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tpm: Add support for Atmel I2C TPMs

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This is based on the work of Teddy Reed <teddy@prosauce.org> published
on GitHub:
 https://github.com/theopolis/tpm-i2c-atmel.git
 34894b988b67e0ae55088d6388e77b0dbf10c07d

That driver was never merged, I have taken it as a starting port,
forward ported, tested and revised the driver:
 - Make it broadly textually similar to the Infineon and Nuvoton I2C
   driver
 - Place everything in a format suitable for mainline inclusion
 - Use high level I2C functions i2c_master_send and
   i2c_master_recv for data xfer
 - Use the timeout system from the core code, by faking out a status
   register
 - Only I2C transfer the number of bytes in the reply, not a fixed
   message size.
 - checkpatch cleanups
 - Testing on ARM Kirkwood, with this device tree, using a
   AT97SC3204T-X1A180
        tpm@29 {
                compatible = "atmel,at97sc3204t";
                reg = <0x29>;
        };

Signed-off-by: Teddy Reed <teddy@prosauce.org>
[jgg: revised and tested]
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
[phuewe: minor whitespace changes]

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
This commit is contained in:
Jason Gunthorpe 2013-10-06 12:43:36 -06:00 committed by Peter Huewe
parent 4c336e4b15
commit a2871c62e1
4 changed files with 295 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
Documentation/devicetree/bindings/i2c/trivial-devices.txt
View file

@ -15,6 +15,7 @@ adi,adt7461 +/-1C TDM Extended Temp Range I.C
adt7461 +/-1C TDM Extended Temp Range I.C
at,24c08 i2c serial eeprom (24cxx)
atmel,24c02 i2c serial eeprom (24cxx)
atmel,at97sc3204t i2c trusted platform module (TPM)
catalyst,24c32 i2c serial eeprom
dallas,ds1307 64 x 8, Serial, I2C Real-Time Clock
dallas,ds1338 I2C RTC with 56-Byte NV RAM

9
drivers/char/tpm/Kconfig
View file

@ -33,6 +33,15 @@ 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_ATMEL
tristate "TPM Interface Specification 1.2 Interface (I2C - Atmel)"
depends on I2C
---help---
If you have an Atmel I2C TPM security chip 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_atmel.
config TCG_TIS_I2C_INFINEON
tristate "TPM Interface Specification 1.2 Interface (I2C - Infineon)"
depends on I2C

1
drivers/char/tpm/Makefile
View file

@ -13,6 +13,7 @@ ifdef CONFIG_TCG_IBMVTPM
endif
endif
obj-$(CONFIG_TCG_TIS) += tpm_tis.o
obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
obj-$(CONFIG_TCG_NSC) += tpm_nsc.o

284
drivers/char/tpm/tpm_i2c_atmel.c Normal file
View file

@ -0,0 +1,284 @@
/*
* ATMEL I2C TPM AT97SC3204T
*
* Copyright (C) 2012 V Lab Technologies
* Teddy Reed <teddy@prosauce.org>
* Copyright (C) 2013, Obsidian Research Corp.
* Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
* Device driver for ATMEL I2C TPMs.
*
* Teddy Reed determined the basic I2C command flow, unlike other I2C TPM
* devices the raw TCG formatted TPM command data is written via I2C and then
* raw TCG formatted TPM command data is returned via I2C.
*
* TGC status/locality/etc functions seen in the LPC implementation do not
* seem to be present.
*
* 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, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses/>.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include "tpm.h"
#define I2C_DRIVER_NAME "tpm_i2c_atmel"
#define TPM_I2C_SHORT_TIMEOUT 750 /* ms */
#define TPM_I2C_LONG_TIMEOUT 2000 /* 2 sec */
#define ATMEL_STS_OK 1
struct priv_data {
size_t len;
/* This is the amount we read on the first try. 25 was chosen to fit a
* fair number of read responses in the buffer so a 2nd retry can be
* avoided in small message cases. */
u8 buffer[sizeof(struct tpm_output_header) + 25];
};
static int i2c_atmel_send(struct tpm_chip *chip, u8 *buf, size_t len)
{
struct priv_data *priv = chip->vendor.priv;
struct i2c_client *client = to_i2c_client(chip->dev);
s32 status;
priv->len = 0;
if (len <= 2)
return -EIO;
status = i2c_master_send(client, buf, len);
dev_dbg(chip->dev,
"%s(buf=%*ph len=%0zx) -> sts=%d\n", __func__,
(int)min_t(size_t, 64, len), buf, len, status);
return status;
}
static int i2c_atmel_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
struct priv_data *priv = chip->vendor.priv;
struct i2c_client *client = to_i2c_client(chip->dev);
struct tpm_output_header *hdr =
(struct tpm_output_header *)priv->buffer;
u32 expected_len;
int rc;
if (priv->len == 0)
return -EIO;
/* Get the message size from the message header, if we didn't get the
* whole message in read_status then we need to re-read the
* message. */
expected_len = be32_to_cpu(hdr->length);
if (expected_len > count)
return -ENOMEM;
if (priv->len >= expected_len) {
dev_dbg(chip->dev,
"%s early(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
(int)min_t(size_t, 64, expected_len), buf, count,
expected_len);
memcpy(buf, priv->buffer, expected_len);
return expected_len;
}
rc = i2c_master_recv(client, buf, expected_len);
dev_dbg(chip->dev,
"%s reread(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
(int)min_t(size_t, 64, expected_len), buf, count,
expected_len);
return rc;
}
static void i2c_atmel_cancel(struct tpm_chip *chip)
{
dev_err(chip->dev, "TPM operation cancellation was requested, but is not supported");
}
static u8 i2c_atmel_read_status(struct tpm_chip *chip)
{
struct priv_data *priv = chip->vendor.priv;
struct i2c_client *client = to_i2c_client(chip->dev);
int rc;
/* The TPM fails the I2C read until it is ready, so we do the entire
* transfer here and buffer it locally. This way the common code can
* properly handle the timeouts. */
priv->len = 0;
memset(priv->buffer, 0, sizeof(priv->buffer));
/* Once the TPM has completed the command the command remains readable
* until another command is issued. */
rc = i2c_master_recv(client, priv->buffer, sizeof(priv->buffer));
dev_dbg(chip->dev,
"%s: sts=%d", __func__, rc);
if (rc <= 0)
return 0;
priv->len = rc;
return ATMEL_STS_OK;
}
static const struct file_operations i2c_atmel_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, 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 *i2c_atmel_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 i2c_atmel_attr_grp = {
.attrs = i2c_atmel_attrs
};
static bool i2c_atmel_req_canceled(struct tpm_chip *chip, u8 status)
{
return 0;
}
static const struct tpm_vendor_specific i2c_atmel = {
.status = i2c_atmel_read_status,
.recv = i2c_atmel_recv,
.send = i2c_atmel_send,
.cancel = i2c_atmel_cancel,
.req_complete_mask = ATMEL_STS_OK,
.req_complete_val = ATMEL_STS_OK,
.req_canceled = i2c_atmel_req_canceled,
.attr_group = &i2c_atmel_attr_grp,
.miscdev.fops = &i2c_atmel_ops,
};
static int i2c_atmel_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int rc;
struct tpm_chip *chip;
struct device *dev = &client->dev;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
chip = tpm_register_hardware(dev, &i2c_atmel);
if (!chip) {
dev_err(dev, "%s() error in tpm_register_hardware\n", __func__);
return -ENODEV;
}
chip->vendor.priv = devm_kzalloc(dev, sizeof(struct priv_data),
GFP_KERNEL);
/* Default timeouts */
chip->vendor.timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
chip->vendor.timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
chip->vendor.timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
chip->vendor.timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
chip->vendor.irq = 0;
/* There is no known way to probe for this device, and all version
* information seems to be read via TPM commands. Thus we rely on the
* TPM startup process in the common code to detect the device. */
if (tpm_get_timeouts(chip)) {
rc = -ENODEV;
goto out_err;
}
if (tpm_do_selftest(chip)) {
rc = -ENODEV;
goto out_err;
}
return 0;
out_err:
tpm_dev_vendor_release(chip);
tpm_remove_hardware(chip->dev);
return rc;
}
static int i2c_atmel_remove(struct i2c_client *client)
{
struct device *dev = &(client->dev);
struct tpm_chip *chip = dev_get_drvdata(dev);
if (chip)
tpm_dev_vendor_release(chip);
tpm_remove_hardware(dev);
kfree(chip);
return 0;
}
static const struct i2c_device_id i2c_atmel_id[] = {
{I2C_DRIVER_NAME, 0},
{}
};
MODULE_DEVICE_TABLE(i2c, i2c_atmel_id);
#ifdef CONFIG_OF
static const struct of_device_id i2c_atmel_of_match[] = {
{.compatible = "atmel,at97sc3204t"},
{},
};
MODULE_DEVICE_TABLE(of, i2c_atmel_of_match);
#endif
static SIMPLE_DEV_PM_OPS(i2c_atmel_pm_ops, tpm_pm_suspend, tpm_pm_resume);
static struct i2c_driver i2c_atmel_driver = {
.id_table = i2c_atmel_id,
.probe = i2c_atmel_probe,
.remove = i2c_atmel_remove,
.driver = {
.name = I2C_DRIVER_NAME,
.owner = THIS_MODULE,
.pm = &i2c_atmel_pm_ops,
.of_match_table = of_match_ptr(i2c_atmel_of_match),
},
};
module_i2c_driver(i2c_atmel_driver);
MODULE_AUTHOR("Jason Gunthorpe <jgunthorpe@obsidianresearch.com>");
MODULE_DESCRIPTION("Atmel TPM I2C Driver");
MODULE_LICENSE("GPL");