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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 "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);
/*
* 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->dev->driver->owner)) {
chip = pos;
break;
}
}
rcu_read_unlock();
return chip;
}
/**
* tpmm_chip_remove() - free chip memory and device number
* @data: points to struct tpm_chip instance
*
* This is used internally by tpmm_chip_alloc() and called by devres
* when the device is released. This function does the opposite of
* tpmm_chip_alloc() freeing memory and the device number.
*/
static void tpmm_chip_remove(void *data)
{
struct tpm_chip *chip = (struct tpm_chip *) data;
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->dev = dev;
devm_add_action(dev, tpmm_chip_remove, chip);
dev_set_drvdata(dev, chip);
return chip;
}
EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
/*
* tpm_chip_register() - create a misc driver for the TPM chip
* @chip: TPM chip to use.
*
* Creates a misc driver for the TPM chip and adds sysfs interfaces for
* the device, PPI and TCPA. As the last step this function adds the
* chip to the list of TPM chips available for use.
*
* NOTE: This function should be only called after the chip initialization
* is complete.
*
* Called from tpm_<specific>.c probe function only for devices
* the driver has determined it should claim. Prior to calling
* this function the specific probe function has called pci_enable_device
* upon errant exit from this function specific probe function should call
* pci_disable_device
*/
int tpm_chip_register(struct tpm_chip *chip)
{
int rc;
rc = tpm_dev_add_device(chip);
if (rc)
return rc;
rc = tpm_sysfs_add_device(chip);
if (rc)
goto del_misc;
rc = tpm_add_ppi(chip);
if (rc)
goto del_sysfs;
chip->bios_dir = tpm_bios_log_setup(chip->devname);
/* 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;
del_sysfs:
tpm_sysfs_del_device(chip);
del_misc:
tpm_dev_del_device(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();
if (chip->bios_dir)
tpm_bios_log_teardown(chip->bios_dir);
tpm_remove_ppi(chip);
tpm_sysfs_del_device(chip);
tpm_dev_del_device(chip);
}
EXPORT_SYMBOL_GPL(tpm_chip_unregister);
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