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 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 */ 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