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; 122 123 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); 139 140 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 } 167 168 static void tpm_dev_del_device(struct tpm_chip *chip) 169 { 170 cdev_del(&chip->cdev); 171 device_unregister(&chip->dev); 172 } 173 174 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 } 195 196 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 */ 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 */ 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