// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019 Linaro Ltd.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/tee_core.h>
#include <linux/uuid.h>
#include "optee_private.h"

static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
{
        if (ver->impl_id == TEE_IMPL_ID_OPTEE)
                return 1;
        else
                return 0;
}

static int get_devices(struct tee_context *ctx, u32 session,
                       struct tee_shm *device_shm, u32 *shm_size,
                       u32 func)
{
        int ret = 0;
        struct tee_ioctl_invoke_arg inv_arg;
        struct tee_param param[4];

        memset(&inv_arg, 0, sizeof(inv_arg));
        memset(&param, 0, sizeof(param));

        inv_arg.func = func;
        inv_arg.session = session;
        inv_arg.num_params = 4;

        /* Fill invoke cmd params */
        param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
        param[0].u.memref.shm = device_shm;
        param[0].u.memref.size = *shm_size;
        param[0].u.memref.shm_offs = 0;

        ret = tee_client_invoke_func(ctx, &inv_arg, param);
        if ((ret < 0) || ((inv_arg.ret != TEEC_SUCCESS) &&
                          (inv_arg.ret != TEEC_ERROR_SHORT_BUFFER))) {
                /*
                 * TEE_ERROR_STORAGE_NOT_AVAILABLE is returned when getting
                 * the list of device TAs that depends on RPMB but a usable
                 * RPMB device isn't found.
                 */
                if (inv_arg.ret == TEE_ERROR_STORAGE_NOT_AVAILABLE)
                        return -ENODEV;
                pr_err("PTA_CMD_GET_DEVICES invoke function err: %x\n",
                       inv_arg.ret);
                return -EINVAL;
        }

        *shm_size = param[0].u.memref.size;

        return 0;
}

static void optee_release_device(struct device *dev)
{
        struct tee_client_device *optee_device = to_tee_client_device(dev);

        kfree(optee_device);
}

static ssize_t need_supplicant_show(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
{
        return 0;
}

static DEVICE_ATTR_RO(need_supplicant);

static int optee_register_device(const uuid_t *device_uuid, u32 func)
{
        struct tee_client_device *optee_device = NULL;
        int rc;

        optee_device = kzalloc_obj(*optee_device);
        if (!optee_device)
                return -ENOMEM;

        optee_device->dev.bus = &tee_bus_type;
        optee_device->dev.release = optee_release_device;
        if (dev_set_name(&optee_device->dev, "optee-ta-%pUb", device_uuid)) {
                kfree(optee_device);
                return -ENOMEM;
        }
        uuid_copy(&optee_device->id.uuid, device_uuid);

        rc = device_register(&optee_device->dev);
        if (rc) {
                pr_err("device registration failed, err: %d\n", rc);
                put_device(&optee_device->dev);
                return rc;
        }

        if (func == PTA_CMD_GET_DEVICES_SUPP)
                device_create_file(&optee_device->dev,
                                   &dev_attr_need_supplicant);

        return 0;
}

static int __optee_enumerate_devices(u32 func)
{
        const uuid_t pta_uuid =
                UUID_INIT(0x7011a688, 0xddde, 0x4053,
                          0xa5, 0xa9, 0x7b, 0x3c, 0x4d, 0xdf, 0x13, 0xb8);
        struct tee_ioctl_open_session_arg sess_arg;
        struct tee_shm *device_shm = NULL;
        const uuid_t *device_uuid = NULL;
        struct tee_context *ctx = NULL;
        u32 shm_size = 0, idx, num_devices = 0;
        int rc;

        memset(&sess_arg, 0, sizeof(sess_arg));

        /* Open context with OP-TEE driver */
        ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, NULL);
        if (IS_ERR(ctx))
                return -ENODEV;

        /* Open session with device enumeration pseudo TA */
        export_uuid(sess_arg.uuid, &pta_uuid);
        sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC;
        sess_arg.num_params = 0;

        rc = tee_client_open_session(ctx, &sess_arg, NULL);
        if ((rc < 0) || (sess_arg.ret != TEEC_SUCCESS)) {
                /* Device enumeration pseudo TA not found */
                rc = 0;
                goto out_ctx;
        }

        rc = get_devices(ctx, sess_arg.session, NULL, &shm_size, func);
        if (rc < 0 || !shm_size)
                goto out_sess;

        device_shm = tee_shm_alloc_kernel_buf(ctx, shm_size);
        if (IS_ERR(device_shm)) {
                pr_err("tee_shm_alloc_kernel_buf failed\n");
                rc = PTR_ERR(device_shm);
                goto out_sess;
        }

        rc = get_devices(ctx, sess_arg.session, device_shm, &shm_size, func);
        if (rc < 0)
                goto out_shm;

        device_uuid = tee_shm_get_va(device_shm, 0);
        if (IS_ERR(device_uuid)) {
                pr_err("tee_shm_get_va failed\n");
                rc = PTR_ERR(device_uuid);
                goto out_shm;
        }

        num_devices = shm_size / sizeof(uuid_t);

        for (idx = 0; idx < num_devices; idx++) {
                rc = optee_register_device(&device_uuid[idx], func);
                if (rc)
                        goto out_shm;
        }

out_shm:
        tee_shm_free(device_shm);
out_sess:
        tee_client_close_session(ctx, sess_arg.session);
out_ctx:
        tee_client_close_context(ctx);

        return rc;
}

int optee_enumerate_devices(u32 func)
{
        return  __optee_enumerate_devices(func);
}

static int __optee_unregister_device(struct device *dev, void *data)
{
        if (!strncmp(dev_name(dev), "optee-ta", strlen("optee-ta")))
                device_unregister(dev);

        return 0;
}

void optee_unregister_devices(void)
{
        bus_for_each_dev(&tee_bus_type, NULL, NULL,
                         __optee_unregister_device);
}