Message-ID: <1335967293-7728-1-git-send-email-peter.huewe@infineon.com>
Date:	Wed, 2 May 2012 16:01:33 +0200
From:	Peter Huewe <peter.huewe@...ineon.com>
To:	Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
CC:	<tpmdd@...horst.net>, <tpmdd-devel@...ts.sourceforge.net>,
	<linux-kernel@...r.kernel.org>, Olof Johansson <olof@...om.net>,
	Luigi Semenzato <semenzato@...gle.com>,
	Peter Huewe <peter.huewe@...ineon.com>
Subject: [PATCH] char/tpm: Add new driver for Infineon I2C TIS TPM

This patch adds a driver to support Infineon's SLB 9635 TT 1.2 Soft I2C
TPMs which follow the TGC TIS 1.2 TPM specification[1] and Infineon's I2C
Protocol Stack Specification 0.20.
The I2C Protocol Stack Specification is a simple adaption of the LPC TIS
Protocol to the I2C Bus.
The I2C TPMs can be used when LPC Bus is not available (i.e. non x86
architectures like ARM).

The driver is based on the tpm_tis.c driver by Leendert van Dorn and Kyleen Hall
and has quite similar functionality.

Tested on Nvidia ARM Tegra2 Development Platform and Beagleboard (ARM OMAP)
Tested with the Trousers[2] TSS API Testsuite v 0.3 [3]
Compile-tested on x86 (32/64-bit)

Updates since version 2.1.2:
- added sysfs entries for duration and timeouts
- updated to new tpm_do_selftest
Updates since version 2.1.0:
- improved error handling
- implemented workarounds needed by the tpm
- fixed typos

References:
[1] http://www.trustedcomputinggroup.org/resources/pc_client_work_group_pc_client_specific_tpm_interface_specification_tis_version_12/
[2] http://trousers.sourceforge.net/
[3] http://sourceforge.net/projects/trousers/files/TSS%20API%20test%20suite/0.3/

Signed-off-by: Peter Huewe <peter.huewe@...ineon.com>
---
 drivers/char/tpm/Kconfig       |   11 +
 drivers/char/tpm/Makefile      |    1 +
 drivers/char/tpm/tpm_tis_i2c.c |  716 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 728 insertions(+), 0 deletions(-)
 create mode 100644 drivers/char/tpm/tpm_tis_i2c.c

diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index a048199..e594d48 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -33,6 +33,17 @@ config TCG_TIS
 	  from within Linux.  To compile this driver as a module, choose
 	  M here; the module will be called tpm_tis.
 
+config TCG_TIS_I2C
+	tristate "TPM Interface Specification 1.2 Interface (I2C)"
+	depends on I2C
+	---help---
+	  If you have a TPM security chip that is compliant with the
+	  TCG TIS 1.2 TPM specification and Infineon's I2C Protocol Stack
+	  Specification 0.20 say Yes and it will be accessible from within
+	  Linux.
+	  To compile this driver as a module, choose M here; the module
+	  will be called tpm_tis_i2c.
+
 config TCG_NSC
 	tristate "National Semiconductor TPM Interface"
 	depends on X86
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index ea3a1e0..b6e051a 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -6,6 +6,7 @@ ifdef CONFIG_ACPI
 	obj-$(CONFIG_TCG_TPM) += tpm_bios.o
 endif
 obj-$(CONFIG_TCG_TIS) += tpm_tis.o
+obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o
 obj-$(CONFIG_TCG_NSC) += tpm_nsc.o
 obj-$(CONFIG_TCG_ATMEL) += tpm_atmel.o
 obj-$(CONFIG_TCG_INFINEON) += tpm_infineon.o
diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c
new file mode 100644
index 0000000..8975abf
--- /dev/null
+++ b/drivers/char/tpm/tpm_tis_i2c.c
@@ -0,0 +1,716 @@
+/*
+ * Copyright (C) 2012 Infineon Technologies
+ *
+ * Authors:
+ * Peter Huewe <peter.huewe@...ineon.com>
+ *
+ * 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 and the
+ * Infineon I2C Protocol Stack Specification v0.20.
+ *
+ * It is based on the original tpm_tis device driver from Leendert van
+ * Dorn and Kyleen Hall.
+ *
+ * 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/i2c.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/wait.h>
+#include "tpm.h"
+
+/* max. buffer size supported by our tpm */
+#define TPM_BUFSIZE 1260
+
+/* max. number of iterations after i2c NAK */
+#define MAX_COUNT 3
+
+#define SLEEP_DURATION_LOW 55
+#define SLEEP_DURATION_HI 65
+
+/* max. number of iterations after i2c NAK for 'long' commands
+ * we need this especially for sending TPM_READY, since the cleanup after the
+ * transtion to the ready state may take some time, but it is unpredictable
+ * how long it will take.
+ */
+#define MAX_COUNT_LONG 50
+
+#define SLEEP_DURATION_LONG_LOW 200
+#define SLEEP_DURATION_LONG_HI 220
+
+/* expected value for DIDVID register */
+#define TPM_TIS_I2C_DID_VID 0x000b15d1L
+
+/* Structure to store I2C TPM specific stuff */
+struct tpm_inf_dev {
+	struct i2c_client *client;
+	u8 buf[TPM_BUFSIZE+sizeof(u8)]; /* max. buffer size + addr */
+	struct tpm_chip *chip;
+};
+
+static struct tpm_inf_dev tpm_dev;
+
+
+/*
+ * iic_tpm_read() - read from TPM register
+ * @addr: register address to read from
+ * @buffer: provided by caller
+ * @len: number of bytes to read
+ *
+ * Read len bytes from TPM register and put them into
+ * buffer (little-endian format, i.e. first byte is put into buffer[0]).
+ *
+ * NOTE: TPM is big-endian for multi-byte values. Multi-byte
+ * values have to be swapped.
+ *
+ * Return -EIO on error, 0 on success.
+ */
+static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
+{
+
+	struct i2c_msg msg1 = { tpm_dev.client->addr, 0, 1, &addr };
+	struct i2c_msg msg2 = { tpm_dev.client->addr, I2C_M_RD, len, buffer };
+
+	int rc;
+	int count;
+
+	for (count = 0; count < MAX_COUNT; count++) {
+		rc = i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
+		if (rc > 0)
+			break; /* break here to skip sleep */
+
+		usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
+	}
+
+	if (rc <= 0)
+		return -EIO;
+
+	/* After the TPM has successfully received the register address it needs
+	 * some time, thus we're sleeping here again, before retrieving the data
+	 */
+	for (count = 0; count < MAX_COUNT; count++) {
+		usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
+		rc = i2c_transfer(tpm_dev.client->adapter, &msg2, 1);
+		if (rc > 0)
+			break;
+
+	}
+
+	if (rc <= 0)
+		return -EIO;
+
+	return 0;
+}
+
+static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
+				unsigned int sleep_low,
+				unsigned int sleep_hi,
+				u8 max_count)
+{
+	int rc = -1;
+	int count;
+
+	struct i2c_msg msg1 = { tpm_dev.client->addr, 0, len + 1, tpm_dev.buf };
+
+	tpm_dev.buf[0] = addr;
+	memcpy(&(tpm_dev.buf[1]), buffer, len);
+
+	for (count = 0; count < max_count; count++) {
+		rc = i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
+		if (rc > 0)
+			break;
+
+		usleep_range(sleep_low, sleep_hi);
+	}
+
+	if (rc <= 0)
+		return -EIO;
+
+	return 0;
+}
+
+/*
+ * iic_tpm_write() - write to TPM register
+ * @addr: register address to write to
+ * @buffer: containing data to be written
+ * @len: number of bytes to write
+ *
+ * Write len bytes from provided buffer to TPM register (little
+ * endian format, i.e. buffer[0] is written as first byte).
+ *
+ * NOTE: TPM is big-endian for multi-byte values. Multi-byte
+ * values have to be swapped.
+ *
+ * NOTE: use this function instead of the iic_tpm_write_generic function.
+ *
+ * Return -EIO on error, 0 on success
+ */
+static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
+{
+	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
+			SLEEP_DURATION_HI, MAX_COUNT);
+}
+
+/*
+ * This function is needed especially for the cleanup situation after
+ * sending TPM_READY
+ * */
+static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
+{
+	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
+			SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
+}
+
+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_defaults {
+	TIS_SHORT_TIMEOUT = 750,	/* ms */
+	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
+};
+
+#define	TPM_ACCESS(l)			(0x0000 | ((l) << 4))
+#define	TPM_STS(l)			(0x0001 | ((l) << 4))
+#define	TPM_DATA_FIFO(l)		(0x0005 | ((l) << 4))
+#define	TPM_DID_VID(l)			(0x0006 | ((l) << 4))
+
+static int check_locality(struct tpm_chip *chip, int loc)
+{
+	u8 buf;
+	int rc;
+
+	rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
+	if (rc < 0)
+		return rc;
+
+	if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
+		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
+		chip->vendor.locality = loc;
+		return loc;
+	}
+
+	return -1;
+}
+
+static void release_locality(struct tpm_chip *chip, int loc, int force)
+{
+	u8 buf;
+	if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
+		return;
+
+	if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
+			(TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
+		buf = TPM_ACCESS_ACTIVE_LOCALITY;
+		iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
+	}
+}
+
+static int request_locality(struct tpm_chip *chip, int loc)
+{
+	unsigned long stop;
+	u8 buf = TPM_ACCESS_REQUEST_USE;
+
+	if (check_locality(chip, loc) >= 0)
+		return loc;
+
+	iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
+
+	/* wait for burstcount */
+	stop = jiffies + chip->vendor.timeout_a;
+	do {
+		if (check_locality(chip, loc) >= 0)
+			return loc;
+		msleep(TPM_TIMEOUT);
+	} while (time_before(jiffies, stop));
+
+	return -1;
+}
+
+static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
+{
+	/* NOTE: since i2c read may fail, return 0 in this case --> time-out */
+	u8 buf;
+	if (iic_tpm_read(TPM_STS(chip->vendor.locality), &buf, 1) < 0)
+		return 0;
+	else
+		return buf;
+}
+
+static void tpm_tis_i2c_ready(struct tpm_chip *chip)
+{
+	/* this causes the current command to be aborted */
+	u8 buf = TPM_STS_COMMAND_READY;
+	iic_tpm_write_long(TPM_STS(chip->vendor.locality), &buf, 1);
+}
+
+static ssize_t get_burstcount(struct tpm_chip *chip)
+{
+	unsigned long stop;
+	ssize_t burstcnt;
+	u8 buf[3];
+
+	/* wait for burstcount */
+	/* which timeout value, spec has 2 answers (c & d) */
+	stop = jiffies + chip->vendor.timeout_d;
+	do {
+		/* Note: STS is little endian */
+		if (iic_tpm_read(TPM_STS(chip->vendor.locality) + 1, buf, 3) < 0)
+			burstcnt = 0;
+		else
+			burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
+
+		if (burstcnt)
+			return burstcnt;
+
+		msleep(TPM_TIMEOUT);
+	} while (time_before(jiffies, stop));
+	return -EBUSY;
+}
+
+static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
+			int *status)
+{
+	unsigned long stop;
+
+	/* check current status */
+	*status = tpm_tis_i2c_status(chip);
+	if ((*status & mask) == mask)
+		return 0;
+
+	stop = jiffies + timeout;
+	do {
+		msleep(TPM_TIMEOUT);
+		*status = tpm_tis_i2c_status(chip);
+		if ((*status & mask) == mask)
+			return 0;
+
+	} while (time_before(jiffies, stop));
+
+	return -ETIME;
+}
+
+static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	size_t size = 0;
+	ssize_t burstcnt;
+	int rc;
+
+	while (size < count) {
+		burstcnt = get_burstcount(chip);
+
+		/* burstcnt < 0 = tpm is busy */
+		if (burstcnt < 0)
+			return burstcnt;
+
+		/* limit received data to max. left */
+		if (burstcnt > (count-size))
+			burstcnt = count-size;
+
+		rc = iic_tpm_read(TPM_DATA_FIFO(chip->vendor.locality),
+				  &(buf[size]),
+				  burstcnt);
+		if (rc == 0)
+			size += burstcnt;
+
+	}
+	return size;
+}
+
+static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+	int size = 0;
+	int expected, status;
+
+	if (count < TPM_HEADER_SIZE) {
+		size = -EIO;
+		goto out;
+	}
+
+	/* read first 10 bytes, including tag, paramsize, and result */
+	size = recv_data(chip, buf, TPM_HEADER_SIZE);
+	if (size < TPM_HEADER_SIZE) {
+		dev_err(chip->dev, "Unable to read header\n");
+		goto out;
+	}
+
+	expected = be32_to_cpu(*(__be32 *) (buf + 2));
+	if ((size_t)expected > count) {
+		size = -EIO;
+		goto out;
+	}
+
+	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
+				expected - TPM_HEADER_SIZE);
+	if (size < expected) {
+		dev_err(chip->dev, "Unable to read remainder of result\n");
+		size = -ETIME;
+		goto out;
+	}
+
+	wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
+	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
+		dev_err(chip->dev, "Error left over data\n");
+		size = -EIO;
+		goto out;
+	}
+
+out:
+	tpm_tis_i2c_ready(chip);
+	/* The TPM needs some time to clean up here,
+	 * so we sleep rather than keeping the bus busy
+	 */
+	usleep_range(2400, 2600);
+	release_locality(chip, chip->vendor.locality, 0);
+	return size;
+}
+
+static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
+{
+	int rc, status;
+	ssize_t burstcnt;
+	size_t count = 0;
+	u8 sts = TPM_STS_GO;
+
+	if (len > TPM_BUFSIZE)
+		return -E2BIG; /* command is too long for our tpm, sorry */
+
+	if (request_locality(chip, 0) < 0)
+		return -EBUSY;
+
+	status = tpm_tis_i2c_status(chip);
+	if ((status & TPM_STS_COMMAND_READY) == 0) {
+		tpm_tis_i2c_ready(chip);
+		if (wait_for_stat
+		    (chip, TPM_STS_COMMAND_READY,
+		     chip->vendor.timeout_b, &status) < 0) {
+			rc = -ETIME;
+			goto out_err;
+		}
+	}
+
+	while (count < len - 1) {
+		burstcnt = get_burstcount(chip);
+		dev_dbg(chip->dev,
+			"send(): count=%zd, len=%zd, burstcount=%zd (plain)\n",
+			count, len, burstcnt);
+
+		/* burstcnt < 0 = tpm is busy */
+		if (burstcnt < 0)
+			return burstcnt;
+
+		if (burstcnt > (len-1-count))
+			burstcnt = len-1-count;
+
+		dev_dbg(chip->dev, "send(): burstcount=%zd\n", burstcnt);
+
+		rc = iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality),
+				   &(buf[count]), burstcnt);
+		if (rc == 0)
+			count += burstcnt;
+
+		wait_for_stat(chip, TPM_STS_VALID,
+				chip->vendor.timeout_c, &status);
+
+		if ((status & TPM_STS_DATA_EXPECT) == 0) {
+			rc = -EIO;
+			goto out_err;
+		}
+
+	}
+
+	dev_dbg(chip->dev, "send(): last byte @ count=%zd\n", count);
+
+	/* write last byte */
+	iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality), &(buf[count]), 1);
+	wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
+	if ((status & TPM_STS_DATA_EXPECT) != 0) {
+		rc = -EIO;
+		goto out_err;
+	}
+
+	/* go and do it */
+	iic_tpm_write(TPM_STS(chip->vendor.locality), &sts, 1);
+
+	return len;
+out_err:
+	tpm_tis_i2c_ready(chip);
+	/* The TPM needs some time to clean up here,
+	 * so we sleep rather than keeping the bus busy
+	 */
+	usleep_range(2400, 2600);
+	release_locality(chip, chip->vendor.locality, 0);
+	return rc;
+}
+
+static const struct file_operations tis_ops = {
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+	.open = tpm_open,
+	.read = tpm_read,
+	.write = tpm_write,
+	.release = tpm_release,
+};
+
+static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
+static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
+static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
+static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
+static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
+static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated, NULL);
+static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps_1_2, NULL);
+static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
+static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
+static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
+
+static struct attribute *tis_attrs[] = {
+	&dev_attr_pubek.attr,
+	&dev_attr_pcrs.attr,
+	&dev_attr_enabled.attr,
+	&dev_attr_active.attr,
+	&dev_attr_owned.attr,
+	&dev_attr_temp_deactivated.attr,
+	&dev_attr_caps.attr,
+	&dev_attr_cancel.attr,
+	&dev_attr_durations.attr,
+	&dev_attr_timeouts.attr, NULL,
+};
+
+static struct attribute_group tis_attr_grp = {
+	.attrs = tis_attrs
+};
+
+static struct tpm_vendor_specific tpm_tis_i2c = {
+	.status = tpm_tis_i2c_status,
+	.recv = tpm_tis_i2c_recv,
+	.send = tpm_tis_i2c_send,
+	.cancel = tpm_tis_i2c_ready,
+	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
+	.req_canceled = TPM_STS_COMMAND_READY,
+	.attr_group = &tis_attr_grp,
+	.miscdev = {
+		    .fops = &tis_ops,},
+};
+
+static int tpm_tis_i2c_init(struct device *dev)
+{
+	u32 vendor;
+	int rc = 0;
+	struct tpm_chip *chip;
+
+	chip = tpm_register_hardware(dev, &tpm_tis_i2c);
+	if (!chip) {
+		rc = -ENODEV;
+		goto out_err;
+	}
+
+	/* Disable interrupts */
+	chip->vendor.irq = 0;
+
+	/* Default timeouts */
+	chip->vendor.timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
+	chip->vendor.timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
+	chip->vendor.timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
+	chip->vendor.timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
+
+	if (request_locality(chip, 0) != 0) {
+		rc = -ENODEV;
+		goto out_vendor;
+	}
+
+	/* read four bytes from DID_VID register */
+	if (iic_tpm_read(TPM_DID_VID(0), (u8 *) &vendor, 4) < 0) {
+		rc = -EIO;
+		goto out_vendor;
+	}
+
+	/* create DID_VID register value, after swapping to little-endian */
+	vendor = be32_to_cpu((__be32) vendor);
+
+	if (vendor != TPM_TIS_I2C_DID_VID) {
+		rc = -ENODEV;
+		goto out_release;
+	}
+
+	dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
+
+	INIT_LIST_HEAD(&chip->vendor.list);
+	tpm_dev.chip = chip;
+
+	tpm_get_timeouts(chip);
+	tpm_do_selftest(chip);
+
+	return 0;
+
+out_release:
+	release_locality(chip, chip->vendor.locality, 1);
+
+out_vendor:
+	tpm_dev_vendor_release(chip);
+	tpm_remove_hardware(chip->dev);
+
+out_err:
+	return rc;
+}
+
+
+static const struct i2c_device_id tpm_i2c_tis_table[] = {
+	{ "tpm_tis_i2c", 0 },
+	{ },
+};
+
+#ifdef CONFIG_PM
+/* NOTE:
+ * Suspend does currently not work Nvidias Tegra2 Platform
+ * but works fine on Beagleboard (arm omap).
+ *
+ * This function will block System Suspend if TPM is not initialized,
+ * however the TPM is usually initialized by BIOS/u-boot or by sending
+ * a tpm startup command.
+ */
+static int tpm_tis_i2c_suspend(struct device *dev)
+{
+	return tpm_pm_suspend(dev, dev->power.power_state);
+}
+
+static int tpm_tis_i2c_resume(struct device *dev)
+{
+	return tpm_pm_resume(dev);
+}
+
+static const struct dev_pm_ops tpm_tis_i2c_ops = {
+	.suspend = tpm_tis_i2c_suspend,
+	.resume = tpm_tis_i2c_resume,
+};
+#endif
+
+
+static int dummy_probe(struct i2c_client *client,
+	const struct i2c_device_id *id)
+{
+	return 0;
+}
+
+static int dummy_remove(struct i2c_client *client)
+{
+	return 0;
+}
+
+static struct i2c_driver tpm_i2c_tis_driver = {
+
+	.id_table = tpm_i2c_tis_table,
+	.probe = dummy_probe,
+	.remove = dummy_remove,
+	.driver	= {
+		.name	= "tpm_tis_i2c",
+		.owner	= THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm     = &tpm_tis_i2c_ops,
+#endif
+	},
+};
+
+
+static struct i2c_adapter *adap;
+static struct i2c_client *client;
+static	struct i2c_board_info info = {
+	I2C_BOARD_INFO("tpm_tis_i2c", 0x20),
+};
+
+
+static int addr = 0x20;
+module_param(addr, int, S_IRUGO);
+MODULE_PARM_DESC(addr, "TPM I2C Device Address (default: 0x20)");
+
+static int bus_id = 2;
+module_param(bus_id, int, S_IRUGO);
+MODULE_PARM_DESC(bus_id, "TPM I2C Bus Id (default: 2)");
+
+static int __init init_tis_i2c(void)
+{
+
+	int rc = 0;
+	info.addr = addr;
+
+
+	if (tpm_dev.client != NULL)
+		return -EBUSY;
+
+	adap = i2c_get_adapter(bus_id);
+	if (!adap)
+		return -ENODEV;
+
+	client = i2c_new_device(adap, &info);
+	if (!client) {
+		i2c_put_adapter(adap);
+		return -ENODEV;
+	}
+
+	rc = i2c_add_driver(&tpm_i2c_tis_driver);
+	if (rc != 0) {
+		i2c_del_driver(&tpm_i2c_tis_driver);
+		i2c_put_adapter(tpm_dev.client->adapter);
+		return -ENODEV;
+	}
+	client->driver = &tpm_i2c_tis_driver;
+
+	tpm_dev.client = client;
+
+	rc = tpm_tis_i2c_init(&client->dev);
+	if (rc < 0) {
+		i2c_del_driver(&tpm_i2c_tis_driver);
+		i2c_put_adapter(tpm_dev.client->adapter);
+		device_del(&(tpm_dev.client->dev));
+	}
+
+	return rc;
+}
+
+static void __exit cleanup_tis_i2c(void)
+{
+	struct tpm_chip *chip = tpm_dev.chip;
+	release_locality(chip, chip->vendor.locality, 1);
+
+	tpm_dev_vendor_release(chip);
+	tpm_remove_hardware(chip->dev);
+
+	i2c_del_driver(&tpm_i2c_tis_driver);
+
+	i2c_put_adapter(tpm_dev.client->adapter);
+
+	/*
+	 * taken from core.c as workaround since
+	 * tpm_remove_hardware requires device structure
+	 */
+	pr_debug("device: '%s': %s\n",
+		dev_name(&(tpm_dev.client->dev)), __func__);
+	device_del(&(tpm_dev.client->dev));
+}
+
+module_init(init_tis_i2c);
+module_exit(cleanup_tis_i2c);
+MODULE_AUTHOR("Peter Huewe <peter.huewe@...ineon.com>");
+MODULE_DESCRIPTION("TPM TIS I2C Driver");
+MODULE_VERSION("2.1.3");
+MODULE_LICENSE("GPL");
-- 
1.7.6.msysgit.0

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