linux_dsm_epyc7002/drivers/char/tpm/tpm-dev.c
Tadeusz Struk 9e1b74a63f tpm: add support for nonblocking operation
Currently the TPM driver only supports blocking calls, which doesn't allow
asynchronous IO operations to the TPM hardware.
This patch changes it and adds support for nonblocking write and a new poll
function to enable applications, which want to take advantage of this.

Tested-by: Philip Tricca <philip.b.tricca@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off--by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
2018-10-05 13:47:33 +03:00

74 lines
1.7 KiB
C

/*
* Copyright (C) 2004 IBM Corporation
* Authors:
* Leendert van Doorn <leendert@watson.ibm.com>
* Dave Safford <safford@watson.ibm.com>
* Reiner Sailer <sailer@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
*
* Copyright (C) 2013 Obsidian Research Corp
* Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
*
* Device file system interface to the TPM
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
*/
#include <linux/slab.h>
#include "tpm-dev.h"
static int tpm_open(struct inode *inode, struct file *file)
{
struct tpm_chip *chip;
struct file_priv *priv;
chip = container_of(inode->i_cdev, struct tpm_chip, cdev);
/* It's assured that the chip will be opened just once,
* by the check of is_open variable, which is protected
* by driver_lock. */
if (test_and_set_bit(0, &chip->is_open)) {
dev_dbg(&chip->dev, "Another process owns this TPM\n");
return -EBUSY;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (priv == NULL)
goto out;
tpm_common_open(file, chip, priv, NULL);
return 0;
out:
clear_bit(0, &chip->is_open);
return -ENOMEM;
}
/*
* Called on file close
*/
static int tpm_release(struct inode *inode, struct file *file)
{
struct file_priv *priv = file->private_data;
tpm_common_release(file, priv);
clear_bit(0, &priv->chip->is_open);
kfree(priv);
return 0;
}
const struct file_operations tpm_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.open = tpm_open,
.read = tpm_common_read,
.write = tpm_common_write,
.poll = tpm_common_poll,
.release = tpm_release,
};