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

static struct class *tsm_class;
static DECLARE_RWSEM(tsm_rwsem);
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(sizeof(*tsm_dev), GFP_KERNEL);
	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);

/* must be invoked between tsm_register / tsm_unregister */
int tsm_ide_stream_register(struct pci_ide *ide)
{
	struct pci_dev *pdev = ide->pdev;
	struct pci_tsm *tsm = pdev->tsm;
	struct tsm_dev *tsm_dev = tsm->tsm_dev;
	int rc;

	rc = sysfs_create_link(&tsm_dev->dev.kobj, &pdev->dev.kobj, ide->name);
	if (rc)
		return rc;

	ide->tsm_dev = tsm_dev;
	return 0;
}
EXPORT_SYMBOL_GPL(tsm_ide_stream_register);

void tsm_ide_stream_unregister(struct pci_ide *ide)
{
	struct tsm_dev *tsm_dev = ide->tsm_dev;

	ide->tsm_dev = NULL;
	sysfs_remove_link(&tsm_dev->dev.kobj, ide->name);
}
EXPORT_SYMBOL_GPL(tsm_ide_stream_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");