EOPNOTSUPP,
+	[INVALID_PARAMETERS] = -EINVAL,
+	[NO_MEMORY] = -ENOMEM,
+	[BUSY] = -EBUSY,
+	[INTERRUPTED] = -EINTR,
+	[DENIED] = -EACCES,
+	[RETRY] = -EAGAIN,
+	[ABORTED] = -ECANCELED,
+};
+
+static __ffa_runtime_data struct ffa_priv_runtime ffa_priv_rt = {0};
+static __ffa_runtime_data bool ffa_runtime_enabled;
+
+/* Arm FF-A driver runtime operations */
+static const __ffa_runtime_data struct ffa_bus_ops_runtime ffa_ops_rt = {
+	.sync_send_receive = ffa_msg_send_direct_req_hdlr_runtime,
+};
+
+#define ffa_get_ops_runtime()		(&ffa_ops_rt)
+#define ffa_get_priv_runtime()		(&ffa_priv_rt)
+
+/**
+ * ffa_copy_runtime_priv() - copy runtime data into resident storage
+ * @priv: pointer to the runtime private data
+ *
+ * Copy boot-time runtime data into the resident runtime storage to be used
+ * after ExitBootServices().
+ */
+void ffa_copy_runtime_priv(const struct ffa_priv_runtime *priv)
+{
+	struct ffa_priv_runtime *priv_rt = ffa_get_priv_runtime();
+
+	if (priv)
+		*priv_rt = *priv;
+}
+
+/**
+ * ffa_runtime_context_enable() - Enable FF-A runtime context
+ *
+ * This function marks the FF-A runtime environment as ready for use by
+ * EFI runtime services. It is called when ExitBootServices() is invoked,
+ * after the FF-A bus device has successfully probed and U-Boot's FF-A
+ * endpoint ID has been discovered and stored in the runtime private data
+ * structure.
+ *
+ * The FF-A runtime flag allows the EFI runtime layer to verify that the
+ * FF-A transport was initialized during the boot phase and that all
+ * runtime-safe FF-A operations may now be used after ExitBootServices().
+ *
+ */
+void ffa_runtime_context_enable(void)
+{
+	ffa_runtime_enabled = true;
+}
+
+/**
+ * ffa_runtime_context_reset() - Reset FF-A runtime resident state
+ *
+ * Clear the resident runtime flag and private data. This is used by the
+ * FF-A unit tests to avoid leaking runtime state across test cases.
+ */
+void ffa_runtime_context_reset(void)
+{
+	struct ffa_priv_runtime *priv_rt = ffa_get_priv_runtime();
+
+	*priv_rt = (struct ffa_priv_runtime){0};
+	ffa_runtime_enabled = false;
+}
+
+/**
+ * ffa_runtime_context_ready() - Query FF-A runtime readiness
+ *
+ * This helper returns whether the FF-A runtime environment has been
+ * enabled during the boot phase. Runtime FF-A operations must check this
+ * flag before attempting any FF-A access, as the U-Boot driver model
+ * (DM/uclass) is no longer available after ExitBootServices().
+ *
+ * The runtime context becomes enabled when ffa_runtime_context_enable()
+ * is called, typically after the FF-A bus device has probed and the
+ * endpoint ID has been discovered and stored in the runtime private
+ * data structure.
+ *
+ * Return: true if FF-A runtime support is ready, false otherwise.
+ */
+bool __ffa_runtime ffa_runtime_context_ready(void)
+{
+	return ffa_runtime_enabled;
+}
+
+/**
+ * ffa_to_std_errno() - convert FF-A error code to standard error code
+ * @ffa_errno:	Error code returned by the FF-A ABI
+ *
+ * Map the given FF-A error code as specified
+ * by the spec to a u-boot standard error code.
+ *
+ * Return: Standard U-Boot errno for known FF-A errors, or -EINVAL otherwise.
+ */
+int __ffa_runtime ffa_to_std_errno(int ffa_errno)
+{
+	int err_idx = -ffa_errno;
+
+	/* Map the FF-A error code to the standard u-boot error code */
+	if (err_idx > 0 && err_idx < MAX_NUMBER_FFA_ERR)
+		return ffa_to_std_errmap[err_idx];
+	return -EINVAL;
+}
+
+/**
+ * ffa_invoke_msg_send_direct_req() - Invokes FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ * @endpoint_id: u-boot endpoint id
+ * @dst_part_id: destination partition ID
+ * @msg: pointer to the message data preallocated by the client (in/out)
+ * @is_smc64: select 64-bit or 32-bit FF-A ABI
+ *
+ * This function invokes FFA_MSG_SEND_DIRECT_{REQ,RESP} FF-A functions.
+ *
+ * FFA_MSG_SEND_DIRECT_REQ is used to send the data to the secure partition.
+ * The response from the secure partition is handled by reading the
+ * FFA_MSG_SEND_DIRECT_RESP arguments.
+ *
+ * The maximum size of the data that can be exchanged is 40 bytes which is
+ * sizeof(struct ffa_send_direct_data) as defined by the FF-A specification 1.0
+ * in the section relevant to FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int __ffa_runtime ffa_invoke_msg_send_direct_req(u16 endpoint_id, u16 dst_part_id,
+						 struct ffa_send_direct_data *msg, bool is_smc64)
+{
+	int ffa_errno;
+	u64 req_mode;
+	ffa_value_t ffa_args_rt;
+	ffa_value_t ffa_res_rt;
+
+	if (is_smc64)
+		req_mode = FFA_SMC_64(FFA_MSG_SEND_DIRECT_REQ);
+	else
+		req_mode = FFA_SMC_32(FFA_MSG_SEND_DIRECT_REQ);
+	efi_memset_runtime(&ffa_args_rt, 0, sizeof(ffa_args_rt));
+	efi_memset_runtime(&ffa_res_rt, 0, sizeof(ffa_res_rt));
+	ffa_args_rt.a0 = req_mode;
+	ffa_args_rt.a1 = PREP_SELF_ENDPOINT_ID(endpoint_id) |
+			 PREP_PART_ENDPOINT_ID(dst_part_id);
+	ffa_args_rt.a2 = 0;
+	ffa_args_rt.a3 = msg->data0;
+	ffa_args_rt.a4 = msg->data1;
+	ffa_args_rt.a5 = msg->data2;
+	ffa_args_rt.a6 = msg->data3;
+	ffa_args_rt.a7 = msg->data4;
+
+	invoke_ffa_fn_runtime(&ffa_args_rt, &ffa_res_rt);
+
+	while (ffa_res_rt.a0 == FFA_SMC_32(FFA_INTERRUPT) ||
+	       ffa_res_rt.a0 == FFA_SMC_64(FFA_INTERRUPT)) {
+		efi_memset_runtime(&ffa_args_rt, 0, sizeof(ffa_args_rt));
+		ffa_args_rt.a0 = (ffa_res_rt.a0 == FFA_SMC_64(FFA_INTERRUPT)) ?
+				  FFA_SMC_64(FFA_RUN) : FFA_SMC_32(FFA_RUN);
+		ffa_args_rt.a1 = ffa_res_rt.a1;
+
+		invoke_ffa_fn_runtime(&ffa_args_rt, &ffa_res_rt);
+	}
+	if (ffa_res_rt.a0 == FFA_SMC_32(FFA_SUCCESS) ||
+	    ffa_res_rt.a0 == FFA_SMC_64(FFA_SUCCESS)) {
+		/* Message sent with no response */
+		return 0;
+	}
+
+	if (ffa_res_rt.a0 == FFA_SMC_32(FFA_MSG_SEND_DIRECT_RESP) ||
+	    ffa_res_rt.a0 == FFA_SMC_64(FFA_MSG_SEND_DIRECT_RESP)) {
+		/* Message sent with response extract the return data */
+		msg->data0 = ffa_res_rt.a3;
+		msg->data1 = ffa_res_rt.a4;
+		msg->data2 = ffa_res_rt.a5;
+		msg->data3 = ffa_res_rt.a6;
+		msg->data4 = ffa_res_rt.a7;
+		return 0;
+	}
+
+	ffa_errno = ffa_res_rt.a2;
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * ffa_msg_send_direct_req_hdlr_runtime() - Runtime implementation of
+ * FFA_MSG_SEND_DIRECT_{REQ,RESP} handler function
+ * @dst_part_id: destination partition ID
+ * @msg: pointer to the message data preallocated by the client (in/out)
+ * @is_smc64: select 64-bit or 32-bit FF-A ABI
+ *
+ * This function calls the ffa_invoke_msg_send_direct_req() function which
+ * invokes FFA_MSG_SEND_DIRECT_{REQ,RESP} FF-A functions.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int __ffa_runtime ffa_msg_send_direct_req_hdlr_runtime(u16 dst_part_id,
+						       struct ffa_send_direct_data *msg,
+						       bool is_smc64)
+{
+	struct ffa_priv_runtime *priv_rt = ffa_get_priv_runtime();
+
+	return ffa_invoke_msg_send_direct_req(priv_rt->id, dst_part_id, msg, is_smc64);
+}
+
+/**
+ * ffa_sync_send_receive_runtime() - Runtime implementation of
+ *                              ffa_sync_send_receive()
+ * @dst_part_id: destination partition ID
+ * @msg: pointer to the message data preallocated by the client (in/out)
+ * @is_smc64: select 64-bit or 32-bit FF-A ABI
+ *
+ * Please see ffa_msg_send_direct_req_hdlr_runtime() description for more details.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int __ffa_runtime ffa_sync_send_receive_runtime(u16 dst_part_id,
+						struct ffa_send_direct_data *msg,
+						bool is_smc64)
+{
+	const struct ffa_bus_ops_runtime *ops_rt = ffa_get_ops_runtime();
+
+	if (!ffa_runtime_context_ready())
+		return -EPERM;
+
+	if (!ops_rt->sync_send_receive)
+		return -ENOSYS;
+
+	return ops_rt->sync_send_receive(dst_part_id, msg, is_smc64);
+}
diff --git a/drivers/firmware/arm-ffa/arm-ffa-uclass.c b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
index eb159dbfade..13e22a1b7f7 100644
--- a/drivers/firmware/arm-ffa/arm-ffa-uclass.c
+++ b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
@@ -7,6 +7,7 @@
  */
 #include <arm_ffa.h>
 #include <arm_ffa_priv.h>
+#include <arm_ffa_runtime.h>
 #include <dm.h>
 #include <log.h>
 #include <malloc.h>
@@ -18,19 +19,6 @@
 #include <linux/errno.h>
 #include <linux/sizes.h>
 
-/* Error mapping declarations */
-
-int ffa_to_std_errmap[MAX_NUMBER_FFA_ERR] = {
-	[NOT_SUPPORTED] = -EOPNOTSUPP,
-	[INVALID_PARAMETERS] = -EINVAL,
-	[NO_MEMORY] = -ENOMEM,
-	[BUSY] = -EBUSY,
-	[INTERRUPTED] = -EINTR,
-	[DENIED] = -EACCES,
-	[RETRY] = -EAGAIN,
-	[ABORTED] = -ECANCELED,
-};
-
 static struct ffa_abi_errmap err_msg_map[FFA_ERRMAP_COUNT] = {
 	[FFA_ID_TO_ERRMAP_ID(FFA_VERSION)] = {
 		{
@@ -94,27 +82,6 @@ static struct ffa_abi_errmap err_msg_map[FFA_ERRMAP_COUNT] = {
 	},
 };
 
-/**
- * ffa_to_std_errno() - convert FF-A error code to standard error code
- * @ffa_errno:	Error code returned by the FF-A ABI
- *
- * Map the given FF-A error code as specified
- * by the spec to a u-boot standard error code.
- *
- * Return:
- *
- * The standard error code on success. . Otherwise, failure
- */
-static int ffa_to_std_errno(int ffa_errno)
-{
-	int err_idx = -ffa_errno;
-
-	/* Map the FF-A error code to the standard u-boot error code */
-	if (err_idx > 0 && err_idx < MAX_NUMBER_FFA_ERR)
-		return ffa_to_std_errmap[err_idx];
-	return -EINVAL;
-}
-
 /**
  * ffa_print_error_log() - print the error log corresponding to the selected FF-A ABI
  * @ffa_id:	FF-A ABI ID
diff --git a/include/arm_ffa_runtime.h b/include/arm_ffa_runtime.h
index 66096db3d24..77b528745e8 100644
--- a/include/arm_ffa_runtime.h
+++ b/include/arm_ffa_runtime.h
@@ -12,6 +12,7 @@
 
 #include <linux/types.h>
 #include <arm_ffa.h>
+#include <arm_ffa_priv.h>
 #include <efi_loader.h>
 
 /**
@@ -38,4 +39,135 @@
  */
 void __ffa_runtime invoke_ffa_fn_runtime(ffa_value_t *args, ffa_value_t *res);
 
+/**
+ * struct ffa_bus_ops_runtime - Operations for FF-A runtime
+ * @sync_send_receive:	callback for the FFA_MSG_SEND_DIRECT_REQ
+ *
+ * The data structure providing all the runtime operations supported by the driver.
+ * This structure is an EFI runtime resident.
+ */
+struct ffa_bus_ops_runtime {
+	int (*sync_send_receive)(u16 dst_part_id, struct ffa_send_direct_data *msg,
+				 bool is_smc64);
+};
+
+/**
+ * ffa_runtime_context_enable() - Enable FF-A runtime context
+ *
+ * This function marks the FF-A runtime environment as ready for use by
+ * EFI runtime services. It is called when ExitBootServices() is invoked,
+ * after the FF-A bus device has successfully probed and U-Boot's FF-A
+ * endpoint ID has been discovered and stored in the runtime private data
+ * structure.
+ *
+ * The FF-A runtime flag allows the EFI runtime layer to verify that the
+ * FF-A transport was initialized during the boot phase and that all
+ * runtime-safe FF-A operations may now be used after ExitBootServices().
+ *
+ */
+void ffa_runtime_context_enable(void);
+
+/**
+ * ffa_runtime_context_reset() - Reset FF-A runtime resident state
+ *
+ * Clear the resident runtime flag and private data. This is used by the
+ * FF-A unit tests to avoid leaking runtime state across test cases.
+ */
+void ffa_runtime_context_reset(void);
+
+/**
+ * ffa_copy_runtime_priv() - copy runtime data into resident storage
+ * @priv: pointer to the runtime private data
+ *
+ * Copy boot-time runtime data into the resident runtime storage to be used
+ * after ExitBootServices().
+ */
+void ffa_copy_runtime_priv(const struct ffa_priv_runtime *priv);
+
+/**
+ * ffa_runtime_context_ready() - Query FF-A runtime readiness
+ *
+ * This helper returns whether the FF-A runtime environment has been
+ * enabled during the boot phase. Runtime FF-A operations must check this
+ * flag before attempting any FF-A access, as the U-Boot driver model
+ * (DM/uclass) is no longer available after ExitBootServices().
+ *
+ * The runtime context becomes enabled when ffa_runtime_context_enable()
+ * is called, typically after the FF-A bus device has probed and the
+ * endpoint ID has been discovered and stored in the runtime private
+ * data structure.
+ *
+ * Return: true if FF-A runtime support is ready, false otherwise.
+ */
+bool __ffa_runtime ffa_runtime_context_ready(void);
+
+/**
+ * ffa_to_std_errno() - convert FF-A error code to standard error code
+ * @ffa_errno:	Error code returned by the FF-A ABI
+ *
+ * Map the given FF-A error code as specified
+ * by the spec to a u-boot standard error code.
+ *
+ * Return: Standard U-Boot errno for known FF-A errors, or -EINVAL otherwise.
+ */
+int __ffa_runtime ffa_to_std_errno(int ffa_errno);
+
+/**
+ * ffa_sync_send_receive_runtime() - Runtime implementation of
+ *                              ffa_sync_send_receive()
+ * @dst_part_id: destination partition ID
+ * @msg: pointer to the message data preallocated by the client (in/out)
+ * @is_smc64: select 64-bit or 32-bit FF-A ABI
+ *
+ * Please see ffa_msg_send_direct_req_hdlr_runtime() description for more details.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int __ffa_runtime ffa_sync_send_receive_runtime(u16 dst_part_id,
+						struct ffa_send_direct_data *msg,
+						bool is_smc64);
+
+/**
+ * ffa_invoke_msg_send_direct_req() - Invokes FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ * @endpoint_id: u-boot endpoint id
+ * @dst_part_id: destination partition ID
+ * @msg: pointer to the message data preallocated by the client (in/out)
+ * @is_smc64: select 64-bit or 32-bit FF-A ABI
+ *
+ * This function invokes FFA_MSG_SEND_DIRECT_{REQ,RESP} FF-A functions.
+ *
+ * FFA_MSG_SEND_DIRECT_REQ is used to send the data to the secure partition.
+ * The response from the secure partition is handled by reading the
+ * FFA_MSG_SEND_DIRECT_RESP arguments.
+ *
+ * The maximum size of the data that can be exchanged is 40 bytes which is
+ * sizeof(struct ffa_send_direct_data) as defined by the FF-A specification 1.0
+ * in the section relevant to FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, error on failure
+ */
+int __ffa_runtime ffa_invoke_msg_send_direct_req(u16 endpoint_id, u16 dst_part_id,
+						 struct ffa_send_direct_data *msg,
+						 bool is_smc64);
+
+/**
+ * ffa_msg_send_direct_req_hdlr_runtime() - Runtime implementation of
+ * FFA_MSG_SEND_DIRECT_{REQ,RESP} handler function
+ * @dst_part_id: destination partition ID
+ * @msg: pointer to the message data preallocated by the client (in/out)
+ * @is_smc64: select 64-bit or 32-bit FF-A ABI
+ *
+ * This function calls the ffa_invoke_msg_send_direct_req() function which
+ * invokes FFA_MSG_SEND_DIRECT_{REQ,RESP} FF-A functions.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int __ffa_runtime ffa_msg_send_direct_req_hdlr_runtime(u16 dst_part_id,
+						       struct ffa_send_direct_data *msg,
+						       bool is_smc64);
+
 #endif
-- 
2.34.1
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