path: root/drivers/char/tpm/tpm_tis.c

/*
 * Copyright (C) 2005, 2006 IBM Corporation
 *
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org
 *
 * This device driver implements the TPM interface as defined in
 * the TCG TPM Interface Spec version 1.2, revision 1.0.
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/pnp.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/acpi.h>
#include <linux/freezer.h>
#include "tpm.h"

#define TPM_HEADER_SIZE 10

enum tis_access {
	TPM_ACCESS_VALID = 0x80,
	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
	TPM_ACCESS_REQUEST_PENDING = 0x04,
	TPM_ACCESS_REQUEST_USE = 0x02,
};

enum tis_status {
	TPM_STS_VALID = 0x80,
	TPM_STS_COMMAND_READY = 0x40,
	TPM_STS_GO = 0x20,
	TPM_STS_DATA_AVAIL = 0x10,
	TPM_STS_DATA_EXPECT = 0x08,
};

enum tis_int_flags {
	TPM_GLOBAL_INT_ENABLE = 0x80000000,
	TPM_INTF_BURST_COUNT_STATIC = 0x100,
	TPM_INTF_CMD_READY_INT = 0x080,
	TPM_INTF_INT_EDGE_FALLING = 0x040,
	TPM_INTF_INT_EDGE_RISING = 0x020,
	TPM_INTF_INT_LEVEL_LOW = 0x010,
	TPM_INTF_INT_LEVEL_HIGH = 0x008,
	TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
	TPM_INTF_STS_VALID_INT = 0x002,
	TPM_INTF_DATA_AVAIL_INT = 0x001,
};

enum tis_defaults {
	TIS_MEM_BASE = 0xFED40000,
	TIS_MEM_LEN = 0x5000,
	TIS_SHORT_TIMEOUT = 750,	/* ms */
	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
};

#define	TPM_ACCESS(l)			(0x0000 | ((l) << 12))
#define	TPM_INT_ENABLE(l)		(0x0008 | ((l) << 12))
#define	TPM_INT_VECTOR(l)		(0x000C | ((l) << 12))
#define	TPM_INT_STATUS(l)		(0x0010 | ((l) << 12))
#define	TPM_INTF_CAPS(l)		(0x0014 | ((l) << 12))
#define	TPM_STS(l)			(0x0018 | ((l) << 12))
#define	TPM_DATA_FIFO(l)		(0x0024 | ((l) << 12))

#define	TPM_DID_VID(l)			(0x0F00 | ((l) << 12))
#define	TPM_RID(l)			(0x0F04 | ((l) << 12))

static LIST_HEAD(tis_chips);
static DEFINE_SPINLOCK(tis_lock);

#if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
static int is_itpm(struct pnp_dev *dev)
{
	struct acpi_device *acpi = pnp_acpi_device(dev);
	struct acpi_hardware_id *id;

	list_for_each_entry(id, &acpi->pnp.ids, list) {
		if (!strcmp("INTC0102", id->id))
			return 1;
	}

	return 0;
}
#else
static inline int is_itpm(struct pnp_dev *dev)
{
	return 0;
}
#endif

static int check_locality(struct tpm_chip *chip, int l)
{
	if ((ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
	     (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
	    (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
		return chip->vendor.locality = l;

	return -1;
}

static void release_locality(struct tpm_chip *chip, int l, int force)
{
	if (force || (ioread8(chip->vendor.iobase + TPM_ACCESS(l)) &
		      (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
	    (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID))
		iowrite8(TPM_ACCESS_ACTIVE_LOCALITY,
			 chip->vendor.iobase + TPM_ACCESS(l));
}

static int request_locality(struct tpm_chip *chip, int l)
{
	unsigned long stop, timeout;
	long rc;

	if (check_locality(chip, l) >= 0)
		return l;

	iowrite8(TPM_ACCESS_REQUEST_USE,
		 chip->vendor.iobase + TPM_ACCESS(l));

	stop = jiffies + chip->vendor.timeout_a;

	if (chip->vendor.irq) {
again:
		timeout = stop - jiffies;
		if ((long)timeout <= 0)
			return -1;
		rc = wait_event_interruptible_timeout(chip->vendor.int_queue,
						      (check_locality
						       (chip, l) >= 0),
						      timeout);
		if (rc > 0)
			return l;
		if (rc == -ERESTARTSYS && freezing(current)) {
			clear_thread_flag(TIF_SIGPENDING);
			goto again;
		}
	} else {
		/* wait for burstcount */
		do {
			if (check_locality(chip, l) >= 0)
				return l;
			msleep(TPM_TIMEOUT);
		}
		while (time_before(jiffies, stop));
	}
	return -1;
}

static u8 tpm_tis_status(struct tpm_chip *chip)
{
	return ioread8(chip->vendor.iobase +
		       TPM_STS(chip->vendor.locality));
}

static void tpm_tis_ready(struct tpm_chip *chip)
{
	/* this causes the current command to be aborted */
	iowrite8(TPM_STS_COMMAND_READY,
		 chip->vendor.iobase + TPM_STS(chip->vendor.locality));
}

static int get_burstcount(struct tpm_chip *chip)
{
	unsigned long stop;
	int burstcnt;

	/* wait for burstcount */
	/* which timeout value, spec has 2 answers (c & d) */
	stop = jiffies