tpm.c

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/*
 * Copyright (C) 2004 IBM Corporation
 *
 * Authors:
 * Leendert van Doorn <[e-mail]>
 * Dave Safford <[e-mail]>
 * Reiner Sailer <[e-mail]>
 * Kylene Hall <[e-mail]>
 *
 * Maintained by: <[e-mail]>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org	 
 *
 * 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.
 * 
 * Note, the TPM chip is not interrupt driven (only polling)
 * and can have very long timeouts (minutes!). Hence the unusual
 * calls to msleep.
 *
 */

#include <linux/sched.h>
#include <linux/poll.h>
#include <linux/spinlock.h>
#include "tpm.h"

enum tpm_const {
	TPM_MINOR = 224,	/* officially assigned */
	TPM_BUFSIZE = 2048,
	TPM_NUM_DEVICES = 256,
};

enum tpm_duration {
	TPM_SHORT = 0,
	TPM_MEDIUM = 1,
	TPM_LONG = 2,
	TPM_UNDEFINED,
};

#define TPM_MAX_ORDINAL 243
#define TPM_MAX_PROTECTED_ORDINAL 12
#define TPM_PROTECTED_ORDINAL_MASK 0xFF

static LIST_HEAD(tpm_chip_list);
static DEFINE_SPINLOCK(driver_lock);
static DECLARE_BITMAP(dev_mask, TPM_NUM_DEVICES);

/*
 * Array with one entry per ordinal defining the maximum amount
 * of time the chip could take to return the result.  The ordinal
 * designation of short, medium or long is defined in a table in
 * TCG Specification TPM Main Part 2 TPM Structures Section 17. The
 * values of the SHORT, MEDIUM, and LONG durations are retrieved
 * from the chip during initialization with a call to tpm_get_timeouts.
 */
static const u8 tpm_protected_ordinal_duration[TPM_MAX_PROTECTED_ORDINAL] = {
	TPM_UNDEFINED,		/* 0 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 5 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 10 */
	TPM_SHORT,
};

static const u8 tpm_ordinal_duration[TPM_MAX_ORDINAL] = {
	TPM_UNDEFINED,		/* 0 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 5 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 10 */
	TPM_SHORT,
	TPM_MEDIUM,
	TPM_LONG,
	TPM_LONG,
	TPM_MEDIUM,		/* 15 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_MEDIUM,
	TPM_LONG,
	TPM_SHORT,		/* 20 */
	TPM_SHORT,
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_SHORT,		/* 25 */
	TPM_SHORT,
	TPM_MEDIUM,
	TPM_SHORT,
	TPM_SHORT,
	TPM_MEDIUM,		/* 30 */
	TPM_LONG,
	TPM_MEDIUM,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,		/* 35 */
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_MEDIUM,		/* 40 */
	TPM_LONG,
	TPM_MEDIUM,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,		/* 45 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_LONG,
	TPM_MEDIUM,		/* 50 */
	TPM_MEDIUM,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 55 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_MEDIUM,		/* 60 */
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_SHORT,
	TPM_SHORT,
	TPM_MEDIUM,		/* 65 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 70 */
	TPM_SHORT,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 75 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_LONG,		/* 80 */
	TPM_UNDEFINED,
	TPM_MEDIUM,
	TPM_LONG,
	TPM_SHORT,
	TPM_UNDEFINED,		/* 85 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 90 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_UNDEFINED,		/* 95 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_MEDIUM,		/* 100 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 105 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 110 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,		/* 115 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_LONG,		/* 120 */
	TPM_LONG,
	TPM_MEDIUM,
	TPM_UNDEFINED,
	TPM_SHORT,
	TPM_SHORT,		/* 125 */
	TPM_SHORT,
	TPM_LONG,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,		/* 130 */
	TPM_MEDIUM,
	TPM_UNDEFINED,
	TPM_SHORT,
	TPM_MEDIUM,
	TPM_UNDEFINED,		/* 135 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 140 */
	TPM_SHORT,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 145 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 150 */
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_SHORT,
	TPM_SHORT,
	TPM_UNDEFINED,		/* 155 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 160 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 165 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_LONG,		/* 170 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 175 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_MEDIUM,		/* 180 */
	TPM_SHORT,
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_MEDIUM,		/* 185 */
	TPM_SHORT,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 190 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 195 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 200 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,
	TPM_SHORT,		/* 205 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_MEDIUM,		/* 210 */
	TPM_UNDEFINED,
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_MEDIUM,
	TPM_UNDEFINED,		/* 215 */
	TPM_MEDIUM,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,
	TPM_SHORT,		/* 220 */
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_SHORT,
	TPM_UNDEFINED,		/* 225 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 230 */
	TPM_LONG,
	TPM_MEDIUM,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,		/* 235 */
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_UNDEFINED,
	TPM_SHORT,		/* 240 */
	TPM_UNDEFINED,
	TPM_MEDIUM,
};

static void user_reader_timeout(unsigned long ptr)
{
	struct tpm_chip *chip = (struct tpm_chip *) ptr;

	schedule_work(&chip->work);
}

static void timeout_work(void *ptr)
{
	struct tpm_chip *chip = ptr;

	down(&chip->buffer_mutex);
	atomic_set(&chip->data_pending, 0);
	memset(chip->data_buffer, 0, TPM_BUFSIZE);
	up(&chip->buffer_mutex);
}

/*
 * Returns max number of jiffies to wait
 */
unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip,
					   u32 ordinal)
{
	int duration_idx = TPM_UNDEFINED;
	int duration = 0;

	if (ordinal < TPM_MAX_ORDINAL)
		duration_idx = tpm_ordinal_duration[ordinal];
	else if ((ordinal & TPM_PROTECTED_ORDINAL_MASK) <
		 TPM_MAX_PROTECTED_ORDINAL)
		duration_idx =
		    tpm_protected_ordinal_duration[ordinal &
						   TPM_PROTECTED_ORDINAL_MASK];

	if (duration_idx != TPM_UNDEFINED)
		duration = chip->vendor.duration[duration_idx];
	if (duration <= 0)
		return 2 * 60 * HZ;
	else
		return duration;
}
EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);

/*
 * Internal kernel interface to transmit TPM commands
 */
static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
			    size_t bufsiz)
{
	ssize_t rc;
	u32 count, ordinal;
	unsigned long stop;

	count = be32_to_cpu(*((__be32 *) (buf + 2)));
	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
	if (count == 0)
		return -ENODATA;
	if (count > bufsiz) {
		dev_err(chip->dev,
			"invalid count value %x %zx \n", count, bufsiz);
		return -E2BIG;
	}

	down(&chip->tpm_mutex);

	if ((rc = chip->vendor.send(chip, (u8 *) buf, count)) < 0) {
		dev_err(chip->dev,
			"tpm_transmit: tpm_send: error %zd\n", rc);
		goto out;
	}

	if (chip->vendor.irq)
		goto out_recv;

	stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal);
	do {
		u8 status = chip->vendor.status(chip);
		if ((status & chip->vendor.req_complete_mask) ==
		    chip->vendor.req_complete_val)
			goto out_recv;

		if ((status == chip->vendor.req_canceled)) {
			dev_err(chip->dev, "Operation Canceled\n");
			rc = -ECANCELED;
			goto out;
		}

		msleep(TPM_TIMEOUT);	/* CHECK */
		rmb();
	} while (time_before(jiffies, stop));

	chip->vendor.cancel(chip);
	dev_err(chip->dev, "Operation Timed out\n");
	rc = -ETIME;
	goto out;

out_recv:
	rc = chip->vendor.recv(chip, (u8 *) buf, bufsiz);
	if (rc < 0)
		dev_err(chip->dev,
			"tpm_transmit: tpm_recv: error %zd\n", rc);
out:
	up(&chip->tpm_mutex);
	return rc;
}

#define TPM_DIGEST_SIZE 20
#define TPM_ERROR_SIZE 10
#define TPM_RET_CODE_IDX 6
#define TPM_GET_CAP_RET_SIZE_IDX 10
#define TPM_GET_CAP_RET_UINT32_1_IDX 14
#define TPM_GET_CAP_RET_UINT32_2_IDX 18
#define TPM_GET_CAP_RET_UINT32_3_IDX 22
#define TPM_GET_CAP_RET_UINT32_4_IDX 26
#define TPM_GET_CAP_PERM_DISABLE_IDX 16
#define TPM_GET_CAP_PERM_INACTIVE_IDX 18
#define TPM_GET_CAP_RET_BOOL_1_IDX 14
#define TPM_GET_CAP_TEMP_INACTIVE_IDX 16

#define TPM_CAP_IDX 13
#define TPM_CAP_SUBCAP_IDX 21

enum tpm_capabilities {
	TPM_CAP_FLAG = 4,
	TPM_CAP_PROP = 5,
};

enum tpm_sub_capabilities {
	TPM_CAP_PROP_PCR = 0x1,
	TPM_CAP_PROP_MANUFACTURER = 0x3,
	TPM_CAP_FLAG_PERM = 0x8,
	TPM_CAP_FLAG_VOL = 0x9,
	TPM_CAP_PROP_OWNER = 0x11,
	TPM_CAP_PROP_TIS_TIMEOUT = 0x15,
	TPM_CAP_PROP_TIS_DURATION = 0x20,
};

/*
 * This is a semi generic GetCapability command for use
 * with the capability type TPM_CAP_PROP or TPM_CAP_FLAG
 * and their associated sub_capabilities.
 */

static const u8 tpm_cap[] = {
	0, 193,			/* TPM_TAG_RQU_COMMAND */
	0, 0, 0, 22,		/* length */
	0, 0, 0, 101,		/* TPM_ORD_GetCapability */
	0, 0, 0, 0,		/* TPM_CAP_<TYPE> */
	0, 0, 0, 4,		/* TPM_CAP_SUB_<TYPE> size */
	0, 0, 1, 0		/* TPM_CAP_SUB_<TYPE> */
};

static ssize_t transmit_cmd(struct tpm_chip *chip, u8 *data, int len,
			    char *desc)
{
	int err;

	len = tpm_transmit(chip, data, len);
	if (len <  0)
		return len;
	if (len == TPM_ERROR_SIZE) {
		err = be32_to_cpu(*((__be32 *) (data + TPM_RET_CODE_IDX)));
		dev_dbg(chip->dev, "A TPM error (%d) occurred %s\n", err, desc);
		return err;
	}
	return 0;
}

void tpm_gen_interrupt(struct tpm_chip *chip)
{
	u8 data[max_t(int, ARRAY_SIZE(tpm_cap), 30)];
	ssize_t rc;

	memcpy(data, tpm_cap, sizeof(tpm_cap));
	data[TPM_CAP_IDX] = TPM_CAP_PROP;
	data[TPM_CAP_SUBCAP_IDX] = TPM_CAP_PROP_TIS_TIMEOUT;

	rc = transmit_cmd(chip, data, sizeof(data),
			"attempting to determine the timeouts");
}
EXPORT_SYMBOL_GPL(tpm_gen_interrupt);

void tpm_get_timeouts(struct tpm_chip *chip)
{
	u8 data[max_t(int, ARRAY_SIZE(tpm_cap), 30)];
	ssize_t rc;
	u32 timeout;

	memcpy(data, tpm_cap, sizeof(tpm_cap));
	data[TPM_CAP_IDX] = TPM_CAP_PROP;
	data[TPM_CAP_SUBCAP_IDX] = TPM_CAP_PROP_TIS_TIMEOUT;

	rc = transmit_cmd(chip, data, sizeof(data),
			"attempting to determine the timeouts");
	if (rc)
		goto duration;

	if (be32_to_cpu(*((__be32 *) (data + TPM_GET_CAP_RET_SIZE_IDX)))
	    != 4 * sizeof(u32))
		goto duration;

	/* Don't overwrite default if value is 0 */
	timeout =
	    be32_to_cpu(*((__be32 *) (data + TPM_GET_CAP_RET_UINT32_1_IDX)));
	if (timeout)
		chip->vendor.timeout_a = msecs_to_jiffies(timeout);
	timeout =
	    be32_to_cpu(*((__be32 *) (data + TPM_GET_CAP_RET_UINT32_2_IDX)));
	if (timeout)
		chip->vendor.timeout_b = msecs_to_jiffies(timeout);
	timeout =
	    be32_to_cpu(*((__be32 *) (data + TPM_GET_CAP_RET_UINT32_3_IDX)));
	if (timeout)
		chip->vendor.timeout_c = msecs_to_jiffies(timeout);
	timeout =
	    be32_to_cpu(*((__be32 *) (data + TPM_GET_CAP_RET_UINT32_4_IDX)));
	if (timeout)
		chip->vendor.timeout_d = msecs_to_jiffies(timeout);

duration:
	memcpy(data, tpm_cap, sizeof(tpm_cap));
	data[TPM_CAP_IDX] = TPM_CAP_PROP;
	data[TPM_CAP_SUBCAP_IDX] = TPM_CAP_PROP_TIS_DURATION;

	rc = transmit_cmd(chip, data, sizeof(data),
			"attempting to determine the durations");
	if (rc)
		return;

	if (be32_to_cpu(*((__be32 *) (data + TPM_GET_CAP_RET_SIZE_IDX)))
	    != 3 * sizeof(u32))
		return;

	chip->vendor.duration[TPM_SHORT] =
	    msecs_to_jiffies(be32_to_cpu
			     (*((__be32 *) (data +
					    TPM_GET_CAP_RET_UINT32_1_IDX))));
	chip->vendor.duration[TPM_MEDIUM] =
	    msecs_to_jiffies(be32_to_cpu
			     (*((__be32 *) (data +
					    TPM_GET_CAP_RET_UINT32_2_IDX))));
	chip->vendor.duration[TPM_LONG] =
	    msecs_to_jiffies(be32_to_cpu
			     (*((__be32 *) (data +
					    TPM_GET_CAP_RET_UINT32_3_IDX))));
}
EXPORT_SYMBOL_GPL(tpm_get_timeouts);

void tpm_continue_selftest(struct tpm_chip *chip)
{
	u8 data[] = {
		0, 193,			/* TPM_TAG_RQU_COMMAND */
		0, 0, 0, 10,		/* length */
		0, 0, 0, 83,		/* TPM_ORD_GetCapability */
	};

	tpm_transmit(chip, data, sizeof(data));
}
EXPORT_SYMBOL_GPL(tpm_continue_selftest);

ssize_t tpm_show_enabled(struct device * dev, struct device_attribute * attr,
			char *buf)
{
	u8 data[max_t(int, ARRAY_SIZE(tpm_cap), 35)];