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 int rc; 92 93 chip = kzalloc(sizeof(*chip), GFP_KERNEL); 94 if (chip == NULL) 95 return ERR_PTR(-ENOMEM); 96 97 mutex_init(&chip->tpm_mutex); 98 INIT_LIST_HEAD(&chip->list); 99 100 chip->ops = ops; 101 102 spin_lock(&driver_lock); 103 chip->dev_num = find_first_zero_bit(dev_mask, TPM_NUM_DEVICES); 104 spin_unlock(&driver_lock); 105 106 if (chip->dev_num >= TPM_NUM_DEVICES) { 107 dev_err(dev, "No available tpm device numbers\n"); 108 kfree(chip); 109 return ERR_PTR(-ENOMEM); 110 } 111 112 set_bit(chip->dev_num, dev_mask); 113 114 scnprintf(chip->devname, sizeof(chip->devname), "tpm%d", chip->dev_num); 115 116 chip->pdev = dev; 117 118 dev_set_drvdata(dev, chip); 119 120 chip->dev.class = tpm_class; 121 chip->dev.release = tpm_dev_release; 122 chip->dev.parent = chip->pdev; 123 #ifdef CONFIG_ACPI 124 chip->dev.groups = chip->groups; 125 #endif 126 127 if (chip->dev_num == 0) 128 chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR); 129 else 130 chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num); 131 132 dev_set_name(&chip->dev, "%s", chip->devname); 133 134 device_initialize(&chip->dev); 135 136 cdev_init(&chip->cdev, &tpm_fops); 137 chip->cdev.owner = chip->pdev->driver->owner; 138 chip->cdev.kobj.parent = &chip->dev.kobj; 139 140 rc = devm_add_action(dev, (void (*)(void *)) put_device, &chip->dev); 141 if (rc) { 142 put_device(&chip->dev); 143 return ERR_PTR(rc); 144 } 145 146 return chip; 147 } 148 EXPORT_SYMBOL_GPL(tpmm_chip_alloc); 149 150 static int tpm_add_char_device(struct tpm_chip *chip) 151 { 152 int rc; 153 154 rc = cdev_add(&chip->cdev, chip->dev.devt, 1); 155 if (rc) { 156 dev_err(&chip->dev, 157 "unable to cdev_add() %s, major %d, minor %d, err=%d\n", 158 chip->devname, MAJOR(chip->dev.devt), 159 MINOR(chip->dev.devt), rc); 160 161 return rc; 162 } 163 164 rc = device_add(&chip->dev); 165 if (rc) { 166 dev_err(&chip->dev, 167 "unable to device_register() %s, major %d, minor %d, err=%d\n", 168 chip->devname, MAJOR(chip->dev.devt), 169 MINOR(chip->dev.devt), rc); 170 171 cdev_del(&chip->cdev); 172 return rc; 173 } 174 175 return rc; 176 } 177 178 static void tpm_del_char_device(struct tpm_chip *chip) 179 { 180 cdev_del(&chip->cdev); 181 device_del(&chip->dev); 182 } 183 184 static int tpm1_chip_register(struct tpm_chip *chip) 185 { 186 int rc; 187 188 if (chip->flags & TPM_CHIP_FLAG_TPM2) 189 return 0; 190 191 rc = tpm_sysfs_add_device(chip); 192 if (rc) 193 return rc; 194 195 chip->bios_dir = tpm_bios_log_setup(chip->devname); 196 197 return 0; 198 } 199 200 static void tpm1_chip_unregister(struct tpm_chip *chip) 201 { 202 if (chip->flags & TPM_CHIP_FLAG_TPM2) 203 return; 204 205 if (chip->bios_dir) 206 tpm_bios_log_teardown(chip->bios_dir); 207 208 tpm_sysfs_del_device(chip); 209 } 210 211 /* 212 * tpm_chip_register() - create a character device for the TPM chip 213 * @chip: TPM chip to use. 214 * 215 * Creates a character device for the TPM chip and adds sysfs attributes for 216 * the device. As the last step this function adds the chip to the list of TPM 217 * chips available for in-kernel use. 218 * 219 * This function should be only called after the chip initialization is 220 * complete. 221 */ 222 int tpm_chip_register(struct tpm_chip *chip) 223 { 224 int rc; 225 226 rc = tpm1_chip_register(chip); 227 if (rc) 228 return rc; 229 230 tpm_add_ppi(chip); 231 232 rc = tpm_add_char_device(chip); 233 if (rc) 234 goto out_err; 235 236 /* Make the chip available. */ 237 spin_lock(&driver_lock); 238 list_add_tail_rcu(&chip->list, &tpm_chip_list); 239 spin_unlock(&driver_lock); 240 241 chip->flags |= TPM_CHIP_FLAG_REGISTERED; 242 243 if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) { 244 rc = __compat_only_sysfs_link_entry_to_kobj(&chip->pdev->kobj, 245 &chip->dev.kobj, 246 "ppi"); 247 if (rc && rc != -ENOENT) { 248 tpm_chip_unregister(chip); 249 return rc; 250 } 251 } 252 253 return 0; 254 out_err: 255 tpm1_chip_unregister(chip); 256 return rc; 257 } 258 EXPORT_SYMBOL_GPL(tpm_chip_register); 259 260 /* 261 * tpm_chip_unregister() - release the TPM driver 262 * @chip: TPM chip to use. 263 * 264 * Takes the chip first away from the list of available TPM chips and then 265 * cleans up all the resources reserved by tpm_chip_register(). 266 * 267 * NOTE: This function should be only called before deinitializing chip 268 * resources. 269 */ 270 void tpm_chip_unregister(struct tpm_chip *chip) 271 { 272 if (!(chip->flags & TPM_CHIP_FLAG_REGISTERED)) 273 return; 274 275 spin_lock(&driver_lock); 276 list_del_rcu(&chip->list); 277 spin_unlock(&driver_lock); 278 synchronize_rcu(); 279 280 if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) 281 sysfs_remove_link(&chip->pdev->kobj, "ppi"); 282 283 tpm1_chip_unregister(chip); 284 tpm_del_char_device(chip); 285 } 286 EXPORT_SYMBOL_GPL(tpm_chip_unregister); 287