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
tpm_open(struct inode * inode,struct file * file)18 static 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 */
tpm_release(struct inode * inode,struct file * file)49 static 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
60 const 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