// SPDX-License-Identifier: GPL-2.0+
/*
 * VFIO based AP device driver
 *
 * Copyright IBM Corp. 2018
 *
 * Author(s): Tony Krowiak <akrowiak@linux.ibm.com>
 *            Pierre Morel <pmorel@linux.ibm.com>
 */

#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <asm/facility.h>
#include "vfio_ap_private.h"
#include "vfio_ap_debug.h"

#define VFIO_AP_ROOT_NAME "vfio_ap"
#define VFIO_AP_DEV_NAME "matrix"

MODULE_AUTHOR("IBM Corporation");
MODULE_DESCRIPTION("VFIO AP device driver, Copyright IBM Corp. 2018");
MODULE_LICENSE("GPL v2");

struct ap_matrix_dev *matrix_dev;
debug_info_t *vfio_ap_dbf_info;

static ssize_t features_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        return sysfs_emit(buf, "guest_matrix hotplug ap_config\n");
}
static DEVICE_ATTR_RO(features);

static struct attribute *matrix_dev_attrs[] = {
        &dev_attr_features.attr,
        NULL,
};
ATTRIBUTE_GROUPS(matrix_dev);

/* Only type 10 adapters (CEX4 and later) are supported
 * by the AP matrix device driver
 */
static struct ap_device_id ap_queue_ids[] = {
        { .dev_type = AP_DEVICE_TYPE_CEX4,
          .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
        { .dev_type = AP_DEVICE_TYPE_CEX5,
          .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
        { .dev_type = AP_DEVICE_TYPE_CEX6,
          .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
        { .dev_type = AP_DEVICE_TYPE_CEX7,
          .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
        { .dev_type = AP_DEVICE_TYPE_CEX8,
          .match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
        { /* end of sibling */ },
};

static struct ap_driver vfio_ap_drv = {
        .probe = vfio_ap_mdev_probe_queue,
        .remove = vfio_ap_mdev_remove_queue,
        .in_use = vfio_ap_mdev_resource_in_use,
        .on_config_changed = vfio_ap_on_cfg_changed,
        .on_scan_complete = vfio_ap_on_scan_complete,
        .ids = ap_queue_ids,
};

static void vfio_ap_matrix_dev_release(struct device *dev)
{
        struct ap_matrix_dev *matrix_dev;

        matrix_dev = container_of(dev, struct ap_matrix_dev, device);
        kfree(matrix_dev);
}

static const struct bus_type matrix_bus = {
        .name = "matrix",
};

static struct device_driver matrix_driver = {
        .name = "vfio_ap",
        .bus = &matrix_bus,
        .suppress_bind_attrs = true,
        .dev_groups = matrix_dev_groups,
};

static int vfio_ap_matrix_dev_create(void)
{
        int ret;
        struct device *root_device;

        root_device = root_device_register(VFIO_AP_ROOT_NAME);
        if (IS_ERR(root_device))
                return PTR_ERR(root_device);

        ret = bus_register(&matrix_bus);
        if (ret)
                goto bus_register_err;

        matrix_dev = kzalloc_obj(*matrix_dev);
        if (!matrix_dev) {
                ret = -ENOMEM;
                goto matrix_alloc_err;
        }

        /* Fill in config info via PQAP(QCI), if available */
        if (test_facility(12)) {
                ret = ap_qci(&matrix_dev->info);
                if (ret)
                        goto matrix_alloc_err;
        }

        mutex_init(&matrix_dev->mdevs_lock);
        INIT_LIST_HEAD(&matrix_dev->mdev_list);
        mutex_init(&matrix_dev->guests_lock);

        dev_set_name(&matrix_dev->device, "%s", VFIO_AP_DEV_NAME);
        matrix_dev->device.parent = root_device;
        matrix_dev->device.bus = &matrix_bus;
        matrix_dev->device.release = vfio_ap_matrix_dev_release;
        matrix_dev->vfio_ap_drv = &vfio_ap_drv;

        ret = device_register(&matrix_dev->device);
        if (ret)
                goto matrix_reg_err;

        ret = driver_register(&matrix_driver);
        if (ret)
                goto matrix_drv_err;

        return 0;

matrix_drv_err:
        device_del(&matrix_dev->device);
matrix_reg_err:
        put_device(&matrix_dev->device);
matrix_alloc_err:
        bus_unregister(&matrix_bus);
bus_register_err:
        root_device_unregister(root_device);
        return ret;
}

static void vfio_ap_matrix_dev_destroy(void)
{
        struct device *root_device = matrix_dev->device.parent;

        driver_unregister(&matrix_driver);
        device_unregister(&matrix_dev->device);
        bus_unregister(&matrix_bus);
        root_device_unregister(root_device);
}

static int __init vfio_ap_dbf_info_init(void)
{
        vfio_ap_dbf_info = debug_register("vfio_ap", 1, 1,
                                          DBF_MAX_SPRINTF_ARGS * sizeof(long));

        if (!vfio_ap_dbf_info)
                return -ENOENT;

        debug_register_view(vfio_ap_dbf_info, &debug_sprintf_view);
        debug_set_level(vfio_ap_dbf_info, DBF_WARN);

        return 0;
}

static int __init vfio_ap_init(void)
{
        int ret;

        ret = vfio_ap_dbf_info_init();
        if (ret)
                return ret;

        /* If there are no AP instructions, there is nothing to pass through. */
        if (!ap_instructions_available())
                return -ENODEV;

        ret = vfio_ap_matrix_dev_create();
        if (ret)
                return ret;

        ret = ap_driver_register(&vfio_ap_drv, THIS_MODULE, VFIO_AP_DRV_NAME);
        if (ret) {
                vfio_ap_matrix_dev_destroy();
                return ret;
        }

        ret = vfio_ap_mdev_register();
        if (ret) {
                ap_driver_unregister(&vfio_ap_drv);
                vfio_ap_matrix_dev_destroy();

                return ret;
        }

        return 0;
}

static void __exit vfio_ap_exit(void)
{
        vfio_ap_mdev_unregister();
        ap_driver_unregister(&vfio_ap_drv);
        vfio_ap_matrix_dev_destroy();
        debug_unregister(vfio_ap_dbf_info);
}

module_init(vfio_ap_init);
module_exit(vfio_ap_exit);