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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2004 IBM Corporation4 * 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 Corp11 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>12 *13 * Device file system interface to the TPM14 */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 protected27 * 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 close48 */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 .open = tpm_open,63 .read = tpm_common_read,64 .write = tpm_common_write,65 .poll = tpm_common_poll,66 .release = tpm_release,67};68