1 /* 2 * Copyright (C) 2004 IBM Corporation 3 * Authors: 4 * Leendert van Doorn <leendert@watson.ibm.com> 5 * Dave Safford <safford@watson.ibm.com> 6 * Reiner Sailer <sailer@watson.ibm.com> 7 * Kylene Hall <kjhall@us.ibm.com> 8 * 9 * Copyright (C) 2013 Obsidian Research Corp 10 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com> 11 * 12 * Device file system interface to the TPM 13 * 14 * This program is free software; you can redistribute it and/or 15 * modify it under the terms of the GNU General Public License as 16 * published by the Free Software Foundation, version 2 of the 17 * License. 18 * 19 */ 20 #include <linux/slab.h> 21 #include "tpm-dev.h" 22 23 static int tpm_open(struct inode *inode, struct file *file) 24 { 25 struct tpm_chip *chip; 26 struct file_priv *priv; 27 28 chip = container_of(inode->i_cdev, struct tpm_chip, cdev); 29 30 /* It's assured that the chip will be opened just once, 31 * by the check of is_open variable, which is protected 32 * by driver_lock. */ 33 if (test_and_set_bit(0, &chip->is_open)) { 34 dev_dbg(&chip->dev, "Another process owns this TPM\n"); 35 return -EBUSY; 36 } 37 38 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 39 if (priv == NULL) 40 goto out; 41 42 tpm_common_open(file, chip, priv, NULL); 43 44 return 0; 45 46 out: 47 clear_bit(0, &chip->is_open); 48 return -ENOMEM; 49 } 50 51 /* 52 * Called on file close 53 */ 54 static int tpm_release(struct inode *inode, struct file *file) 55 { 56 struct file_priv *priv = file->private_data; 57 58 tpm_common_release(file, priv); 59 clear_bit(0, &priv->chip->is_open); 60 kfree(priv); 61 62 return 0; 63 } 64 65 const struct file_operations tpm_fops = { 66 .owner = THIS_MODULE, 67 .llseek = no_llseek, 68 .open = tpm_open, 69 .read = tpm_common_read, 70 .write = tpm_common_write, 71 .poll = tpm_common_poll, 72 .release = tpm_release, 73 }; 74