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