// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2024-2025 Intel Corporation. All rights reserved. */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/tsm.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/cleanup.h>
#include <linux/pci-tsm.h>

static struct class *tsm_class;
static DEFINE_IDA(tsm_ida);

static int match_id(struct device *dev, const void *data)
{
        struct tsm_dev *tsm_dev = container_of(dev, struct tsm_dev, dev);
        int id = *(const int *)data;

        return tsm_dev->id == id;
}

struct tsm_dev *find_tsm_dev(int id)
{
        struct device *dev = class_find_device(tsm_class, NULL, &id, match_id);

        if (!dev)
                return NULL;
        return container_of(dev, struct tsm_dev, dev);
}

static struct tsm_dev *alloc_tsm_dev(struct device *parent)
{
        struct device *dev;
        int id;

        struct tsm_dev *tsm_dev __free(kfree) =
                kzalloc_obj(*tsm_dev);
        if (!tsm_dev)
                return ERR_PTR(-ENOMEM);

        id = ida_alloc(&tsm_ida, GFP_KERNEL);
        if (id < 0)
                return ERR_PTR(id);

        tsm_dev->id = id;
        dev = &tsm_dev->dev;
        dev->parent = parent;
        dev->class = tsm_class;
        device_initialize(dev);

        return no_free_ptr(tsm_dev);
}

static struct tsm_dev *tsm_register_pci_or_reset(struct tsm_dev *tsm_dev,
                                                 struct pci_tsm_ops *pci_ops)
{
        int rc;

        if (!pci_ops)
                return tsm_dev;

        tsm_dev->pci_ops = pci_ops;
        rc = pci_tsm_register(tsm_dev);
        if (rc) {
                dev_err(tsm_dev->dev.parent,
                        "PCI/TSM registration failure: %d\n", rc);
                device_unregister(&tsm_dev->dev);
                return ERR_PTR(rc);
        }

        /* Notify TSM userspace that PCI/TSM operations are now possible */
        kobject_uevent(&tsm_dev->dev.kobj, KOBJ_CHANGE);
        return tsm_dev;
}

struct tsm_dev *tsm_register(struct device *parent, struct pci_tsm_ops *pci_ops)
{
        struct tsm_dev *tsm_dev __free(put_tsm_dev) = alloc_tsm_dev(parent);
        struct device *dev;
        int rc;

        if (IS_ERR(tsm_dev))
                return tsm_dev;

        dev = &tsm_dev->dev;
        rc = dev_set_name(dev, "tsm%d", tsm_dev->id);
        if (rc)
                return ERR_PTR(rc);

        rc = device_add(dev);
        if (rc)
                return ERR_PTR(rc);

        return tsm_register_pci_or_reset(no_free_ptr(tsm_dev), pci_ops);
}
EXPORT_SYMBOL_GPL(tsm_register);

void tsm_unregister(struct tsm_dev *tsm_dev)
{
        if (tsm_dev->pci_ops)
                pci_tsm_unregister(tsm_dev);
        device_unregister(&tsm_dev->dev);
}
EXPORT_SYMBOL_GPL(tsm_unregister);

static void tsm_release(struct device *dev)
{
        struct tsm_dev *tsm_dev = container_of(dev, typeof(*tsm_dev), dev);

        ida_free(&tsm_ida, tsm_dev->id);
        kfree(tsm_dev);
}

static int __init tsm_init(void)
{
        tsm_class = class_create("tsm");
        if (IS_ERR(tsm_class))
                return PTR_ERR(tsm_class);

        tsm_class->dev_release = tsm_release;
        return 0;
}
module_init(tsm_init)

static void __exit tsm_exit(void)
{
        class_destroy(tsm_class);
}
module_exit(tsm_exit)

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("TEE Security Manager Class Device");