tpm: Add support for Atmel I2C TPMs (a2871c62) · Commits · 戴 / test

Documentation/devicetree/bindings/i2c/trivial-devices.txt

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/char/tpm/Kconfig

+9 −0

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		@@ -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

drivers/char/tpm/Makefile

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Original line number	Diff line number	Diff line
		@@ -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

drivers/char/tpm/tpm_i2c_atmel.c

0 → 100644

+284 −0

Original line number	Diff line number	Diff line
		/*
		* 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");

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