1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004 IBM Corporation
4 * Authors:
5 * Leendert van Doorn <leendert@watson.ibm.com>
6 * Dave Safford <safford@watson.ibm.com>
7 * Reiner Sailer <sailer@watson.ibm.com>
8 * Kylene Hall <kjhall@us.ibm.com>
9 *
10 * Copyright (C) 2013 Obsidian Research Corp
11 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
12 *
13 * Device file system interface to the TPM
14 */
15#include <linux/slab.h>
16#include "tpm-dev.h"
17
18static int tpm_open(struct inode *inode, struct file *file)
19{
20	struct tpm_chip *chip;
21	struct file_priv *priv;
22
23	chip = container_of(inode->i_cdev, struct tpm_chip, cdev);
24
25	/* It's assured that the chip will be opened just once,
26	 * by the check of is_open variable, which is protected
27	 * by driver_lock. */
28	if (test_and_set_bit(0, &chip->is_open)) {
29		dev_dbg(&chip->dev, "Another process owns this TPM\n");
30		return -EBUSY;
31	}
32
33	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
34	if (priv == NULL)
35		goto out;
36
37	tpm_common_open(file, chip, priv, NULL);
38
39	return 0;
40
41 out:
42	clear_bit(0, &chip->is_open);
43	return -ENOMEM;
44}
45
46/*
47 * Called on file close
48 */
49static int tpm_release(struct inode *inode, struct file *file)
50{
51	struct file_priv *priv = file->private_data;
52
53	tpm_common_release(file, priv);
54	clear_bit(0, &priv->chip->is_open);
55	kfree(priv);
56
57	return 0;
58}
59
60const struct file_operations tpm_fops = {
61	.owner = THIS_MODULE,
62	.llseek = no_llseek,
63	.open = tpm_open,
64	.read = tpm_common_read,
65	.write = tpm_common_write,
66	.poll = tpm_common_poll,
67	.release = tpm_release,
68};
69