arm_ffa: introduce sandbox FF-A support

Emulate Secure World's FF-A ABIs and allow testing U-Boot FF-A support

Features of the sandbox FF-A support:

- Introduce an FF-A emulator
- Introduce an FF-A device driver for FF-A comms with emulated Secure World
- Provides test methods allowing to read the status of the inspected ABIs

The sandbox FF-A emulator supports only 64-bit direct messaging.

Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>

5 files changed, 848 insertions, 19 deletions

diff --git a/drivers/firmware/arm-ffa/Kconfig b/drivers/firmware/arm-ffa/Kconfig
index 9200c8028b..fc668c109d 100644
--- a/drivers/firmware/arm-ffa/Kconfig
+++ b/drivers/firmware/arm-ffa/Kconfig
@@ -2,9 +2,9 @@
 
 config ARM_FFA_TRANSPORT
 	bool "Enable Arm Firmware Framework for Armv8-A driver"
-	depends on DM && ARM64
-	select ARM_SMCCC
-	select ARM_SMCCC_FEATURES
+	depends on DM && (ARM64 || SANDBOX)
+	select ARM_SMCCC if !SANDBOX
+	select ARM_SMCCC_FEATURES if !SANDBOX
 	select LIB_UUID
 	select DEVRES
 	help
@@ -32,5 +32,10 @@ config ARM_FFA_TRANSPORT
 	  Generic FF-A methods are implemented in the Uclass (arm-ffa-uclass.c).
 	  Arm specific methods are implemented in the Arm driver (arm-ffa.c).
 
-	  For more details about the FF-A support, please refer to doc/arch/arm64.ffa.rst
+	  FF-A sandbox is provided to run FF-A under sandbox and allows to test the FF-A Uclass.
+	  Sandbox support includes an emulator for Arm FF-A which emulates the FF-A side of
+	  the Secure World and provides FF-A ABIs inspection methods (ffa-emul-uclass.c).
+	  An FF-A sandbox driver is also provided for FF-A communication with the emulated
+	  Secure World (sandbox_ffa.c).
 
+	  For more details about the FF-A support, please refer to doc/arch/arm64.ffa.rst
diff --git a/drivers/firmware/arm-ffa/Makefile b/drivers/firmware/arm-ffa/Makefile
index 11b1766285..318123a7f4 100644
--- a/drivers/firmware/arm-ffa/Makefile
+++ b/drivers/firmware/arm-ffa/Makefile
@@ -5,4 +5,12 @@
 # Authors:
 #   Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
 
-obj-y += arm-ffa-uclass.o arm-ffa.o
+# build the generic FF-A methods
+obj-y += arm-ffa-uclass.o
+ifeq ($(CONFIG_SANDBOX),y)
+# build the FF-A sandbox emulator and driver
+obj-y += ffa-emul-uclass.o sandbox_ffa.o
+else
+# build the Arm64 FF-A driver
+obj-y += arm-ffa.o
+endif
diff --git a/drivers/firmware/arm-ffa/ffa-emul-uclass.c b/drivers/firmware/arm-ffa/ffa-emul-uclass.c
new file mode 100644
index 0000000000..5562bbaac3
--- /dev/null
+++ b/drivers/firmware/arm-ffa/ffa-emul-uclass.c
@@ -0,0 +1,720 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
+ *
+ * Authors:
+ *   Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+#include <common.h>
+#include <dm.h>
+#include <mapmem.h>
+#include <string.h>
+#include <asm/global_data.h>
+#include <asm/sandbox_arm_ffa.h>
+#include <asm/sandbox_arm_ffa_priv.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/root.h>
+#include <linux/errno.h>
+#include <linux/sizes.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* The partitions (SPs) table */
+static struct ffa_partition_desc sandbox_partitions[SANDBOX_PARTITIONS_CNT] = {
+	{
+		.info = { .id = SANDBOX_SP1_ID, .exec_ctxt = 0x5687, .properties = 0x89325621 },
+		.sp_uuid = {
+			.a1 = SANDBOX_SERVICE1_UUID_A1,
+			.a2 = SANDBOX_SERVICE1_UUID_A2,
+			.a3 = SANDBOX_SERVICE1_UUID_A3,
+			.a4 = SANDBOX_SERVICE1_UUID_A4,
+		}
+	},
+	{
+		.info = { .id = SANDBOX_SP3_ID, .exec_ctxt = 0x7687, .properties = 0x23325621 },
+		.sp_uuid = {
+			.a1 = SANDBOX_SERVICE2_UUID_A1,
+			.a2 = SANDBOX_SERVICE2_UUID_A2,
+			.a3 = SANDBOX_SERVICE2_UUID_A3,
+			.a4 = SANDBOX_SERVICE2_UUID_A4,
+		}
+	},
+	{
+		.info = { .id = SANDBOX_SP2_ID, .exec_ctxt = 0x9587, .properties = 0x45325621 },
+		.sp_uuid = {
+			.a1 = SANDBOX_SERVICE1_UUID_A1,
+			.a2 = SANDBOX_SERVICE1_UUID_A2,
+			.a3 = SANDBOX_SERVICE1_UUID_A3,
+			.a4 = SANDBOX_SERVICE1_UUID_A4,
+		}
+	},
+	{
+		.info = { .id = SANDBOX_SP4_ID, .exec_ctxt = 0x1487, .properties = 0x70325621 },
+		.sp_uuid = {
+			.a1 = SANDBOX_SERVICE2_UUID_A1,
+			.a2 = SANDBOX_SERVICE2_UUID_A2,
+			.a3 = SANDBOX_SERVICE2_UUID_A3,
+			.a4 = SANDBOX_SERVICE2_UUID_A4,
+		}
+	}
+
+};
+
+/* The emulator functions */
+
+/**
+ * sandbox_ffa_version() - Emulated FFA_VERSION handler function
+ * @emul: The sandbox FF-A emulator device
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_VERSION FF-A function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+
+static int sandbox_ffa_version(struct udevice *emul, ffa_value_t *pargs, ffa_value_t *res)
+{
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	priv->fwk_version = FFA_VERSION_1_0;
+	res->a0 = priv->fwk_version;
+
+	/* x1-x7 MBZ */
+	memset(FFA_X1X7_MBZ_REG_START, 0, FFA_X1X7_MBZ_CNT * sizeof(ulong));
+
+	return 0;
+}
+
+/**
+ * sandbox_ffa_id_get() - Emulated FFA_ID_GET handler function
+ * @emul: The sandbox FF-A emulator device
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_ID_GET FF-A function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_id_get(struct udevice *emul, ffa_value_t *pargs, ffa_value_t *res)
+{
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	res->a0 = FFA_SMC_32(FFA_SUCCESS);
+	res->a1 = 0;
+
+	priv->id = NS_PHYS_ENDPOINT_ID;
+	res->a2 = priv->id;
+
+	/* x3-x7 MBZ */
+	memset(FFA_X3_MBZ_REG_START, 0, FFA_X3X7_MBZ_CNT * sizeof(ulong));
+
+	return 0;
+}
+
+/**
+ * sandbox_ffa_features() - Emulated FFA_FEATURES handler function
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_FEATURES FF-A function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_features(ffa_value_t *pargs, ffa_value_t *res)
+{
+	res->a1 = 0;
+
+	if (pargs->a1 == FFA_SMC_64(FFA_RXTX_MAP)) {
+		res->a0 = FFA_SMC_32(FFA_SUCCESS);
+		res->a2 = RXTX_BUFFERS_MIN_SIZE;
+		res->a3 = 0;
+		/* x4-x7 MBZ */
+		memset(FFA_X4X7_MBZ_REG_START, 0, FFA_X4X7_MBZ_CNT * sizeof(ulong));
+		return 0;
+	}
+
+	res->a0 = FFA_SMC_32(FFA_ERROR);
+	res->a2 = -NOT_SUPPORTED;
+	/* x3-x7 MBZ */
+	memset(FFA_X3_MBZ_REG_START, 0, FFA_X3X7_MBZ_CNT * sizeof(ulong));
+	log_err("FF-A interface %lx not implemented\n", pargs->a1);
+
+	return ffa_to_std_errmap[NOT_SUPPORTED];
+}
+
+/**
+ * sandbox_ffa_partition_info_get() - Emulated FFA_PARTITION_INFO_GET handler
+ * @emul: The sandbox FF-A emulator device
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_PARTITION_INFO_GET FF-A function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_partition_info_get(struct udevice *emul, ffa_value_t *pargs,
+					  ffa_value_t *res)
+{
+	struct ffa_partition_info *rxbuf_desc_info = NULL;
+	u32 descs_cnt;
+	u32 descs_size_bytes;
+	int ret;
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	res->a0 = FFA_SMC_32(FFA_ERROR);
+
+	if (!priv->pair.rxbuf) {
+		res->a2 = -DENIED;
+		ret = ffa_to_std_errmap[DENIED];
+		goto cleanup;
+	}
+
+	if (priv->pair_info.rxbuf_owned) {
+		res->a2 = -BUSY;
+		ret = ffa_to_std_errmap[BUSY];
+		goto cleanup;
+	}
+
+	if (!priv->partitions.descs) {
+		priv->partitions.descs = sandbox_partitions;
+		priv->partitions.count = SANDBOX_PARTITIONS_CNT;
+	}
+
+	descs_size_bytes = SANDBOX_PARTITIONS_CNT *
+		sizeof(struct ffa_partition_desc);
+
+	/* Abort if the RX buffer size is smaller than the descs buffer size */
+	if ((priv->pair_info.rxtx_buf_size * SZ_4K) < descs_size_bytes) {
+		res->a2 = -NO_MEMORY;
+		ret = ffa_to_std_errmap[NO_MEMORY];
+		goto cleanup;
+	}
+
+	rxbuf_desc_info = priv->pair.rxbuf;
+
+	/* No UUID specified. Return the information of all partitions */
+	if (!pargs->a1 && !pargs->a2 && !pargs->a3 && !pargs->a4) {
+		for (descs_cnt = 0; descs_cnt < SANDBOX_PARTITIONS_CNT; descs_cnt++)
+			*(rxbuf_desc_info++) = priv->partitions.descs[descs_cnt].info;
+
+		res->a0 = FFA_SMC_32(FFA_SUCCESS);
+		res->a2 = SANDBOX_PARTITIONS_CNT;
+		/* Transfer ownership to the consumer: the non secure world */
+		priv->pair_info.rxbuf_owned = 1;
+		ret = 0;
+
+		goto cleanup;
+	}
+
+	/* A UUID specified. Return the info of all SPs matching the UUID */
+
+	for (descs_cnt = 0 ; descs_cnt < SANDBOX_PARTITIONS_CNT ; descs_cnt++)
+		if (pargs->a1 == priv->partitions.descs[descs_cnt].sp_uuid.a1 &&
+		    pargs->a2 == priv->partitions.descs[descs_cnt].sp_uuid.a2 &&
+		    pargs->a3 == priv->partitions.descs[descs_cnt].sp_uuid.a3 &&
+		    pargs->a4 == priv->partitions.descs[descs_cnt].sp_uuid.a4) {
+			*(rxbuf_desc_info++) = priv->partitions.descs[descs_cnt].info;
+		}
+
+	if (rxbuf_desc_info != priv->pair.rxbuf) {
+		res->a0 = FFA_SMC_32(FFA_SUCCESS);
+		/* Store the partitions count */
+		res->a2 = (ulong)
+			(rxbuf_desc_info - (struct ffa_partition_info *)
+			 priv->pair.rxbuf);
+		ret = 0;
+
+		/* Transfer ownership to the consumer: the non secure world */
+		priv->pair_info.rxbuf_owned = 1;
+	} else {
+		/* Unrecognized UUID */
+		res->a2 = -INVALID_PARAMETERS;
+		ret = ffa_to_std_errmap[INVALID_PARAMETERS];
+	}
+
+cleanup:
+
+	log_err("FFA_PARTITION_INFO_GET (%ld)\n", res->a2);
+
+	res->a1 = 0;
+
+	/* x3-x7 MBZ */
+	memset(FFA_X3_MBZ_REG_START, 0, FFA_X3X7_MBZ_CNT * sizeof(ulong));
+
+	return ret;
+}
+
+/**
+ * sandbox_ffa_rxtx_map() - Emulated FFA_RXTX_MAP handler
+ * @emul: The sandbox FF-A emulator device
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_RXTX_MAP FF-A function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_rxtx_map(struct udevice *emul, ffa_value_t *pargs, ffa_value_t *res)
+{
+	int ret;
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	res->a0 = FFA_SMC_32(FFA_ERROR);
+
+	if (priv->pair.txbuf && priv->pair.rxbuf) {
+		res->a2 = -DENIED;
+		ret = ffa_to_std_errmap[DENIED];
+		goto feedback;
+	}
+
+	if (pargs->a3 >= RXTX_BUFFERS_MIN_PAGES && pargs->a1 && pargs->a2) {
+		priv->pair.txbuf = map_sysmem(pargs->a1, 0);
+		priv->pair.rxbuf = map_sysmem(pargs->a2, 0);
+		priv->pair_info.rxtx_buf_size = pargs->a3;
+		priv->pair_info.rxbuf_mapped = 1;
+		res->a0 = FFA_SMC_32(FFA_SUCCESS);
+		res->a2 = 0;
+		ret = 0;
+		goto feedback;
+	}
+
+	if (!pargs->a1 || !pargs->a2) {
+		res->a2 = -INVALID_PARAMETERS;
+		ret = ffa_to_std_errmap[INVALID_PARAMETERS];
+	} else {
+		res->a2 = -NO_MEMORY;
+		ret = ffa_to_std_errmap[NO_MEMORY];
+	}
+
+	log_err("Error in FFA_RXTX_MAP arguments (%d)\n",
+		(int)res->a2);
+
+feedback:
+
+	res->a1 = 0;
+
+	/* x3-x7 MBZ */
+	memset(FFA_X3_MBZ_REG_START, 0, FFA_X3X7_MBZ_CNT * sizeof(ulong));
+
+	return ret;
+}
+
+/**
+ * sandbox_ffa_rxtx_unmap() - Emulated FFA_RXTX_UNMAP handler
+ * @emul: The sandbox FF-A emulator device
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_RXTX_UNMAP FF-A function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_rxtx_unmap(struct udevice *emul, ffa_value_t *pargs, ffa_value_t *res)
+{
+	int ret;
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	res->a0 = FFA_SMC_32(FFA_ERROR);
+	res->a2 = -INVALID_PARAMETERS;
+	ret = ffa_to_std_errmap[INVALID_PARAMETERS];
+
+	if (GET_NS_PHYS_ENDPOINT_ID(pargs->a1) != priv->id)
+		goto feedback;
+
+	if (priv->pair.txbuf && priv->pair.rxbuf) {
+		priv->pair.txbuf = 0;
+		priv->pair.rxbuf = 0;
+		priv->pair_info.rxtx_buf_size = 0;
+		priv->pair_info.rxbuf_mapped = 0;
+		res->a0 = FFA_SMC_32(FFA_SUCCESS);
+		res->a2 = 0;
+		ret = 0;
+		goto feedback;
+	}
+
+	log_err("No buffer pair registered on behalf of the caller\n");
+
+feedback:
+
+	res->a1 = 0;
+
+	/* x3-x7 MBZ */
+	memset(FFA_X3_MBZ_REG_START, 0, FFA_X3X7_MBZ_CNT * sizeof(ulong));
+
+	return ret;
+}
+
+/**
+ * sandbox_ffa_rx_release() - Emulated FFA_RX_RELEASE handler
+ * @emul: The sandbox FF-A emulator device
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_RX_RELEASE FF-A function.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_rx_release(struct udevice *emul, ffa_value_t *pargs, ffa_value_t *res)
+{
+	int ret;
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	if (!priv->pair_info.rxbuf_owned) {
+		res->a0 = FFA_SMC_32(FFA_ERROR);
+		res->a2 = -DENIED;
+		ret = ffa_to_std_errmap[DENIED];
+	} else {
+		priv->pair_info.rxbuf_owned = 0;
+		res->a0 = FFA_SMC_32(FFA_SUCCESS);
+		res->a2 = 0;
+		ret = 0;
+	}
+
+	res->a1 = 0;
+
+	/* x3-x7 MBZ */
+	memset(FFA_X3_MBZ_REG_START, 0, FFA_X3X7_MBZ_CNT * sizeof(ulong));
+
+	return ret;
+}
+
+/**
+ * sandbox_ffa_sp_valid() - Check SP validity
+ * @emul: The sandbox FF-A emulator device
+ * @part_id:	partition ID to check
+ *
+ * Search the input ID in the descriptors table.
+ *
+ * Return:
+ *
+ * 1 on success (Partition found). Otherwise, failure
+ */
+static int sandbox_ffa_sp_valid(struct udevice *emul, u16 part_id)
+{
+	u32 descs_cnt;
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	for (descs_cnt = 0 ; descs_cnt < SANDBOX_PARTITIONS_CNT ; descs_cnt++)
+		if (priv->partitions.descs[descs_cnt].info.id == part_id)
+			return 1;
+
+	return 0;
+}
+
+/**
+ * sandbox_ffa_msg_send_direct_req() - Emulated FFA_MSG_SEND_DIRECT_{REQ,RESP} handler
+ * @emul: The sandbox FF-A emulator device
+ * @pargs: The SMC call input arguments a0-a7
+ * @res:  The SMC return data
+ *
+ * Emulate FFA_MSG_SEND_DIRECT_{REQ,RESP} FF-A ABIs.
+ * Only SMC 64-bit is supported in Sandbox.
+ *
+ * Emulating interrupts is not supported. So, FFA_RUN and FFA_INTERRUPT are not
+ * supported. In case of success FFA_MSG_SEND_DIRECT_RESP is returned with
+ * default pattern data (0xff).
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_msg_send_direct_req(struct udevice *emul,
+					   ffa_value_t *pargs, ffa_value_t *res)
+{
+	u16 part_id;
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	part_id = GET_DST_SP_ID(pargs->a1);
+
+	if (GET_NS_PHYS_ENDPOINT_ID(pargs->a1) != priv->id ||
+	    !sandbox_ffa_sp_valid(emul, part_id) || pargs->a2) {
+		res->a0 = FFA_SMC_32(FFA_ERROR);
+		res->a1 = 0;
+		res->a2 = -INVALID_PARAMETERS;
+
+		/* x3-x7 MBZ */
+		memset(FFA_X3_MBZ_REG_START, 0, FFA_X3X7_MBZ_CNT * sizeof(ulong));
+
+		return ffa_to_std_errmap[INVALID_PARAMETERS];
+	}
+
+	res->a0 = FFA_SMC_64(FFA_MSG_SEND_DIRECT_RESP);
+
+	res->a1 = PREP_SRC_SP_ID(part_id) |
+		PREP_NS_PHYS_ENDPOINT_ID(priv->id);
+
+	res->a2 = 0;
+
+	/* Return 0xff bytes as a response */
+	res->a3 = -1UL;
+	res->a4 = -1UL;
+	res->a5 = -1UL;
+	res->a6 = -1UL;
+	res->a7 = -1UL;
+
+	return 0;
+}
+
+/**
+ * sandbox_ffa_get_rxbuf_flags() - Read the mapping/ownership flags
+ * @emul: The sandbox FF-A emulator device
+ * @queried_func_id:	The FF-A function to be queried
+ * @func_data:  Pointer to the FF-A function arguments container structure
+ *
+ * Query the status flags of the following emulated
+ * ABIs: FFA_RXTX_MAP, FFA_RXTX_UNMAP, FFA_RX_RELEASE.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_get_rxbuf_flags(struct udevice *emul, u32 queried_func_id,
+				       struct ffa_sandbox_data *func_data)
+{
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	if (!func_data)
+		return -EINVAL;
+
+	if (!func_data->data0 || func_data->data0_size != sizeof(u8))
+		return -EINVAL;
+
+	switch (queried_func_id) {
+	case FFA_RXTX_MAP:
+	case FFA_RXTX_UNMAP:
+		*((u8 *)func_data->data0) = priv->pair_info.rxbuf_mapped;
+		return 0;
+	case FFA_RX_RELEASE:
+		*((u8 *)func_data->data0) = priv->pair_info.rxbuf_owned;
+		return 0;
+	default:
+		log_err("The querried FF-A interface flag (%d) undefined\n",
+			queried_func_id);
+		return -EINVAL;
+	}
+}
+
+/**
+ * sandbox_ffa_get_fwk_version() - Return the FFA framework version
+ * @emul: The sandbox FF-A emulator device
+ * @func_data:  Pointer to the FF-A function arguments container structure
+ *
+ * Return the FFA framework version read from the FF-A emulator data.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_get_fwk_version(struct udevice *emul, struct ffa_sandbox_data *func_data)
+{
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	if (!func_data)
+		return -EINVAL;
+
+	if (!func_data->data0 ||
+	    func_data->data0_size != sizeof(priv->fwk_version))
+		return -EINVAL;
+
+	*((u32 *)func_data->data0) = priv->fwk_version;
+
+	return 0;
+}
+
+/**
+ * sandbox_ffa_get_parts() - Return the address of partitions data
+ * @emul: The sandbox FF-A emulator device
+ * @func_data:  Pointer to the FF-A function arguments container structure
+ *
+ * Return the address of partitions data read from the FF-A emulator data.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_get_parts(struct udevice *emul, struct ffa_sandbox_data *func_data)
+{
+	struct sandbox_ffa_emul *priv = dev_get_priv(emul);
+
+	if (!func_data)
+		return -EINVAL;
+
+	if (!func_data->data0 ||
+	    func_data->data0_size != sizeof(struct ffa_partitions *))
+		return -EINVAL;
+
+	*((struct ffa_partitions **)func_data->data0) = &priv->partitions;
+
+	return 0;
+}
+
+/**
+ * sandbox_query_ffa_emul_state() - Inspect the FF-A ABIs
+ * @queried_func_id:	The FF-A function to be queried
+ * @func_data:  Pointer to the FF-A function arguments container structure
+ *
+ * Query the status of FF-A ABI specified in the input argument.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int sandbox_query_ffa_emul_state(u32 queried_func_id,
+				 struct ffa_sandbox_data *func_data)
+{
+	struct udevice *emul;
+	int ret;
+
+	ret = uclass_first_device_err(UCLASS_FFA_EMUL, &emul);
+	if (ret) {
+		log_err("Cannot find FF-A emulator during querying state\n");
+		return ret;
+	}
+
+	switch (queried_func_id) {
+	case FFA_RXTX_MAP:
+	case FFA_RXTX_UNMAP:
+	case FFA_RX_RELEASE:
+		return sandbox_ffa_get_rxbuf_flags(emul, queried_func_id, func_data);
+	case FFA_VERSION:
+		return sandbox_ffa_get_fwk_version(emul, func_data);
+	case FFA_PARTITION_INFO_GET:
+		return sandbox_ffa_get_parts(emul, func_data);
+	default:
+		log_err("Undefined FF-A interface (%d)\n",
+			queried_func_id);
+		return -EINVAL;
+	}
+}
+
+/**
+ * sandbox_arm_ffa_smccc_smc() - FF-A SMC call emulation
+ * @args:	the SMC call arguments
+ * @res:	the SMC call returned data
+ *
+ * Emulate the FF-A ABIs SMC call.
+ * The emulated FF-A ABI is identified and invoked.
+ * FF-A emulation is based on the FF-A specification 1.0
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure.
+ * FF-A protocol error codes are returned using the registers arguments as
+ * described by the specification
+ */
+void sandbox_arm_ffa_smccc_smc(ffa_value_t *args, ffa_value_t *res)
+{
+	int ret = 0;
+	struct udevice *emul;
+
+	ret = uclass_first_device_err(UCLASS_FFA_EMUL, &emul);
+	if (ret) {
+		log_err("Cannot find FF-A emulator during SMC emulation\n");
+		return;
+	}
+
+	switch (args->a0) {
+	case FFA_SMC_32(FFA_VERSION):
+		ret = sandbox_ffa_version(emul, args, res);
+		break;
+	case FFA_SMC_32(FFA_PARTITION_INFO_GET):
+		ret = sandbox_ffa_partition_info_get(emul, args, res);
+		break;
+	case FFA_SMC_32(FFA_RXTX_UNMAP):
+		ret = sandbox_ffa_rxtx_unmap(emul, args, res);
+		break;
+	case FFA_SMC_64(FFA_MSG_SEND_DIRECT_REQ):
+		ret = sandbox_ffa_msg_send_direct_req(emul, args, res);
+		break;
+	case FFA_SMC_32(FFA_ID_GET):
+		ret = sandbox_ffa_id_get(emul, args, res);
+		break;
+	case FFA_SMC_32(FFA_FEATURES):
+		ret = sandbox_ffa_features(args, res);
+		break;
+	case FFA_SMC_64(FFA_RXTX_MAP):
+		ret = sandbox_ffa_rxtx_map(emul, args, res);
+		break;
+	case FFA_SMC_32(FFA_RX_RELEASE):
+		ret = sandbox_ffa_rx_release(emul, args, res);
+		break;
+	default:
+		log_err("Undefined FF-A interface (%lx)\n",
+			args->a0);
+	}
+
+	if (ret != 0)
+		log_err("FF-A ABI internal failure (%d)\n", ret);
+}
+
+/**
+ * invoke_ffa_fn() - SMC wrapper
+ * @args: FF-A ABI arguments to be copied to Xn registers
+ * @res: FF-A ABI return data to be copied from Xn registers
+ *
+ * Calls the emulated SMC call.
+ */
+void invoke_ffa_fn(ffa_value_t args, ffa_value_t *res)
+{
+	sandbox_arm_ffa_smccc_smc(&args, res);
+}
+
+/**
+ * ffa_emul_find() - Find the FF-A emulator
+ * @dev:	the sandbox FF-A device (sandbox-arm-ffa)
+ * @emulp:	the FF-A emulator device (sandbox-ffa-emul)
+ *
+ * Search for the FF-A emulator and returns its device pointer.
+ *
+ * Return:
+ * 0 on success. Otherwise, failure
+ */
+int ffa_emul_find(struct udevice *dev, struct udevice **emulp)
+{
+	int ret;
+
+	ret = uclass_first_device_err(UCLASS_FFA_EMUL, emulp);
+	if (ret) {
+		log_err("Cannot find FF-A emulator\n");
+		return ret;
+	}
+
+	log_info("FF-A emulator ready to use\n");
+
+	return 0;
+}
+
+UCLASS_DRIVER(ffa_emul) = {
+	.name		= "ffa_emul",
+	.id		= UCLASS_FFA_EMUL,
+	.post_bind = dm_scan_fdt_dev,
+};
+
+static const struct udevice_id sandbox_ffa_emul_ids[] = {
+	{ .compatible = "sandbox,arm-ffa-emul" },
+	{ }
+};
+
+/* Declaring the sandbox FF-A emulator under UCLASS_FFA_EMUL */
+U_BOOT_DRIVER(sandbox_ffa_emul) = {
+	.name		= "sandbox_ffa_emul",
+	.id		= UCLASS_FFA_EMUL,
+	.of_match	= sandbox_ffa_emul_ids,
+	.priv_auto	= sizeof(struct sandbox_ffa_emul),
+};
diff --git a/drivers/firmware/arm-ffa/sandbox_arm_ffa_priv.h b/drivers/firmware/arm-ffa/sandbox_arm_ffa_priv.h
deleted file mode 100644
index 4338f9c9b1..0000000000
--- a/drivers/firmware/arm-ffa/sandbox_arm_ffa_priv.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
- *
- * Authors:
- *   Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
- */
-
-#ifndef __SANDBOX_ARM_FFA_PRV_H
-#define __SANDBOX_ARM_FFA_PRV_H
-
-/* Future sandbox support private declarations */
-
-#endif
diff --git a/drivers/firmware/arm-ffa/sandbox_ffa.c b/drivers/firmware/arm-ffa/sandbox_ffa.c
new file mode 100644
index 0000000000..ef9491ccea
--- /dev/null
+++ b/drivers/firmware/arm-ffa/sandbox_ffa.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office@arm.com>
+ *
+ * Authors:
+ *   Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+#include <common.h>
+#include <arm_ffa.h>
+#include <dm.h>
+#include <log.h>
+#include <asm/global_data.h>
+#include <asm/sandbox_arm_ffa_priv.h>
+#include <dm/device-internal.h>
+#include <linux/errno.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * sandbox_ffa_discover() - perform sandbox FF-A discovery
+ * @dev: The sandbox FF-A bus device
+ * Try to discover the FF-A framework. Discovery is performed by
+ * querying the FF-A framework version from secure world using the FFA_VERSION ABI.
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int sandbox_ffa_discover(struct udevice *dev)
+{
+	int ret;
+	struct udevice *emul;
+
+	log_info("Emulated FF-A framework discovery\n");
+
+	ret = ffa_emul_find(dev, &emul);
+	if (ret) {
+		log_err("Cannot find FF-A emulator\n");
+		return ret;
+	}
+
+	ret = ffa_get_version_hdlr(dev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * sandbox_ffa_probe() - The sandbox FF-A driver probe function
+ * @dev:	the sandbox-arm-ffa device
+ * Save the emulator device in uc_priv.
+ * Return:
+ *
+ * 0 on success.
+ */
+static int sandbox_ffa_probe(struct udevice *dev)
+{
+	int ret;
+	struct ffa_priv *uc_priv = dev_get_uclass_priv(dev);
+
+	ret = uclass_first_device_err(UCLASS_FFA_EMUL, &uc_priv->emul);
+	if (ret) {
+		log_err("Cannot find FF-A emulator\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * sandbox_ffa_bind() - The sandbox FF-A driver bind function
+ * @dev:	the sandbox-arm-ffa device
+ * Try to discover the emulated FF-A bus.
+ * Return:
+ *
+ * 0 on success.
+ */
+static int sandbox_ffa_bind(struct udevice *dev)
+{
+	int ret;
+
+	ret = sandbox_ffa_discover(dev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/* Sandbox Arm FF-A emulator operations */
+
+static const struct ffa_bus_ops sandbox_ffa_ops = {
+	.partition_info_get = ffa_get_partitions_info_hdlr,
+	.sync_send_receive = ffa_msg_send_direct_req_hdlr,
+	.rxtx_unmap = ffa_unmap_rxtx_buffers_hdlr,
+};
+
+static const struct udevice_id sandbox_ffa_id[] = {
+	{ "sandbox,arm-ffa", 0 },
+	{ },
+};
+
+/* Declaring the sandbox FF-A driver under UCLASS_FFA */
+U_BOOT_DRIVER(sandbox_arm_ffa) = {
+	.name		= "sandbox_arm_ffa",
+	.of_match = sandbox_ffa_id,
+	.id		= UCLASS_FFA,
+	.bind		= sandbox_ffa_bind,
+	.probe		= sandbox_ffa_probe,
+	.ops		= &sandbox_ffa_ops,
+};