Re: [PATCH v2 1/6] arm_ffa: introduce Arm FF-A low-level driver

Abdellatif El Khlifi
2022-09-26T11:30:48Z

On Fri, May 13, 2022 at 04:40:36PM +0200, Jens Wiklander wrote:
> On Fri, Apr 15, 2022 at 01:27:58PM +0100, abdellatif.elkhlifi@arm.com wrote:
> > From: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> >
> > Add the driver implementing Arm Firmware Framework for Armv8-A v1.0
> >
> > 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 uses SMC32 calling convention.
>
> How come only the SMC32 calling convention is used? What if you need
> 64-bit pointers for some reason (RXTX_MAP comes to mind) ? Doing the
> 64-bit calling convention at the same time can't be much more work.

Thanks for the feedback. SMC64 support has been added in v3 patchset.
Please refer to the latest work provided by v4:
https://lore.kernel.org/all/20220926101723.9965-2-abdellatif.elkhlifi@arm.com/

>
> >
> > 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 provides helper FF-A interfaces for user layers.
> > These helper functions allow clients to pass data and select the
> > FF-A function to use for the communication with secure world.
> >
> > Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > ---
> > MAINTAINERS | 8 +
> > arch/arm/cpu/armv8/smccc-call.S | 27 +
> > arch/arm/lib/asm-offsets.c | 6 +
> > common/board_r.c | 7 +
> > drivers/Kconfig | 2 +
> > drivers/Makefile | 1 +
> > drivers/arm-ffa/Kconfig | 27 +
> > drivers/arm-ffa/Makefile | 6 +
> > drivers/arm-ffa/arm-ffa-uclass.c | 64 ++
> > drivers/arm-ffa/arm_ffa_prv.h | 193 +++++
> > drivers/arm-ffa/core.c | 1349 ++++++++++++++++++++++++++++++
> > include/arm_ffa.h | 190 +++++
> > include/arm_ffa_helper.h | 45 +
> > include/dm/uclass-id.h | 1 +
> > include/linux/arm-smccc.h | 28 +-
> > lib/Kconfig | 1 +
> > lib/Makefile | 1 +
> > lib/arm-ffa/Kconfig | 6 +
> > lib/arm-ffa/Makefile | 8 +
> > lib/arm-ffa/arm_ffa_helper.c | 188 +++++
> > lib/efi_loader/efi_boottime.c | 17 +
> > 21 files changed, 2174 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/arm-ffa/Kconfig
> > create mode 100644 drivers/arm-ffa/Makefile
> > create mode 100644 drivers/arm-ffa/arm-ffa-uclass.c
> > create mode 100644 drivers/arm-ffa/arm_ffa_prv.h
> > create mode 100644 drivers/arm-ffa/core.c
> > create mode 100644 include/arm_ffa.h
> > create mode 100644 include/arm_ffa_helper.h
> > create mode 100644 lib/arm-ffa/Kconfig
> > create mode 100644 lib/arm-ffa/Makefile
> > create mode 100644 lib/arm-ffa/arm_ffa_helper.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index aca97cd2a3..efa17206b8 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -232,6 +232,14 @@ F: board/CZ.NIC/
> > F: configs/turris_*_defconfig
> > F: include/configs/turris_*.h
> >
> > +ARM FF-A
> > +M: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > +S: Maintained
> > +F: drivers/arm-ffa/
> > +F: include/arm_ffa.h
> > +F: include/arm_ffa_helper.h
> > +F: lib/arm-ffa/
> > +
> > ARM FREESCALE IMX
> > M: Stefano Babic <sbabic@denx.de>
> > M: Fabio Estevam <festevam@gmail.com>
> > diff --git a/arch/arm/cpu/armv8/smccc-call.S b/arch/arm/cpu/armv8/smccc-call.S
> > index dc92b28777..9a6aebf194 100644
> > --- a/arch/arm/cpu/armv8/smccc-call.S
> > +++ b/arch/arm/cpu/armv8/smccc-call.S
> > @@ -1,6 +1,8 @@
> > /* SPDX-License-Identifier: GPL-2.0 */
> > /*
> > * Copyright (c) 2015, Linaro Limited
> > + * (C) Copyright 2022 ARM Limited
> > + * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > */
> > #include <linux/linkage.h>
> > #include <linux/arm-smccc.h>
> > @@ -45,3 +47,28 @@ ENDPROC(__arm_smccc_smc)
> > ENTRY(__arm_smccc_hvc)
> > SMCCC hvc
> > ENDPROC(__arm_smccc_hvc)
> > +
> > +#if (IS_ENABLED(CONFIG_ARM_FFA_TRANSPORT))
> > +
> > + .macro FFASMCCC instr
> > + .cfi_startproc
> > + \instr #0
> > + ldr x9, [sp]
> > + stp x0, x1, [x9, #ARM_SMCCC_RES_X0_OFFS]
> > + stp x2, x3, [x9, #ARM_SMCCC_RES_X2_OFFS]
> > + stp x4, x5, [x9, #ARM_SMCCC_RES_X4_OFFS]
> > + stp x6, x7, [x9, #ARM_SMCCC_RES_X6_OFFS]
> > + ret
> > + .cfi_endproc
> > + .endm
> > +
> > +/*
> > + * void arm_ffa_smccc_smc(unsigned long a0, unsigned long a1, unsigned long a2,
> > + * unsigned long a3, unsigned long a4, unsigned long a5,
> > + * unsigned long a6, unsigned long a7, struct arm_smccc_res *res)
> > + */
> > +ENTRY(__arm_ffa_smccc_smc)
> > + FFASMCCC smc
> > +ENDPROC(__arm_ffa_smccc_smc)
> > +
> > +#endif
> > diff --git a/arch/arm/lib/asm-offsets.c b/arch/arm/lib/asm-offsets.c
> > index 22fd541f9a..02a4a42fe6 100644
> > --- a/arch/arm/lib/asm-offsets.c
> > +++ b/arch/arm/lib/asm-offsets.c
> > @@ -9,6 +9,8 @@
> > * generate asm statements containing #defines,
> > * compile this file to assembler, and then extract the
> > * #defines from the assembly-language output.
> > + *
> > + * (C) Copyright 2022 ARM Limited
> > */
> >
> > #include <common.h>
> > @@ -115,6 +117,10 @@ int main(void)
> > #ifdef CONFIG_ARM_SMCCC
> > DEFINE(ARM_SMCCC_RES_X0_OFFS, offsetof(struct arm_smccc_res, a0));
> > DEFINE(ARM_SMCCC_RES_X2_OFFS, offsetof(struct arm_smccc_res, a2));
> > +#if (IS_ENABLED(CONFIG_ARM_FFA_TRANSPORT))
> > + DEFINE(ARM_SMCCC_RES_X4_OFFS, offsetof(struct arm_smccc_res, a4));
> > + DEFINE(ARM_SMCCC_RES_X6_OFFS, offsetof(struct arm_smccc_res, a6));
> > +#endif
> > DEFINE(ARM_SMCCC_QUIRK_ID_OFFS, offsetof(struct arm_smccc_quirk, id));
> > DEFINE(ARM_SMCCC_QUIRK_STATE_OFFS, offsetof(struct arm_smccc_quirk, state));
> > #endif
> > diff --git a/common/board_r.c b/common/board_r.c
> > index b92c1bb0be..bb5f1d0aa6 100644
> > --- a/common/board_r.c
> > +++ b/common/board_r.c
> > @@ -62,6 +62,10 @@
> > #include <asm-generic/gpio.h>
> > #include <efi_loader.h>
> >
> > +#ifdef CONFIG_ARM_FFA_TRANSPORT
> > +#include <arm_ffa_helper.h>
> > +#endif
> > +
> > DECLARE_GLOBAL_DATA_PTR;
> >
> > ulong monitor_flash_len;
> > @@ -771,6 +775,9 @@ static init_fnc_t init_sequence_r[] = {
> > INIT_FUNC_WATCHDOG_RESET
> > initr_net,
> > #endif
> > +#ifdef CONFIG_ARM_FFA_TRANSPORT
> > + ffa_helper_bus_discover,
> > +#endif
> > #ifdef CONFIG_POST
> > initr_post,
> > #endif
> > diff --git a/drivers/Kconfig b/drivers/Kconfig
> > index b26ca8cf70..e83c23789d 100644
> > --- a/drivers/Kconfig
> > +++ b/drivers/Kconfig
> > @@ -6,6 +6,8 @@ source "drivers/core/Kconfig"
> >
> > source "drivers/adc/Kconfig"
> >
> > +source "drivers/arm-ffa/Kconfig"
> > +
> > source "drivers/ata/Kconfig"
> >
> > source "drivers/axi/Kconfig"
> > diff --git a/drivers/Makefile b/drivers/Makefile
> > index 4e7cf28440..6671d2a604 100644
> > --- a/drivers/Makefile
> > +++ b/drivers/Makefile
> > @@ -107,6 +107,7 @@ obj-y += iommu/
> > obj-y += smem/
> > obj-y += thermal/
> > obj-$(CONFIG_TEE) += tee/
> > +obj-$(CONFIG_ARM_FFA_TRANSPORT) += arm-ffa/
> > obj-y += axi/
> > obj-y += ufs/
> > obj-$(CONFIG_W1) += w1/
> > diff --git a/drivers/arm-ffa/Kconfig b/drivers/arm-ffa/Kconfig
> > new file mode 100644
> > index 0000000000..23815534c4
> > --- /dev/null
> > +++ b/drivers/arm-ffa/Kconfig
> > @@ -0,0 +1,27 @@
> > +# 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 if ARM64
> > + select LIB_UUID
> > + select ARM_FFA_TRANSPORT_HELPERS
> > + 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.
> > diff --git a/drivers/arm-ffa/Makefile b/drivers/arm-ffa/Makefile
> > new file mode 100644
> > index 0000000000..7bc9a336a9
> > --- /dev/null
> > +++ b/drivers/arm-ffa/Makefile
> > @@ -0,0 +1,6 @@
> > +# SPDX-License-Identifier: GPL-2.0+
> > +#
> > +# (C) Copyright 2022 Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > +#
> > +
> > +obj-y += arm-ffa-uclass.o core.o
> > diff --git a/drivers/arm-ffa/arm-ffa-uclass.c b/drivers/arm-ffa/arm-ffa-uclass.c
> > new file mode 100644
> > index 0000000000..2439f87586
> > --- /dev/null
> > +++ b/drivers/arm-ffa/arm-ffa-uclass.c
> > @@ -0,0 +1,64 @@
> > +// 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 <arm_ffa.h>
> > +#include <errno.h>
> > +#include <log.h>
> > +#include <asm/global_data.h>
> > +
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> > +UCLASS_DRIVER(ffa) = {
> > + .name = "ffa",
> > + .id = UCLASS_FFA,
> > +};
> > +
> > +/**
> > + * ffa_get_invoke_func - performs a call to the FF-A driver dispatcher
> > + * @func_id: The FF-A function to be used
> > + * @func_data: Pointer to the FF-A function arguments
> > + * container structure. This also includes
> > + * pointers to the returned data needed by
> > + * clients.
> > + *
> > + * This runtime function passes the FF-A function ID and its arguments to
> > + * the FF-A driver dispatcher.
> > + * This function is called by the FF-A helper functions.
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int __ffa_runtime ffa_get_invoke_func(u32 func_id, struct ffa_interface_data *func_data)
> > +{
> > + if (!ffa_device_get_ops()->invoke_func)
> > + return -EINVAL;
> > +
> > + return ffa_device_get_ops()->invoke_func(func_id, func_data);
> > +}
> > +
> > +/**
> > + * ffa_bus_discover - discover FF-A bus and probe the arm_ffa device
> > + *
> > + * This boot time function makes sure the FF-A bus is discoverable.
> > + * Then, the arm_ffa device is probed and ready to use.
> > + * This function is called automatically at initcalls
> > + * level (after u-boot relocation).
> > + *
> > + * 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:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int ffa_bus_discover(void)
> > +{
> > + return ffa_get_device();
> > +}
> > diff --git a/drivers/arm-ffa/arm_ffa_prv.h b/drivers/arm-ffa/arm_ffa_prv.h
> > new file mode 100644
> > index 0000000000..44f258addb
> > --- /dev/null
> > +++ b/drivers/arm-ffa/arm_ffa_prv.h
> > @@ -0,0 +1,193 @@
> > +/* 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 <dm/read.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)))
> > +
> > +/* The FF-A SMC function prototype definition */
> > +
> > +typedef void (*invoke_ffa_fn_t)(unsigned long a0, unsigned long a1,
> > + unsigned long a2, unsigned long a3, unsigned long a4,
> > + unsigned long a5, unsigned long a6, unsigned long a7,
> > + struct arm_smccc_res *res);
> > +
> > +/**
> > + * enum ffa_conduit - Arm FF-A conduits supported by the Arm FF-A driver
> > + * Currently only SMC32 is supported.
> > + */
> > +enum ffa_conduit {
> > + FFA_CONDUIT_SMC = 0,
> > +};
>
> Why is this enum needed?

Removed in v4. Please check https://lore.kernel.org/all/20220926101723.9965-5-abdellatif.elkhlifi@arm.com/

>
> > +
> > +/**
> > + * FFA_DECLARE_ARGS - FF-A functions local variables
> > + * @a0-a7: local variables used to set registers x0-x7
> > + * @res: the structure hosting the FF-A function return data
> > + *
> > + * A helper macro for declaring local variables for the FF-A functions arguments.
> > + * The x0-x7 registers are used to exchange data with the secure world.
> > + * But, only the bottom 32-bit of thes registers contains the data.
> > + */
> > +#define FFA_DECLARE_ARGS \
> > + unsigned long a0 = 0; \
> > + unsigned long a1 = 0; \
> > + unsigned long a2 = 0; \
> > + unsigned long a3 = 0; \
> > + unsigned long a4 = 0; \
> > + unsigned long a5 = 0; \
> > + unsigned long a6 = 0; \
> > + unsigned long a7 = 0; \
> > + struct arm_smccc_res res = {0}
> > +
> > +/* FF-A error codes */
> > +#define FFA_ERR_STAT_NOT_SUPPORTED (-1)
> > +#define FFA_ERR_STAT_INVALID_PARAMETERS (-2)
> > +#define FFA_ERR_STAT_NO_MEMORY (-3)
> > +#define FFA_ERR_STAT_BUSY (-4)
> > +#define FFA_ERR_STAT_INTERRUPTED (-5)
> > +#define FFA_ERR_STAT_DENIED (-6)
> > +#define FFA_ERR_STAT_RETRY (-7)
> > +#define FFA_ERR_STAT_ABORTED (-8)
> > +
> > +/**
> > + * struct ffa_features_desc - FF-A functions features
> > + * @func_id: FF-A function
> > + * @field1: features read from register w2
> > + * @field2: features read from register w3
> > + *
> > + * Data structure describing the features of the FF-A functions queried by
> > + * FFA_FEATURES
> > + */
> > +struct ffa_features_desc {
> > + u32 func_id;
> > + u32 field1;
> > + u32 field2;
> > +};
> > +
> > +/**
> > + * enum ffa_rxtx_buf_sizes - minimum sizes supported
> > + * for the RX/TX buffers
> > + */
> > +enum ffa_rxtx_buf_sizes {
> > + RXTX_4K,
> > + RXTX_64K,
> > + RXTX_16K
> > +};
> > +
> > +/*
> > + * Number of the FF-A interfaces features descriptors
> > + * currently only FFA_RXTX_MAP descriptor is supported
> > + */
> > +#define FFA_FEATURE_DESC_CNT (1)
> > +
> > +/**
> > + * 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
> > + *
> > + * 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 */
> > +};
> > +
> > +/**
> > + * struct ffa_partition_desc - the secure partition descriptor
> > + * @info: partition information
> > + * @UUID: UUID
> > + *
> > + * Each partition has its descriptor containing the partitions information and the UUID
> > + */
> > +struct ffa_partition_desc {
> > + struct ffa_partition_info info;
> > + union ffa_partition_uuid 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
> > + * @fwk_version: FF-A framework version
> > + * @id: u-boot endpoint ID
> > + * @partitions: The partitions descriptors structure
> > + * @pair: The RX/TX buffers pair
> > + * @conduit: The selected conduit
> > + * @invoke_ffa_fn: The function executing the FF-A function
> > + * @features: Table of the FF-A functions having features
> > + *
> > + * The driver data structure hosting all resident data.
> > + */
> > +struct ffa_prvdata {
> > + struct udevice *dev;
> > + u32 fwk_version;
> > + u16 id;
> > + struct ffa_partitions partitions;
> > + struct ffa_rxtxpair pair;
> > + enum ffa_conduit conduit;
> > + invoke_ffa_fn_t invoke_ffa_fn;
> > + struct ffa_features_desc features[FFA_FEATURE_DESC_CNT];
> > +};
> > +
> > +#endif
> > diff --git a/drivers/arm-ffa/core.c b/drivers/arm-ffa/core.c
> > new file mode 100644
> > index 0000000000..09e4eb753a
> > --- /dev/null
> > +++ b/drivers/arm-ffa/core.c
> > @@ -0,0 +1,1349 @@
> > +// 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 <asm/io.h>
> > +#include <common.h>
> > +#include <dm.h>
> > +#include <dm/device-internal.h>
> > +#include <dm/root.h>
> > +#include <linux/errno.h>
> > +#include <linux/sizes.h>
> > +#include <log.h>
> > +#include <malloc.h>
> > +#include <mapmem.h>
> > +#include <string.h>
> > +
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> > +/**
> > + * The device private data structure containing all the resident
> > + * data read from secure world
> > + */
> > +struct ffa_prvdata __ffa_runtime_data ffa_priv_data = {0};
> > +
> > +/*
> > + * Driver functions
> > + */
> > +
> > +/**
> > + * ffa_get_device - create, bind and probe the arm_ffa device
> > + *
> > + * This boot time 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:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int ffa_get_device(void)
> > +{
> > + int ret;
> > +
> > + if (ffa_priv_data.dev)
> > + return FFA_ERR_STAT_SUCCESS;
> > +
> > + ret = device_bind(dm_root(),
> > + DM_DRIVER_GET(arm_ffa),
> > + FFA_DRV_NAME,
> > + NULL,
> > + ofnode_null(),
> > + &ffa_priv_data.dev);
> > + if (ret) {
> > + ffa_priv_data.dev = NULL;
> > + return ret;
> > + }
> > +
> > + /* The FF-A bus discovery succeeds when probing is successful */
> > + ret = device_probe(ffa_priv_data.dev);
> > + if (ret) {
> > + ffa_err("can not probe the device");
> > + device_unbind(ffa_priv_data.dev);
> > + ffa_priv_data.dev = NULL;
> > + return ret;
> > + }
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +}
> > +
> > +/**
> > + * ffa_get_version - FFA_VERSION handler function
> > + *
> > + * This is the boot time function that implements FFA_VERSION FF-A function
> > + * to get from the secure world the FF-A framework version
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_get_version(void)
> > +{
> > + u16 major, minor;
> > +
> > + FFA_DECLARE_ARGS;
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + panic("[FFA] no private data found\n");
> > +
> > + a0 = FFA_VERSION;
> > + a1 = FFA_VERSION_1_0;
> > + ffa_priv_data.invoke_ffa_fn(a0, a1, a2, a3, a4, a5, a6, a7, &res);
> > +
> > + if (res.a0 == FFA_ERR_STAT_NOT_SUPPORTED) {
> > + ffa_err("A Firmware Framework implementation does not exist");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + 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 FFA_ERR_STAT_SUCCESS;
> > + }
> > +
> > + ffa_info("Versions are incompatible ");
>
> This is an error, perhaps better to use ffa_err() instead. And mention
> the versions in question also since the info level might be disabled.

Done. Please refer to v4 for the latest updates on that part.

>
> > + return -EPROTONOSUPPORT;
> > +}
> > +
> > +/**
> > + * ffa_get_endpoint_id - FFA_ID_GET handler function
> > + *
> > + * This is the boot time function that implements FFA_ID_GET FF-A function
> > + * to get from the secure world u-boot endpoint ID
>
> This is to get the vm id from an eventual hypervisor, or 0 if there
> isn't any hypervisor.

The FF-A 1.0 spec says: ID value 0 must be returned at the Non-secure
physical FF-A instance. In our case the Non-secure physical FF-A
instance is u-boot. The comment in the function header is trying to
be as close as possible to what the spec is saying.

>
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_get_endpoint_id(void)
> > +{
> > + FFA_DECLARE_ARGS;
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + panic("[FFA] no private data found\n");
> > +
> > + a0 = FFA_ID_GET;
> > +
> > + ffa_priv_data.invoke_ffa_fn(a0, a1, a2, a3, a4, a5, a6, a7, &res);
> > +
> > + switch (res.a0) {
> > + case FFA_ERROR:
> > + {
> > + if (((int)res.a2) == FFA_ERR_STAT_NOT_SUPPORTED) {
> > + ffa_err("This function is not implemented at this FF-A instance");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + ffa_err("Undefined error code (%d)", ((int)res.a2));
> > + return -EINVAL;
> > + }
>
> Are these extra braces really needed? Same below.

error handling has been redesigned to use error mappings.
Please refer to v4: https://lore.kernel.org/all/20220926101723.9965-5-abdellatif.elkhlifi@arm.com/

>
> > + case FFA_SUCCESS:
> > + {
> > + ffa_priv_data.id = GET_SELF_ENDPOINT_ID(res.a2);
> > + ffa_info("endpoint ID is %u", ffa_priv_data.id);
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > + }
> > + default:
> > + {
> > + ffa_err("Undefined response function (0x%lx)", res.a0);
> > + return -EINVAL;
> > + }
> > + }
> > +}
> > +
> > +/**
> > + * ffa_get_features_desc - returns the features descriptor of the specified
> > + * FF-A function
> > + * @func_id: the FF-A function which the features are to be retrieved
> > + *
> > + * This is a boot time function that searches the features descriptor of the
> > + * specified FF-A function
> > + *
> > + * Return:
> > + *
> > + * When found, the address of the features descriptor is returned. Otherwise, NULL.
> > + */
> > +static struct ffa_features_desc *ffa_get_features_desc(u32 func_id)
> > +{
> > + u32 desc_idx;
> > +
> > + /*
> > + * search for the descriptor of the selected FF-A interface
> > + */
> > + for (desc_idx = 0; desc_idx < FFA_FEATURE_DESC_CNT ; desc_idx++)
> > + if (ffa_priv_data.features[desc_idx].func_id == func_id)
> > + return &ffa_priv_data.features[desc_idx];
> > +
> > + return NULL;
> > +}
> > +
> > +/**
> > + * ffa_get_rxtx_map_features - FFA_FEATURES handler function with FFA_RXTX_MAP
> > + * argument
> > + *
> > + * This is the boot time function that implements FFA_FEATURES FF-A function
> > + * to retrieve the FFA_RXTX_MAP features
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_get_rxtx_map_features(void)
> > +{
> > + FFA_DECLARE_ARGS;
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + panic("[FFA] no private data found\n");
> > +
> > + a0 = FFA_FEATURES;
> > + a1 = FFA_RXTX_MAP;
> > +
> > + ffa_priv_data.invoke_ffa_fn(a0, a1, a2, a3, a4, a5, a6, a7, &res);
> > +
> > + switch (res.a0) {
> > + case FFA_ERROR:
> > + {
> > + if (((int)res.a2) == FFA_ERR_STAT_NOT_SUPPORTED) {
> > + ffa_err("FFA_RXTX_MAP is not implemented at this FF-A instance");
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + ffa_err("Undefined error code (%d)", ((int)res.a2));
> > + return -EINVAL;
> > + }
> > + case FFA_SUCCESS:
> > + {
> > + u32 desc_idx;
> > +
> > + /*
> > + * search for an empty descriptor
> > + */
> > + for (desc_idx = 0; desc_idx < FFA_FEATURE_DESC_CNT ; desc_idx++)
> > + if (!ffa_priv_data.features[desc_idx].func_id) {
> > + /*
> > + * populate the descriptor with
> > + * the interface features data
> > + */
> > + ffa_priv_data.features[desc_idx].func_id =
> > + FFA_RXTX_MAP;
> > + ffa_priv_data.features[desc_idx].field1 =
> > + res.a2;
> > +
> > + ffa_info("FFA_RXTX_MAP features data 0x%lx",
> > + res.a2);
>
> This seems a bit more complicated than necessary. How about just save
> the block size in a separate fields in ffa_priv_data? That would also
> make it easier to understand what this value is without looking it up in
> the spec to remind oneself.

Done in v4. rxtx_min_pages field has been added in the ffa_rxtxpair
structure and replaces the older logic.

>
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > + }
> > +
> > + ffa_err("Cannot save FFA_RXTX_MAP features data. Descriptors table full");
> > + return -ENOBUFS;
> > + }
> > + default:
> > + {
> > + ffa_err("Undefined response function (0x%lx)",
> > + res.a0);
> > + return -EINVAL;
> > + }
> > + }
> > +}
> > +
> > +/**
> > + * ffa_get_rxtx_buffers_pages_cnt - reads from the features data descriptors
> > + * the minimum number of pages in each of the RX/TX
> > + * buffers
> > + * @buf_4k_pages: Pointer to the minimum number of pages
> > + *
> > + * This is the boot time function that returns the minimum number of pages
> > + * in each of the RX/TX buffers
> > + *
> > + * Return:
> > + *
> > + * buf_4k_pages points to the returned number of pages
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_get_rxtx_buffers_pages_cnt(size_t *buf_4k_pages)
> > +{
> > + struct ffa_features_desc *desc = NULL;
> > +
> > + if (!buf_4k_pages)
> > + return -EINVAL;
> > +
> > + desc = ffa_get_features_desc(FFA_RXTX_MAP);
> > + if (!desc)
> > + return -EINVAL;
> > +
> > + switch (desc->field1) {
> > + case RXTX_4K:
> > + *buf_4k_pages = 1;
> > + break;
> > + case RXTX_16K:
> > + *buf_4k_pages = 4;
> > + break;
> > + case RXTX_64K:
> > + *buf_4k_pages = 16;
> > + break;
> > + default:
> > + ffa_err("RX/TX buffer size not supported");
> > + return -EINVAL;
> > + }
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +}
> > +
> > +/**
> > + * ffa_free_rxtx_buffers - frees the RX/TX buffers
> > + * @buf_4k_pages: the minimum number of pages in each of the RX/TX
> > + * buffers
> > + *
> > + * This is the boot time function used to free the RX/TX buffers
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_free_rxtx_buffers(size_t buf_4k_pages)
> > +{
> > + efi_status_t free_rxbuf_ret, free_txbuf_ret;
> > +
> > + ffa_info("Freeing RX/TX buffers");
> > +
> > + free_rxbuf_ret = efi_free_pages(ffa_priv_data.pair.rxbuf, buf_4k_pages);
> > + free_txbuf_ret = efi_free_pages(ffa_priv_data.pair.txbuf, buf_4k_pages);
> > +
> > + if (free_rxbuf_ret != EFI_SUCCESS || free_txbuf_ret != EFI_SUCCESS) {
> > + ffa_err("Failed to free RX/TX buffers (rx: %lu , tx: %lu)",
> > + free_rxbuf_ret,
> > + free_txbuf_ret);
> > + return -EINVAL;
> > + }
> > +
> > + ffa_priv_data.pair.rxbuf = 0;
> > + ffa_priv_data.pair.txbuf = 0;
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +}
> > +
> > +/**
> > + * ffa_alloc_rxtx_buffers - allocates the RX/TX buffers
> > + * @buf_4k_pages: the minimum number of pages in each of the RX/TX
> > + * buffers
> > + *
> > + * This is the boot time function used by ffa_map_rxtx_buffers to allocate
> > + * the RX/TX buffers before mapping them
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_alloc_rxtx_buffers(size_t buf_4k_pages)
> > +{
> > +#if CONFIG_IS_ENABLED(EFI_LOADER)
> > +
> > + efi_status_t efi_ret;
> > + void *virt_txbuf;
> > + void *virt_rxbuf;
> > +
> > + ffa_info("Using %lu 4KB page(s) for RX/TX buffers size",
> > + buf_4k_pages);
> > +
> > + efi_ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
> > + EFI_BOOT_SERVICES_DATA,
> > + buf_4k_pages,
> > + &ffa_priv_data.pair.rxbuf);
> > +
> > + if (efi_ret != EFI_SUCCESS) {
> > + ffa_priv_data.pair.rxbuf = 0;
> > + ffa_err("Failure to allocate RX buffer (EFI error: 0x%lx)",
> > + efi_ret);
> > +
> > + return -ENOBUFS;
> > + }
> > +
> > + ffa_info("RX buffer at virtual address 0x%llx",
> > + ffa_priv_data.pair.rxbuf);
> > +
> > + virt_rxbuf = (void *)ffa_priv_data.pair.rxbuf;
> > +
> > + /*
> > + * make sure the buffer is clean before use
> > + */
> > + memset(virt_rxbuf, 0, buf_4k_pages * SZ_4K);
> > +
> > + efi_ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
> > + EFI_RUNTIME_SERVICES_DATA,
> > + buf_4k_pages,
> > + &ffa_priv_data.pair.txbuf);
> > +
> > + if (efi_ret != EFI_SUCCESS) {
> > + efi_free_pages(ffa_priv_data.pair.rxbuf, buf_4k_pages);
> > + ffa_priv_data.pair.rxbuf = 0;
> > + ffa_priv_data.pair.txbuf = 0;
> > + ffa_err("Failure to allocate the TX buffer (EFI error: 0x%lx)"
> > + , efi_ret);
> > +
> > + return -ENOBUFS;
> > + }
> > +
> > + ffa_info("TX buffer at virtual address 0x%llx",
> > + ffa_priv_data.pair.txbuf);
> > +
> > + virt_txbuf = (void *)ffa_priv_data.pair.txbuf;
> > +
> > + /*
> > + * make sure the buffer is clean before use
> > + */
> > + memset(virt_txbuf, 0, buf_4k_pages * SZ_4K);
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +
> > +#else
> > + return -ENOBUFS;
> > +#endif
> > +}
> > +
> > +/**
> > + * ffa_map_rxtx_buffers - FFA_RXTX_MAP handler function
> > + * @buf_4k_pages: the minimum number of pages in each of the RX/TX
> > + * buffers
> > + *
> > + * This is the boot time function that implements FFA_RXTX_MAP FF-A function
> > + * to map the RX/TX buffers
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_map_rxtx_buffers(size_t buf_4k_pages)
> > +{
> > + int ret;
> > +
> > + FFA_DECLARE_ARGS;
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + panic("[FFA] no private data found\n");
> > +
> > + ret = ffa_alloc_rxtx_buffers(buf_4k_pages);
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + return ret;
> > +
> > + a0 = FFA_RXTX_MAP;
> > + a1 = ffa_priv_data.pair.txbuf;
> > + a2 = ffa_priv_data.pair.rxbuf;
> > + a3 = buf_4k_pages;
> > +
> > + ffa_priv_data.invoke_ffa_fn(a0, a1, a2, a3, a4, a5, a6, a7, &res);
> > +
> > + switch (res.a0) {
> > + case FFA_ERROR:
> > + {
> > + switch (((int)res.a2)) {
> > + case FFA_ERR_STAT_INVALID_PARAMETERS:
> > + ffa_err("One or more fields in input parameters is incorrectly encoded");
> > + ret = -EPERM;
> > + break;
> > + case FFA_ERR_STAT_NO_MEMORY:
> > + ffa_err("Not enough memory");
> > + ret = -ENOMEM;
> > + break;
> > + case FFA_ERR_STAT_DENIED:
> > + ffa_err("Buffer pair already registered");
> > + ret = -EACCES;
> > + break;
> > + case FFA_ERR_STAT_NOT_SUPPORTED:
> > + ffa_err("This function is not implemented at this FF-A instance");
> > + ret = -EOPNOTSUPP;
> > + break;
> > + default:
> > + ffa_err("Undefined error (%d)",
> > + ((int)res.a2));
> > + ret = -EINVAL;
> > + }
>
> How about lookup table like in the kernel instead? It seems that this
> kind of translation will be needed a few times.

Done in v4.

>
>
> > + break;
> > + }
> > + case FFA_SUCCESS:
> > + ffa_info("RX/TX buffers mapped");
> > + return FFA_ERR_STAT_SUCCESS;
> > + default:
> > + ffa_err("Undefined response function (0x%lx)",
> > + res.a0);
> > + ret = -EINVAL;
> > + }
> > +
> > + ffa_free_rxtx_buffers(buf_4k_pages);
> > +
> > + return ret;
> > +}
> > +
> > +/**
> > + * ffa_unmap_rxtx_buffers - FFA_RXTX_UNMAP handler function
> > + *
> > + * This is the boot time function that implements FFA_RXTX_UNMAP FF-A function
> > + * to unmap the RX/TX buffers
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_unmap_rxtx_buffers(void)
> > +{
> > + FFA_DECLARE_ARGS;
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + panic("[FFA] no private data found\n");
> > +
> > + a0 = FFA_RXTX_UNMAP;
> > + a1 = PREP_SELF_ENDPOINT_ID(ffa_priv_data.id);
> > +
> > + ffa_priv_data.invoke_ffa_fn(a0, a1, a2, a3, a4, a5, a6, a7, &res);
> > +
> > + switch (res.a0) {
> > + case FFA_ERROR:
> > + {
> > + if (((int)res.a2) == FFA_ERR_STAT_NOT_SUPPORTED)
> > + panic("[FFA] FFA_RXTX_UNMAP is not implemented at this FF-A instance\n");
> > + else if (((int)res.a2) == FFA_ERR_STAT_INVALID_PARAMETERS)
> > + panic("[FFA] There is no buffer pair registered on behalf of the caller\n");
> > + else
> > + panic("[FFA] Undefined error (%d)\n", ((int)res.a2));
> > + }
> > + case FFA_SUCCESS:
> > + {
> > + size_t buf_4k_pages = 0;
> > + int ret;
> > +
> > + ret = ffa_get_rxtx_buffers_pages_cnt(&buf_4k_pages);
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + panic("[FFA] RX/TX buffers unmapped but failure in getting pages count\n");
> > +
> > + ret = ffa_free_rxtx_buffers(buf_4k_pages);
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + panic("[FFA] RX/TX buffers unmapped but failure in freeing the memory\n");
> > +
> > + ffa_info("RX/TX buffers unmapped and memory freed");
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > + }
> > + default:
> > + panic("[FFA] Undefined response function (0x%lx)", res.a0);
> > + }
> > +}
> > +
> > +/**
> > + * ffa_release_rx_buffer - FFA_RX_RELEASE handler function
> > + *
> > + * This is the boot time function that invokes FFA_RX_RELEASE FF-A function
> > + * to release the ownership of the RX buffer
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_release_rx_buffer(void)
> > +{
> > + FFA_DECLARE_ARGS;
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + panic("[FFA] no private data found\n");
> > +
> > + a0 = FFA_RX_RELEASE;
> > +
> > + ffa_priv_data.invoke_ffa_fn(a0, a1, a2, a3, a4, a5, a6, a7, &res);
> > +
> > + switch (res.a0) {
> > + case FFA_ERROR:
> > + {
> > + if (((int)res.a2) == FFA_ERR_STAT_NOT_SUPPORTED)
> > + panic("[FFA] FFA_RX_RELEASE is not implemented at this FF-A instance\n");
> > + else if (((int)res.a2) == FFA_ERR_STAT_DENIED)
> > + panic("[FFA] Caller did not have ownership of the RX buffer\n");
> > + else
> > + panic("[FFA] Undefined error (%d)\n", ((int)res.a2));
> > + }
> > + case FFA_SUCCESS:
> > + return FFA_ERR_STAT_SUCCESS;
> > +
> > + default:
> > + panic("[FFA] Undefined response function (0x%lx)\n", res.a0);
> > + }
> > +}
> > +
> > +/**
> > + * ffa_uuid_are_identical - checks whether two given UUIDs are identical
> > + * @uuid1: first UUID
> > + * @uuid2: second UUID
> > + *
> > + * This is a boot time function 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 union ffa_partition_uuid *uuid1,
> > + const union ffa_partition_uuid *uuid2)
> > +{
> > + if (!uuid1 || !uuid2)
> > + return 0;
> > +
> > + return (!memcmp(uuid1, uuid2, sizeof(union 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 is the boot time function that 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
> > + * FFA_ERR_STAT_SUCCESS is returned on success. Otherwise, failure
> > + */
> > +static int ffa_read_partitions_info(u32 count, union ffa_partition_uuid *part_uuid)
> > +{
> > + if (!count) {
> > + ffa_err("No partition detected");
> > + return -ENODATA;
> > + }
> > +
> > + ffa_info("Reading partitions data from the RX buffer");
> > +
> > +#if CONFIG_IS_ENABLED(EFI_LOADER)
> > +
> > + if (!part_uuid) {
> > + /*
> > + * querying information of all partitions
> > + */
> > + u64 data_pages;
> > + u64 data_bytes;
> > + efi_status_t efi_ret;
> > + size_t buf_4k_pages = 0;
> > + u32 desc_idx;
> > + struct ffa_partition_info *parts_info;
> > + int ret;
> > +
> > + data_bytes = count * sizeof(struct ffa_partition_desc);
> > + data_pages = efi_size_in_pages(data_bytes);
> > +
> > + /*
> > + * get the RX buffer size in pages
> > + */
> > + ret = ffa_get_rxtx_buffers_pages_cnt(&buf_4k_pages);
> > + if (ret != FFA_ERR_STAT_SUCCESS) {
> > + ffa_err("Can not get the RX buffer size (error %d)", ret);
> > + return ret;
> > + }
> > +
> > + if (data_pages > buf_4k_pages) {
> > + ffa_err("Partitions data size exceeds the RX buffer size:");
> > + ffa_err(" Sizes in pages: data %llu , RX buffer %lu ",
> > + data_pages,
> > + buf_4k_pages);
> > +
> > + return -ENOMEM;
> > + }
> > +
> > + efi_ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
> > + EFI_RUNTIME_SERVICES_DATA,
> > + data_pages,
> > + (u64 *)&ffa_priv_data.partitions.descs);
> > +
> > + if (efi_ret != EFI_SUCCESS) {
> > + ffa_priv_data.partitions.descs = NULL;
> > +
> > + ffa_err("Cannot allocate partitions data buffer (EFI error 0x%lx)",
> > + efi_ret);
> > +
> > + return -ENOBUFS;
> > + }
> > +
> > + /*
> > + * make sure the buffer is clean before use
> > + */
> > + memset(ffa_priv_data.partitions.descs, 0,
> > + data_pages * SZ_4K);
> > +
> > + 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].UUID =
> > + *part_uuid;
> > +
> > + desc_found = 1;
> > + break;
> > + }
> > + }
> > +
> > + if (!desc_found)
> > + return -ENODATA;
> > + }
> > + }
> > +#else
> > +#warning "arm_ffa: reading FFA_PARTITION_INFO_GET data not implemented"
> > +#endif
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +}
> > +
> > +/**
> > + * ffa_query_partitions_info - invokes FFA_PARTITION_INFO_GET
> > + * and saves partitions data
>
> Strange indentation.
>
> > + * @part_uuid: Pointer to the partition(s) UUID
> > + * @pcount: Pointer to the number of partitions variable filled when querying
> > + *
> > + * This is the boot time function that 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
> > + * FFA_ERR_STAT_SUCCESS is returned on success. Otherwise, failure
> > + */
> > +static int ffa_query_partitions_info(union ffa_partition_uuid *part_uuid,
> > + u32 *pcount)
> > +{
> > + unsigned long a0 = 0;
> > + union ffa_partition_uuid query_uuid = {0};
> > + unsigned long a5 = 0;
> > + unsigned long a6 = 0;
> > + unsigned long a7 = 0;
> > + struct arm_smccc_res res = {0};
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + panic("[FFA] no private data found\n");
> > +
> > + a0 = FFA_PARTITION_INFO_GET;
>
> Why no initialize a0 with with value above instead?

following the new interface design a0 is set at the invoke_ffa_fn callback call.
Please refer to v4 for the latest update on that.

>
> > +
> > + /*
> > + * 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;
> > + }
> > +
> > + ffa_priv_data.invoke_ffa_fn(a0, query_uuid.words.a1, query_uuid.words.a2,
> > + query_uuid.words.a3, query_uuid.words.a4,
> > + a5, a6, a7, &res);
> > +
> > + switch (res.a0) {
> > + case FFA_ERROR:
> > + {
> > + switch (((int)res.a2)) {
> > + case FFA_ERR_STAT_INVALID_PARAMETERS:
> > + ffa_err("Unrecognized UUID");
> > + return -EPERM;
> > + case FFA_ERR_STAT_NO_MEMORY:
> > + ffa_err("Results cannot fit in RX buffer of the caller");
> > + return -ENOMEM;
> > + case FFA_ERR_STAT_DENIED:
> > + ffa_err("Callee is not in a state to handle this request");
> > + return -EACCES;
> > + case FFA_ERR_STAT_NOT_SUPPORTED:
> > + ffa_err("This function is not implemented at this FF-A instance");
> > + return -EOPNOTSUPP;
> > + case FFA_ERR_STAT_BUSY:
> > + ffa_err("RX buffer of the caller is not free");
> > + return -EBUSY;
> > + default:
> > + ffa_err("Undefined error (%d)", ((int)res.a2));
> > + return -EINVAL;
> > + }
> > + }
> > + case 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(res.a2, part_uuid);
> > + if (ret)
> > + ffa_err("Failed to read partition(s) data , error (%d)", ret);
> > + }
> > +
> > + /*
> > + * return the SP count
> > + */
> > + if (part_uuid) {
> > + if (!ret)
> > + *pcount = res.a2;
> > + else
> > + *pcount = 0;
> > + }
> > + /*
> > + * 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 secure world
> > + */
>
> if there's a hypervisor we're returning the buffer to the hypervisor instead.
> how about "... back to the SPM or hypervisor"?

Done

>
> > + ret = ffa_release_rx_buffer();
> > +
> > + if (!part_uuid && !res.a2) {
> > + ffa_err("[FFA] no partition installed in the system");
> > + return -ENODEV;
> > + }
> > +
> > + return ret;
> > + }
> > + default:
> > + ffa_err("Undefined response function (0x%lx)", res.a0);
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +/**
> > + * ffa_get_partitions_info - FFA_PARTITION_INFO_GET handler function
> > + * @func_data: Pointer to the FF-A function arguments container structure.
> > + * The passed arguments:
> > + * Mode 1: When getting from the driver the number of
> > + * secure partitions:
> > + * @data0_size: UUID size
> > + * @data0: pointer to the UUID (little endian)
> > + * @data1_size: size of the number of partitions
> > + * variable
> > + * @data1: pointer to the number of partitions
> > + * variable. The variable will be set
> > + * by the driver
> > + * Mode 2: When requesting the driver to return the
> > + * partitions information:
> > + * @data0_size: UUID size
> > + * @data0: pointer to the UUID (little endian)
> > + * @data1_size: size of the SPs information buffer
> > + * @data1: pointer to SPs information buffer
> > + * (allocated by the client).
> > + * The buffer will be filled by the driver
> > + *
> > + * This is the boot time function that 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:
> > + *
> > + * @data1: When pointing to the number of partitions variable, the number is
> > + * set by the driver.
> > + * When pointing to the partitions information buffer, the buffer will be
> > + * filled by the driver.
> > + *
> > + * On success FFA_ERR_STAT_SUCCESS is returned. Otherwise, failure
> > + */
> > +static int ffa_get_partitions_info(struct ffa_interface_data *func_data)
> > +{
> > + /*
> > + * 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;
> > + union ffa_partition_uuid *part_uuid;
> > + u32 client_desc_max_cnt;
> > + u32 parts_found = 0;
> > +
> > + if (!func_data) {
> > + ffa_err("No function data provided");
> > + return -EINVAL;
> > + }
> > +
> > + if (!ffa_priv_data.partitions.count || !ffa_priv_data.partitions.descs)
> > + panic("[FFA] No partition installed\n");
> > +
> > + if (func_data->data0_size == sizeof(union ffa_partition_uuid) &&
> > + func_data->data0 &&
> > + func_data->data1_size == sizeof(u32) &&
> > + func_data->data1) {
> > + /*
> > + * data0 (in): pointer to UUID
> > + * data1 (in): pointer to SP count
> > + * Out: SP count returned in the count variable pointed by data1
> > + */
> > +
> > + fill_data = 0;
> > +
> > + ffa_info("Preparing for checking partitions count");
> > +
> > + } else if ((func_data->data0_size == sizeof(union ffa_partition_uuid)) &&
> > + func_data->data0 &&
> > + (func_data->data1_size >= sizeof(struct ffa_partition_info)) &&
> > + !(func_data->data1_size % sizeof(struct ffa_partition_info)) &&
> > + func_data->data1) {
> > + /*
> > + * data0 (in): pointer to UUID
> > + * data1 (in): pointer to SPs descriptors buffer
> > + * (created by the client)
> > + * Out: SPs descriptors returned in the buffer
> > + * pointed by data1
> > + */
> > +
> > + fill_data = 1;
> > +
> > + client_desc_idx = 0;
> > +
> > + /*
> > + * number of empty descriptors preallocated by the caller
> > + */
> > + client_desc_max_cnt =
> > + func_data->data1_size / sizeof(struct ffa_partition_info);
> > +
> > + ffa_info("Preparing for filling partitions info");
> > +
> > + } else {
> > + ffa_err("Invalid function arguments provided");
> > + return -EINVAL;
> > + }
> > +
> > + part_uuid = (union ffa_partition_uuid *)func_data->data0;
> > +
> > + 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].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 data1
> > + */
> > +
> > + if (client_desc_idx < client_desc_max_cnt) {
> > + ((struct ffa_partition_info *)
> > + func_data->data1)[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 == FFA_ERR_STAT_SUCCESS) {
> > + if (!fill_data) {
> > + *((u32 *)func_data->data1) = parts_found;
> > +
> > + ffa_info("Number of partition(s) found matching the UUID: %d",
> > + parts_found);
> > + } else {
> > + /*
> > + * we want to read SPs info
> > + */
> > +
> > + /*
> > + * If SPs data filled, retry searching SP info again
> > + */
> > + if (parts_found)
> > + ret = ffa_get_partitions_info(func_data);
> > + else
> > + ret = -ENODATA;
> > + }
> > + }
> > +
> > + return ret;
> > + }
> > +
> > + /* partition(s) found */
> > + if (!fill_data)
> > + *((u32 *)func_data->data1) = parts_found;
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +}
> > +
> > +/**
> > + * ffa_cache_partitions_info - Queries and saves all secure partitions data
> > + *
> > + * This is a boot time function that 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:
> > + *
> > + * FFA_ERR_STAT_SUCCESS 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
> > + * @func_data: Pointer to the FF-A function arguments container structure.
> > + * The passed arguments:
> > + * @data0_size: partition ID size
> > + * @data0: pointer to the partition ID
> > + * @data1_size: exchanged data size
> > + * @data1: pointer to the data buffer preallocated by
> > + * the client (in/out)
> > + *
> > + * This is the runtime function that 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 20 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:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
>
> This API looks quite complicated. Wouldn't it be easier to let the
> caller supply the struct ffa_send_direct_data *msg pointer directly
> instead, like in the Linux kernel driver. The approach here prevents the
> compiler from helping with type checks etc.

This has been addressed following the new interface design and alignment with
the kernel driver. Please refer to v4 for the latest updates on that.

>
> > +static int __ffa_runtime ffa_msg_send_direct_req(struct ffa_interface_data
> > + *func_data)
> > +{
> > + u16 dst_part_id;
> > + unsigned long a0 = 0;
> > + unsigned long a1 = 0;
> > + unsigned long a2 = 0;
> > + struct ffa_send_direct_data *msg;
> > + struct arm_smccc_res res = {0};
> > +
> > + if (!ffa_priv_data.invoke_ffa_fn)
> > + return -ENODEV;
> > +
> > + if (!func_data)
> > + return -EINVAL;
> > +
> > + /* No partition installed */
> > + if (!ffa_priv_data.partitions.count || !ffa_priv_data.partitions.descs)
> > + return -ENODEV;
> > +
> > + /* Undefined interface parameters */
> > + if (func_data->data0_size != sizeof(u16) ||
> > + !func_data->data0 ||
> > + func_data->data1_size != FFA_MSG_SEND_DIRECT_MAX_SIZE ||
>
> FFA_MSG_SEND_DIRECT_MAX_SIZE? It's more like FFA_MSG_SEND_DIRECT_ONLY_SIZE.
>
> > + !func_data->data1)
> > + return -EINVAL;
> > +
> > + dst_part_id = *((u16 *)func_data->data0);
> > + msg = func_data->data1;
> > +
> > + a0 = FFA_MSG_SEND_DIRECT_REQ;
> > +
> > + a1 = PREP_SELF_ENDPOINT_ID(ffa_priv_data.id) |
> > + PREP_PART_ENDPOINT_ID(dst_part_id);
> > +
> > + ffa_priv_data.invoke_ffa_fn(a0, a1, a2,
> > + msg->a3,
> > + msg->a4,
> > + msg->a5,
> > + msg->a6,
> > + msg->a7,
> > + &res);
> > +
> > + while (res.a0 == FFA_INTERRUPT)
> > + ffa_priv_data.invoke_ffa_fn(FFA_RUN, res.a1,
> > + 0, 0, 0, 0, 0, 0,
> > + &res);
> > +
> > + switch (res.a0) {
> > + case FFA_ERROR:
> > + {
> > + switch (((int)res.a2)) {
> > + case FFA_ERR_STAT_INVALID_PARAMETERS:
> > + /* Invalid endpoint ID or non-zero reserved register */
> > + return -EPERM;
> > + case FFA_ERR_STAT_ABORTED:
> > + /* Message target ran into unexpected error and has aborted */
> > + return -ECONNABORTED;
> > + case FFA_ERR_STAT_DENIED:
> > + /* Callee is not in a state to handle this request */
> > + return -EACCES;
> > + case FFA_ERR_STAT_NOT_SUPPORTED:
> > + /* This function is not implemented at this FF-A instance */
> > + return -EOPNOTSUPP;
> > + case FFA_ERR_STAT_BUSY:
> > + /* Message target is busy */
> > + return -EBUSY;
> > + default:
> > + /* Undefined error */
> > + return -ENXIO;
> > + }
> > + }
> > + case FFA_SUCCESS:
> > +
> > + /* Message sent with no response */
> > + return FFA_ERR_STAT_SUCCESS;
> > +
> > + case FFA_MSG_SEND_DIRECT_RESP:
> > +
> > + /*
> > + * Message sent with response
> > + * extract the 32-bit wide return data
> > + */
> > + msg->a3 = (u32)res.a3;
> > + msg->a4 = (u32)res.a4;
> > + msg->a5 = (u32)res.a5;
> > + msg->a6 = (u32)res.a6;
> > + msg->a7 = (u32)res.a7;
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +
> > + default:
> > + /* Undefined response function */
> > + return -ENOENT;
> > + }
> > +}
> > +
> > +/**
> > + * invoke_ffa_drv_api - The driver dispatcher function
> > + * @func_id: The FF-A function to be used
> > + * @func_data: Pointer to the FF-A function arguments container
> > + * structure. This also includes pointers to the
> > + * returned data needed by clients.
> > + * The dispatcher is a runtime function that selects the FF-A function handler
> > + * based on the input FF-A function ID.
> > + * The input arguments are passed to the handler function.
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int __ffa_runtime invoke_ffa_drv_api(u32 func_id,
> > + struct ffa_interface_data *func_data)
> > +{
> > + if (!ffa_priv_data.dev)
> > + return -ENODEV;
> > +
>
> I don't see the point with this funnel layer. It would in my opinion be
> easier to have one function pointer for each of the provided FF-A
> functions.
>
> I wouldn't mind if the interface was a bit more like the interface
> provided in the Linux kernel, at least the parts we're going to support
> here. It would for sure help later when updating the OP-TEE driver to
> use this FF-A driver.

This has been addressed following the new interface design and
alignment with the kernel driver. Please refer to v4 for the
latest updates on that. ffa_bus_ops has been introduced and
contains all the exported callbacks.

>
> > + switch (func_id) {
> > + case FFA_PARTITION_INFO_GET:
> > + return ffa_get_partitions_info(func_data);
> > + case FFA_RXTX_UNMAP:
> > + return ffa_unmap_rxtx_buffers();
> > + case FFA_MSG_SEND_DIRECT_REQ:
> > + return ffa_msg_send_direct_req(func_data);
> > + default:
> > + /* Undefined FF-A interface */
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +/**
> > + * ffa_set_conduit - Set the conduit
> > + *
> > + * This boot time function clears the private data structure and sets the conduit
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_set_conduit(void)
> > +{
> > + ffa_priv_data.conduit = FFA_CONDUIT_SMC;
> > +
> > + ffa_priv_data.invoke_ffa_fn = arm_ffa_smccc_smc;
> > +
> > + ffa_info("Conduit is SMC");
>
> What if there's a hypervisor? Then HVC should be used instead.

We are only supporting SMC at this stage

>
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +}
> > +
> > +/**
> > + * 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 the specified FF-A calls
> > + * - 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.
> > + * However, once the driver is successfully probed and an FF-A anomaly is
> > + * detected when clients invoke the driver operations, the driver cause
> > + * u-boot to panic because the client would not know what to do in such conditions.
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +static int ffa_probe(struct udevice *dev)
> > +{
> > + int ret;
> > + size_t buf_4k_pages = 0;
> > +
> > + ret = ffa_set_conduit();
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + return ret;
> > +
> > + ret = ffa_get_version();
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + return ret;
> > +
> > + ret = ffa_get_endpoint_id();
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + return ret;
> > +
> > + ret = ffa_get_rxtx_map_features();
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + return ret;
> > +
> > + ret = ffa_get_rxtx_buffers_pages_cnt(&buf_4k_pages);
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + return ret;
> > +
> > + ret = ffa_map_rxtx_buffers(buf_4k_pages);
>
> This function only suceeds if compiled with EFI runtime support, so probing will always fail without EFI runtime support.
>
> If compiled with EFI runtime support, how is this supposed to work with
> the kernel FF-A driver? The FF-A framework only supports one buffer pair
> per component and I don't see where the buffer pair is freed when U-Boot
> is done.

From patchset v3, FF-A core driver has been decoupled from EFI. It can
be compiled without EFI support. Please refer to v4 for the latest work
on that. Freeing the RX/TX buffers is done in 2 locations.

1/ When RX/TX buffers are unmapped at ExitBootServices(). At EFI runtime
RX/TX buffers created by u-boot do not exist anymore.
2/ When the arm_ffa device is removed (please see ffa_remove function)

>
> > + if (ret != FFA_ERR_STAT_SUCCESS)
> > + return ret;
> > +
> > + ret = ffa_cache_partitions_info();
> > + if (ret != FFA_ERR_STAT_SUCCESS) {
> > + ffa_free_rxtx_buffers(buf_4k_pages);
> > + return ret;
> > + }
> > +
> > + return FFA_ERR_STAT_SUCCESS;
> > +}
> > +
> > +/**
> > + * ffa_drv_ops - The driver operations runtime structure
> > + * @invoke_func: The driver dispatcher
> > + */
> > +struct ffa_ops __ffa_runtime_data ffa_drv_ops = {
> > + .invoke_func = invoke_ffa_drv_api
> > +};
> > +
> > +/**
> > + * ffa_device_get_ops - driver operations getter
> > + *
> > + * Return:
> > + * This runtime function returns a pointer to the driver operations structure
> > + */
> > +const struct ffa_ops * __ffa_runtime ffa_device_get_ops(void)
> > +{
> > + return &ffa_drv_ops;
> > +}
> > +
> > +/**
> > + * Declaring the arm_ffa driver under UCLASS_FFA
> > + */
> > +
> > +U_BOOT_DRIVER(arm_ffa) = {
> > + .name = FFA_DRV_NAME,
> > + .id = UCLASS_FFA,
> > + .probe = ffa_probe,
> > +};
> > diff --git a/include/arm_ffa.h b/include/arm_ffa.h
> > new file mode 100644
> > index 0000000000..98db01ee72
> > --- /dev/null
> > +++ b/include/arm_ffa.h
> > @@ -0,0 +1,190 @@
> > +/* 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/arm-smccc.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__)
> > +
> > +/*
> > + * The driver operations success error code
> > + */
> > +#define FFA_ERR_STAT_SUCCESS (0)
> > +
> > +#if CONFIG_IS_ENABLED(EFI_LOADER)
> > +
> > +#include <efi_loader.h>
> > +
> > +/*
> > + * __ffa_runtime_data and __ffa_runtime - controls whether data/code are
> > + * available after calling the EFI ExitBootServices service.
> > + * Data/code tagged with these keywords are resident (available at boot time and
> > + * at runtime)
> > + */
> > +
> > +#define __ffa_runtime_data __efi_runtime_data
> > +#define __ffa_runtime __efi_runtime
> > +
> > +#else
> > +
> > +#define __ffa_runtime_data
> > +#define __ffa_runtime
> > +
> > +#endif
> > +
> > +/*
> > + * 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_VERSION FFA_SMC_32(0x63)
> > +#define FFA_ID_GET FFA_SMC_32(0x69)
> > +#define FFA_FEATURES FFA_SMC_32(0x64)
> > +#define FFA_PARTITION_INFO_GET FFA_SMC_32(0x68)
>
> Too much indentation, same below
>
> > +#define FFA_RXTX_MAP FFA_SMC_32(0x66)
> > +#define FFA_RXTX_UNMAP FFA_SMC_32(0x67)
> > +#define FFA_RX_RELEASE FFA_SMC_32(0x65)
> > +#define FFA_MSG_SEND_DIRECT_REQ FFA_SMC_32(0x6F)
> > +#define FFA_MSG_SEND_DIRECT_RESP FFA_SMC_32(0x70)
> > +#define FFA_RUN FFA_SMC_32(0x6D)
> > +#define FFA_ERROR FFA_SMC_32(0x60)
> > +#define FFA_SUCCESS FFA_SMC_32(0x61)
> > +#define FFA_INTERRUPT FFA_SMC_32(0x62)
> > +
> > +/*
> > + * 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}
> > + * @a3-a7: Data read/written from/to w3-w7 registers
> > + *
> > + * Data structure containing the data to be sent by FFA_MSG_SEND_DIRECT_REQ
> > + * or read from FFA_MSG_SEND_DIRECT_RESP
> > + */
> > +struct __packed ffa_send_direct_data {
> > + u32 a3; /* w3 */
> > + u32 a4; /* w4 */
> > + u32 a5; /* w5 */
> > + u32 a6; /* w6 */
> > + u32 a7; /* w7 */
> > +};
> > +
> > +#define FFA_MSG_SEND_DIRECT_MAX_SIZE (sizeof(struct ffa_send_direct_data))
> > +
> > +/* UUID data size */
> > +#define UUID_SIZE (16)
> > +
> > +/*
> > + * union ffa_partition_uuid - Data union hosting the UUID
> > + * transmitted by FFA_PARTITION_INFO_GET
> > + * @words: data structure giving 32-bit words access to the UUID data
> > + * @bytes: data structure giving byte access to the UUID data
> > + *
> > + * The structure holds little-endian UUID data.
> > + */
> > +union ffa_partition_uuid {
> > + struct __packed words {
> > + u32 a1; /* w1 */
> > + u32 a2; /* w2 */
> > + u32 a3; /* w3 */
> > + u32 a4; /* w4 */
> > + } words;
> > + u8 bytes[UUID_SIZE];
> > +};
> > +
> > +/**
> > + * struct ffa_interface_data - generic FF-A interface data structure used to exchange
> > + * data between user layers and the driver
> > + * @data0_size: size of the first argument
> > + * @data0: pointer to the first argument
> > + * @data1_size>: size of the second argument
> > + * @data1: pointer to the second argument
> > + *
> > + * Using this structure user layers can pass various types of data with different sizes.
> > + * The driver internal functions can detect the nature of this data, verfy compliance
> > + * then execute the request when appropriate.
> > + */
> > +struct ffa_interface_data {
> > + u32 data0_size; /* size of the first argument */
> > + void *data0; /* pointer to the first argument */
> > + u32 data1_size; /* size of the second argument */
> > + void *data1; /* pointer to the second argument */
> > +};
> > +
> > +/**
> > + * struct ffa_ops - The driver operations structure
> > + * @invoke_func: function pointer to the invoke function
> > + *
> > + * The data structure providing all the operations supported by the driver.
> > + * This structure is resident.
> > + */
> > +struct ffa_ops {
> > + /* the driver dispatcher */
> > + int (*invoke_func)(u32 func_id, struct ffa_interface_data *func_data);
> > +};
> > +
> > +/**
> > + * The device driver and the Uclass driver public functions
> > + */
> > +
> > +/**
> > + * ffa_get_invoke_func - performs a call to the FF-A driver dispatcher
> > + */
> > +int __ffa_runtime ffa_get_invoke_func(u32 func_id,
> > + struct ffa_interface_data *func_data);
> > +
> > +/**
> > + * ffa_device_get_ops - driver operations getter
> > + */
> > +const struct ffa_ops * __ffa_runtime ffa_device_get_ops(void);
> > +
> > +/**
> > + * ffa_get_device - create, bind and probe the arm_ffa device
> > + */
> > +int ffa_get_device(void);
> > +
> > +/**
> > + * ffa_bus_discover - discover FF-A bus and probes the arm_ffa device
> > + */
> > +int ffa_bus_discover(void);
> > +#endif
> > diff --git a/include/arm_ffa_helper.h b/include/arm_ffa_helper.h
> > new file mode 100644
> > index 0000000000..1cf68748f0
> > --- /dev/null
> > +++ b/include/arm_ffa_helper.h
> > @@ -0,0 +1,45 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
> > +/*
> > + * (C) Copyright 2022 ARM Limited
> > + * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > + */
> > +
> > +#ifndef __ARM_FFA_HELPER_H
> > +#define __ARM_FFA_HELPER_H
> > +
> > +#include <arm_ffa.h>
> > +
> > +/*
> > + * This header is public. Including this header provides all data structures
> > + * and definitions needed by clients to use the FF-A transport driver
> > + *
> > + * It also provides helper functions allowing to pass data and invoke FF-A functions
> > + */
> > +
> > +/**
> > + * ffa_helper_get_partitions_info - Wrapper function for FFA_PARTITION_INFO_GET
> > + */
> > +int ffa_helper_get_partitions_info(struct ffa_interface_data *func_data);
> > +
> > +/**
> > + * ffa_helper_unmap_rxtx_buffers - Wrapper function for FFA_RXTX_UNMAP
> > + */
> > +int ffa_helper_unmap_rxtx_buffers(void);
> > +
> > +/**
> > + * ffa_helper_msg_send_direct_req - Wrapper function for
> > + * FFA_MSG_SEND_DIRECT_{REQ,RESP}
> > + */
> > +int __ffa_runtime ffa_helper_msg_send_direct_req(struct ffa_interface_data
> > + *func_data);
> > +
> > +/**
> > + * ffa_helper_bus_discover - Wrapper function for FF-A bus discovery
> > + */
> > +int ffa_helper_bus_discover(void);
> > +
> > +/**
> > + * ffa_uuid_str_to_bin - Converts a big endian UUID string to a little endian buffer
> > + */
> > +int ffa_uuid_str_to_bin(const char *uuid_str, unsigned char *uuid_bin);
> > +#endif
> > diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
> > index 0e26e1d138..a1181b8f48 100644
> > --- a/include/dm/uclass-id.h
> > +++ b/include/dm/uclass-id.h
> > @@ -52,6 +52,7 @@ 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_FS_FIRMWARE_LOADER, /* Generic loader */
> > UCLASS_GPIO, /* Bank of general-purpose I/O pins */
> > diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
> > index 7f2be23394..d58c7c104b 100644
> > --- a/include/linux/arm-smccc.h
> > +++ b/include/linux/arm-smccc.h
> > @@ -1,6 +1,8 @@
> > /* SPDX-License-Identifier: GPL-2.0 */
> > /*
> > * Copyright (c) 2015, Linaro Limited
> > + * (C) Copyright 2022 ARM Limited
> > + * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > */
> > #ifndef __LINUX_ARM_SMCCC_H
> > #define __LINUX_ARM_SMCCC_H
> > @@ -57,13 +59,17 @@
> > #include <linux/types.h>
> > /**
> > * struct arm_smccc_res - Result from SMC/HVC call
> > - * @a0-a3 result values from registers 0 to 3
> > + * @a0-a7 result values from registers 0 to 7
> > */
> > struct arm_smccc_res {
> > unsigned long a0;
> > unsigned long a1;
> > unsigned long a2;
> > unsigned long a3;
> > + unsigned long a4;
> > + unsigned long a5;
> > + unsigned long a6;
> > + unsigned long a7;
> > };
> >
> > /**
> > @@ -113,6 +119,26 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
> > unsigned long a5, unsigned long a6, unsigned long a7,
> > struct arm_smccc_res *res, struct arm_smccc_quirk *quirk);
> >
> > +#if (IS_ENABLED(CONFIG_ARM_FFA_TRANSPORT))
> > +/**
> > + * __arm_ffa_smccc_smc() - make SMC calls used for FF-A transport
> > + * @a0-a7: arguments passed in 64-bit registers x0 to x7
> > + * @res: result values from 64-bit registers x0 to x7
> > + *
> > + * This function is used to make SMC calls following SMC32 Calling Convention.
> > + * The content of the supplied parameters is copied to registers x0 to x7 prior
> > + * to the SMC instruction. The SMC call return data is 32-bit data read from
> > + * registers x0 tp x7.
> > + */
> > +asmlinkage void __arm_ffa_smccc_smc(unsigned long a0, unsigned long a1,
> > + unsigned long a2, unsigned long a3, unsigned long a4,
> > + unsigned long a5, unsigned long a6, unsigned long a7,
> > + struct arm_smccc_res *res);
> > +
> > +#define arm_ffa_smccc_smc __arm_ffa_smccc_smc
> > +
> > +#endif
> > +
>
> How about leaving the FF-A bit out of this and only have generic SMCCC
> support? That would make it easier to bring in updates from Linux
> without reinventing the wheel. I would also be nice to know which
> version of the SMCCC we're using.

Done through this patch: https://lore.kernel.org/all/20220926101723.9965-2-abdellatif.elkhlifi@arm.com/

>
> Cheers,
> Jens
>
> > #define arm_smccc_smc(...) __arm_smccc_smc(__VA_ARGS__, NULL)
> >
> > #define arm_smccc_smc_quirk(...) __arm_smccc_smc(__VA_ARGS__)
> > diff --git a/lib/Kconfig b/lib/Kconfig
> > index effe735365..9006e8d44c 100644
> > --- a/lib/Kconfig
> > +++ b/lib/Kconfig
> > @@ -845,6 +845,7 @@ config SMBIOS_PARSER
> > source lib/efi/Kconfig
> > source lib/efi_loader/Kconfig
> > source lib/optee/Kconfig
> > +source lib/arm-ffa/Kconfig
> >
> > config TEST_FDTDEC
> > bool "enable fdtdec test"
> > diff --git a/lib/Makefile b/lib/Makefile
> > index 13fe5fb7a4..36f67cd94e 100644
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -9,6 +9,7 @@ obj-$(CONFIG_EFI) += efi/
> > obj-$(CONFIG_EFI_LOADER) += efi_driver/
> > obj-$(CONFIG_EFI_LOADER) += efi_loader/
> > obj-$(CONFIG_CMD_BOOTEFI_SELFTEST) += efi_selftest/
> > +obj-$(CONFIG_ARM_FFA_TRANSPORT_HELPERS) += arm-ffa/
> > obj-$(CONFIG_LZMA) += lzma/
> > obj-$(CONFIG_BZIP2) += bzip2/
> > obj-$(CONFIG_TIZEN) += tizen/
> > diff --git a/lib/arm-ffa/Kconfig b/lib/arm-ffa/Kconfig
> > new file mode 100644
> > index 0000000000..79acbc5a8f
> > --- /dev/null
> > +++ b/lib/arm-ffa/Kconfig
> > @@ -0,0 +1,6 @@
> > +config ARM_FFA_TRANSPORT_HELPERS
> > + bool "Enable interface helpers for Arm Firmware Framework for Armv8-A"
> > + depends on ARM_FFA_TRANSPORT
> > + help
> > + User layers call FF-A interfaces using helper functions which
> > + pass the data and the FF-A function ID to the low level driver
> > diff --git a/lib/arm-ffa/Makefile b/lib/arm-ffa/Makefile
> > new file mode 100644
> > index 0000000000..cba625fde4
> > --- /dev/null
> > +++ b/lib/arm-ffa/Makefile
> > @@ -0,0 +1,8 @@
> > +# SPDX-License-Identifier: GPL-2.0+
> > +#
> > +# (C) Copyright 2022 Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > +#
> > +
> > +# This file only gets included when CONFIG_ARM_FFA_TRANSPORT_HELPERS is set
> > +
> > +obj-y += arm_ffa_helper.o
> > diff --git a/lib/arm-ffa/arm_ffa_helper.c b/lib/arm-ffa/arm_ffa_helper.c
> > new file mode 100644
> > index 0000000000..a291b000a7
> > --- /dev/null
> > +++ b/lib/arm-ffa/arm_ffa_helper.c
> > @@ -0,0 +1,188 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * (C) Copyright 2022 ARM Limited
> > + * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > + */
> > +
> > +#include <common.h>
> > +#include <arm_ffa_helper.h>
> > +#include <uuid.h>
> > +
> > +/**
> > + * ffa_helper_get_partitions_info - Wrapper function for FFA_PARTITION_INFO_GET
> > + *
> > + * @func_data: Pointer to the FF-A function arguments container
> > + * structure.
> > + * The passed arguments:
> > + * Mode 1: When getting from the driver the number of
> > + * secure partitions:
> > + * @data0_size: UUID size
> > + * @data0: pointer to the UUID (little endian)
> > + * @data1_size: size of the number of partitions
> > + * variable
> > + * @data1: pointer to the number of partitions
> > + * variable. The variable will be set
> > + * by the driver
> > + * Mode 2: When requesting the driver to return the
> > + * partitions information:
> > + * @data0_size: UUID size
> > + * @data0: pointer to the UUID (little endian)
> > + * @data1_size: size of the SPs information buffer
> > + * @data1: pointer to SPs information buffer
> > + * (allocated by the client).
> > + * The buffer will be filled by the driver
> > + *
> > + * This is the boot time function used by clients who wants to get from secure
> > + * world the partition(s) information.
> > + *
> > + * 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 client should use
> > + * ffa_helper_get_partitions_info to pass the UUID information to the driver
> > + * which uses PARTITION_INFO_GET to obtain the partition(s) information.
> > + *
> > + * ffa_helper_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.
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int ffa_helper_get_partitions_info(struct ffa_interface_data *func_data)
> > +{
> > + return ffa_get_invoke_func(FFA_PARTITION_INFO_GET, func_data);
> > +}
> > +
> > +/**
> > + * ffa_helper_unmap_rxtx_buffers - Wrapper function for FFA_RXTX_UNMAP
> > + *
> > + * This is the boot time function that allows clients to unmap the RX/TX
> > + * buffers
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int ffa_helper_unmap_rxtx_buffers(void)
> > +{
> > + return ffa_get_invoke_func(FFA_RXTX_UNMAP, NULL);
> > +}
> > +
> > +/**
> > + * ffa_helper_msg_send_direct_req - Wrapper function for
> > + * FFA_MSG_SEND_DIRECT_{REQ,RESP}
> > + * @func_data: Pointer to the FF-A function arguments container structure.
> > + * The passed arguments:
> > + * @data0_size: partition ID size
> > + * @data0: pointer to the partition ID
> > + * @data1_size: exchanged data size
> > + * @data1: pointer to the data buffer preallocated by the client (in/out)
> > + *
> > + * This is the runtime function that allows clients to send data to the secure
> > + * world partitions. The arm_ffa driver uses FFA_MSG_SEND_DIRECT_REQ to send the
> > + * data to the secure partition. The response from the secure partition is
> > + * handled internally by the driver using FFA_MSG_SEND_DIRECT_RESP and returned
> > + * to ffa_helper_msg_send_direct_req through @func_data
> > + *
> > + * The maximum size of the data that can be exchanged is 20 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}
> > + *
> > + * The client should pre-allocate a buffer pointed by @data1 which the size
> > + * is sizeof(struct ffa_send_direct_data)
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int __ffa_runtime ffa_helper_msg_send_direct_req(struct ffa_interface_data
> > + *func_data)
> > +{
> > + return ffa_get_invoke_func(FFA_MSG_SEND_DIRECT_REQ, func_data);
> > +}
> > +
> > +/**
> > + * ffa_helper_bus_discover - Wrapper function for FF-A bus discovery
> > + *
> > + * This boot time function should be called to discover the FF-A bus and
> > + * probe the FF-A device.
> > + * To achieve that, this function is called automatically at initcalls
> > + * level (after u-boot relocation).
> > + *
> > + * Return:
> > + *
> > + * FFA_ERR_STAT_SUCCESS on success. Otherwise, failure
> > + */
> > +int ffa_helper_bus_discover(void)
> > +{
> > + return ffa_bus_discover();
> > +}
> > +
> > +/**
> > + * ffa_uuid_str_to_bin - Converts a big endian UUID string to a little endian buffer
> > + * @uuid_str: UUID string in big endian format (36 bytes wide + '/0')
> > + * @uuid_bin: preallocated 16 bytes UUID buffer in little endian format
> > + *
> > + * UUID binary format used by the FF-A framework (16 bytes):
> > + *
> > + * [LSB] 4B-2B-2B-2B-6B (little endian data fields)
> > + *
> > + * UUID string is 36 length of characters (36 bytes):
> > + *
> > + * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
> > + * be be be be be
> > + *
> > + * where x is a hexadecimal character. Fields are separated by '-'s.
> > + * When converting to a binary UUID, these endianness rules apply:
> > + * be: means the field in the string is considered a big endian hex number
> > + * and should be converted to little endian binary format
> > + *
> > + * Return:
> > + *
> > + * uuid_bin filled with little endian UUID data
> > + * On success 0 is returned. Otherwise, failure code.
> > + */
> > +int ffa_uuid_str_to_bin(const char *uuid_str, unsigned char *uuid_bin)
> > +{
> > + u16 tmp16 = 0;
> > + u32 tmp32 = 0;
> > + u64 tmp64 = 0;
> > +
> > + if (!uuid_str_valid(uuid_str) || !uuid_bin)
> > + return -EINVAL;
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp32 = simple_strtoul(uuid_str, NULL, 16);
> > + memcpy(uuid_bin, &tmp32, 4);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp16 = simple_strtoul(uuid_str + 9, NULL, 16);
> > + memcpy(uuid_bin + 4, &tmp16, 2);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp16 = simple_strtoul(uuid_str + 14, NULL, 16);
> > + memcpy(uuid_bin + 6, &tmp16, 2);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp16 = simple_strtoul(uuid_str + 19, NULL, 16);
> > + memcpy(uuid_bin + 8, &tmp16, 2);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp64 = simple_strtoull(uuid_str + 24, NULL, 16);
> > + memcpy(uuid_bin + 10, (char *)&tmp64, 6);
> > +
> > + return 0;
> > +}
> > diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> > index 5bcb8253ed..cffa2c69d6 100644
> > --- a/lib/efi_loader/efi_boottime.c
> > +++ b/lib/efi_loader/efi_boottime.c
> > @@ -23,6 +23,10 @@
> > #include <asm/setjmp.h>
> > #include <linux/libfdt_env.h>
> >
> > +#if defined(CONFIG_ARM_FFA_TRANSPORT)
> > +#include <arm_ffa_helper.h>
> > +#endif
> > +
> > DECLARE_GLOBAL_DATA_PTR;
> >
> > /* Task priority level */
> > @@ -2114,6 +2118,10 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
> > struct efi_event *evt, *next_event;
> > efi_status_t ret = EFI_SUCCESS;
> >
> > +#if defined(CONFIG_ARM_FFA_TRANSPORT)
> > + int ffa_ret;
> > +#endif
> > +
> > EFI_ENTRY("%p, %zx", image_handle, map_key);
> >
> > /* Check that the caller has read the current memory map */
> > @@ -2174,6 +2182,15 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
> > dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);
> > }
> >
> > +#if defined(CONFIG_ARM_FFA_TRANSPORT)
> > + /* unmap FF-A RX/TX buffers */
> > + ffa_ret = ffa_helper_unmap_rxtx_buffers();
> > + if (ffa_ret)
> > + debug("[efi_boottime][ERROR]: can not unmap FF-A RX/TX buffers\n");
> > + else
> > + debug("[efi_boottime][INFO]: FF-A RX/TX buffers unmapped\n");
> > +#endif
> > +
> > /* Patch out unsupported runtime function */
> > efi_runtime_detach();
> >
> > --
> > 2.17.1
> >