Re: [PATCH v6 03/10] arm_ffa: introduce Arm FF-A low-level driver

Abdellatif El Khlifi
2022-11-08T11:29:22Z

On Tue, Oct 25, 2022 at 11:31:11AM +0200, Jens Wiklander wrote:
> On Thu, Oct 13, 2022 at 11:38:50AM +0100, Abdellatif El Khlifi wrote:
> > 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.
> >
> > 32-bit version of the ABIs is supported and 64-bit version of FFA_RXTX_MAP
> > and FFA_MSG_SEND_DIRECT_{REQ, RESP}.
> >
> > In u-boot FF-A design, FF-A is considered as a discoverable bus.
>
> U-Boot

All comments in this patch are addressed in v7, thanks.

>
> > 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
> >
> > [1]: https://developer.arm.com/documentation/den0077/latest/
> >
> > 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:
> > ===============
> >
> > 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 | 207 ++++
> > 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 | 196 +++
> > drivers/firmware/arm-ffa/core.c | 1337 +++++++++++++++++++++
> > include/arm_ffa.h | 93 ++
> > include/dm/uclass-id.h | 4 +
> > 12 files changed, 1900 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 a26b36c7c2..496f47a516 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -248,6 +248,13 @@ 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..e98d2cf2b3
> > --- /dev/null
> > +++ b/doc/arch/arm64.ffa.rst
> > @@ -0,0 +1,207 @@
> > +.. 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
> > +
> > +FF-A and SMC specifications
> > +-------------------------------------------
> > +
> > +The current implementation of the driver relies on FF-A specification v1.0
> > +and uses SMC32 calling convention.
> > +
> > +At this stage we only need the FF-A v1.0 features.
> > +
> > +The driver has been tested with Optee OS which supports SMC32 for most of
>
> s/Optee OS/OP-TEE/
>
> > +the SMC ABIs.
> > +
> > +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
>
> U-Boot, please search and replace.
>
> > +-------------------------------------------
> > +
> > +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).
> > +
> > +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
> > +
> > +- 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 a 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
>
> It may be worth mentioning that this is an implementation defined
> command.
>
> > +
> > + 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 792d9182c3..8d1ab0ad4e 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 8b6fead351..b06b1ae481 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 9d9f69a3c9..bf8d7b8cfc 100644
> > --- a/drivers/Makefile
> > +++ b/drivers/Makefile
> > @@ -111,6 +111,7 @@ 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..f1427535f9
> > --- /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.
>
> U-Boot
>
> > + 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/README.ffa.drv
>
> Not 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..7bc90f7f66
> > --- /dev/null
> > +++ b/drivers/firmware/arm-ffa/arm_ffa_prv.h
> > @@ -0,0 +1,196 @@
> > +/* 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*/
> > +};
> > +
> > +/* number of the errors supported by the FF-A specification */
> > +#define MAX_NUMBER_FFA_ERR 9
> > +
> > +/* 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_device_get - create, bind and probe the arm_ffa device
> > + */
> > +int ffa_device_get(void);
> > +
> > +/**
> > + * 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..324367d12b
> > --- /dev/null
> > +++ b/drivers/firmware/arm-ffa/core.c
> > @@ -0,0 +1,1337 @@
> > +// 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] = {
> > + 0,
> > + -EOPNOTSUPP, /* NOT_SUPPORTED */
> > + -EINVAL, /* INVALID_PARAMETERS */
> > + -ENOMEM, /* NO_MEMORY */
> > + -EBUSY, /* BUSY */
> > + -EINTR, /* INTERRUPTED */
> > + -EACCES, /* DENIED */
> > + -EAGAIN, /* RETRY */
> > + -ECANCELED, /* ABORTED */
> > +};
> > +
> > +struct ffa_abi_errmap err_msg_map[FFA_ERRMAP_COUNT] = {
> > + [FFA_ID_TO_ERRMAP_ID(FFA_VERSION)] = {
> > + {
> > + "",
>
> Shouldn't all these empty strings be NULL instead? Given that's that
> what you check for in ffa_print_error_log() below.
>
> You could save a few lines by using designated initializers for only the
> used elements in err_str for each FF-A function ID.
>
> > + "NOT_SUPPORTED: A Firmware Framework implementation does not exist",
> > + "", /* INVALID_PARAMETERS */
> > + "", /* NO_MEMORY */
> > + "", /* BUSY */
> > + "", /* INTERRUPTED */
> > + "", /* DENIED */
> > + "", /* RETRY */
> > + "", /* ABORTED */
> > + },
> > + },
> > + [FFA_ID_TO_ERRMAP_ID(FFA_ID_GET)] = {
> > + {
> > + "",
> > + "NOT_SUPPORTED: This function is not implemented at this FF-A instance",
> > + "", /* INVALID_PARAMETERS */
> > + "", /* NO_MEMORY */
> > + "", /* BUSY */
> > + "", /* INTERRUPTED */
> > + "", /* DENIED */
> > + "", /* RETRY */
> > + "", /* ABORTED */
> > + },
> > + },
> > + [FFA_ID_TO_ERRMAP_ID(FFA_FEATURES)] = {
> > + {
> > + "",
> > + "NOT_SUPPORTED: FFA_RXTX_MAP is not implemented at this FF-A instance",
> > + "", /* INVALID_PARAMETERS */
> > + "", /* NO_MEMORY */
> > + "", /* BUSY */
> > + "", /* INTERRUPTED */
> > + "", /* DENIED */
> > + "", /* RETRY */
> > + "", /* ABORTED */
> > + },
> > + },
> > + [FFA_ID_TO_ERRMAP_ID(FFA_PARTITION_INFO_GET)] = {
> > + {
> > + "",
> > + "NOT_SUPPORTED: This function is not implemented at this FF-A instance",
> > + "INVALID_PARAMETERS: Unrecognized UUID",
> > + "NO_MEMORY: Results cannot fit in RX buffer of the caller",
> > + "BUSY: RX buffer of the caller is not free",
> > + "", /* INTERRUPTED */
> > + "DENIED: Callee is not in a state to handle this request",
> > + "", /* RETRY */
> > + "", /* ABORTED */
> > + },
> > + },
> > + [FFA_ID_TO_ERRMAP_ID(FFA_RXTX_UNMAP)] = {
> > + {
> > + "",
> > + "NOT_SUPPORTED: FFA_RXTX_UNMAP is not implemented at this FF-A instance",
> > + "INVALID_PARAMETERS: No buffer pair registered on behalf of the caller",
> > + "", /* NO_MEMORY */
> > + "", /* BUSY */
> > + "", /* INTERRUPTED */
> > + "", /* DENIED */
> > + "", /* RETRY */
> > + "", /* ABORTED */
> > + },
> > + },
> > + [FFA_ID_TO_ERRMAP_ID(FFA_RX_RELEASE)] = {
> > + {
> > + "",
> > + "NOT_SUPPORTED: FFA_RX_RELEASE is not implemented at this FF-A instance",
> > + "", /* INVALID_PARAMETERS */
> > + "", /* NO_MEMORY */
> > + "", /* BUSY */
> > + "", /* INTERRUPTED */
> > + "DENIED: Caller did not have ownership of the RX buffer",
> > + "", /* RETRY */
> > + "", /* ABORTED */
> > + },
> > + },
> > + [FFA_ID_TO_ERRMAP_ID(FFA_RXTX_MAP)] = {
> > + {
> > + "",
> > + "NOT_SUPPORTED: This function is not implemented at this FF-A instance",
> > + "INVALID_PARAMETERS: Field(s) in input parameters incorrectly encoded",
> > + "NO_MEMORY: Not enough memory",
> > + "", /* BUSY */
> > + "", /* INTERRUPTED */
> > + "DENIED: Buffer pair already registered",
> > + "", /* RETRY */
> > + "", /* ABORTED */
> > + },
> > + },
> > +};
> > +
> > +/**
> > + * 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_msg_map[abi_idx].err_str[err_idx])
>
> err_str can't be NULL since it's an array in the struct ffa_abi_errmap.
>
> > + 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
> > + *
> > + * 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(void)
> > +{
> > + int ret;
> > + struct udevice *dev = NULL;
> > +
> > + ret = device_bind(dm_root(),
> > + DM_DRIVER_GET(arm_ffa),
> > + FFA_DRV_NAME,
> > + NULL,
> > + ofnode_null(),
> > + &dev);
>
> There's no need for separate lines for each argument, please fold up a bit.
>
> > + 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;
> > + }
> > +
> > + 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
>
> It's generally preferred to have comma after the last initializer too.
>
> It could also be worth comparing with the style (alignment and folding
> up where possible) of the corresponding driver in the Linux kernel which
> I find a bit easier to read. However, checkpatch seems happy enough so I
> guess it's not a big deal.
>
> I asked earlier why you're not supporting the latest version, 1.1, but
> you never answered that.
>
> > + }, &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((u32)res.a2);
>
> The cast isn't needed.
>
> > +
> > + 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
>
> A space is missing after the '*'.
>
> > + */
> > +
> > + 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
> > + *
> > + * 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(void)
> > +{
> > + 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
> > + */
> > +int ffa_uuid_are_identical(const struct ffa_partition_uuid *uuid1,
> > + const struct ffa_partition_uuid *uuid2)
>
> Would it make sense to use the bool type instead?
>
> > +{
> > + 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
> > + * @parts_size: 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:
> > + * @uuid_str: pointer to the UUID string
> > + * @parts_size: pointer to the size of the SPs information buffer in bytes
> > + * @buffer: pointer to SPs information buffer
> > + * (allocated by the client).
> > + * 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:
> > + *
> > + * @parts_size: 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(const char *uuid_str,
> > + u32 *parts_size, struct ffa_partition_info *buffer)
> > +{
> > + /*
> > + * fill_data:
> > + * 0: return the SP count
> > + * 1: fill SP data and return it to the caller
> > + * -1: undefined mode
> > + */
> > + int fill_data = -1;
> > + u32 desc_idx, client_desc_idx;
> > + struct ffa_partition_uuid part_uuid = {0};
> > + u32 client_desc_max_cnt;
> > + u32 parts_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 (!parts_size) {
> > + ffa_err("no size/count provided");
> > + return -EINVAL;
> > + }
> > +
> > + if (be_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 ((*parts_size >= sizeof(struct ffa_partition_info)) &&
> > + !(*parts_size % sizeof(struct ffa_partition_info))) {
> > + /* Mode 2: retrieving the partitions information */
> > +
> > + fill_data = 1;
> > +
> > + client_desc_idx = 0;
> > +
> > + /*
> > + * number of empty descriptors preallocated by the caller
> > + */
> > + client_desc_max_cnt = *parts_size / sizeof(struct ffa_partition_info);
> > +
> > + 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);
> > +
> > + parts_found++;
> > +
> > + if (fill_data) {
> > + /*
> > + * trying to fill the partition info in the input buffer
> > + */
> > +
> > + if (client_desc_idx < client_desc_max_cnt) {
> > + 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 (!parts_found) {
> > + int ret;
> > +
> > + ffa_info("No partition found. Querying framework ...");
> > +
> > + ret = ffa_query_partitions_info(&part_uuid, &parts_found);
> > +
> > + if (ret == 0) {
> > + if (!fill_data) {
> > + *parts_size = parts_found;
> > +
> > + ffa_info("Number of partition(s) found matching the UUID: %d",
> > + parts_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 (parts_found)
> > + ret = ffa_get_partitions_info(uuid_str, parts_size, buffer);
> > + else
> > + ret = -ENODATA;
> > + }
> > + }
> > +
> > + return ret;
> > + }
> > +
> > + /* partition(s) found */
> > + if (!fill_data)
> > + *parts_size = parts_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
> > + * @dst_part_id: destination partition ID
> > + * @msg: pointer to the message data preallocated by the client (in/out)
> > + *
> > + * 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(u16 dst_part_id, struct ffa_send_direct_data *msg)
> > +{
> > + ffa_value_t res = {0};
> > + int ffa_errno;
> > +
> > + 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;
> > +
> > + ffa_priv_data->invoke_ffa_fn((ffa_value_t){
> > + .a0 = FFA_SMC_64(FFA_MSG_SEND_DIRECT_REQ),
> > + .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 == FFA_SMC_64(FFA_MSG_SEND_DIRECT_RESP)) {
> > + /*
> > + * 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();
>
> I've asked this before, but never got an answer:
> Why are we saving all the found partitions in a cache? It seems that
> FFA_PARTITION_INFO_GET could be called each time when needed instead
> without any noticeable overhead. Or is the result cached for some other
> reason?
>
> Cheers,
> Jens
>
> > + 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();
> > +
> > + 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 the arm_ffa device
> > + *
> > + * 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(void)
> > +{
> > + int ret = 0;
> > +
> > + if (!ffa_priv_data)
> > + ret = ffa_device_get();
> > +
> > + 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..d146e7b328
> > --- /dev/null
> > +++ b/include/arm_ffa.h
> > @@ -0,0 +1,93 @@
> > +/* 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 __packed 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 __packed 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 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)(const char *uuid_str,
> > + u32 *parts_size, struct ffa_partition_info *buffer);
> > + int (*sync_send_receive)(u16 dst_part_id, struct ffa_send_direct_data *msg);
> > + int (*rxtx_unmap)(void);
> > +};
> > +
> > +/**
> > + * 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(void);
> > +
> > +#endif
> > diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> > index a432e43871..5dd698b7a9 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_FUZZING_ENGINE, /* Fuzzing engine */
> > UCLASS_FS_FIRMWARE_LOADER, /* Generic loader */
> > --
> > 2.17.1
> >