1/*
2 * Copyright (C) 2004 IBM Corporation
3 * Copyright (C) 2014 Intel Corporation
4 *
5 * Authors:
6 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
7 * Leendert van Doorn <leendert@watson.ibm.com>
8 * Dave Safford <safford@watson.ibm.com>
9 * Reiner Sailer <sailer@watson.ibm.com>
10 * Kylene Hall <kjhall@us.ibm.com>
11 *
12 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
13 *
14 * TPM chip management routines.
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License as
18 * published by the Free Software Foundation, version 2 of the
19 * License.
20 *
21 */
22
23#include <linux/poll.h>
24#include <linux/slab.h>
25#include <linux/mutex.h>
26#include <linux/spinlock.h>
27#include <linux/freezer.h>
28#include <linux/major.h>
29#include "tpm.h"
30#include "tpm_eventlog.h"
31
32static DECLARE_BITMAP(dev_mask, TPM_NUM_DEVICES);
33static LIST_HEAD(tpm_chip_list);
34static DEFINE_SPINLOCK(driver_lock);
35
36struct class *tpm_class;
37dev_t tpm_devt;
38
39/*
40 * tpm_chip_find_get - return tpm_chip for a given chip number
41 * @chip_num the device number for the chip
42 */
43struct tpm_chip *tpm_chip_find_get(int chip_num)
44{
45	struct tpm_chip *pos, *chip = NULL;
46
47	rcu_read_lock();
48	list_for_each_entry_rcu(pos, &tpm_chip_list, list) {
49		if (chip_num != TPM_ANY_NUM && chip_num != pos->dev_num)
50			continue;
51
52		if (try_module_get(pos->pdev->driver->owner)) {
53			chip = pos;
54			break;
55		}
56	}
57	rcu_read_unlock();
58	return chip;
59}
60
61/**
62 * tpm_dev_release() - free chip memory and the device number
63 * @dev: the character device for the TPM chip
64 *
65 * This is used as the release function for the character device.
66 */
67static void tpm_dev_release(struct device *dev)
68{
69	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
70
71	spin_lock(&driver_lock);
72	clear_bit(chip->dev_num, dev_mask);
73	spin_unlock(&driver_lock);
74	kfree(chip);
75}
76
77/**
78 * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
79 * @dev: device to which the chip is associated
80 * @ops: struct tpm_class_ops instance
81 *
82 * Allocates a new struct tpm_chip instance and assigns a free
83 * device number for it. Caller does not have to worry about
84 * freeing the allocated resources. When the devices is removed
85 * devres calls tpmm_chip_remove() to do the job.
86 */
87struct tpm_chip *tpmm_chip_alloc(struct device *dev,
88				 const struct tpm_class_ops *ops)
89{
90	struct tpm_chip *chip;
91
92	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
93	if (chip == NULL)
94		return ERR_PTR(-ENOMEM);
95
96	mutex_init(&chip->tpm_mutex);
97	INIT_LIST_HEAD(&chip->list);
98
99	chip->ops = ops;
100
101	spin_lock(&driver_lock);
102	chip->dev_num = find_first_zero_bit(dev_mask, TPM_NUM_DEVICES);
103	spin_unlock(&driver_lock);
104
105	if (chip->dev_num >= TPM_NUM_DEVICES) {
106		dev_err(dev, "No available tpm device numbers\n");
107		kfree(chip);
108		return ERR_PTR(-ENOMEM);
109	}
110
111	set_bit(chip->dev_num, dev_mask);
112
113	scnprintf(chip->devname, sizeof(chip->devname), "tpm%d", chip->dev_num);
114
115	chip->pdev = dev;
116
117	dev_set_drvdata(dev, chip);
118
119	chip->dev.class = tpm_class;
120	chip->dev.release = tpm_dev_release;
121	chip->dev.parent = chip->pdev;
122
123	if (chip->dev_num == 0)
124		chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
125	else
126		chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
127
128	dev_set_name(&chip->dev, "%s", chip->devname);
129
130	device_initialize(&chip->dev);
131
132	cdev_init(&chip->cdev, &tpm_fops);
133	chip->cdev.owner = chip->pdev->driver->owner;
134	chip->cdev.kobj.parent = &chip->dev.kobj;
135
136	return chip;
137}
138EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
139
140static int tpm_dev_add_device(struct tpm_chip *chip)
141{
142	int rc;
143
144	rc = cdev_add(&chip->cdev, chip->dev.devt, 1);
145	if (rc) {
146		dev_err(&chip->dev,
147			"unable to cdev_add() %s, major %d, minor %d, err=%d\n",
148			chip->devname, MAJOR(chip->dev.devt),
149			MINOR(chip->dev.devt), rc);
150
151		device_unregister(&chip->dev);
152		return rc;
153	}
154
155	rc = device_add(&chip->dev);
156	if (rc) {
157		dev_err(&chip->dev,
158			"unable to device_register() %s, major %d, minor %d, err=%d\n",
159			chip->devname, MAJOR(chip->dev.devt),
160			MINOR(chip->dev.devt), rc);
161
162		return rc;
163	}
164
165	return rc;
166}
167
168static void tpm_dev_del_device(struct tpm_chip *chip)
169{
170	cdev_del(&chip->cdev);
171	device_unregister(&chip->dev);
172}
173
174static int tpm1_chip_register(struct tpm_chip *chip)
175{
176	int rc;
177
178	if (chip->flags & TPM_CHIP_FLAG_TPM2)
179		return 0;
180
181	rc = tpm_sysfs_add_device(chip);
182	if (rc)
183		return rc;
184
185	rc = tpm_add_ppi(chip);
186	if (rc) {
187		tpm_sysfs_del_device(chip);
188		return rc;
189	}
190
191	chip->bios_dir = tpm_bios_log_setup(chip->devname);
192
193	return 0;
194}
195
196static void tpm1_chip_unregister(struct tpm_chip *chip)
197{
198	if (chip->flags & TPM_CHIP_FLAG_TPM2)
199		return;
200
201	if (chip->bios_dir)
202		tpm_bios_log_teardown(chip->bios_dir);
203
204	tpm_remove_ppi(chip);
205
206	tpm_sysfs_del_device(chip);
207}
208
209/*
210 * tpm_chip_register() - create a character device for the TPM chip
211 * @chip: TPM chip to use.
212 *
213 * Creates a character device for the TPM chip and adds sysfs attributes for
214 * the device. As the last step this function adds the chip to the list of TPM
215 * chips available for in-kernel use.
216 *
217 * This function should be only called after the chip initialization is
218 * complete.
219 */
220int tpm_chip_register(struct tpm_chip *chip)
221{
222	int rc;
223
224	rc = tpm1_chip_register(chip);
225	if (rc)
226		return rc;
227
228	rc = tpm_dev_add_device(chip);
229	if (rc)
230		goto out_err;
231
232	/* Make the chip available. */
233	spin_lock(&driver_lock);
234	list_add_rcu(&chip->list, &tpm_chip_list);
235	spin_unlock(&driver_lock);
236
237	chip->flags |= TPM_CHIP_FLAG_REGISTERED;
238
239	return 0;
240out_err:
241	tpm1_chip_unregister(chip);
242	return rc;
243}
244EXPORT_SYMBOL_GPL(tpm_chip_register);
245
246/*
247 * tpm_chip_unregister() - release the TPM driver
248 * @chip: TPM chip to use.
249 *
250 * Takes the chip first away from the list of available TPM chips and then
251 * cleans up all the resources reserved by tpm_chip_register().
252 *
253 * NOTE: This function should be only called before deinitializing chip
254 * resources.
255 */
256void tpm_chip_unregister(struct tpm_chip *chip)
257{
258	if (!(chip->flags & TPM_CHIP_FLAG_REGISTERED))
259		return;
260
261	spin_lock(&driver_lock);
262	list_del_rcu(&chip->list);
263	spin_unlock(&driver_lock);
264	synchronize_rcu();
265
266	tpm1_chip_unregister(chip);
267	tpm_dev_del_device(chip);
268}
269EXPORT_SYMBOL_GPL(tpm_chip_unregister);
270