diff options
Diffstat (limited to 'drivers/char/tpm/tpm-chip.c')
-rw-r--r-- | drivers/char/tpm/tpm-chip.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c new file mode 100644 index 000000000..1082d4bb0 --- /dev/null +++ b/drivers/char/tpm/tpm-chip.c @@ -0,0 +1,269 @@ +/* + * Copyright (C) 2004 IBM Corporation + * Copyright (C) 2014 Intel Corporation + * + * Authors: + * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> + * Leendert van Doorn <leendert@watson.ibm.com> + * Dave Safford <safford@watson.ibm.com> + * Reiner Sailer <sailer@watson.ibm.com> + * Kylene Hall <kjhall@us.ibm.com> + * + * Maintained by: <tpmdd-devel@lists.sourceforge.net> + * + * TPM chip management routines. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2 of the + * License. + * + */ + +#include <linux/poll.h> +#include <linux/slab.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> +#include <linux/freezer.h> +#include <linux/major.h> +#include "tpm.h" +#include "tpm_eventlog.h" + +static DECLARE_BITMAP(dev_mask, TPM_NUM_DEVICES); +static LIST_HEAD(tpm_chip_list); +static DEFINE_SPINLOCK(driver_lock); + +struct class *tpm_class; +dev_t tpm_devt; + +/* + * tpm_chip_find_get - return tpm_chip for a given chip number + * @chip_num the device number for the chip + */ +struct tpm_chip *tpm_chip_find_get(int chip_num) +{ + struct tpm_chip *pos, *chip = NULL; + + rcu_read_lock(); + list_for_each_entry_rcu(pos, &tpm_chip_list, list) { + if (chip_num != TPM_ANY_NUM && chip_num != pos->dev_num) + continue; + + if (try_module_get(pos->pdev->driver->owner)) { + chip = pos; + break; + } + } + rcu_read_unlock(); + return chip; +} + +/** + * tpm_dev_release() - free chip memory and the device number + * @dev: the character device for the TPM chip + * + * This is used as the release function for the character device. + */ +static void tpm_dev_release(struct device *dev) +{ + struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev); + + spin_lock(&driver_lock); + clear_bit(chip->dev_num, dev_mask); + spin_unlock(&driver_lock); + kfree(chip); +} + +/** + * tpmm_chip_alloc() - allocate a new struct tpm_chip instance + * @dev: device to which the chip is associated + * @ops: struct tpm_class_ops instance + * + * Allocates a new struct tpm_chip instance and assigns a free + * device number for it. Caller does not have to worry about + * freeing the allocated resources. When the devices is removed + * devres calls tpmm_chip_remove() to do the job. + */ +struct tpm_chip *tpmm_chip_alloc(struct device *dev, + const struct tpm_class_ops *ops) +{ + struct tpm_chip *chip; + + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (chip == NULL) + return ERR_PTR(-ENOMEM); + + mutex_init(&chip->tpm_mutex); + INIT_LIST_HEAD(&chip->list); + + chip->ops = ops; + + spin_lock(&driver_lock); + chip->dev_num = find_first_zero_bit(dev_mask, TPM_NUM_DEVICES); + spin_unlock(&driver_lock); + + if (chip->dev_num >= TPM_NUM_DEVICES) { + dev_err(dev, "No available tpm device numbers\n"); + kfree(chip); + return ERR_PTR(-ENOMEM); + } + + set_bit(chip->dev_num, dev_mask); + + scnprintf(chip->devname, sizeof(chip->devname), "tpm%d", chip->dev_num); + + chip->pdev = dev; + + dev_set_drvdata(dev, chip); + + chip->dev.class = tpm_class; + chip->dev.release = tpm_dev_release; + chip->dev.parent = chip->pdev; + + if (chip->dev_num == 0) + chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR); + else + chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num); + + dev_set_name(&chip->dev, "%s", chip->devname); + + device_initialize(&chip->dev); + + cdev_init(&chip->cdev, &tpm_fops); + chip->cdev.owner = chip->pdev->driver->owner; + chip->cdev.kobj.parent = &chip->dev.kobj; + + return chip; +} +EXPORT_SYMBOL_GPL(tpmm_chip_alloc); + +static int tpm_dev_add_device(struct tpm_chip *chip) +{ + int rc; + + rc = cdev_add(&chip->cdev, chip->dev.devt, 1); + if (rc) { + dev_err(&chip->dev, + "unable to cdev_add() %s, major %d, minor %d, err=%d\n", + chip->devname, MAJOR(chip->dev.devt), + MINOR(chip->dev.devt), rc); + + device_unregister(&chip->dev); + return rc; + } + + rc = device_add(&chip->dev); + if (rc) { + dev_err(&chip->dev, + "unable to device_register() %s, major %d, minor %d, err=%d\n", + chip->devname, MAJOR(chip->dev.devt), + MINOR(chip->dev.devt), rc); + + return rc; + } + + return rc; +} + +static void tpm_dev_del_device(struct tpm_chip *chip) +{ + cdev_del(&chip->cdev); + device_unregister(&chip->dev); +} + +static int tpm1_chip_register(struct tpm_chip *chip) +{ + int rc; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) + return 0; + + rc = tpm_sysfs_add_device(chip); + if (rc) + return rc; + + rc = tpm_add_ppi(chip); + if (rc) { + tpm_sysfs_del_device(chip); + return rc; + } + + chip->bios_dir = tpm_bios_log_setup(chip->devname); + + return 0; +} + +static void tpm1_chip_unregister(struct tpm_chip *chip) +{ + if (chip->flags & TPM_CHIP_FLAG_TPM2) + return; + + if (chip->bios_dir) + tpm_bios_log_teardown(chip->bios_dir); + + tpm_remove_ppi(chip); + + tpm_sysfs_del_device(chip); +} + +/* + * tpm_chip_register() - create a character device for the TPM chip + * @chip: TPM chip to use. + * + * Creates a character device for the TPM chip and adds sysfs attributes for + * the device. As the last step this function adds the chip to the list of TPM + * chips available for in-kernel use. + * + * This function should be only called after the chip initialization is + * complete. + */ +int tpm_chip_register(struct tpm_chip *chip) +{ + int rc; + + rc = tpm1_chip_register(chip); + if (rc) + return rc; + + rc = tpm_dev_add_device(chip); + if (rc) + goto out_err; + + /* Make the chip available. */ + spin_lock(&driver_lock); + list_add_rcu(&chip->list, &tpm_chip_list); + spin_unlock(&driver_lock); + + chip->flags |= TPM_CHIP_FLAG_REGISTERED; + + return 0; +out_err: + tpm1_chip_unregister(chip); + return rc; +} +EXPORT_SYMBOL_GPL(tpm_chip_register); + +/* + * tpm_chip_unregister() - release the TPM driver + * @chip: TPM chip to use. + * + * Takes the chip first away from the list of available TPM chips and then + * cleans up all the resources reserved by tpm_chip_register(). + * + * NOTE: This function should be only called before deinitializing chip + * resources. + */ +void tpm_chip_unregister(struct tpm_chip *chip) +{ + if (!(chip->flags & TPM_CHIP_FLAG_REGISTERED)) + return; + + spin_lock(&driver_lock); + list_del_rcu(&chip->list); + spin_unlock(&driver_lock); + synchronize_rcu(); + + tpm1_chip_unregister(chip); + tpm_dev_del_device(chip); +} +EXPORT_SYMBOL_GPL(tpm_chip_unregister); |