[PATCH v2 02/25] arm_ffa: Add FFA_MEM_SHARE support

Jens Wiklander jens.wiklander at linaro.org
Wed Aug 20 19:38:21 CEST 2025


Hi,

On Fri, Jul 11, 2025 at 4:49 PM <abdellatif.elkhlifi at arm.com> wrote:
>
> From: Abdellatif El Khlifi <abdellatif.elkhlifi at arm.com>
>
> Add to the FF-A bus FFA_MEM_SHARE ABI
>
> The FFA_MEM_SHARE is a memory management ABI described in the FF-A v1.0
> specification [1].
>
> This ABI starts a transaction to grant access to a memory region
> to one or more Borrowers (aka Secure Partitions or endpoints).
>
> This work is based on the implementation in Linux kernel [2].
>
> [1]: https://developer.arm.com/documentation/den0077/a/?lang=en
> [2]: commit cc2195fe536c28e192df5d07e6dd277af36814b4
>      Files: drivers/firmware/arm_ffa/driver.c , include/linux/arm_ffa.h
>
> Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi at arm.com>
> Cc: Tom Rini <trini at konsulko.com>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> Cc: Jens Wiklander <jens.wiklander at linaro.org>
> Cc: Casey Connolly <casey.connolly at linaro.org>
> Cc: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
>
> ---
>
> Changelog of changes:
> ===========================
>
> v2:
>
> * As suggested by Heinrich: The ops NULL check removed
>
> v1:
>
> * Add FFA_MEM_SHARE support
>
>  doc/arch/arm64.ffa.rst                    |   2 +
>  drivers/firmware/arm-ffa/arm-ffa-uclass.c | 210 ++++++++++++++++++++++
>  drivers/firmware/arm-ffa/arm-ffa.c        |   3 +-
>  include/arm_ffa.h                         |  86 ++++++++-
>  include/arm_ffa_priv.h                    | 142 ++++++++++++++-
>  5 files changed, 439 insertions(+), 4 deletions(-)
>
> diff --git a/doc/arch/arm64.ffa.rst b/doc/arch/arm64.ffa.rst
> index f966f8ba6af..3eec735d741 100644
> --- a/doc/arch/arm64.ffa.rst
> +++ b/doc/arch/arm64.ffa.rst
> @@ -185,6 +185,7 @@ The following features are provided:
>      - FFA_INTERRUPT
>      - FFA_MSG_SEND_DIRECT_REQ
>      - FFA_MSG_SEND_DIRECT_RESP
> +    - FFA_MEM_SHARE
>
>  - Support for the 64-bit version of the following ABIs:
>
> @@ -203,6 +204,7 @@ The following features are provided:
>      - ffa_partition_info_get
>      - ffa_sync_send_receive
>      - ffa_rxtx_unmap
> +    - ffa_memory_share
>
>  - FF-A bus discovery makes sure FF-A framework is responsive and compatible
>    with the driver
> diff --git a/drivers/firmware/arm-ffa/arm-ffa-uclass.c b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
> index 32dd9458da9..9af574760d2 100644
> --- a/drivers/firmware/arm-ffa/arm-ffa-uclass.c
> +++ b/drivers/firmware/arm-ffa/arm-ffa-uclass.c
> @@ -95,6 +95,20 @@ static struct ffa_abi_errmap err_msg_map[FFA_ERRMAP_COUNT] = {
>                         "DENIED: Buffer pair already registered",
>                 },
>         },
> +       [FFA_ID_TO_ERRMAP_ID(FFA_MEM_SHARE)] = {
> +               {
> +                       [ABORTED] =
> +                       "ABORTED: Failure in the transmission of fragments or in time slicing",
> +                       [INVALID_PARAMETERS] =
> +                       "INVALID_PARAMETERS: Validation failed for the Memory Transaction or the Endpoint memory access descriptor",
> +                       [NO_MEMORY] =
> +                       "NO_MEMORY: Insufficient memory to complete this operation",
> +                       [BUSY] =
> +                       "BUSY: The TX buffer is busy",
> +                       [DENIED] =
> +                       "DENIED: Memory region ownership, permission, access or attributes error",
> +               },
> +       },
>  };
>
>  /**
> @@ -929,6 +943,177 @@ int ffa_msg_send_direct_req_hdlr(struct udevice *dev, u16 dst_part_id,
>         return ffa_to_std_errno(ffa_errno);
>  }
>
> +/**
> + * ffa_mem_desc_offset() - helper for descriptors offset calculation
> + * @count: An integer defining the number of Endpoint memory access descriptors
> + *
> + * Calculate the offset of the Endpoint memory access descriptor and
> + * the Composite memory region descriptor.
> + *
> + * Return:
> + *
> + * The descriptor offset.
> + */
> +static inline u32 ffa_mem_desc_offset(int count)

"inline" doesn't make much difference in a .c file.

> +{
> +       u32 offset = count * sizeof(struct ffa_mem_region_attributes);
> +
> +       offset += sizeof(struct ffa_mem_region);
> +
> +       return offset;
> +}
> +
> +/**
> + * ffa_setup_and_transmit() - set up the memory and transmit data using FF-A
> + * @dev: The FF-A bus device
> + * @func_id: An integer identifying the function
> + * @buffer: A pointer to the data to be transmitted (FF-A TX buffer)
> + * @args: A pointer to a structure containing additional user arguments
> + *
> + * Setup the memory transaction related to the access to a specified
> + * memory region.
> + * Currently we support FFA_MEM_SHARE only.
> + *
> + * Return:
> + *
> + * 0 on success. . Otherwise, failure
> + */
> +static int ffa_setup_and_transmit(struct udevice *dev, u32 func_id,
> +                                 void *buffer, struct ffa_mem_ops_args *args)
> +{
> +       ffa_value_t res = {0};
> +       int ffa_errno;
> +       u32 composite_offset;
> +       u32 total_length;
> +       struct ffa_mem_region *mem_region = buffer;
> +       struct ffa_composite_mem_region *composite;
> +       struct ffa_mem_region_addr_range *constituent;
> +       struct ffa_mem_region_attributes *ep_mem_access;
> +       u32 idx;
> +       struct ffa_priv *uc_priv;
> +
> +       uc_priv = dev_get_uclass_priv(dev);
> +
> +       mem_region->tag = args->tag;
> +       mem_region->flags = args->flags;
> +       mem_region->sender_id = uc_priv->id;
> +
> +       /*
> +        * These attributes are only valid for FFA_MEM_SHARE.
> +        * They are not valid for FFA_MEM_LEND (no implemented).
> +        */
> +       if (func_id == FFA_MEM_SHARE)
> +               mem_region->attributes = FFA_MEM_NORMAL | FFA_MEM_WRITE_BACK
> +                                | FFA_MEM_INNER_SHAREABLE;
> +       else
> +               mem_region->attributes = 0;
> +
> +       mem_region->handle = 0;
> +       mem_region->ep_count = args->nattrs;
> +       mem_region->reserved1 = 0;
> +       mem_region->reserved2 = 0;
> +
> +       ep_mem_access = buffer + ffa_mem_desc_offset(0);
> +
> +       composite_offset = ffa_mem_desc_offset(args->nattrs);
> +
> +       /* Multiple borrowers supported */
> +       for (idx = 0; idx < args->nattrs; idx++, ep_mem_access++) {
> +               ep_mem_access->receiver = args->attrs[idx].receiver;
> +               ep_mem_access->attrs = args->attrs[idx].attrs;
> +               ep_mem_access->composite_off = composite_offset;
> +               ep_mem_access->flag = 0;
> +               ep_mem_access->reserved = 0;
> +       }
> +
> +       /* Only one Composite and one Constituent memory region supported */
> +       composite = buffer + composite_offset;
> +       composite->total_pg_cnt = args->pg_cnt;
> +       composite->addr_range_cnt = FFA_MEM_CONSTITUENTS;
> +       composite->reserved = 0;
> +
> +       constituent = &composite->constituents[0];
> +       constituent->address = map_to_sysmem(args->address);
> +       constituent->pg_cnt = args->pg_cnt;
> +       constituent->reserved = 0;
> +
> +       total_length = composite_offset + sizeof(*composite) +
> +               sizeof(*constituent);
> +
> +       /*
> +        * Note: Time slicing is not supported.
> +        * It's only available to EL1 and S-EL1 endpoints.
> +        */

Isn't U-Boot an EL1 endpoint?

> +
> +       invoke_ffa_fn((ffa_value_t){
> +                       .a0 = FFA_SMC_32(func_id),
> +                       .a1 = total_length,
> +                       .a2 = total_length,
> +                       .a3 = 0, /* the TX buffer is used */
> +                       .a4 = 0, /* the TX buffer is used */
> +                       },
> +                       &res
> +       );
> +
> +       if (res.a0 != FFA_SMC_32(FFA_SUCCESS)) {
> +               ffa_errno = res.a2;
> +               ffa_print_error_log(func_id, ffa_errno);
> +               return ffa_to_std_errno(ffa_errno);
> +       }
> +
> +       args->g_handle = PACK_HANDLE(res.a2, res.a3);
> +       return 0;
> +}
> +
> +/**
> + * ffa_memory_ops() - wrapper for the memory management ABIs
> + * @dev: The FF-A bus device
> + * @func_id: An integer identifying the function
> + * @args: A pointer to a structure containing additional user arguments
> + *
> + * Verify the use of the TX buffer then call ffa_setup_and_transmit().
> + * Currently we support FFA_MEM_SHARE only.
> + *
> + * Return:
> + *
> + * 0 on success. Otherwise, failure
> + */
> +static int ffa_memory_ops(struct udevice *dev, u32 func_id,
> +                         struct ffa_mem_ops_args *args)
> +{
> +       void *buffer;
> +       struct ffa_priv *uc_priv = dev_get_uclass_priv(dev);
> +
> +       if (!args->use_txbuf) {
> +               log_err("only TX buffer supported\n");
> +               return -EPROTONOSUPPORT;
> +       }
> +
> +       buffer = uc_priv->pair.txbuf;
> +
> +       if (!buffer || !args->attrs || !args->address)
> +               return -EINVAL;
> +
> +       return ffa_setup_and_transmit(dev, func_id, buffer, args);
> +}
> +
> +/**
> + * ffa_memory_share_hdlr() - FFA_MEM_SHARE handler function
> + * @dev: The FF-A bus device
> + * @args: A pointer to a structure containing additional user arguments
> + *
> + * Implement FFA_MEM_SHARE FF-A function
> + * to grant access to a memory region to one or more Borrowers.
> + *
> + * Return:
> + *
> + * 0 on success. Otherwise, failure
> + */
> +int ffa_memory_share_hdlr(struct udevice *dev, struct ffa_mem_ops_args *args)
> +{
> +       return ffa_memory_ops(dev, FFA_MEM_SHARE, args);
> +}
> +
>  /* FF-A driver operations (used by clients for communicating with FF-A)*/
>
>  /**
> @@ -1006,6 +1191,31 @@ int ffa_rxtx_unmap(struct udevice *dev)
>         return ops->rxtx_unmap(dev);
>  }
>
> +/**
> + * ffa_memory_share() - FFA_MEM_SHARE driver operation
> + * @dev: The FF-A bus device
> + * @args: A pointer to a structure containing additional user arguments
> + *
> + * Driver operation for FFA_MEM_SHARE.
> + * Please see ffa_memory_share_hdlr() description for more details.
> + *
> + * Return:
> + *
> + * 0 on success. Otherwise, failure
> + */
> +int ffa_memory_share(struct udevice *dev, struct ffa_mem_ops_args *args)
> +{
> +       struct ffa_bus_ops *ops = ffa_get_ops(dev);
> +
> +       if (!args)
> +               return -EINVAL;
> +
> +       if (!ops->memory_share)
> +               return -ENOSYS;
> +
> +       return ops->memory_share(dev, args);
> +}
> +
>  /**
>   * ffa_do_probe() - probing FF-A framework
>   * @dev:       the FF-A bus device (arm_ffa)
> diff --git a/drivers/firmware/arm-ffa/arm-ffa.c b/drivers/firmware/arm-ffa/arm-ffa.c
> index 94e6105cb38..df904cae412 100644
> --- a/drivers/firmware/arm-ffa/arm-ffa.c
> +++ b/drivers/firmware/arm-ffa/arm-ffa.c
> @@ -1,6 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0+
>  /*
> - * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office at arm.com>
> + * Copyright 2022-2023, 2025 Arm Limited and/or its affiliates <open-source-office at arm.com>
>   *
>   * Authors:
>   *   Abdellatif El Khlifi <abdellatif.elkhlifi at arm.com>
> @@ -84,6 +84,7 @@ static const struct ffa_bus_ops ffa_ops = {
>         .partition_info_get = ffa_get_partitions_info_hdlr,
>         .sync_send_receive = ffa_msg_send_direct_req_hdlr,
>         .rxtx_unmap = ffa_unmap_rxtx_buffers_hdlr,
> +       .memory_share = ffa_memory_share_hdlr,
>  };
>
>  /* Registering the FF-A driver as an SMCCC feature driver */
> diff --git a/include/arm_ffa.h b/include/arm_ffa.h
> index 2994d8ee3ae..b91b0279371 100644
> --- a/include/arm_ffa.h
> +++ b/include/arm_ffa.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0+ */
>  /*
> - * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office at arm.com>
> + * Copyright 2022-2023, 2025 Arm Limited and/or its affiliates <open-source-office at arm.com>
>   *
>   * Authors:
>   *   Abdellatif El Khlifi <abdellatif.elkhlifi at arm.com>
> @@ -81,11 +81,74 @@ struct ffa_send_direct_data {
>
>  struct udevice;
>
> +/**
> + * struct ffa_mem_region_attributes - Endpoint memory access descriptor
> + *
> + * The data structure used in memory management transactions to create an
> + * association between an endpoint, memory access permissions and a composite
> + * memory region description.
> + *
> + * For more details, please refer to Table 5.16 and Table 5.15 in the FF-A
> + * specification v1.0.
> + *
> + * This structure was taken from Linux.
> + */
> +struct ffa_mem_region_attributes {
> +       /* The ID of the VM to which the memory is being given or shared. */
> +       u16 receiver;
> +       /*
> +        * The permissions with which the memory region should be mapped in the
> +        * receiver's page table.
> +        */
> +#define FFA_MEM_EXEC           BIT(3)
> +#define FFA_MEM_NO_EXEC                BIT(2)
> +#define FFA_MEM_RW             BIT(1)
> +#define FFA_MEM_RO             BIT(0)
> +       u8 attrs;
> +       /*
> +        * Flags used during FFA_MEM_RETRIEVE_REQ and FFA_MEM_RETRIEVE_RESP
> +        * for memory regions with multiple borrowers.
> +        */
> +#define FFA_MEM_RETRIEVE_SELF_BORROWER BIT(0)
> +       u8 flag;
> +       /*
> +        * Offset in bytes from the start of the outer `ffa_memory_region` to
> +        * an `struct ffa_mem_region_addr_range`.
> +        */
> +       u32 composite_off;
> +       u64 reserved;
> +};
> +
> +/**
> + * struct ffa_mem_ops_args - User arguments to the memory management ABIs
> + * @use_txbuf: Whether to use the TX buffer for the memory transaction
> + * @nattrs:    Number of the borrowers
> + * @flags:     Memory transaction flags
> + * @tag:       The tag associated with the transaction
> + * @g_handle:  Globally unique Handle to identify the memory region (out)
> + * @address:   Virtual address of the memory region
> + * @attrs:     Memory access permissions of each borrower
> + *
> + * The structured filled by the user and passed to the memory
> + * management ABIs (e.g: FFA_MEM_SHARE)
> + */
> +struct ffa_mem_ops_args {
> +       bool use_txbuf;
> +       u32 nattrs;
> +       u32 flags;
> +       u64 tag;
> +       u64 g_handle;
> +       void *address;
> +       u32 pg_cnt;
> +       struct ffa_mem_region_attributes *attrs;
> +};
> +
>  /**
>   * struct ffa_bus_ops - Operations for FF-A
>   * @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
> + * @memory_share:      callback for the FFA_MEM_SHARE
>   *
>   * The data structure providing all the operations supported by the driver.
>   * This structure is EFI runtime resident.
> @@ -97,6 +160,7 @@ struct ffa_bus_ops {
>                                  struct ffa_send_direct_data *msg,
>                                  bool is_smc64);
>         int (*rxtx_unmap)(struct udevice *dev);
> +       int (*memory_share)(struct udevice *dev, struct ffa_mem_ops_args *args);
>  };
>
>  #define ffa_get_ops(dev)        ((struct ffa_bus_ops *)(dev)->driver->ops)
> @@ -196,6 +260,26 @@ int ffa_partition_info_get(struct udevice *dev, const char *uuid_str,
>  int ffa_get_partitions_info_hdlr(struct udevice *dev, const char *uuid_str,
>                                  u32 *sp_count, struct ffa_partition_desc **sp_descs);
>
> +/**
> + * ffa_memory_share() - FFA_MEM_SHARE driver operation
> + * Please see ffa_memory_share_hdlr() description for more details.
> + */
> +int ffa_memory_share(struct udevice *dev, struct ffa_mem_ops_args *args);
> +
> +/**
> + * ffa_memory_share_hdlr() - FFA_MEM_SHARE handler function
> + * @dev: The FF-A bus device
> + * @args: A pointer to a structure containing additional user arguments
> + *
> + * Implement FFA_MEM_SHARE FF-A function
> + * to grant access to a memory region to one or more Borrowers.
> + *
> + * Return:
> + *
> + * 0 on success. Otherwise, failure
> + */
> +int ffa_memory_share_hdlr(struct udevice *dev, struct ffa_mem_ops_args *args);
> +
>  struct ffa_priv;
>
>  /**
> diff --git a/include/arm_ffa_priv.h b/include/arm_ffa_priv.h
> index d564c33c647..a259911d5b9 100644
> --- a/include/arm_ffa_priv.h
> +++ b/include/arm_ffa_priv.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0+ */
>  /*
> - * Copyright 2022-2023 Arm Limited and/or its affiliates <open-source-office at arm.com>
> + * Copyright 2022-2023, 2025 Arm Limited and/or its affiliates <open-source-office at arm.com>
>   *
>   * Authors:
>   *   Abdellatif El Khlifi <abdellatif.elkhlifi at arm.com>
> @@ -132,10 +132,11 @@ enum ffa_abis {
>         FFA_RUN                   = 0x6d,
>         FFA_MSG_SEND_DIRECT_REQ   = 0x6f,
>         FFA_MSG_SEND_DIRECT_RESP  = 0x70,
> +       FFA_MEM_SHARE             = 0x73,
>
>         /* 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 */
> +       FFA_LAST_ID               = FFA_MEM_SHARE, /* Highest number ID */
>  };
>
>  enum ffa_abi_errcode {
> @@ -219,6 +220,143 @@ struct ffa_priv {
>         struct ffa_rxtxpair pair;
>  };
>
> +/* FF-A memory management ABIs data structures */
> +
> +/**
> + * struct ffa_mem_region - Lend, donate or share memory transaction descriptor
> + *
> + * Specifies the data structure that must be used by the Owner/Lender and a
> + * Borrower/Receiver in a transaction to donate, lend or share a memory region.
> + * It specifies the memory region description, properties and other transaction
> + * attributes in an invocation of the following ABIs.
> + *
> + * FFA_MEM_DONATE.
> + * FFA_MEM_LEND.
> + * FFA_MEM_SHARE.
> + * FFA_MEM_RETRIEVE_REQ.
> + * FFA_MEM_RETRIEVE_RESP.
> + *
> + * For more details, please refer to the Table 5.19 in the FF-A specification
> + * v1.0.
> + *
> + * The interpretation of some fields depends on the ABI this structure is used
> + * with. This variance in behavior is also specified in the Table 5.19.
> + *
> + * This structure was taken from Linux and adapted to FF-A v1.0.
> + */
> +struct ffa_mem_region {
> +       /* The ID of the VM/owner which originally sent the memory region */
> +       u16 sender_id;
> +#define FFA_MEM_NORMAL         BIT(5)
> +#define FFA_MEM_DEVICE         BIT(4)
> +
> +#define FFA_MEM_WRITE_BACK     (3 << 2)
> +#define FFA_MEM_NON_CACHEABLE  BIT(2)
> +
> +#define FFA_DEV_nGnRnE         (0 << 2)
> +#define FFA_DEV_nGnRE          BIT(2)

Prefer (1 << 2) here. That's also what's used in the kernel code.

> +#define FFA_DEV_nGRE           (2 << 2)
> +#define FFA_DEV_GRE            (3 << 2)
> +
> +#define FFA_MEM_NON_SHAREABLE  (0)
> +#define FFA_MEM_OUTER_SHAREABLE        (2)
> +#define FFA_MEM_INNER_SHAREABLE        (3)
> +       /* Memory region attributes */
> +       u8 attributes;
> +
> +       u8 reserved1;
> +
> +/*
> + * Clear memory region contents after unmapping it from the sender and
> + * before mapping it for any receiver.
> + */
> +#define FFA_MEM_CLEAR                  BIT(0)
> +/*
> + * Whether the hypervisor may time slice the memory sharing or retrieval
> + * operation.
> + */
> +#define FFA_TIME_SLICE_ENABLE          BIT(1)
> +
> +#define FFA_MEM_RETRIEVE_TYPE_IN_RESP  (0 << 3)
> +#define FFA_MEM_RETRIEVE_TYPE_SHARE    BIT(3)

Please use (1 << 3) for this value, like in the kernel.


Cheers,
Jens

> +#define FFA_MEM_RETRIEVE_TYPE_LEND     (2 << 3)
> +#define FFA_MEM_RETRIEVE_TYPE_DONATE   (3 << 3)
> +
> +#define FFA_MEM_RETRIEVE_ADDR_ALIGN_HINT       BIT(9)
> +#define FFA_MEM_RETRIEVE_ADDR_ALIGN(x)         ((x) << 5)
> +       /* Flags to control behaviour of the transaction. */
> +       u32 flags;
> +#define HANDLE_LOW_MASK                GENMASK_ULL(31, 0)
> +#define HANDLE_HIGH_MASK       GENMASK_ULL(63, 32)
> +#define HANDLE_LOW(x)          ((u32)(FIELD_GET(HANDLE_LOW_MASK, (x))))
> +#define        HANDLE_HIGH(x)          ((u32)(FIELD_GET(HANDLE_HIGH_MASK, (x))))
> +
> +#define PACK_HANDLE(l, h)              \
> +       (FIELD_PREP(HANDLE_LOW_MASK, (l)) | FIELD_PREP(HANDLE_HIGH_MASK, (h)))
> +       /*
> +        * A globally-unique ID assigned by the hypervisor for a region
> +        * of memory being sent between VMs.
> +        */
> +       u64 handle;
> +       /*
> +        * An implementation defined value associated with the receiver and the
> +        * memory region.
> +        */
> +       u64 tag;
> +
> +       u32 reserved2;
> +
> +       /*
> +        * The number of `ffa_mem_region_attributes` entries included in this
> +        * transaction.
> +        */
> +       u32 ep_count;
> +};
> +
> +/**
> + * struct ffa_mem_region_addr_range - Constituent memory region descriptor
> + *
> + * Each descriptor specifies the base address and size of a virtually or
> + * physically contiguous memory region.
> + *
> + * For more details, please refer to Table 5.14 in the FF-A
> + * specification v1.0.
> + *
> + * This structure was taken from Linux.
> + */
> +struct ffa_mem_region_addr_range {
> +       /* The base IPA of the constituent memory region, aligned to 4 kiB */
> +       u64 address;
> +       /* The number of 4 kiB pages in the constituent memory region. */
> +       u32 pg_cnt;
> +       u32 reserved;
> +};
> +
> +/**
> + * struct ffa_composite_mem_region - Composite memory region descriptor
> + *
> + * For more details, please refer to Table 5.13 in the FF-A
> + * specification v1.0.
> + *
> + * This structure was taken from Linux.
> + */
> +struct ffa_composite_mem_region {
> +       /*
> +        * The total number of 4 kiB pages included in this memory region. This
> +        * must be equal to the sum of page counts specified in each
> +        * `struct ffa_mem_region_addr_range`.
> +        */
> +       u32 total_pg_cnt;
> +       /* The number of constituents included in this memory region range */
> +#define FFA_MEM_CONSTITUENTS           (1)
> +       u32 addr_range_cnt;
> +       u64 reserved;
> +       /** An array of `addr_range_cnt` memory region constituents. */
> +       struct ffa_mem_region_addr_range constituents[];
> +};
> +
> +/* Functions prototypes */
> +
>  /**
>   * ffa_get_version_hdlr() - FFA_VERSION handler function
>   * @dev: The FF-A bus device
> --
> 2.25.1
>


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