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![Jason Gunthorpe](/assets/img/avatar_default.png)
The TCG standard startup sequence (get timeouts, tpm startup, etc) for TPM and TPM2 chips is being open coded in many drivers, move it into the core code. tpm_tis and tpm_crb are used as the basis for the core code implementation and the easy drivers are converted. In the process several small drivers bugs relating to error handling this flow are fixed. For now the flag TPM_OPS_AUTO_STARTUP is optional to allow a staged driver roll out, but ultimately all drivers should use this flow and the flag removed. Some drivers still do not implement the startup sequence at all and will need to be tested with it enabled. Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Tested-by: Andrew Zamansky <andrew.zamansky@nuvoton.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
226 lines
6.4 KiB
C
226 lines
6.4 KiB
C
/*
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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 = dev_get_drvdata(&chip->dev);
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struct i2c_client *client = to_i2c_client(chip->dev.parent);
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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 = dev_get_drvdata(&chip->dev);
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struct i2c_client *client = to_i2c_client(chip->dev.parent);
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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 = dev_get_drvdata(&chip->dev);
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struct i2c_client *client = to_i2c_client(chip->dev.parent);
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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 bool i2c_atmel_req_canceled(struct tpm_chip *chip, u8 status)
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{
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return false;
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}
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static const struct tpm_class_ops i2c_atmel = {
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.flags = TPM_OPS_AUTO_STARTUP,
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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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};
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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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struct tpm_chip *chip;
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struct device *dev = &client->dev;
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struct priv_data *priv;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -ENODEV;
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chip = tpmm_chip_alloc(dev, &i2c_atmel);
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if (IS_ERR(chip))
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return PTR_ERR(chip);
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priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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/* Default timeouts */
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chip->timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
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chip->timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
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chip->timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
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chip->timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
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dev_set_drvdata(&chip->dev, priv);
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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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return tpm_chip_register(chip);
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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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tpm_chip_unregister(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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.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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