[PATCH v8 03/10] arm_ffa: introduce Arm FF-A low-level driver

[Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>]

Add the core driver implementing Arm Firmware Framework for Armv8-A v1.0

The Firmware Framework for Arm A-profile processors (FF-A v1.0) [1]
describes interfaces (ABIs) that standardize communication
between the Secure World and Normal World leveraging TrustZone
technology.

This driver uses 64-bit registers as per SMCCCv1.2 spec and comes
on top of the SMCCC layer. The driver provides the FF-A ABIs needed for
querying the FF-A framework from the secure world.

The driver uses SMC32 calling convention which means using the first
32-bit data of the Xn registers.

All supported ABIs come with their 32-bit version except FFA_RXTX_MAP
which has 64-bit version supported.

Both 32-bit and 64-bit direct messaging are supported which allows both
32-bit and 64-bit clients to use the FF-A bus.

In U-Boot FF-A design, FF-A is considered as a discoverable bus.
The Secure World is considered as one entity to communicate with
using the FF-A bus. FF-A communication is handled by one device and
one instance (the bus). This FF-A driver takes care of all the
interactions between Normal world and Secure World.

The driver exports its operations to be used by upper layers.

Exported operations:

- partition_info_get
- sync_send_receive
- rxtx_unmap

For more details please refer to the driver documentation [2].

[1]: https://developer.arm.com/documentation/den0077/latest/
[2]: doc/arch/arm64.ffa.rst

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

---

Changelog:
===============

v8:

* make ffa_get_partitions_info() second argument to be an SP count in both
  modes
* update ffa_bus_prvdata_get() to return a pointer rather than a pointer
  address
* remove packing from ffa_partition_info and ffa_send_direct_data structures
* pass the FF-A bus device to the bus operations

v7:

* add support for 32-bit direct messaging
* rename be_uuid_str_to_le_bin() to uuid_str_to_le_bin()
* improve the declaration of error handling mapping
* stating in doc/arch/arm64.ffa.rst that EFI runtime is not supported

v6:

* drop use of EFI runtime support (We decided with Linaro to add this later)
* drop discovery from initcalls (discovery will be on demand by FF-A users)
* set the alignment of the RX/TX buffers to the larger translation granule size
* move FF-A RX/TX buffers unmapping at ExitBootServices() to a separate commit
* update the documentation and move it to doc/arch/arm64.ffa.rst

v4:

* add doc/README.ffa.drv
* moving the FF-A driver work to drivers/firmware/arm-ffa
* use less #ifdefs in lib/efi_loader/efi_boottime.c and replace
  #if defined by #if CONFIG_IS_ENABLED
* improving error handling by mapping the FF-A errors to standard errors
  and logs
* replacing panics with an error log and returning an error code
* improving features discovery in FFA_FEATURES by introducing
  rxtx_min_pages private data field
* add ffa_remove and ffa_unbind functions
* improve how the driver behaves when bus discovery is done more than
  once

v3:

* align the interfaces of the U-Boot FF-A driver with those in the linux
  FF-A driver
* remove the FF-A helper layer
* make the U-Boot FF-A driver independent from EFI
* provide an optional config that enables copying the driver data to EFI
  runtime section at ExitBootServices service
* use 64-bit version of FFA_RXTX_MAP, FFA_MSG_SEND_DIRECT_{REQ, RESP}

v2:

* make FF-A bus discoverable using device_{bind, probe} APIs
* remove device tree support

v1:

* introduce FF-A bus driver with device tree support

MAINTAINERS                               |    7 +
 doc/arch/arm64.ffa.rst                    |  218 ++++
 doc/arch/index.rst                        |    1 +
 drivers/Kconfig                           |    2 +
 drivers/Makefile                          |    1 +
 drivers/firmware/arm-ffa/Kconfig          |   30 +
 drivers/firmware/arm-ffa/Makefile         |    6 +
 drivers/firmware/arm-ffa/arm-ffa-uclass.c |   16 +
 drivers/firmware/arm-ffa/arm_ffa_prv.h    |  200 ++++
 drivers/firmware/arm-ffa/core.c           | 1315 +++++++++++++++++++++
 include/arm_ffa.h                         |   97 ++
 include/dm/uclass-id.h                    |    4 +
 12 files changed, 1897 insertions(+)
 create mode 100644 doc/arch/arm64.ffa.rst
 create mode 100644 drivers/firmware/arm-ffa/Kconfig
 create mode 100644 drivers/firmware/arm-ffa/Makefile
 create mode 100644 drivers/firmware/arm-ffa/arm-ffa-uclass.c
 create mode 100644 drivers/firmware/arm-ffa/arm_ffa_prv.h
 create mode 100644 drivers/firmware/arm-ffa/core.c
 create mode 100644 include/arm_ffa.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 97b2f69f65..dcd32cf83a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -263,6 +263,13 @@ F:	drivers/net/cortina_ni.h
 F:	drivers/net/phy/ca_phy.c
 F:	configs/cortina_presidio-asic-pnand_defconfig
 
+ARM FF-A
+M:	Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+S:	Maintained
+F:	doc/arch/arm64.ffa.rst
+F:	drivers/firmware/arm-ffa/
+F:	include/arm_ffa.h
+
 ARM FREESCALE IMX
 M:	Stefano Babic <sbabic@denx.de>
 M:	Fabio Estevam <festevam@gmail.com>
diff --git a/doc/arch/arm64.ffa.rst b/doc/arch/arm64.ffa.rst
new file mode 100644
index 0000000000..dfcec82e45
--- /dev/null
+++ b/doc/arch/arm64.ffa.rst
@@ -0,0 +1,218 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Arm FF-A Driver
+===============
+
+Summary
+-------
+
+FF-A stands for Firmware Framework for Arm A-profile processors.
+
+FF-A specifies interfaces that enable a pair of software sandboxes to
+communicate with each other. A sandbox aka partition could
+be a VM in the Normal or Secure world, an application in S-EL0, or a
+Trusted OS in S-EL1.
+
+This FF-A driver implements the interfaces to communicate with partitions in
+the Secure world aka Secure partitions (SPs).
+
+The driver specifically focuses on communicating with SPs that isolate portions
+of EFI runtime services that must run in a protected environment which is
+inaccessible by the Host OS or Hypervisor. Examples of such services are
+set/get variables.
+
+FF-A driver uses the SMC ABIs defined by the FF-A specification to:
+
+- Discover the presence of SPs of interest
+- Access an SP's service through communication protocols
+  e.g. EFI MM communication protocol
+
+At this stage of development the FF-A driver supports EFI boot time only.
+
+Runtime support will be added in future developments.
+
+FF-A and SMC specifications
+-------------------------------------------
+
+The current implementation of the driver relies on FF-A specification v1.0
+and uses SMC32 calling convention which means using the first 32-bit data of the
+Xn registers.
+
+At this stage we only need the FF-A v1.0 features.
+
+The driver has been tested with OP-TEE which supports SMC32 calling convention.
+
+For more details please refer to the FF-A v1.0 spec:
+https://documentation-service.arm.com/static/5fb7e8a6ca04df4095c1d65e?token=
+
+Hypervisors are supported if they are configured to trap SMC calls.
+
+The FF-A driver uses 64-bit registers as per SMCCCv1.2 specification.
+
+For more details please refer to the SMC Calling Convention v1.2 spec:
+https://documentation-service.arm.com/static/5f8edaeff86e16515cdbe4c6?token=
+
+Supported hardware
+--------------------------------
+
+Aarch64 plaforms
+
+Configuration
+----------------------
+
+CONFIG_ARM_FFA_TRANSPORT
+    Enables the FF-A bus driver. Turn this on if you want to use FF-A
+    communication.
+
+CONFIG_SANDBOX_FFA
+    Enables FF-A Sandbox driver. This emulates the FF-A ABIs handling under
+    Sandbox and provides functional tests for FF-A.
+
+FF-A ABIs under the hood
+---------------------------------------
+
+Invoking an FF-A ABI involves providing to the secure world/hypervisor the
+expected arguments from the ABI.
+
+The ABI arguments are stored in x0 to x7 registers. Then, an SMC instruction
+is executed.
+
+At the secure side level or hypervisor the ABI is handled at a higher exception
+level and the arguments are read and processed.
+
+The response is put back through x0 to x7 registers and control is given back
+to the U-Boot FF-A driver (non-secure world).
+
+The driver reads the response and processes it accordingly.
+
+This methodology applies to all the FF-A ABIs in the driver.
+
+FF-A bus discovery in U-Boot
+-------------------------------------------
+
+When CONFIG_ARM_FFA_TRANSPORT is enabled, the FF-A bus is discovered on
+demand by the clients (users).
+
+Clients can discover the FF-A bus using ffa_bus_discover() API which triggers the
+discovery process.
+
+ffa_bus_discover() creates, binds and probes the arm_ffa device using
+device_{bind, probe} APIs.
+
+The discovery process consists in communicating with secure world (or hypervisor)
+and querying specific data.
+
+The discovery process takes place during the arm_ffa device probing which is
+handled by ffa_probe().
+
+The FF-A bus discovery is successful and the bus is ready for use when these
+operations succeed:
+
+- querying the FF-A framework version
+- querying from secure world the U-Boot endpoint ID
+- querying from secure world the RX/TX mapping  features
+- mapping the RX/TX buffers
+- querying from secure world all the partitions information
+
+Discovery failure results in a probing failure and the arm_ffa device is
+destroyed.
+
+Requirements for clients
+-------------------------------------
+
+When using the FF-A bus with EFI, clients must:
+
+- Query SPs in EFI boot time mode using the service UUID.
+- Unmap RX/TX buffers before EFI runtime mode starts.
+
+The RX/TX buffers are only available at EFI boot time. Querying partitions is
+done at boot time and data is cached for future use.
+
+RX/TX buffers should be unmapped by the user before EFI runtime mode
+starts. The driver provides a bus operation for that: rxtx_unmap()
+
+If  RX/TX buffers created by U-Boot are not unmapped and by
+consequence becoming available at EFI runtime, secure world will get confused
+about RX/TX buffers ownership (U-Boot vs kernel).
+
+When invoking FF-A direct messaging, clients should specify which ABI protocol
+they want to use (32-bit vs 64-bit). Selecting the protocol means using
+the 32-bit or 64-bit version of FFA_MSG_SEND_DIRECT_{REQ, RESP}.
+The calling convention stays the same: SMC32.
+
+The bus driver layer
+------------------------------
+
+The driver comes on top of the SMCCC layer and is implemented in
+drivers/firmware/arm-ffa/core.c
+
+The driver provides the following features:
+
+- Support for the 32-bit version of the following ABIs:
+
+FFA_VERSION
+FFA_ID_GET
+FFA_FEATURES
+FFA_PARTITION_INFO_GET
+FFA_RXTX_UNMAP
+FFA_RX_RELEASE
+FFA_RUN
+FFA_ERROR
+FFA_SUCCESS
+FFA_INTERRUPT
+FFA_MSG_SEND_DIRECT_REQ
+FFA_MSG_SEND_DIRECT_RESP
+
+- Support for the 64-bit version of the following ABIs:
+
+FFA_RXTX_MAP
+FFA_MSG_SEND_DIRECT_REQ
+FFA_MSG_SEND_DIRECT_RESP
+
+- Processing the received data from the secure world/hypervisor and caching it
+
+- Hiding from upper layers the FF-A protocol and registers details. Upper
+  layers focus on exchanged data, the driver takes care of how to transport
+  that to the secure world/hypervisor using FF-A
+
+- The driver provides callbacks to be used by clients to access the FF-A bus:
+
+partition_info_get
+sync_send_receive
+rxtx_unmap
+
+- FF-A bus discovery makes sure FF-A framework is responsive and compatible
+  with the driver
+
+- FF-A bus can be compiled and used without EFI
+
+Using armffa command
+-----------------------------------
+
+armffa is an implementation defined command showcasing how to use the FF-A driver and how to invoke
+its operations.
+
+This provides a guidance to the client developers on how to call the FF-A bus
+interfaces.
+
+Usage:
+
+armffa <sub-command> <arguments>
+
+sub-commands:
+
+        getpart <partition UUID>
+
+            lists the partition(s) info
+
+        ping <partition ID>
+
+            sends a data pattern to the specified partition
+
+        devlist
+
+            displays the arm_ffa device info
+
+Contributors
+------------
+   * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
diff --git a/doc/arch/index.rst b/doc/arch/index.rst
index b3e85f9bf3..cf1cfc9287 100644
--- a/doc/arch/index.rst
+++ b/doc/arch/index.rst
@@ -8,6 +8,7 @@ Architecture-specific doc
 
    arc
    arm64
+   arm64.ffa
    m68k
    mips
    nios2
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 75ac149d31..ff75b7c3f8 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -6,6 +6,8 @@ source "drivers/core/Kconfig"
 
 source "drivers/adc/Kconfig"
 
+source "drivers/firmware/arm-ffa/Kconfig"
+
 source "drivers/ata/Kconfig"
 
 source "drivers/axi/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index ac2d83af4e..d23009577e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -112,6 +112,7 @@ obj-y += iommu/
 obj-y += smem/
 obj-y += thermal/
 obj-$(CONFIG_TEE) += tee/
+obj-$(CONFIG_ARM_FFA_TRANSPORT) += firmware/arm-ffa/
 obj-y += axi/
 obj-y += ufs/
 obj-$(CONFIG_W1) += w1/
diff --git a/drivers/firmware/arm-ffa/Kconfig b/drivers/firmware/arm-ffa/Kconfig
new file mode 100644
index 0000000000..e4914b9bc7
--- /dev/null
+++ b/drivers/firmware/arm-ffa/Kconfig
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config ARM_FFA_TRANSPORT
+	bool "Enable Arm Firmware Framework for Armv8-A driver"
+	depends on DM && ARM64
+	select ARM_SMCCC
+	select LIB_UUID
+	select DEVRES
+	help
+	  The Firmware Framework for Arm A-profile processors (FF-A)
+	  describes interfaces (ABIs) that standardize communication
+	  between the Secure World and Normal World leveraging TrustZone
+	  technology.
+
+	  This driver is based on FF-A specification v1.0 and uses SMC32
+	  calling convention.
+
+	  FF-A specification:
+
+	  https://developer.arm.com/documentation/den0077/a/?lang=en
+
+	  In U-Boot FF-A design, FF-A is considered as a discoverable bus.
+	  The Secure World is considered as one entity to communicate with
+	  using the FF-A bus.
+	  FF-A communication is handled by one device and one instance (the bus).
+	  This FF-A driver takes care of all the interactions between Normal world
+	  and Secure World.
+
+	  For more details about the FF-A driver, please refer to doc/arch/arm64.ffa.rst
+
diff --git a/drivers/firmware/arm-ffa/Makefile b/drivers/firmware/arm-ffa/Makefile
new file mode 100644
index 0000000000..043a8915be
--- /dev/null
+++ b/drivers/firmware/arm-ffa/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# (C) Copyright 2022
+# Abdellatif El Khlifi, Arm Limited, abdellatif.elkhlifi@arm.com.
+
+obj-y += arm-ffa-uclass.o core.o
diff --git a/drivers/firmware/arm-ffa/arm-ffa-uclass.c b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
new file mode 100644
index 0000000000..7d9695d289
--- /dev/null
+++ b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2022 ARM Limited
+ * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+UCLASS_DRIVER(ffa) = {
+	.name		= "ffa",
+	.id		= UCLASS_FFA,
+};
diff --git a/drivers/firmware/arm-ffa/arm_ffa_prv.h b/drivers/firmware/arm-ffa/arm_ffa_prv.h
new file mode 100644
index 0000000000..4eea7dc036
--- /dev/null
+++ b/drivers/firmware/arm-ffa/arm_ffa_prv.h
@@ -0,0 +1,200 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2022 ARM Limited
+ * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+
+#ifndef __ARM_FFA_PRV_H
+#define __ARM_FFA_PRV_H
+
+#include <arm_ffa.h>
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/arm-smccc.h>
+
+/*
+ * This header is private. It is exclusively used by the FF-A driver
+ */
+
+/* FF-A core driver name */
+#define FFA_DRV_NAME "arm_ffa"
+
+/* FF-A driver version definitions */
+
+#define MAJOR_VERSION_MASK		GENMASK(30, 16)
+#define MINOR_VERSION_MASK		GENMASK(15, 0)
+#define GET_FFA_MAJOR_VERSION(x)		\
+				((u16)(FIELD_GET(MAJOR_VERSION_MASK, (x))))
+#define GET_FFA_MINOR_VERSION(x)		\
+				((u16)(FIELD_GET(MINOR_VERSION_MASK, (x))))
+#define PACK_VERSION_INFO(major, minor)			\
+	(FIELD_PREP(MAJOR_VERSION_MASK, (major)) |	\
+	 FIELD_PREP(MINOR_VERSION_MASK, (minor)))
+
+#define FFA_MAJOR_VERSION		(1)
+#define FFA_MINOR_VERSION		(0)
+#define FFA_VERSION_1_0		\
+			PACK_VERSION_INFO(FFA_MAJOR_VERSION, FFA_MINOR_VERSION)
+
+/* Endpoint ID mask (u-boot endpoint ID) */
+
+#define GET_SELF_ENDPOINT_ID_MASK		GENMASK(15, 0)
+#define GET_SELF_ENDPOINT_ID(x)		\
+			((u16)(FIELD_GET(GET_SELF_ENDPOINT_ID_MASK, (x))))
+
+#define PREP_SELF_ENDPOINT_ID_MASK		GENMASK(31, 16)
+#define PREP_SELF_ENDPOINT_ID(x)		\
+			(FIELD_PREP(PREP_SELF_ENDPOINT_ID_MASK, (x)))
+
+/* Partition endpoint ID mask  (partition with which u-boot communicates with) */
+
+#define PREP_PART_ENDPOINT_ID_MASK		GENMASK(15, 0)
+#define PREP_PART_ENDPOINT_ID(x)		\
+			(FIELD_PREP(PREP_PART_ENDPOINT_ID_MASK, (x)))
+
+/*
+ * Definitions of the Arm FF-A interfaces supported by the Arm FF-A driver
+ */
+
+#define FFA_SMC(calling_convention, func_num)				\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, (calling_convention),	\
+			   ARM_SMCCC_OWNER_STANDARD, (func_num))
+
+#define FFA_SMC_32(func_num)				FFA_SMC(ARM_SMCCC_SMC_32, (func_num))
+#define FFA_SMC_64(func_num)				FFA_SMC(ARM_SMCCC_SMC_64, (func_num))
+
+enum ffa_abis {
+	FFA_ERROR                 = 0x60,
+	FFA_SUCCESS               = 0x61,
+	FFA_INTERRUPT             = 0x62,
+	FFA_VERSION               = 0x63,
+	FFA_FEATURES              = 0x64,
+	FFA_RX_RELEASE            = 0x65,
+	FFA_RXTX_MAP              = 0x66,
+	FFA_RXTX_UNMAP            = 0x67,
+	FFA_PARTITION_INFO_GET    = 0x68,
+	FFA_ID_GET                = 0x69,
+	FFA_RUN                   = 0x6D,
+	FFA_MSG_SEND_DIRECT_REQ   = 0x6F,
+	FFA_MSG_SEND_DIRECT_RESP  = 0x70,
+
+	/* to be updated when adding new FFA IDs */
+	FFA_FIRST_ID              = FFA_ERROR, /* lowest number ID*/
+	FFA_LAST_ID               = FFA_MSG_SEND_DIRECT_RESP, /* highest number ID*/
+};
+
+enum ffa_abi_errcode {
+	NOT_SUPPORTED = 1,
+	INVALID_PARAMETERS,
+	NO_MEMORY,
+	BUSY,
+	INTERRUPTED,
+	DENIED,
+	RETRY,
+	ABORTED,
+	MAX_NUMBER_FFA_ERR
+};
+
+/* container structure and helper macros to map between an FF-A error and relevant error log */
+struct ffa_abi_errmap {
+	char *err_str[MAX_NUMBER_FFA_ERR];
+};
+
+#define FFA_ERRMAP_COUNT (FFA_LAST_ID - FFA_FIRST_ID + 1)
+#define FFA_ID_TO_ERRMAP_ID(ffa_id) ((ffa_id) - FFA_FIRST_ID)
+
+/* The FF-A SMC function definitions */
+
+typedef struct arm_smccc_1_2_regs ffa_value_t;
+typedef void (*invoke_ffa_fn_t)(ffa_value_t args, ffa_value_t *res);
+
+/*
+ * struct ffa_partition_uuid - 16 bytes UUID transmitted by FFA_PARTITION_INFO_GET
+ * @a1-4:	32-bit words access to the UUID data
+ *
+ */
+struct ffa_partition_uuid {
+	u32 a1; /* w1 */
+	u32 a2; /* w2 */
+	u32 a3; /* w3 */
+	u32 a4; /* w4 */
+};
+
+/**
+ * enum ffa_rxtx_buf_sizes - minimum sizes supported
+ * for the RX/TX buffers
+ */
+enum ffa_rxtx_buf_sizes {
+	RXTX_4K,
+	RXTX_64K,
+	RXTX_16K
+};
+
+/**
+ * struct ffa_rxtxpair - structure hosting the RX/TX buffers virtual addresses
+ * @rxbuf:	virtual address of the RX buffer
+ * @txbuf:	virtual address of the TX buffer
+ * @rxtx_min_pages:	RX/TX buffers minimum size in pages
+ *
+ * Data structure hosting the virtual addresses of the mapped RX/TX buffers
+ * These addresses are used by the FF-A functions that use the RX/TX buffers
+ */
+struct ffa_rxtxpair {
+	u64 rxbuf; /* virtual address */
+	u64 txbuf; /* virtual address */
+	size_t rxtx_min_pages; /* minimum number of pages in each of the RX/TX buffers */
+};
+
+/**
+ * struct ffa_partition_desc - the secure partition descriptor
+ * @info:	partition information
+ * @sp_uuid:	the secure partition UUID
+ *
+ * Each partition has its descriptor containing the partitions information and the UUID
+ */
+struct ffa_partition_desc {
+	struct ffa_partition_info info;
+	struct ffa_partition_uuid sp_uuid;
+};
+
+/**
+ * struct ffa_partitions - descriptors for all secure partitions
+ * @count:	The number of partitions descriptors
+ * @descs	The partitions descriptors table
+ *
+ * This data structure contains the partitions descriptors table
+ */
+struct ffa_partitions {
+	u32 count;
+	struct ffa_partition_desc *descs; /* virtual address */
+};
+
+/**
+ * struct ffa_prvdata - the driver private data structure
+ *
+ * @dev:	The arm_ffa device under u-boot driver model
+ * @ffa_ops:	The driver operations structure
+ * @fwk_version:	FF-A framework version
+ * @id:	u-boot endpoint ID
+ * @partitions:	The partitions descriptors structure
+ * @pair:	The RX/TX buffers pair
+ * @invoke_ffa_fn:	The function executing the FF-A function
+ *
+ * The driver data structure hosting all resident data.
+ */
+struct ffa_prvdata {
+	struct udevice *dev;
+	struct ffa_bus_ops ffa_ops;
+	u32 fwk_version;
+	u16 id;
+	struct ffa_partitions partitions;
+	struct ffa_rxtxpair pair;
+	invoke_ffa_fn_t invoke_ffa_fn;
+};
+
+/**
+ * ffa_bus_prvdata_get - bus driver private data getter
+ */
+struct ffa_prvdata *ffa_bus_prvdata_get(void);
+
+#endif
diff --git a/drivers/firmware/arm-ffa/core.c b/drivers/firmware/arm-ffa/core.c
new file mode 100644
index 0000000000..0b1f8e6a07
--- /dev/null
+++ b/drivers/firmware/arm-ffa/core.c
@@ -0,0 +1,1315 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2022 ARM Limited
+ * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+
+#include "arm_ffa_prv.h"
+#include <asm/global_data.h>
+#include <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/devres.h>
+#include <dm/root.h>
+#include <linux/errno.h>
+#include <linux/sizes.h>
+#include <log.h>
+#include <malloc.h>
+#include <string.h>
+#include <uuid.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * The device private data structure containing all the
+ * data read from secure world
+ */
+struct ffa_prvdata *ffa_priv_data;
+
+/* 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,
+};
+
+struct ffa_abi_errmap err_msg_map[FFA_ERRMAP_COUNT] = {
+	[FFA_ID_TO_ERRMAP_ID(FFA_VERSION)] = {
+		{
+			[NOT_SUPPORTED] =
+			"NOT_SUPPORTED: A Firmware Framework implementation does not exist",
+		},
+	},
+	[FFA_ID_TO_ERRMAP_ID(FFA_ID_GET)] = {
+		{
+			[NOT_SUPPORTED] =
+			"NOT_SUPPORTED: This function is not implemented at this FF-A instance",
+		},
+	},
+	[FFA_ID_TO_ERRMAP_ID(FFA_FEATURES)] = {
+		{
+			[NOT_SUPPORTED] =
+			"NOT_SUPPORTED: FFA_RXTX_MAP is not implemented at this FF-A instance",
+		},
+	},
+	[FFA_ID_TO_ERRMAP_ID(FFA_PARTITION_INFO_GET)] = {
+		{
+			[NOT_SUPPORTED] =
+			"NOT_SUPPORTED: This function is not implemented at this FF-A instance",
+			[INVALID_PARAMETERS] =
+			"INVALID_PARAMETERS: Unrecognized UUID",
+			[NO_MEMORY] =
+			"NO_MEMORY: Results cannot fit in RX buffer of the caller",
+			[BUSY] =
+			"BUSY: RX buffer of the caller is not free",
+			[DENIED] =
+			"DENIED: Callee is not in a state to handle this request",
+		},
+	},
+	[FFA_ID_TO_ERRMAP_ID(FFA_RXTX_UNMAP)] = {
+		{
+			[NOT_SUPPORTED] =
+			"NOT_SUPPORTED: FFA_RXTX_UNMAP is not implemented at this FF-A instance",
+			[INVALID_PARAMETERS] =
+			"INVALID_PARAMETERS: No buffer pair registered on behalf of the caller",
+		},
+	},
+	[FFA_ID_TO_ERRMAP_ID(FFA_RX_RELEASE)] = {
+		{
+			[NOT_SUPPORTED] =
+			"NOT_SUPPORTED: FFA_RX_RELEASE is not implemented at this FF-A instance",
+			[DENIED] =
+			"DENIED: Caller did not have ownership of the RX buffer",
+		},
+	},
+	[FFA_ID_TO_ERRMAP_ID(FFA_RXTX_MAP)] = {
+		{
+			[NOT_SUPPORTED] =
+			"NOT_SUPPORTED: This function is not implemented at this FF-A instance",
+			[INVALID_PARAMETERS] =
+			"INVALID_PARAMETERS: Field(s) in input parameters incorrectly encoded",
+			[NO_MEMORY] =
+			"NO_MEMORY: Not enough memory",
+			[DENIED] =
+			"DENIED: Buffer pair already registered",
+		},
+	},
+};
+
+/**
+ * ffa_to_std_errno - convert FF-A error code to standard error code
+ * @ffa_errno:	Error code returned by the FF-A ABI
+ *
+ * This function maps 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
+ */
+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
+ * @ffa_errno:	Error code returned by the FF-A ABI
+ *
+ * This function maps the FF-A error code to the error log relevant to the
+ * selected FF-A ABI. Then the error log is printed.
+ *
+ * Return:
+ *
+ * 0 on success. . Otherwise, failure
+ */
+int ffa_print_error_log(u32 ffa_id, int ffa_errno)
+{
+	int err_idx = -ffa_errno, abi_idx = 0;
+
+	/* map the FF-A error code to the corresponding error log */
+
+	if (err_idx <= 0 || err_idx >= MAX_NUMBER_FFA_ERR)
+		return -EINVAL;
+
+	if (ffa_id < FFA_FIRST_ID || ffa_id > FFA_LAST_ID)
+		return -EINVAL;
+
+	abi_idx = FFA_ID_TO_ERRMAP_ID(ffa_id);
+	if (abi_idx < 0 || abi_idx >= FFA_ERRMAP_COUNT)
+		return -EINVAL;
+
+	if (!err_msg_map[abi_idx].err_str[err_idx])
+		return -EINVAL;
+
+	ffa_err("%s", err_msg_map[abi_idx].err_str[err_idx]);
+
+	return 0;
+}
+
+/*
+ * Driver core functions
+ */
+
+/**
+ * ffa_remove_device - removes the arm_ffa device
+ * @dev:	the device to be removed
+ *
+ * This function makes sure the arm_ffa device is removed
+ * No need to free the kmalloced data when the device is destroyed.
+ * It's automatically done by devm management by
+ * device_remove() -> device_free() -> devres_release_probe().
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int ffa_remove_device(struct udevice *dev)
+{
+	int ret;
+
+	if (!dev) {
+		ffa_err("no udevice found");
+		return -ENODEV;
+	}
+
+	ret = device_remove(dev, DM_REMOVE_NORMAL);
+	if (ret) {
+		ffa_err("unable to remove. err:%d\n", ret);
+		return ret;
+	}
+
+	ffa_info("device removed and freed");
+
+	ret = device_unbind(dev);
+	if (ret) {
+		ffa_err("unable to unbind. err:%d\n", ret);
+		return ret;
+	}
+
+	ffa_info("device unbound");
+
+	return 0;
+}
+
+/**
+ * ffa_device_get - create, bind and probe the arm_ffa device
+ * @pdev: the address of a device pointer (to be filled when the arm_ffa bus device is created
+ *       successfully)
+ *
+ * This function makes sure the arm_ffa device is
+ * created, bound to this driver, probed and ready to use.
+ * Arm FF-A transport is implemented through a single U-Boot
+ * device managing the FF-A bus (arm_ffa).
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int ffa_device_get(struct udevice **pdev)
+{
+	int ret;
+	struct udevice *dev = NULL;
+
+	ret = device_bind(dm_root(), DM_DRIVER_GET(arm_ffa), FFA_DRV_NAME, NULL, ofnode_null(),
+			  &dev);
+	if (ret)
+		return ret;
+
+	/* The FF-A bus discovery succeeds when probing is successful */
+	ret = device_probe(dev);
+	if (ret) {
+		ffa_err("arm_ffa device probing failed");
+		ffa_remove_device(dev);
+		return ret;
+	}
+
+	if (pdev)
+		*pdev = dev;
+
+	return 0;
+}
+
+/**
+ * ffa_get_version - FFA_VERSION handler function
+ *
+ * This function implements FFA_VERSION FF-A function
+ * to get from the secure world the FF-A framework version
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_get_version(void)
+{
+	u16 major, minor;
+	ffa_value_t res = {0};
+	int ffa_errno;
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_32(FFA_VERSION), .a1 = FFA_VERSION_1_0,
+			}, &res);
+
+	ffa_errno = res.a0;
+	if (ffa_errno < 0) {
+		ffa_print_error_log(FFA_VERSION, ffa_errno);
+		return ffa_to_std_errno(ffa_errno);
+	}
+
+	major = GET_FFA_MAJOR_VERSION(res.a0);
+	minor = GET_FFA_MINOR_VERSION(res.a0);
+
+	ffa_info("FF-A driver %d.%d\nFF-A framework %d.%d",
+		 FFA_MAJOR_VERSION, FFA_MINOR_VERSION, major, minor);
+
+	if ((major == FFA_MAJOR_VERSION && minor >= FFA_MINOR_VERSION)) {
+		ffa_info("Versions are compatible ");
+
+		ffa_priv_data->fwk_version = res.a0;
+
+		return 0;
+	}
+
+	ffa_err("versions are incompatible\nExpected: %d.%d , Found: %d.%d\n",
+		FFA_MAJOR_VERSION, FFA_MINOR_VERSION, major, minor);
+
+	return -EPROTONOSUPPORT;
+}
+
+/**
+ * ffa_get_endpoint_id - FFA_ID_GET handler function
+ *
+ * This function implements FFA_ID_GET FF-A function
+ * to get from the secure world u-boot endpoint ID
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_get_endpoint_id(void)
+{
+	ffa_value_t res = {0};
+	int ffa_errno;
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_32(FFA_ID_GET),
+			}, &res);
+
+	if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
+		ffa_priv_data->id = GET_SELF_ENDPOINT_ID((u32)res.a2);
+		ffa_info("endpoint ID is %u", ffa_priv_data->id);
+
+		return 0;
+	}
+
+	ffa_errno = res.a2;
+
+	ffa_print_error_log(FFA_ID_GET, ffa_errno);
+
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * ffa_set_rxtx_buffers_pages_cnt - sets the minimum number of pages in each of the RX/TX buffers
+ * @prop_field: properties field obtained from FFA_FEATURES ABI
+ *
+ * This function sets the minimum number of pages
+ *  in each of the RX/TX buffers in the private data structure
+ *
+ * Return:
+ *
+ * buf_4k_pages points to the returned number of pages
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_set_rxtx_buffers_pages_cnt(u32 prop_field)
+{
+	if (!ffa_priv_data)
+		return -EINVAL;
+
+	switch (prop_field) {
+	case RXTX_4K:
+		ffa_priv_data->pair.rxtx_min_pages = 1;
+		break;
+	case RXTX_16K:
+		ffa_priv_data->pair.rxtx_min_pages = 4;
+		break;
+	case RXTX_64K:
+		ffa_priv_data->pair.rxtx_min_pages = 16;
+		break;
+	default:
+		ffa_err("RX/TX buffer size not supported");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * ffa_get_rxtx_map_features - FFA_FEATURES handler function with FFA_RXTX_MAP argument
+ *
+ * This function implements FFA_FEATURES FF-A function
+ * to retrieve the FFA_RXTX_MAP features
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_get_rxtx_map_features(void)
+{
+	ffa_value_t res = {0};
+	int ffa_errno;
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_32(FFA_FEATURES),
+			.a1 = FFA_SMC_64(FFA_RXTX_MAP),
+			}, &res);
+
+	if (res.a0 == FFA_SMC_32(FFA_SUCCESS))
+		return ffa_set_rxtx_buffers_pages_cnt(res.a2);
+
+	ffa_errno = res.a2;
+	ffa_print_error_log(FFA_FEATURES, ffa_errno);
+
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * ffa_free_rxtx_buffers - frees the RX/TX buffers
+ *
+ * This  function  frees the RX/TX buffers
+ *
+ */
+static void ffa_free_rxtx_buffers(void)
+{
+	ffa_info("Freeing RX/TX buffers");
+
+	if (ffa_priv_data->pair.rxbuf) {
+		free((void *)ffa_priv_data->pair.rxbuf);
+		ffa_priv_data->pair.rxbuf = 0;
+	}
+
+	if (ffa_priv_data->pair.txbuf) {
+		free((void *)ffa_priv_data->pair.txbuf);
+		ffa_priv_data->pair.txbuf = 0;
+	}
+}
+
+/**
+ * ffa_alloc_rxtx_buffers - allocates the RX/TX buffers
+ *
+ * This function is used by ffa_map_rxtx_buffers to allocate
+ * the RX/TX buffers before mapping them. The allocated memory is physically
+ * contiguous since memalign ends up calling malloc which allocates
+ * contiguous memory in u-boot.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_alloc_rxtx_buffers(void)
+{
+	u64 bytes;
+
+	ffa_info("Using %lu 4KB page(s) for RX/TX buffers size",
+		 ffa_priv_data->pair.rxtx_min_pages);
+
+	bytes = ffa_priv_data->pair.rxtx_min_pages * SZ_4K;
+
+	/*
+	 * The alignment of the RX and TX buffers must be equal
+	 * to the larger translation granule size
+	 */
+
+	ffa_priv_data->pair.rxbuf = (u64)memalign(bytes, bytes);
+	if (!ffa_priv_data->pair.rxbuf) {
+		ffa_err("failure to allocate RX buffer");
+		return -ENOBUFS;
+	}
+
+	ffa_info("RX buffer at virtual address 0x%llx", ffa_priv_data->pair.rxbuf);
+
+	ffa_priv_data->pair.txbuf = (u64)memalign(bytes, bytes);
+	if (!ffa_priv_data->pair.txbuf) {
+		free((void *)ffa_priv_data->pair.rxbuf);
+		ffa_priv_data->pair.rxbuf = 0;
+		ffa_err("failure to allocate the TX buffer");
+		return -ENOBUFS;
+	}
+
+	ffa_info("TX buffer at virtual address 0x%llx", ffa_priv_data->pair.txbuf);
+
+	/*
+	 * make sure the buffers are cleared before use
+	 */
+	memset((void *)ffa_priv_data->pair.rxbuf, 0, bytes);
+	memset((void *)ffa_priv_data->pair.txbuf, 0, bytes);
+
+	return 0;
+}
+
+/**
+ * ffa_map_rxtx_buffers - FFA_RXTX_MAP handler function
+ *
+ * This function implements FFA_RXTX_MAP FF-A function
+ * to map the RX/TX buffers
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_map_rxtx_buffers(void)
+{
+	int ret;
+	ffa_value_t res = {0};
+	int ffa_errno;
+
+	ret = ffa_alloc_rxtx_buffers();
+	if (ret)
+		return ret;
+
+	/*
+	 * we need to pass the physical addresses of the RX/TX buffers
+	 * in u-boot physical/virtual mapping is 1:1
+	 * no need to convert from virtual to physical
+	 */
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_64(FFA_RXTX_MAP),
+			.a1 = ffa_priv_data->pair.txbuf,
+			.a2 = ffa_priv_data->pair.rxbuf,
+			.a3 = ffa_priv_data->pair.rxtx_min_pages,
+			}, &res);
+
+	if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
+		ffa_info("RX/TX buffers mapped");
+		return 0;
+	}
+
+	ffa_errno = res.a2;
+	ffa_print_error_log(FFA_RXTX_MAP, ffa_errno);
+
+	ffa_free_rxtx_buffers();
+
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * ffa_unmap_rxtx_buffers - FFA_RXTX_UNMAP handler function
+ *	@dev: The arm_ffa bus device
+ *
+ * This function implements FFA_RXTX_UNMAP FF-A function
+ * to unmap the RX/TX buffers
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_unmap_rxtx_buffers(struct udevice *dev)
+{
+	ffa_value_t res = {0};
+	int ffa_errno;
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_32(FFA_RXTX_UNMAP),
+			.a1 = PREP_SELF_ENDPOINT_ID(ffa_priv_data->id),
+			}, &res);
+
+	if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
+		ffa_free_rxtx_buffers();
+		return 0;
+	}
+
+	ffa_errno = res.a2;
+	ffa_print_error_log(FFA_RXTX_UNMAP, ffa_errno);
+
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * ffa_release_rx_buffer - FFA_RX_RELEASE handler function
+ *
+ * This function invokes FFA_RX_RELEASE FF-A function
+ * to release the ownership of the RX buffer
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_release_rx_buffer(void)
+{
+	ffa_value_t res = {0};
+	int ffa_errno;
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_32(FFA_RX_RELEASE),
+			}, &res);
+
+	if (res.a0 == FFA_SMC_32(FFA_SUCCESS))
+		return 0;
+
+	ffa_errno = res.a2;
+	ffa_print_error_log(FFA_RX_RELEASE, ffa_errno);
+
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * ffa_uuid_are_identical - checks whether two given UUIDs are identical
+ * @uuid1: first UUID
+ * @uuid2: second UUID
+ *
+ * This function is used by ffa_read_partitions_info to search
+ * for a UUID in the partitions descriptors table
+ *
+ * Return:
+ *
+ * 1 when UUIDs match. Otherwise, 0
+ */
+bool ffa_uuid_are_identical(const struct ffa_partition_uuid *uuid1,
+			    const struct ffa_partition_uuid *uuid2)
+{
+	if (!uuid1 || !uuid2)
+		return 0;
+
+	return !memcmp(uuid1, uuid2, sizeof(struct ffa_partition_uuid));
+}
+
+/**
+ * ffa_read_partitions_info - reads the data queried by FFA_PARTITION_INFO_GET
+ *							and saves it in the private structure
+ * @count: The number of partitions queried
+ * @part_uuid: Pointer to the partition(s) UUID
+ *
+ * This function reads the partitions information
+ * returned by the FFA_PARTITION_INFO_GET and saves it in the private
+ * data structure.
+ *
+ * Return:
+ *
+ * The private data structure is updated with the partition(s) information
+ * 0 is returned on success. Otherwise, failure
+ */
+static int ffa_read_partitions_info(u32 count, struct ffa_partition_uuid *part_uuid)
+{
+	if (!count) {
+		ffa_err("no partition detected");
+		return -ENODATA;
+	}
+
+	ffa_info("Reading partitions data from the RX buffer");
+
+	if (!part_uuid) {
+		/*
+		 * querying information of all partitions
+		 */
+		u64 buf_bytes;
+		u64 data_bytes;
+		u32 desc_idx;
+		struct ffa_partition_info *parts_info;
+
+		data_bytes = count * sizeof(struct ffa_partition_desc);
+
+		buf_bytes = ffa_priv_data->pair.rxtx_min_pages * SZ_4K;
+
+		if (data_bytes > buf_bytes) {
+			ffa_err("partitions data size exceeds the RX buffer size:");
+			ffa_err("    sizes in bytes: data %llu , RX buffer %llu ",
+				data_bytes,
+				buf_bytes);
+
+			return -ENOMEM;
+		}
+
+		ffa_priv_data->partitions.descs = devm_kmalloc(ffa_priv_data->dev, data_bytes,
+							       __GFP_ZERO);
+		if (!ffa_priv_data->partitions.descs) {
+			ffa_err("cannot  allocate partitions data buffer");
+			return -ENOMEM;
+		}
+
+		parts_info = (struct ffa_partition_info *)ffa_priv_data->pair.rxbuf;
+
+		for (desc_idx = 0 ; desc_idx < count ; desc_idx++) {
+			ffa_priv_data->partitions.descs[desc_idx].info =
+				parts_info[desc_idx];
+
+			ffa_info("Partition ID %x : info cached",
+				 ffa_priv_data->partitions.descs[desc_idx].info.id);
+		}
+
+		ffa_priv_data->partitions.count = count;
+
+		ffa_info("%d partition(s) found and cached", count);
+
+	} else {
+		u32 rx_desc_idx, cached_desc_idx;
+		struct ffa_partition_info *parts_info;
+		u8 desc_found;
+
+		parts_info = (struct ffa_partition_info *)ffa_priv_data->pair.rxbuf;
+
+		/*
+		 * search for the SP IDs read from the RX buffer
+		 * in the already cached SPs.
+		 * Update the UUID when ID found.
+		 */
+		for (rx_desc_idx = 0; rx_desc_idx < count ; rx_desc_idx++) {
+			desc_found = 0;
+
+			/*
+			 * search the current ID in the cached partitions
+			 */
+			for (cached_desc_idx = 0;
+			     cached_desc_idx < ffa_priv_data->partitions.count;
+			     cached_desc_idx++) {
+				/*
+				 * save the UUID
+				 */
+				if (ffa_priv_data->partitions.descs[cached_desc_idx].info.id ==
+				    parts_info[rx_desc_idx].id) {
+					ffa_priv_data->partitions.descs[cached_desc_idx].sp_uuid =
+						*part_uuid;
+
+					desc_found = 1;
+					break;
+				}
+			}
+
+			if (!desc_found)
+				return -ENODATA;
+		}
+	}
+
+	return  0;
+}
+
+/**
+ * ffa_query_partitions_info - invokes FFA_PARTITION_INFO_GET and saves partitions data
+ *
+ * @part_uuid: Pointer to the partition(s) UUID
+ * @pcount: Pointer to the number of partitions variable filled when querying
+ *
+ * This function executes the FFA_PARTITION_INFO_GET
+ * to query the partitions data. Then, it calls ffa_read_partitions_info
+ * to save the data in the private data structure.
+ *
+ * After reading the data the RX buffer is released using ffa_release_rx_buffer
+ *
+ * Return:
+ *
+ * When part_uuid is NULL, all partitions data are retrieved from secure world
+ * When part_uuid is non NULL, data for partitions matching the given UUID are
+ * retrieved and the number of partitions is returned
+ * 0 is returned on success. Otherwise, failure
+ */
+static int ffa_query_partitions_info(struct ffa_partition_uuid *part_uuid,
+				     u32 *pcount)
+{
+	struct ffa_partition_uuid query_uuid = {0};
+	ffa_value_t res = {0};
+	int ffa_errno;
+
+	/*
+	 * If a UUID is specified. Information for one or more
+	 * partitions in the system is queried. Otherwise, information
+	 * for all installed partitions is queried
+	 */
+
+	if (part_uuid) {
+		if (!pcount)
+			return -EINVAL;
+
+		query_uuid = *part_uuid;
+	} else if (pcount) {
+		return -EINVAL;
+	}
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_32(FFA_PARTITION_INFO_GET),
+			.a1 = query_uuid.a1,
+			.a2 = query_uuid.a2,
+			.a3 = query_uuid.a3,
+			.a4 = query_uuid.a4,
+			}, &res);
+
+	if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
+		int ret;
+
+		/*
+		 * res.a2 contains the count of partition information descriptors
+		 * populated in the RX buffer
+		 */
+		if (res.a2) {
+			ret = ffa_read_partitions_info((u32)res.a2, part_uuid);
+			if (ret) {
+				ffa_err("failed to read partition(s) data , error (%d)", ret);
+				ffa_release_rx_buffer();
+				return -EINVAL;
+			}
+		}
+
+		/*
+		 * return the SP count (when querying using a UUID)
+		 */
+		if (pcount)
+			*pcount = (u32)res.a2;
+
+		/*
+		 * After calling FFA_PARTITION_INFO_GET the buffer ownership
+		 * is assigned to the consumer (u-boot). So, we need to give
+		 * the ownership back to the SPM or hypervisor
+		 */
+		ret = ffa_release_rx_buffer();
+
+		return ret;
+	}
+
+	ffa_errno = res.a2;
+	ffa_print_error_log(FFA_PARTITION_INFO_GET, ffa_errno);
+
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * ffa_get_partitions_info - FFA_PARTITION_INFO_GET handler function
+ *
+ * The passed arguments:
+ * Mode 1: When getting from the driver the number of
+ *	secure partitions:
+ *	@uuid_str: pointer to the UUID string
+ *	@sp_count: pointer to the variable that contains the number of partitions
+ *			 The variable will be set by the driver
+ *	@buffer: NULL
+ *
+ * Mode 2: When requesting the driver to return the
+ *	partitions information:
+ *	@dev: The arm_ffa bus device
+ *	@uuid_str: pointer to the UUID string
+ *	@sp_count: pointer to the variable that contains the number of empty partition descriptors
+ *			 The variable will be read by the driver
+ *	@buffer: pointer to SPs information buffer
+ *		(allocated by the client and contains empty @sp_count descriptors).
+ *		The buffer will be filled by the driver
+ *
+ * This function queries the secure partition data from
+ * the private data structure. If not found, it invokes FFA_PARTITION_INFO_GET
+ * FF-A function to query the partition information from secure world.
+ *
+ * A client of the FF-A driver should know the UUID of the service it wants to
+ * access. It should use the UUID to request the FF-A driver to provide the
+ * partition(s) information of the service. The FF-A driver uses
+ * PARTITION_INFO_GET to obtain this information. This is implemented through
+ * ffa_get_partitions_info function.
+ * A new FFA_PARTITION_INFO_GET call is issued (first one performed through
+ * ffa_cache_partitions_info) allowing to retrieve the partition(s) information.
+ * They are not saved (already done). We only update the UUID in the cached area.
+ * This assumes that partitions data does not change in the secure world.
+ * Otherwise u-boot will have an outdated partition data. The benefit of caching
+ * the information in the FF-A driver is to accommodate discovery after
+ * ExitBootServices().
+ *
+ * When invoked through a client request, ffa_get_partitions_info should be
+ * called twice. First call is to get from the driver the number of secure
+ * partitions (SPs) associated to a particular UUID.
+ * Then, the caller (client) allocates the buffer to host the SPs data and
+ * issues a 2nd call. Then, the driver fills the SPs data in the pre-allocated
+ * buffer.
+ *
+ * To achieve the mechanism described above, ffa_get_partitions_info uses the
+ * following functions:
+ *		ffa_read_partitions_info
+ *		ffa_query_partitions_info
+ *
+ * Return:
+ *
+ * @sp_count: When pointing to the number of partitions variable, the number is
+ * set by the driver.
+ * When pointing to the partitions information buffer size, the buffer will be
+ * filled by the driver.
+ *
+ * On success 0 is returned. Otherwise, failure
+ */
+static int ffa_get_partitions_info(struct udevice *dev, const char *uuid_str,
+				   u32 *sp_count, struct ffa_partition_info *buffer)
+{
+	/*
+	 * fill_data:
+	 * 0: return the SP count
+	 * 1: fill SP data and return it to the caller
+	 */
+	bool fill_data = 0;
+	u32 desc_idx, client_desc_idx;
+	struct ffa_partition_uuid part_uuid = {0};
+	u32 sp_found = 0;
+
+	if (!ffa_priv_data->partitions.count || !ffa_priv_data->partitions.descs) {
+		ffa_err("no partition installed");
+		return -EINVAL;
+	}
+
+	if (!uuid_str) {
+		ffa_err("no UUID provided");
+		return -EINVAL;
+	}
+
+	if (!sp_count) {
+		ffa_err("no size/count provided");
+		return -EINVAL;
+	}
+
+	if (uuid_str_to_le_bin(uuid_str, (unsigned char *)&part_uuid)) {
+		ffa_err("invalid UUID");
+		return -EINVAL;
+	}
+
+	if (!buffer) {
+		/* Mode 1: getting the number of secure partitions */
+
+		fill_data = 0;
+
+		ffa_info("Preparing for checking partitions count");
+
+	} else if (*sp_count) {
+		/* Mode 2: retrieving the partitions information */
+
+		fill_data = 1;
+
+		client_desc_idx = 0;
+
+		ffa_info("Preparing for filling partitions info");
+
+	} else {
+		ffa_err("invalid function arguments provided");
+		return -EINVAL;
+	}
+
+	ffa_info("Searching partitions using the provided UUID");
+
+	/*
+	 * search in the cached partitions
+	 */
+	for (desc_idx = 0;
+	     desc_idx < ffa_priv_data->partitions.count;
+	     desc_idx++) {
+		if (ffa_uuid_are_identical(&ffa_priv_data->partitions.descs[desc_idx].sp_uuid,
+					   &part_uuid)) {
+			ffa_info("Partition ID %x matches the provided UUID",
+				 ffa_priv_data->partitions.descs[desc_idx].info.id);
+
+			sp_found++;
+
+			if (fill_data) {
+				/*
+				 * trying to fill the partition info in the input buffer
+				 */
+
+				if (client_desc_idx < *sp_count) {
+					buffer[client_desc_idx++] =
+						ffa_priv_data->partitions.descs[desc_idx].info;
+					continue;
+				}
+
+				ffa_err("failed to fill the current descriptor client buffer full");
+				return -ENOBUFS;
+			}
+		}
+	}
+
+	if (!sp_found) {
+		int ret;
+
+		ffa_info("No partition found. Querying framework ...");
+
+		ret = ffa_query_partitions_info(&part_uuid, &sp_found);
+
+		if (ret == 0) {
+			if (!fill_data) {
+				*sp_count = sp_found;
+
+				ffa_info("Number of partition(s) found matching the UUID: %d",
+					 sp_found);
+			} else {
+				/*
+				 * If SPs data detected, they are already in the private data
+				 * structure, retry searching SP data again to return them
+				 *  to the caller
+				 */
+				if (sp_found)
+					ret = ffa_get_partitions_info(dev, uuid_str, sp_count,
+								      buffer);
+				else
+					ret = -ENODATA;
+			}
+		}
+
+		return ret;
+	}
+
+	/* partition(s) found */
+	if (!fill_data)
+		*sp_count = sp_found;
+
+	return 0;
+}
+
+/**
+ * ffa_cache_partitions_info - Queries and saves all secure partitions data
+ *
+ * This function invokes FFA_PARTITION_INFO_GET FF-A
+ * function to query from secure world all partitions information.
+ *
+ * The FFA_PARTITION_INFO_GET call is issued with nil UUID as an argument.
+ * All installed partitions information are returned. We cache them in the
+ * resident private data structure and we keep the UUID field empty
+ * (in FF-A 1.0 UUID is not provided by the partition descriptor)
+ *
+ * This function is called at the device probing level.
+ * ffa_cache_partitions_info uses ffa_query_partitions_info to get the data
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_cache_partitions_info(void)
+{
+	return ffa_query_partitions_info(NULL, NULL);
+}
+
+/**
+ * ffa_msg_send_direct_req - FFA_MSG_SEND_DIRECT_{REQ,RESP} handler function
+ * @dev: The arm_ffa bus device
+ * @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 implements 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, failure
+ */
+static int ffa_msg_send_direct_req(struct udevice *dev, u16 dst_part_id,
+				   struct ffa_send_direct_data *msg, bool is_smc64)
+{
+	ffa_value_t res = {0};
+	int ffa_errno;
+	u64 req_mode, resp_mode;
+
+	if (!ffa_priv_data || !ffa_priv_data->invoke_ffa_fn)
+		return -EINVAL;
+
+	/* No partition installed */
+	if (!ffa_priv_data->partitions.count || !ffa_priv_data->partitions.descs)
+		return -ENODEV;
+
+	if (is_smc64) {
+		req_mode = FFA_SMC_64(FFA_MSG_SEND_DIRECT_REQ);
+		resp_mode = FFA_SMC_64(FFA_MSG_SEND_DIRECT_RESP);
+	} else {
+		req_mode = FFA_SMC_32(FFA_MSG_SEND_DIRECT_REQ);
+		resp_mode = FFA_SMC_32(FFA_MSG_SEND_DIRECT_RESP);
+	}
+
+	ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = req_mode,
+			.a1 = PREP_SELF_ENDPOINT_ID(ffa_priv_data->id) |
+				PREP_PART_ENDPOINT_ID(dst_part_id),
+			.a2 = 0,
+			.a3 = msg->data0,
+			.a4 = msg->data1,
+			.a5 = msg->data2,
+			.a6 = msg->data3,
+			.a7 = msg->data4,
+			}, &res);
+
+	while (res.a0 == FFA_SMC_32(FFA_INTERRUPT))
+		ffa_priv_data->invoke_ffa_fn((ffa_value_t){
+			.a0 = FFA_SMC_32(FFA_RUN),
+			.a1 = res.a1,
+			}, &res);
+
+	if (res.a0 == FFA_SMC_32(FFA_SUCCESS)) {
+		/* Message sent with no response */
+		return 0;
+	}
+
+	if (res.a0 == resp_mode) {
+		/*
+		 * Message sent with response
+		 * extract the return data
+		 */
+		msg->data0 = res.a3;
+		msg->data1 = res.a4;
+		msg->data2 = res.a5;
+		msg->data3 = res.a6;
+		msg->data4 = res.a7;
+
+		return 0;
+	}
+
+	ffa_errno = res.a2;
+	return ffa_to_std_errno(ffa_errno);
+}
+
+/**
+ * __arm_ffa_fn_smc - 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 low level SMC assembly function
+ *
+ * Return: void
+ */
+void __arm_ffa_fn_smc(ffa_value_t args, ffa_value_t *res)
+{
+	arm_smccc_1_2_smc(&args, res);
+}
+
+/**
+ * ffa_set_smc_conduit - Set the SMC conduit
+ *
+ * This function selects the SMC conduit by setting the driver invoke function
+ * to SMC assembly function
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_set_smc_conduit(void)
+{
+	ffa_priv_data->invoke_ffa_fn = __arm_ffa_fn_smc;
+
+	if (!ffa_priv_data->invoke_ffa_fn) {
+		ffa_err("failure to set the invoke function");
+		return -EINVAL;
+	}
+
+	ffa_info("Conduit is SMC");
+
+	return 0;
+}
+
+/**
+ * ffa_set_bus_ops - Set the bus driver operations
+ *
+ * Setting the driver callbacks.
+ *
+ */
+static void ffa_set_bus_ops(void)
+{
+	ffa_priv_data->ffa_ops.partition_info_get = ffa_get_partitions_info;
+	ffa_priv_data->ffa_ops.sync_send_receive = ffa_msg_send_direct_req;
+	ffa_priv_data->ffa_ops.rxtx_unmap = ffa_unmap_rxtx_buffers;
+}
+
+/**
+ * ffa_alloc_prvdata - allocate the driver main data structure and sets the device
+ * @dev:	the arm_ffa device
+ *
+ * This function creates the main data structure embedding all the driver data.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_alloc_prvdata(struct udevice *dev)
+{
+	if (!dev) {
+		ffa_err("no udevice found");
+		return -ENODEV;
+	}
+
+	/* The device is registered with the DM. Let's create the driver main data structure*/
+
+	ffa_priv_data = devm_kmalloc(dev, sizeof(struct ffa_prvdata), __GFP_ZERO);
+	if (!ffa_priv_data) {
+		ffa_err("can not allocate the driver main data structure");
+		return -ENOMEM;
+	}
+
+	ffa_priv_data->dev = dev;
+
+	return 0;
+}
+
+/**
+ * ffa_probe - The driver probe function
+ * @dev:	the arm_ffa device
+ *
+ * Probing is done at boot time and triggered by the uclass device discovery.
+ * At probe level the following actions are done:
+ *	- setting the conduit
+ *	- querying the FF-A framework version
+ *	- querying from secure world the u-boot endpoint ID
+ *	- querying from secure world the supported features of FFA_RXTX_MAP
+ *	- mapping the RX/TX buffers
+ *	- querying from secure world all the partitions information
+ *
+ * All data queried from secure world is saved in the resident private data structure.
+ *
+ * The probe will fail if either FF-A framework is not detected or the
+ * FF-A requests are not behaving correctly. This ensures that the
+ * driver is not installed and its operations are not exported to the clients.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+static int ffa_probe(struct udevice *dev)
+{
+	int ret;
+
+	ret = ffa_alloc_prvdata(dev);
+	if (ret != 0)
+		return ret;
+
+	ffa_set_bus_ops();
+
+	ret = ffa_set_smc_conduit();
+	if (ret != 0)
+		return ret;
+
+	ret = ffa_get_version();
+	if (ret != 0)
+		return ret;
+
+	ret = ffa_get_endpoint_id();
+	if (ret != 0)
+		return ret;
+
+	ret = ffa_get_rxtx_map_features();
+	if (ret != 0)
+		return ret;
+
+	ret = ffa_map_rxtx_buffers();
+	if (ret != 0)
+		return ret;
+
+	ret = ffa_cache_partitions_info();
+	if (ret != 0) {
+		ffa_free_rxtx_buffers();
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * ffa_remove - The driver remove function
+ * @dev:	the arm_ffa device
+ * When the device is about to be removed ,  unmap the RX/TX buffers and free the memory
+ * Return:
+ *
+ * 0 on success.
+ */
+static int ffa_remove(struct udevice *dev)
+{
+	ffa_info("removing the device");
+
+	ffa_unmap_rxtx_buffers(dev);
+
+	if (ffa_priv_data->pair.rxbuf || ffa_priv_data->pair.txbuf)
+		ffa_free_rxtx_buffers();
+
+	return 0;
+}
+
+/**
+ * ffa_unbind - The driver unbind function
+ * @dev:	the arm_ffa device
+ * After the device is removed and memory freed the device is unbound
+ * Return:
+ *
+ * 0 on success.
+ */
+static int ffa_unbind(struct udevice *dev)
+{
+	ffa_info("unbinding the device , private data already released");
+
+	ffa_priv_data = NULL;
+
+	return 0;
+}
+
+/**
+ * ffa_bus_ops_get - bus driver operations getter
+ *
+ * Return:
+ * This function returns a pointer to the driver operations structure
+ */
+const struct ffa_bus_ops *ffa_bus_ops_get(void)
+{
+	return &ffa_priv_data->ffa_ops;
+}
+
+/**
+ * ffa_bus_prvdata_get - bus driver private data getter
+ *
+ * Return:
+ * This function returns a pointer to the main private data structure
+ */
+struct ffa_prvdata *ffa_bus_prvdata_get(void)
+{
+	return ffa_priv_data;
+}
+
+/**
+ * ffa_bus_discover - discover FF-A bus and probe arm_ffa device
+ * @pdev: the address of a device pointer (to be filled when the arm_ffa bus device is created
+ *       successfully)
+ *
+ * This function makes sure the FF-A bus is discoverable.
+ * When probing succeeds FF-A discovery is done. The arm_ffa device is ready to use.
+ *
+ * When the bus was already discovered successfully the discovery will not run again.
+ *
+ * Arm FF-A transport is implemented through arm_ffa u-boot device managing the FF-A
+ * communication.
+ * All FF-A clients should use the arm_ffa device to use the FF-A transport.
+ *
+ * Return:
+ *
+ * 0 on success. Otherwise, failure
+ */
+int ffa_bus_discover(struct udevice **pdev)
+{
+	int ret = 0;
+
+	if (!ffa_priv_data) {
+		ret = ffa_device_get(pdev);
+
+	return ret;
+}
+
+/**
+ * Declaring the arm_ffa driver under UCLASS_FFA
+ */
+
+U_BOOT_DRIVER(arm_ffa) = {
+	.name		= FFA_DRV_NAME,
+	.id		= UCLASS_FFA,
+	.probe		= ffa_probe,
+	.remove		= ffa_remove,
+	.unbind		= ffa_unbind,
+};
diff --git a/include/arm_ffa.h b/include/arm_ffa.h
new file mode 100644
index 0000000000..74b16174c2
--- /dev/null
+++ b/include/arm_ffa.h
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2022 ARM Limited
+ * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
+ */
+
+#ifndef __ARM_FFA_H
+#define __ARM_FFA_H
+
+#include <linux/printk.h>
+
+/*
+ * This header is public. It can be used by clients to access
+ * data structures and definitions they need
+ */
+
+/*
+ * Macros for displaying logs
+ */
+
+#define ffa_info(fmt, ...)  pr_info("[FFA] " fmt "\n", ##__VA_ARGS__)
+#define ffa_err(fmt, ...)  pr_err("[FFA] " fmt "\n", ##__VA_ARGS__)
+
+/*
+ * struct ffa_partition_info - Partition information descriptor
+ * @id:	Partition ID
+ * @exec_ctxt:	Execution context count
+ * @properties:	Partition properties
+ *
+ * Data structure containing information about partitions instantiated in the system
+ * This structure is filled with the data queried by FFA_PARTITION_INFO_GET
+ */
+struct ffa_partition_info {
+	u16 id;
+	u16 exec_ctxt;
+/* partition supports receipt of direct requests */
+#define FFA_PARTITION_DIRECT_RECV	BIT(0)
+/* partition can send direct requests. */
+#define FFA_PARTITION_DIRECT_SEND	BIT(1)
+/* partition can send and receive indirect messages. */
+#define FFA_PARTITION_INDIRECT_MSG	BIT(2)
+	u32 properties;
+};
+
+/*
+ * struct ffa_send_direct_data - Data structure hosting the data
+ *                                       used by FFA_MSG_SEND_DIRECT_{REQ,RESP}
+ * @data0-4:	Data read/written from/to x3-x7 registers
+ *
+ * Data structure containing the data to be sent by FFA_MSG_SEND_DIRECT_REQ
+ * or read from FFA_MSG_SEND_DIRECT_RESP
+ */
+
+/* For use with FFA_MSG_SEND_DIRECT_{REQ,RESP} which pass data via registers */
+struct ffa_send_direct_data {
+	unsigned long data0; /* w3/x3 */
+	unsigned long data1; /* w4/x4 */
+	unsigned long data2; /* w5/x5 */
+	unsigned long data3; /* w6/x6 */
+	unsigned long data4; /* w7/x7 */
+};
+
+struct udevice;
+
+/**
+ * struct ffa_bus_ops - The driver operations structure
+ * @partition_info_get:	callback for the FFA_PARTITION_INFO_GET
+ * @sync_send_receive:	callback for the FFA_MSG_SEND_DIRECT_REQ
+ * @rxtx_unmap:	callback for the FFA_RXTX_UNMAP
+ *
+ * The data structure providing all the operations supported by the driver.
+ * This structure is EFI runtime resident.
+ */
+struct ffa_bus_ops {
+	int (*partition_info_get)(struct udevice *dev, const char *uuid_str,
+				  u32 *sp_count, struct ffa_partition_info *buffer);
+	int (*sync_send_receive)(struct udevice *dev, u16 dst_part_id,
+				 struct ffa_send_direct_data *msg,
+				 bool is_smc64);
+	int (*rxtx_unmap)(struct udevice *dev);
+};
+
+/**
+ * The device driver and the Uclass driver public functions
+ */
+
+/**
+ * ffa_bus_ops_get - driver operations getter
+ */
+const struct ffa_bus_ops *ffa_bus_ops_get(void);
+
+/**
+ * ffa_bus_discover - discover FF-A bus and probes the arm_ffa device
+ */
+int ffa_bus_discover(struct udevice **pdev);
+
+#endif
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 376f741cc2..fa08a66ac8 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -4,6 +4,9 @@
  *
  * (C) Copyright 2012
  * Pavel Herrmann <morpheus.ibis@gmail.com>
+ *
+ * (C) Copyright 2022 ARM Limited
+ * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
  */
 
 #ifndef _DM_UCLASS_ID_H
@@ -55,6 +58,7 @@ enum uclass_id {
 	UCLASS_EFI_MEDIA,	/* Devices provided by UEFI firmware */
 	UCLASS_ETH,		/* Ethernet device */
 	UCLASS_ETH_PHY,		/* Ethernet PHY device */
+	UCLASS_FFA,		/* Arm Firmware Framework for Armv8-A */
 	UCLASS_FIRMWARE,	/* Firmware */
 	UCLASS_FPGA,		/* FPGA device */
 	UCLASS_FUZZING_ENGINE,	/* Fuzzing engine */
-- 
2.17.1