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
32 static DECLARE_BITMAP(dev_mask, TPM_NUM_DEVICES);
33 static LIST_HEAD(tpm_chip_list);
34 static DEFINE_SPINLOCK(driver_lock);
35
36 struct class *tpm_class;
37 dev_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 */
tpm_chip_find_get(int chip_num)43 struct 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 */
tpm_dev_release(struct device * dev)67 static 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 */
tpmm_chip_alloc(struct device * dev,const struct tpm_class_ops * ops)87 struct 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 }
138 EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
139
tpm_dev_add_device(struct tpm_chip * chip)140 static 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
tpm_dev_del_device(struct tpm_chip * chip)168 static void tpm_dev_del_device(struct tpm_chip *chip)
169 {
170 cdev_del(&chip->cdev);
171 device_unregister(&chip->dev);
172 }
173
tpm1_chip_register(struct tpm_chip * chip)174 static 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
tpm1_chip_unregister(struct tpm_chip * chip)196 static 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 */
tpm_chip_register(struct tpm_chip * chip)220 int 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;
240 out_err:
241 tpm1_chip_unregister(chip);
242 return rc;
243 }
244 EXPORT_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 */
tpm_chip_unregister(struct tpm_chip * chip)256 void 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 }
269 EXPORT_SYMBOL_GPL(tpm_chip_unregister);
270