// SPDX-License-Identifier: GPL-2.0+
/*
 *  Uclass for EFI drivers
 *
 *  Copyright (c) 2017 Heinrich Schuchardt
 *
 * For each EFI driver the uclass
 * - creates a handle
 * - installs the driver binding protocol
 *
 * The uclass provides the bind, start, and stop entry points for the driver
 * binding protocol.
 *
 * In bind() and stop() it checks if the controller implements the protocol
 * supported by the EFI driver. In the start() function it calls the bind()
 * function of the EFI driver. In the stop() function it destroys the child
 * controllers.
 */

#include <efi_driver.h>

/*
 * Check node type. We do not support partitions as controller handles.
 *
 * @handle      handle to be checked
 * @return      status code
 */
static efi_status_t check_node_type(efi_handle_t handle)
{
        efi_status_t r, ret = EFI_SUCCESS;
        const struct efi_device_path *dp;

        /* Open the device path protocol */
        r = EFI_CALL(systab.boottime->open_protocol(
                        handle, &efi_guid_device_path, (void **)&dp,
                        NULL, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL));
        if (r == EFI_SUCCESS && dp) {
                /* Get the last node */
                const struct efi_device_path *node = efi_dp_last_node(dp);
                /* We do not support partitions as controller */
                if (!node || node->type == DEVICE_PATH_TYPE_MEDIA_DEVICE)
                        ret = EFI_UNSUPPORTED;
        }
        return ret;
}

/*
 * Check if the driver supports the controller.
 *
 * @this                        driver binding protocol
 * @controller_handle           handle of the controller
 * @remaining_device_path       path specifying the child controller
 * @return                      status code
 */
static efi_status_t EFIAPI efi_uc_supported(
                struct efi_driver_binding_protocol *this,
                efi_handle_t controller_handle,
                struct efi_device_path *remaining_device_path)
{
        efi_status_t r, ret;
        void *interface;
        struct efi_driver_binding_extended_protocol *bp =
                        (struct efi_driver_binding_extended_protocol *)this;

        EFI_ENTRY("%p, %p, %ls", this, controller_handle,
                  efi_dp_str(remaining_device_path));

        ret = EFI_CALL(systab.boottime->open_protocol(
                        controller_handle, bp->ops->protocol,
                        &interface, this->driver_binding_handle,
                        controller_handle, EFI_OPEN_PROTOCOL_BY_DRIVER));
        switch (ret) {
        case EFI_ACCESS_DENIED:
        case EFI_ALREADY_STARTED:
                goto out;
        case EFI_SUCCESS:
                break;
        default:
                ret = EFI_UNSUPPORTED;
                goto out;
        }

        ret = check_node_type(controller_handle);

        r = EFI_CALL(systab.boottime->close_protocol(
                                controller_handle, bp->ops->protocol,
                                this->driver_binding_handle,
                                controller_handle));
        if (r != EFI_SUCCESS)
                ret = EFI_UNSUPPORTED;
out:
        return EFI_EXIT(ret);
}

/*
 * Create child controllers and attach driver.
 *
 * @this                        driver binding protocol
 * @controller_handle           handle of the controller
 * @remaining_device_path       path specifying the child controller
 * @return                      status code
 */
static efi_status_t EFIAPI efi_uc_start(
                struct efi_driver_binding_protocol *this,
                efi_handle_t controller_handle,
                struct efi_device_path *remaining_device_path)
{
        efi_status_t r, ret;
        void *interface = NULL;
        struct efi_driver_binding_extended_protocol *bp =
                        (struct efi_driver_binding_extended_protocol *)this;

        EFI_ENTRY("%p, %pUl, %ls", this, controller_handle,
                  efi_dp_str(remaining_device_path));

        /* Attach driver to controller */
        ret = EFI_CALL(systab.boottime->open_protocol(
                        controller_handle, bp->ops->protocol,
                        &interface, this->driver_binding_handle,
                        controller_handle, EFI_OPEN_PROTOCOL_BY_DRIVER));
        switch (ret) {
        case EFI_ACCESS_DENIED:
        case EFI_ALREADY_STARTED:
                goto out;
        case EFI_SUCCESS:
                break;
        default:
                ret =  EFI_UNSUPPORTED;
                goto out;
        }
        ret = check_node_type(controller_handle);
        if (ret != EFI_SUCCESS) {
                r = EFI_CALL(systab.boottime->close_protocol(
                                controller_handle, bp->ops->protocol,
                                this->driver_binding_handle,
                                controller_handle));
                if (r != EFI_SUCCESS)
                        EFI_PRINT("Failure to close handle\n");
                goto out;
        }

        /* TODO: driver specific stuff */
        bp->ops->bind(controller_handle, interface);

out:
        return EFI_EXIT(ret);
}

/*
 * Remove a single child controller from the parent controller.
 *
 * @controller_handle   parent controller
 * @child_handle        child controller
 * @return              status code
 */
static efi_status_t disconnect_child(efi_handle_t controller_handle,
                                     efi_handle_t child_handle)
{
        efi_status_t ret;
        efi_guid_t *guid_controller = NULL;
        efi_guid_t *guid_child_controller = NULL;

        ret = EFI_CALL(systab.boottime->close_protocol(
                                controller_handle, guid_controller,
                                child_handle, child_handle));
        if (ret != EFI_SUCCESS) {
                EFI_PRINT("Cannot close protocol\n");
                return ret;
        }
        ret = EFI_CALL(systab.boottime->uninstall_protocol_interface(
                                child_handle, guid_child_controller, NULL));
        if (ret != EFI_SUCCESS) {
                EFI_PRINT("Cannot uninstall protocol interface\n");
                return ret;
        }
        return ret;
}

/*
 * Remove child controllers and disconnect the controller.
 *
 * @this                        driver binding protocol
 * @controller_handle           handle of the controller
 * @number_of_children          number of child controllers to remove
 * @child_handle_buffer         handles of the child controllers to remove
 * @return                      status code
 */
static efi_status_t EFIAPI efi_uc_stop(
                struct efi_driver_binding_protocol *this,
                efi_handle_t controller_handle,
                size_t number_of_children,
                efi_handle_t *child_handle_buffer)
{
        efi_status_t ret;
        efi_uintn_t count;
        struct efi_open_protocol_info_entry *entry_buffer;
        efi_guid_t *guid_controller = NULL;

        EFI_ENTRY("%p, %pUl, %zu, %p", this, controller_handle,
                  number_of_children, child_handle_buffer);

        /* Destroy provided child controllers */
        if (number_of_children) {
                efi_uintn_t i;

                for (i = 0; i < number_of_children; ++i) {
                        ret = disconnect_child(controller_handle,
                                               child_handle_buffer[i]);
                        if (ret != EFI_SUCCESS)
                                return ret;
                }
                return EFI_SUCCESS;
        }

        /* Destroy all children */
        ret = EFI_CALL(systab.boottime->open_protocol_information(
                                        controller_handle, guid_controller,
                                        &entry_buffer, &count));
        if (ret != EFI_SUCCESS)
                goto out;
        while (count) {
                if (entry_buffer[--count].attributes &
                    EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER) {
                        ret = disconnect_child(
                                        controller_handle,
                                        entry_buffer[count].agent_handle);
                        if (ret != EFI_SUCCESS)
                                goto out;
                }
        }
        ret = EFI_CALL(systab.boottime->free_pool(entry_buffer));
        if (ret != EFI_SUCCESS)
                printf("%s(%u) %s: ERROR: Cannot free pool\n",
                       __FILE__, __LINE__, __func__);

        /* Detach driver from controller */
        ret = EFI_CALL(systab.boottime->close_protocol(
                        controller_handle, guid_controller,
                        this->driver_binding_handle, controller_handle));
out:
        return EFI_EXIT(ret);
}

static efi_status_t efi_add_driver(struct driver *drv)
{
        efi_status_t ret;
        const struct efi_driver_ops *ops = drv->ops;
        struct efi_driver_binding_extended_protocol *bp;

        debug("EFI: Adding driver '%s'\n", drv->name);
        if (!ops->protocol) {
                printf("EFI: ERROR: protocol GUID missing for driver '%s'\n",
                       drv->name);
                return EFI_INVALID_PARAMETER;
        }
        bp = calloc(1, sizeof(struct efi_driver_binding_extended_protocol));
        if (!bp)
                return EFI_OUT_OF_RESOURCES;

        bp->bp.supported = efi_uc_supported;
        bp->bp.start = efi_uc_start;
        bp->bp.stop = efi_uc_stop;
        bp->bp.version = 0xffffffff;
        bp->ops = drv->ops;

        ret = efi_create_handle(&bp->bp.driver_binding_handle);
        if (ret != EFI_SUCCESS) {
                free(bp);
                goto out;
        }
        bp->bp.image_handle = bp->bp.driver_binding_handle;
        ret = efi_add_protocol(bp->bp.driver_binding_handle,
                               &efi_guid_driver_binding_protocol, bp);
        if (ret != EFI_SUCCESS) {
                efi_delete_handle(bp->bp.driver_binding_handle);
                free(bp);
                goto out;
        }
out:
        return ret;
}

/*
 * Initialize the EFI drivers.
 * Called by board_init_r().
 *
 * @return      0 = success, any other value will stop further execution
 */
efi_status_t efi_driver_init(void)
{
        struct driver *drv;
        efi_status_t ret = EFI_SUCCESS;

        /* Save 'gd' pointer */
        efi_save_gd();

        debug("EFI: Initializing EFI driver framework\n");
        for (drv = ll_entry_start(struct driver, driver);
             drv < ll_entry_end(struct driver, driver); ++drv) {
                if (drv->id == UCLASS_EFI) {
                        ret = efi_add_driver(drv);
                        if (ret != EFI_SUCCESS) {
                                printf("EFI: ERROR: failed to add driver %s\n",
                                       drv->name);
                                break;
                        }
                }
        }
        return ret;
}

static int efi_uc_init(struct uclass *class)
{
        printf("EFI: Initializing UCLASS_EFI\n");
        return 0;
}

static int efi_uc_destroy(struct uclass *class)
{
        printf("Destroying  UCLASS_EFI\n");
        return 0;
}

UCLASS_DRIVER(efi) = {
        .name           = "efi",
        .id             = UCLASS_EFI,
        .init           = efi_uc_init,
        .destroy        = efi_uc_destroy,
};