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