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/*
* 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 <linux/of.h>
#include "tpm.h"
#include "tpm_eventlog.h"
DEFINE_IDR(dev_nums_idr);
static DEFINE_MUTEX(idr_lock);
struct class *tpm_class;
dev_t tpm_devt;
/**
* tpm_try_get_ops() - Get a ref to the tpm_chip
* @chip: Chip to ref
*
* The caller must already have some kind of locking to ensure that chip is
* valid. This function will lock the chip so that the ops member can be
* accessed safely. The locking prevents tpm_chip_unregister from
* completing, so it should not be held for long periods.
*
* Returns -ERRNO if the chip could not be got.
*/
int tpm_try_get_ops(struct tpm_chip *chip)
{
int rc = -EIO;
get_device(&chip->dev);
down_read(&chip->ops_sem);
if (!chip->ops)
goto out_lock;
if (!try_module_get(chip->dev.parent->driver->owner))
goto out_lock;
return 0;
out_lock:
up_read(&chip->ops_sem);
put_device(&chip->dev);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_try_get_ops);
/**
* tpm_put_ops() - Release a ref to the tpm_chip
* @chip: Chip to put
*
* This is the opposite pair to tpm_try_get_ops(). After this returns chip may
* be kfree'd.
*/
void tpm_put_ops(struct tpm_chip *chip)
{
module_put(chip->dev.parent->driver->owner);
up_read(&chip->ops_sem);
put_device(&chip->dev);
}
EXPORT_SYMBOL_GPL(tpm_put_ops);
/**
* tpm_chip_find_get() - return tpm_chip for a given chip number
* @chip_num: id to find
*
* The return'd chip has been tpm_try_get_ops'd and must be released via
* tpm_put_ops
*/
struct tpm_chip *tpm_chip_find_get(int chip_num)
{
struct tpm_chip *chip, *res = NULL;
int chip_prev;
mutex_lock(&idr_lock);
if (chip_num == TPM_ANY_NUM) {
chip_num = 0;
do {
chip_prev = chip_num;
chip = idr_get_next(&dev_nums_idr, &chip_num);
if (chip && !tpm_try_get_ops(chip)) {
res = chip;
break;
}
} while (chip_prev != chip_num);
} else {
chip = idr_find_slowpath(&dev_nums_idr, chip_num);
if (chip && !tpm_try_get_ops(chip))
res = chip;
}
mutex_unlock(&idr_lock);
return res;
}
/**
* 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);
mutex_lock(&idr_lock);
idr_remove(&dev_nums_idr, chip->dev_num);
mutex_unlock(&idr_lock);
kfree(chip);
}
/**
* tpm_class_shutdown() - prepare the TPM device for loss of power.
* @dev: device to which the chip is associated.
*
* Issues a TPM2_Shutdown command prior to loss of power, as required by the
* TPM 2.0 spec.
* Then, calls bus- and device- specific shutdown code.
*
* XXX: This codepath relies on the fact that sysfs is not enabled for
* TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2
* has sysfs support enabled before TPM sysfs's implicit locking is fixed.
*/
static int tpm_class_shutdown(struct device *dev)
{
struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
down_write(&chip->ops_sem);
tpm2_shutdown(chip, TPM2_SU_CLEAR);
chip->ops = NULL;
up_write(&chip->ops_sem);
}
/* Allow bus- and device-specific code to run. Note: since chip->ops
* is NULL, more-specific shutdown code will not be able to issue TPM
* commands.
*/
if (dev->bus && dev->bus->shutdown)
dev->bus->shutdown(dev);
else if (dev->driver && dev->driver->shutdown)
dev->driver->shutdown(dev);
return 0;
}
/**
* 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;
int rc;
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (chip == NULL)
return ERR_PTR(-ENOMEM);
mutex_init(&chip->tpm_mutex);
init_rwsem(&chip->ops_sem);
chip->ops = ops;
mutex_lock(&idr_lock);
rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
mutex_unlock(&idr_lock);
if (rc < 0) {
dev_err(dev, "No available tpm device numbers\n");
kfree(chip);
return ERR_PTR(rc);
}
chip->dev_num = rc;
scnprintf(chip->devname, sizeof(chip->devname), "tpm%d", chip->dev_num);
dev_set_drvdata(dev, chip);
chip->dev.class = tpm_class;
chip->dev.class->shutdown = tpm_class_shutdown;
chip->dev.release = tpm_dev_release;
chip->dev.parent = dev;
#ifdef CONFIG_ACPI
chip->dev.groups = chip->groups;
#endif
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 = dev->driver->owner;
chip->cdev.kobj.parent = &chip->dev.kobj;
rc = devm_add_action(dev, (void (*)(void *)) put_device, &chip->dev);
if (rc) {
put_device(&chip->dev);
return ERR_PTR(rc);
}
return chip;
}
EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
static int tpm_add_char_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);
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);
cdev_del(&chip->cdev);
return rc;
}
/* Make the chip available. */
mutex_lock(&idr_lock);
idr_replace(&dev_nums_idr, chip, chip->dev_num);
mutex_unlock(&idr_lock);
return rc;
}
static void tpm_del_char_device(struct tpm_chip *chip)
{
cdev_del(&chip->cdev);
device_del(&chip->dev);
/* Make the chip unavailable. */
mutex_lock(&idr_lock);
idr_replace(&dev_nums_idr, NULL, chip->dev_num);
mutex_unlock(&idr_lock);
/* Make the driver uncallable. */
down_write(&chip->ops_sem);
chip->ops = NULL;
up_write(&chip->ops_sem);
}
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;
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_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)
{
#ifdef CONFIG_OF
struct device_node *np;
#endif
int rc;
#ifdef CONFIG_OF
np = of_find_node_by_name(NULL, "vtpm");
if (np) {
if (of_property_read_bool(np, "powered-while-suspended"))
chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
}
of_node_put(np);
#endif
rc = tpm1_chip_register(chip);
if (rc)
return rc;
tpm_add_ppi(chip);
rc = tpm_add_char_device(chip);
if (rc)
goto out_err;
chip->flags |= TPM_CHIP_FLAG_REGISTERED;
if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
rc = __compat_only_sysfs_link_entry_to_kobj(
&chip->dev.parent->kobj, &chip->dev.kobj, "ppi");
if (rc && rc != -ENOENT) {
tpm_chip_unregister(chip);
return rc;
}
}
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().
*
* Once this function returns the driver call backs in 'op's will not be
* running and will no longer start.
*
* 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;
if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
tpm1_chip_unregister(chip);
tpm_del_char_device(chip);
}
EXPORT_SYMBOL_GPL(tpm_chip_unregister);