tpm: Add support for Atmel I2C TPMs
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
Peter Huewe
Родитель
4c336e4b15
Коммит
a2871c62e1
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@ -15,6 +15,7 @@ adi,adt7461 +/-1C TDM Extended Temp Range I.C
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adt7461 +/-1C TDM Extended Temp Range I.C
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at,24c08 i2c serial eeprom (24cxx)
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atmel,24c02 i2c serial eeprom (24cxx)
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atmel,at97sc3204t i2c trusted platform module (TPM)
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catalyst,24c32 i2c serial eeprom
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dallas,ds1307 64 x 8, Serial, I2C Real-Time Clock
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dallas,ds1338 I2C RTC with 56-Byte NV RAM
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@ -33,6 +33,15 @@ config TCG_TIS
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from within Linux. To compile this driver as a module, choose
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M here; the module will be called tpm_tis.
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config TCG_TIS_I2C_ATMEL
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tristate "TPM Interface Specification 1.2 Interface (I2C - Atmel)"
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depends on I2C
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---help---
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If you have an Atmel I2C TPM security chip say Yes and it will be
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accessible from within Linux.
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To compile this driver as a module, choose M here; the module will
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be called tpm_tis_i2c_atmel.
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config TCG_TIS_I2C_INFINEON
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tristate "TPM Interface Specification 1.2 Interface (I2C - Infineon)"
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depends on I2C
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@ -13,6 +13,7 @@ ifdef CONFIG_TCG_IBMVTPM
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endif
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endif
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obj-$(CONFIG_TCG_TIS) += tpm_tis.o
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obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
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obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
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obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
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obj-$(CONFIG_TCG_NSC) += tpm_nsc.o
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@ -0,0 +1,284 @@
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/*
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* ATMEL I2C TPM AT97SC3204T
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*
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* Copyright (C) 2012 V Lab Technologies
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* Teddy Reed <teddy@prosauce.org>
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* Copyright (C) 2013, Obsidian Research Corp.
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* Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
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* Device driver for ATMEL I2C TPMs.
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*
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* Teddy Reed determined the basic I2C command flow, unlike other I2C TPM
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* devices the raw TCG formatted TPM command data is written via I2C and then
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* raw TCG formatted TPM command data is returned via I2C.
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*
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* TGC status/locality/etc functions seen in the LPC implementation do not
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* seem to be present.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see http://www.gnu.org/licenses/>.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include "tpm.h"
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#define I2C_DRIVER_NAME "tpm_i2c_atmel"
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#define TPM_I2C_SHORT_TIMEOUT 750 /* ms */
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#define TPM_I2C_LONG_TIMEOUT 2000 /* 2 sec */
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#define ATMEL_STS_OK 1
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struct priv_data {
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size_t len;
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/* This is the amount we read on the first try. 25 was chosen to fit a
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* fair number of read responses in the buffer so a 2nd retry can be
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* avoided in small message cases. */
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u8 buffer[sizeof(struct tpm_output_header) + 25];
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};
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static int i2c_atmel_send(struct tpm_chip *chip, u8 *buf, size_t len)
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{
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struct priv_data *priv = chip->vendor.priv;
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struct i2c_client *client = to_i2c_client(chip->dev);
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s32 status;
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priv->len = 0;
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if (len <= 2)
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return -EIO;
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status = i2c_master_send(client, buf, len);
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dev_dbg(chip->dev,
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"%s(buf=%*ph len=%0zx) -> sts=%d\n", __func__,
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(int)min_t(size_t, 64, len), buf, len, status);
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return status;
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}
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static int i2c_atmel_recv(struct tpm_chip *chip, u8 *buf, size_t count)
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{
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struct priv_data *priv = chip->vendor.priv;
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struct i2c_client *client = to_i2c_client(chip->dev);
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struct tpm_output_header *hdr =
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(struct tpm_output_header *)priv->buffer;
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u32 expected_len;
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int rc;
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if (priv->len == 0)
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return -EIO;
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/* Get the message size from the message header, if we didn't get the
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* whole message in read_status then we need to re-read the
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* message. */
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expected_len = be32_to_cpu(hdr->length);
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if (expected_len > count)
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return -ENOMEM;
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if (priv->len >= expected_len) {
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dev_dbg(chip->dev,
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"%s early(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
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(int)min_t(size_t, 64, expected_len), buf, count,
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expected_len);
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memcpy(buf, priv->buffer, expected_len);
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return expected_len;
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}
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rc = i2c_master_recv(client, buf, expected_len);
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dev_dbg(chip->dev,
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"%s reread(buf=%*ph count=%0zx) -> ret=%d\n", __func__,
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(int)min_t(size_t, 64, expected_len), buf, count,
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expected_len);
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return rc;
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}
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static void i2c_atmel_cancel(struct tpm_chip *chip)
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{
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dev_err(chip->dev, "TPM operation cancellation was requested, but is not supported");
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}
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static u8 i2c_atmel_read_status(struct tpm_chip *chip)
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{
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struct priv_data *priv = chip->vendor.priv;
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struct i2c_client *client = to_i2c_client(chip->dev);
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int rc;
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/* The TPM fails the I2C read until it is ready, so we do the entire
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* transfer here and buffer it locally. This way the common code can
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* properly handle the timeouts. */
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priv->len = 0;
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memset(priv->buffer, 0, sizeof(priv->buffer));
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/* Once the TPM has completed the command the command remains readable
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* until another command is issued. */
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rc = i2c_master_recv(client, priv->buffer, sizeof(priv->buffer));
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dev_dbg(chip->dev,
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"%s: sts=%d", __func__, rc);
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if (rc <= 0)
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return 0;
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priv->len = rc;
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return ATMEL_STS_OK;
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}
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static const struct file_operations i2c_atmel_ops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.open = tpm_open,
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.read = tpm_read,
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.write = tpm_write,
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.release = tpm_release,
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};
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static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
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static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
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static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
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static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
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static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
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static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated, NULL);
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static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL);
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static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
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static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
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static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
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static struct attribute *i2c_atmel_attrs[] = {
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&dev_attr_pubek.attr,
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&dev_attr_pcrs.attr,
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&dev_attr_enabled.attr,
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&dev_attr_active.attr,
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&dev_attr_owned.attr,
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&dev_attr_temp_deactivated.attr,
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&dev_attr_caps.attr,
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&dev_attr_cancel.attr,
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&dev_attr_durations.attr,
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&dev_attr_timeouts.attr,
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NULL,
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};
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static struct attribute_group i2c_atmel_attr_grp = {
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.attrs = i2c_atmel_attrs
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};
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static bool i2c_atmel_req_canceled(struct tpm_chip *chip, u8 status)
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{
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return 0;
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}
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static const struct tpm_vendor_specific i2c_atmel = {
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.status = i2c_atmel_read_status,
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.recv = i2c_atmel_recv,
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.send = i2c_atmel_send,
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.cancel = i2c_atmel_cancel,
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.req_complete_mask = ATMEL_STS_OK,
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.req_complete_val = ATMEL_STS_OK,
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.req_canceled = i2c_atmel_req_canceled,
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.attr_group = &i2c_atmel_attr_grp,
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.miscdev.fops = &i2c_atmel_ops,
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};
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static int i2c_atmel_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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int rc;
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struct tpm_chip *chip;
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struct device *dev = &client->dev;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -ENODEV;
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chip = tpm_register_hardware(dev, &i2c_atmel);
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if (!chip) {
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dev_err(dev, "%s() error in tpm_register_hardware\n", __func__);
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return -ENODEV;
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}
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chip->vendor.priv = devm_kzalloc(dev, sizeof(struct priv_data),
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GFP_KERNEL);
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/* Default timeouts */
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chip->vendor.timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
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chip->vendor.timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
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chip->vendor.timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
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chip->vendor.timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
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chip->vendor.irq = 0;
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/* There is no known way to probe for this device, and all version
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* information seems to be read via TPM commands. Thus we rely on the
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* TPM startup process in the common code to detect the device. */
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if (tpm_get_timeouts(chip)) {
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rc = -ENODEV;
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goto out_err;
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}
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if (tpm_do_selftest(chip)) {
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rc = -ENODEV;
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goto out_err;
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}
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return 0;
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out_err:
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tpm_dev_vendor_release(chip);
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tpm_remove_hardware(chip->dev);
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return rc;
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}
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static int i2c_atmel_remove(struct i2c_client *client)
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{
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struct device *dev = &(client->dev);
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struct tpm_chip *chip = dev_get_drvdata(dev);
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if (chip)
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tpm_dev_vendor_release(chip);
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tpm_remove_hardware(dev);
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kfree(chip);
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return 0;
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}
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static const struct i2c_device_id i2c_atmel_id[] = {
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{I2C_DRIVER_NAME, 0},
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{}
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};
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MODULE_DEVICE_TABLE(i2c, i2c_atmel_id);
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#ifdef CONFIG_OF
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static const struct of_device_id i2c_atmel_of_match[] = {
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{.compatible = "atmel,at97sc3204t"},
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{},
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};
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MODULE_DEVICE_TABLE(of, i2c_atmel_of_match);
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#endif
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static SIMPLE_DEV_PM_OPS(i2c_atmel_pm_ops, tpm_pm_suspend, tpm_pm_resume);
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static struct i2c_driver i2c_atmel_driver = {
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.id_table = i2c_atmel_id,
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.probe = i2c_atmel_probe,
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.remove = i2c_atmel_remove,
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.driver = {
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.name = I2C_DRIVER_NAME,
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.owner = THIS_MODULE,
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.pm = &i2c_atmel_pm_ops,
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.of_match_table = of_match_ptr(i2c_atmel_of_match),
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},
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};
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module_i2c_driver(i2c_atmel_driver);
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MODULE_AUTHOR("Jason Gunthorpe <jgunthorpe@obsidianresearch.com>");
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MODULE_DESCRIPTION("Atmel TPM I2C Driver");
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MODULE_LICENSE("GPL");
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