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#ifdef CONFIG_ACPI
123	chip->dev.groups = chip->groups;
124#endif
125
126	if (chip->dev_num == 0)
127		chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
128	else
129		chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
130
131	dev_set_name(&chip->dev, "%s", chip->devname);
132
133	device_initialize(&chip->dev);
134
135	cdev_init(&chip->cdev, &tpm_fops);
136	chip->cdev.owner = chip->pdev->driver->owner;
137	chip->cdev.kobj.parent = &chip->dev.kobj;
138
139	devm_add_action(dev, (void (*)(void *)) put_device, &chip->dev);
140
141	return chip;
142}
143EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
144
145static int tpm_add_char_device(struct tpm_chip *chip)
146{
147	int rc;
148
149	rc = cdev_add(&chip->cdev, chip->dev.devt, 1);
150	if (rc) {
151		dev_err(&chip->dev,
152			"unable to cdev_add() %s, major %d, minor %d, err=%d\n",
153			chip->devname, MAJOR(chip->dev.devt),
154			MINOR(chip->dev.devt), rc);
155
156		return rc;
157	}
158
159	rc = device_add(&chip->dev);
160	if (rc) {
161		dev_err(&chip->dev,
162			"unable to device_register() %s, major %d, minor %d, err=%d\n",
163			chip->devname, MAJOR(chip->dev.devt),
164			MINOR(chip->dev.devt), rc);
165
166		cdev_del(&chip->cdev);
167		return rc;
168	}
169
170	return rc;
171}
172
173static void tpm_del_char_device(struct tpm_chip *chip)
174{
175	cdev_del(&chip->cdev);
176	device_del(&chip->dev);
177}
178
179static int tpm1_chip_register(struct tpm_chip *chip)
180{
181	int rc;
182
183	if (chip->flags & TPM_CHIP_FLAG_TPM2)
184		return 0;
185
186	rc = tpm_sysfs_add_device(chip);
187	if (rc)
188		return rc;
189
190	chip->bios_dir = tpm_bios_log_setup(chip->devname);
191
192	return 0;
193}
194
195static void tpm1_chip_unregister(struct tpm_chip *chip)
196{
197	if (chip->flags & TPM_CHIP_FLAG_TPM2)
198		return;
199
200	if (chip->bios_dir)
201		tpm_bios_log_teardown(chip->bios_dir);
202
203	tpm_sysfs_del_device(chip);
204}
205
206/*
207 * tpm_chip_register() - create a character device for the TPM chip
208 * @chip: TPM chip to use.
209 *
210 * Creates a character device for the TPM chip and adds sysfs attributes for
211 * the device. As the last step this function adds the chip to the list of TPM
212 * chips available for in-kernel use.
213 *
214 * This function should be only called after the chip initialization is
215 * complete.
216 */
217int tpm_chip_register(struct tpm_chip *chip)
218{
219	int rc;
220
221	rc = tpm1_chip_register(chip);
222	if (rc)
223		return rc;
224
225	tpm_add_ppi(chip);
226
227	rc = tpm_add_char_device(chip);
228	if (rc)
229		goto out_err;
230
231	/* Make the chip available. */
232	spin_lock(&driver_lock);
233	list_add_tail_rcu(&chip->list, &tpm_chip_list);
234	spin_unlock(&driver_lock);
235
236	chip->flags |= TPM_CHIP_FLAG_REGISTERED;
237
238	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
239		rc = __compat_only_sysfs_link_entry_to_kobj(&chip->pdev->kobj,
240							    &chip->dev.kobj,
241							    "ppi");
242		if (rc && rc != -ENOENT) {
243			tpm_chip_unregister(chip);
244			return rc;
245		}
246	}
247
248	return 0;
249out_err:
250	tpm1_chip_unregister(chip);
251	return rc;
252}
253EXPORT_SYMBOL_GPL(tpm_chip_register);
254
255/*
256 * tpm_chip_unregister() - release the TPM driver
257 * @chip: TPM chip to use.
258 *
259 * Takes the chip first away from the list of available TPM chips and then
260 * cleans up all the resources reserved by tpm_chip_register().
261 *
262 * NOTE: This function should be only called before deinitializing chip
263 * resources.
264 */
265void tpm_chip_unregister(struct tpm_chip *chip)
266{
267	if (!(chip->flags & TPM_CHIP_FLAG_REGISTERED))
268		return;
269
270	spin_lock(&driver_lock);
271	list_del_rcu(&chip->list);
272	spin_unlock(&driver_lock);
273	synchronize_rcu();
274
275	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
276		sysfs_remove_link(&chip->pdev->kobj, "ppi");
277
278	tpm1_chip_unregister(chip);
279	tpm_del_char_device(chip);
280}
281EXPORT_SYMBOL_GPL(tpm_chip_unregister);
282