components/rpc/ffarpc/caller/linux/ffarpc_caller.c

/*
 * Copyright (c) 2020-2021, Arm Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include "ffarpc_caller.h"
#include <arm_ffa_user.h>
#include <rpc/ffarpc/endpoint/ffarpc_call_args.h>
#include <rpc/ffarpc/endpoint/ffarpc_call_ops.h>
#include <protocols/rpc/common/packed-c/status.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#define DEFAULT_SHMEM_BUF_SIZE			(4096)

static rpc_call_handle call_begin(void *context, uint8_t **req_buf, size_t req_len);
static rpc_status_t call_invoke(void *context, rpc_call_handle handle, uint32_t opcode,
			    int *opstatus, uint8_t **resp_buf, size_t *resp_len);
static void call_end(void *context, rpc_call_handle handle);

static int kernel_write_req_buf(struct ffarpc_caller *s);
static int kernel_read_resp_buf(struct ffarpc_caller *s);
static int share_mem_with_partition(struct ffarpc_caller *s);
static int unshare_mem_with_partition(struct ffarpc_caller *s);



struct rpc_caller *ffarpc_caller_init(struct ffarpc_caller *s, const char *device_path)
{
	struct rpc_caller *base = &s->rpc_caller;

	base->context = s;
	base->call_begin = call_begin;
	base->call_invoke = call_invoke;
	base->call_end = call_end;

	s->device_path = device_path;
	s->fd = -1;
	s->call_ep_id = 0;
	s->shared_mem_handle = 0;
	s->shared_mem_required_size = DEFAULT_SHMEM_BUF_SIZE;
	s->req_buf = NULL;
	s->req_len = 0;
	s->resp_buf = NULL;
	s->resp_len = 0;
	s->is_call_transaction_in_progess = false;

	return base;
}

void ffarpc_caller_deinit(struct ffarpc_caller *s)
{
	s->rpc_caller.context = NULL;
	s->rpc_caller.call_begin = NULL;
	s->rpc_caller.call_invoke = NULL;
	s->rpc_caller.call_end = NULL;

	call_end(s, s);
	ffarpc_caller_close(s);
}

size_t ffarpc_caller_discover(const struct ffarpc_caller *s, const struct uuid_canonical *uuid,
						uint16_t *partition_ids, size_t discover_limit)
{
	size_t discover_count = 0;

	if (uuid && partition_ids && s->device_path) {
		int fd;

		fd = open(s->device_path, O_RDWR);

		if (fd >= 0) {
			int ioctl_status;
			struct ffa_ioctl_ep_desc discovered_partition;

			discovered_partition.uuid_ptr = (uintptr_t)&uuid->characters;
			discovered_partition.id = 0;

			ioctl_status = ioctl(fd, FFA_IOC_GET_PART_ID, &discovered_partition);

			if ((ioctl_status == 0) && (discover_count < discover_limit)) {
				partition_ids[discover_count] = discovered_partition.id;
				++discover_count;
			}

			close(fd);
		}
	}

    return discover_count;
}

int ffarpc_caller_open(struct ffarpc_caller *s, uint16_t call_ep_id)
{
    int ioctl_status = -1;

	if (s->device_path) {

		s->fd = open(s->device_path, O_RDWR);

		if (s->fd >= 0) {
			/* Allocate resource for session */
			ioctl_status = ioctl(s->fd, FFA_IOC_SHM_INIT, &s->shared_mem_handle);

			if (ioctl_status == 0) {
				/* Session successfully opened */
				s->call_ep_id = call_ep_id;
				ioctl_status = share_mem_with_partition(s);
			}

			if (ioctl_status != 0)  {
				/* Resource allocation or sharing error */
				close(s->fd);
				s->fd = -1;
			}
		}
	}

    return ioctl_status;
}

int ffarpc_caller_close(struct ffarpc_caller *s)
{
    int ioctl_status = -1;

    if (s->fd >= 0) {

        unshare_mem_with_partition(s);
        ioctl_status = ioctl(s->fd, FFA_IOC_SHM_DEINIT);
        close(s->fd);
        s->fd = -1;
        s->call_ep_id = 0;
    }

    return ioctl_status;
}

static rpc_call_handle call_begin(void *context, uint8_t **req_buf, size_t req_len)
{
	rpc_call_handle handle = NULL;
	struct ffarpc_caller *s = (struct ffarpc_caller*)context;

    if (!s->is_call_transaction_in_progess) {

        s->is_call_transaction_in_progess = true;
        handle = s;

        if (req_len > 0) {

            s->req_buf = malloc(req_len);

            if (s->req_buf) {

                *req_buf = s->req_buf;
                s->req_len = req_len;
            }
            else {
                /* Failed to allocate req buffer */
                handle = NULL;
                s->is_call_transaction_in_progess = false;
            }
        }
        else {

            *req_buf = NULL;
            s->req_buf = NULL;
            s->req_len = req_len;
        }
    }

    return handle;
}

static rpc_status_t call_invoke(void *context, rpc_call_handle handle, uint32_t opcode,
			    int *opstatus, uint8_t **resp_buf, size_t *resp_len)
{
    rpc_status_t rpc_status = TS_RPC_ERROR_INTERNAL;
	struct ffarpc_caller *s = (struct ffarpc_caller*)context;

    if ((handle == s) && s->is_call_transaction_in_progess) {
        int kernel_op_status = 0;

        if (s->req_len > 0) {
            kernel_op_status = kernel_write_req_buf(s);
        }

        if (kernel_op_status == 0) {
            /* Make direct call to send the request */
            struct ffa_ioctl_msg_args direct_msg;
            memset(&direct_msg, 0, sizeof(direct_msg));

		    direct_msg.dst_id = s->call_ep_id;
		    direct_msg.args[FFA_CALL_ARGS_OPCODE] = (uint64_t)opcode;
		    direct_msg.args[FFA_CALL_ARGS_REQ_DATA_LEN] = (uint64_t)s->req_len;

            kernel_op_status = ioctl(s->fd, FFA_IOC_MSG_SEND, &direct_msg);

            if (kernel_op_status == 0) {
                /* Send completed normally - ffa return args in msg_args struct */
                s->resp_len = (size_t)direct_msg.args[FFA_CALL_ARGS_RESP_DATA_LEN];
                rpc_status = (int)direct_msg.args[FFA_CALL_ARGS_RESP_RPC_STATUS];
                *opstatus = (int)direct_msg.args[FFA_CALL_ARGS_RESP_OP_STATUS];

                if (s->resp_len > 0) {
                    s->resp_buf = malloc(s->resp_len);

                    if (s->resp_buf) {
                        kernel_op_status = kernel_read_resp_buf(s);

                        if (kernel_op_status != 0) {
                            /* Failed to read response buffer */
                            rpc_status = TS_RPC_ERROR_INTERNAL;
                        }
                    }
                    else {
                        /* Failed to allocate response buffer */
                        s->resp_len = 0;
                        rpc_status = TS_RPC_ERROR_INTERNAL;
                    }
                }
                else {
					/* No response parameters */
                    s->resp_buf = NULL;
                }

                *resp_len = s->resp_len;
                *resp_buf = s->resp_buf;
	        }
        }
	}

    return rpc_status;
}

static void call_end(void *context, rpc_call_handle handle)
{
	struct ffarpc_caller *s = (struct ffarpc_caller*)context;

	if ((handle == s) && s->is_call_transaction_in_progess) {

        /* Call transaction complete so free resource */
        free(s->req_buf);
        s->req_buf = NULL;
        s->req_len = 0;

        free(s->resp_buf);
        s->resp_buf = NULL;
        s->resp_len = 0;

        s->is_call_transaction_in_progess = false;
    }
}

static int kernel_write_req_buf(struct ffarpc_caller *s) {

    int ioctl_status;
    struct ffa_ioctl_buf_desc req_descr;

    req_descr.buf_ptr = (uintptr_t)s->req_buf;
    req_descr.buf_len = s->req_len;
    ioctl_status = ioctl(s->fd, FFA_IOC_SHM_WRITE, &req_descr);

    return ioctl_status;
}


static int kernel_read_resp_buf(struct ffarpc_caller *s) {

    int ioctl_status;
    struct ffa_ioctl_buf_desc resp_descr;

    resp_descr.buf_ptr = (uintptr_t)s->resp_buf;
    resp_descr.buf_len = s->resp_len;
    ioctl_status = ioctl(s->fd, FFA_IOC_SHM_READ, &resp_descr);

    return ioctl_status;
}

static int share_mem_with_partition(struct ffarpc_caller *s) {

    int ioctl_status;
    struct ffa_ioctl_msg_args direct_msg;
    memset(&direct_msg, 0, sizeof(direct_msg));

    direct_msg.dst_id = s->call_ep_id;
    direct_msg.args[FFA_CALL_ARGS_OPCODE] = (uint64_t)FFA_CALL_OPCODE_SHARE_BUF;
    direct_msg.args[FFA_CALL_ARGS_SHARE_MEM_HANDLE_LSW] = (uint32_t)s->shared_mem_handle;
    direct_msg.args[FFA_CALL_ARGS_SHARE_MEM_HANDLE_MSW] = (uint32_t)(s->shared_mem_handle >> 32);
    direct_msg.args[FFA_CALL_ARGS_SHARE_MEM_SIZE] = (uint64_t)s->shared_mem_required_size;

    ioctl_status = ioctl(s->fd, FFA_IOC_MSG_SEND, &direct_msg);

    return ioctl_status;
}

static int unshare_mem_with_partition(struct ffarpc_caller *s) {

    int ioctl_status;
    struct ffa_ioctl_msg_args direct_msg;
    memset(&direct_msg, 0, sizeof(direct_msg));

    direct_msg.dst_id = s->call_ep_id;
    direct_msg.args[FFA_CALL_ARGS_OPCODE] = (uint64_t)FFA_CALL_OPCODE_UNSHARE_BUF;
    direct_msg.args[FFA_CALL_ARGS_SHARE_MEM_HANDLE_LSW] = (uint32_t)s->shared_mem_handle;
    direct_msg.args[FFA_CALL_ARGS_SHARE_MEM_HANDLE_MSW] = (uint32_t)(s->shared_mem_handle >> 32);

    ioctl_status = ioctl(s->fd, FFA_IOC_MSG_SEND, &direct_msg);

    return ioctl_status;
}