From: Amir Mizinski <amirmizi6@xxxxxxxxx> I2c support for TPM devices is currently available as a vendor-specific TPM driver. This patch implements the infrustructure for a TCG complient TPM I2C driver with the functionality required to communicate with a TPM device over i2C according to the "TCG PC Client PTP Interface Specification" And "Device Driver Design Principles for TPM 2.0". References: [1] "TCG PC Client Platform TPM Profile(PTP) Interface Specification for TPM 2.0" Version 01.03 Revision 22 at: https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/ [2] "TCG PC Client Device Driver Design Principles for TPM 2.0" Version 1.0 Revision 27 at: https://trustedcomputinggroup.org/resource/tcg-pc-client-device-driver-design-principles-for-tpm-2-0/ Signed-off-by: Amir Mizinski <amirmizi6@xxxxxxxxx> Tested-by: Eddie James <eajames@xxxxxxxxxxxxx> Tested-by: Joel Stanley <joel@xxxxxxxxx> --- drivers/char/tpm/Kconfig | 12 +++ drivers/char/tpm/Makefile | 1 + drivers/char/tpm/tpm_tis_i2c.c | 227 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 240 insertions(+) create mode 100644 drivers/char/tpm/tpm_tis_i2c.c diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig index 4308f9c..1395968 100644 --- a/drivers/char/tpm/Kconfig +++ b/drivers/char/tpm/Kconfig @@ -86,6 +86,18 @@ config TCG_TIS_SYNQUACER To compile this driver as a module, choose M here; the module will be called tpm_tis_synquacer. +config TCG_TIS_I2C + tristate "TPM I2C Interface Specification" + depends on I2C + select CRC_CCITT + select TCG_TIS_CORE + help + If you have a TPM security chip, compliant with the TCG TPM PTP + (I2C interface) specification and connected to an I2C bus master, + 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_TIS_I2C_CR50 tristate "TPM Interface Specification 2.0 Interface (I2C - CR50)" depends on I2C diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile index 66d39ea..0222b1d 100644 --- a/drivers/char/tpm/Makefile +++ b/drivers/char/tpm/Makefile @@ -29,6 +29,7 @@ tpm_tis_spi-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o obj-$(CONFIG_TCG_TIS_I2C_CR50) += tpm_tis_i2c_cr50.o +obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o obj-$(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 diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c new file mode 100644 index 0000000..b57c485 --- /dev/null +++ b/drivers/char/tpm/tpm_tis_i2c.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2014-2021 Nuvoton Technology corporation + * + * TPM TIS I2C + * + * TPM TIS I2C Device Driver Interface for devices that implement the TPM I2C + * Interface defined by "TCG PC Client Platform TPM Profile (PTP) Specification + * version 01.05 r14" and "TCG PC Client Device Driver Design Principles + * version 1.0 r27" for TPM 2.0 at www.trustedcomputinggroup.org + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/wait.h> +#include <linux/acpi.h> +#include <linux/freezer.h> + +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/gpio.h> +#include <linux/of_irq.h> +#include <linux/of_gpio.h> +#include <linux/tpm.h> +#include "tpm.h" +#include "tpm_tis_core.h" + +#define TPM_LOC_SEL 0x04 +#define TPM_I2C_INTERFACE_CAPABILITY 0x30 +#define TPM_I2C_DEVICE_ADDRESS 0x38 +#define TPM_DATA_CSUM_ENABLE 0x40 +#define TPM_I2C_DID_VID 0x48 +#define TPM_I2C_RID 0x4C + +struct tpm_tis_i2c_phy { + struct tpm_tis_data priv; + struct i2c_client *i2c_client; + u8 *iobuf; +}; + +static inline struct tpm_tis_i2c_phy *to_tpm_tis_i2c_phy(struct tpm_tis_data + *data) +{ + return container_of(data, struct tpm_tis_i2c_phy, priv); +} + +static u8 address_to_register(u32 addr) +{ + addr &= 0xFFF; + + switch (addr) { + // adapt register addresses that have changed compared to + // older TIS versions + case TPM_ACCESS(0): + return 0x04; + case TPM_LOC_SEL: + return 0x00; + case TPM_DID_VID(0): + return 0x48; + case TPM_RID(0): + return 0x4C; + default: + return addr; + } +} + +static int tpm_tis_i2c_read_bytes(struct tpm_tis_data *data, u32 addr, + u16 len, u8 *result) +{ + struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data); + int ret = 0; + int i = 0; + u8 reg = address_to_register(addr); + struct i2c_msg msgs[] = { + { + .addr = phy->i2c_client->addr, + .len = sizeof(reg), + .buf = ®, + }, + { + .addr = phy->i2c_client->addr, + .len = len, + .buf = result, + .flags = I2C_M_RD, + }, + }; + + do { + ret = i2c_transfer(phy->i2c_client->adapter, msgs, + ARRAY_SIZE(msgs)); + usleep_range(250, 300); // wait default GUARD_TIME of 250µs + + } while (ret < 0 && i++ < TPM_RETRY); + + if (ret < 0) + return ret; + + return 0; +} + +static int tpm_tis_i2c_write_bytes(struct tpm_tis_data *data, u32 addr, + u16 len, const u8 *value) +{ + struct tpm_tis_i2c_phy *phy = to_tpm_tis_i2c_phy(data); + int ret = 0; + int i = 0; + + if (phy->iobuf) { + if (len > TPM_BUFSIZE - 1) + return -EIO; + + phy->iobuf[0] = address_to_register(addr); + memcpy(phy->iobuf + 1, value, len); + + { + struct i2c_msg msgs[] = { + { + .addr = phy->i2c_client->addr, + .len = len + 1, + .buf = phy->iobuf, + }, + }; + + do { + ret = i2c_transfer(phy->i2c_client->adapter, + msgs, ARRAY_SIZE(msgs)); + // wait default GUARD_TIME of 250µs + usleep_range(250, 300); + } while (ret < 0 && i++ < TPM_RETRY); + } + } else { + u8 reg = address_to_register(addr); + + struct i2c_msg msgs[] = { + { + .addr = phy->i2c_client->addr, + .len = sizeof(reg), + .buf = ®, + }, + { + .addr = phy->i2c_client->addr, + .len = len, + .buf = (u8 *)value, + .flags = I2C_M_NOSTART, + }, + }; + do { + ret = i2c_transfer(phy->i2c_client->adapter, msgs, + ARRAY_SIZE(msgs)); + // wait default GUARD_TIME of 250µs + usleep_range(250, 300); + } while (ret < 0 && i++ < TPM_RETRY); + } + + if (ret < 0) + return ret; + + return 0; +} + +static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume); + +static const struct tpm_tis_phy_ops tpm_i2c_phy_ops = { + .read_bytes = tpm_tis_i2c_read_bytes, + .write_bytes = tpm_tis_i2c_write_bytes, +}; + +static int tpm_tis_i2c_probe(struct i2c_client *dev, + const struct i2c_device_id *id) +{ + struct tpm_tis_i2c_phy *phy; + int rc; + const u8 loc_init = 0; + + phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_i2c_phy), + GFP_KERNEL); + if (!phy) + return -ENOMEM; + + phy->i2c_client = dev; + + if (!i2c_check_functionality(dev->adapter, I2C_FUNC_NOSTART)) { + phy->iobuf = devm_kmalloc(&dev->dev, TPM_BUFSIZE, GFP_KERNEL); + if (!phy->iobuf) + return -ENOMEM; + } + + // select locality 0 (the driver will access only via locality 0) + rc = tpm_tis_i2c_write_bytes(&phy->priv, TPM_LOC_SEL, 1, &loc_init); + if (rc < 0) + return rc; + + return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_i2c_phy_ops, + NULL); +} + +static const struct i2c_device_id tpm_tis_i2c_id[] = { + {"tpm_tis_i2c", 0}, + {} +}; +MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_id); + +static const struct of_device_id of_tis_i2c_match[] = { + { .compatible = "nuvoton,npct75x", }, + { .compatible = "tcg,tpm-tis-i2c", }, + {} +}; +MODULE_DEVICE_TABLE(of, of_tis_i2c_match); + +static struct i2c_driver tpm_tis_i2c_driver = { + .driver = { + .owner = THIS_MODULE, + .name = "tpm_tis_i2c", + .pm = &tpm_tis_pm, + .of_match_table = of_match_ptr(of_tis_i2c_match), + }, + .probe = tpm_tis_i2c_probe, + .id_table = tpm_tis_i2c_id, +}; + +module_i2c_driver(tpm_tis_i2c_driver); + +MODULE_DESCRIPTION("TPM Driver"); +MODULE_LICENSE("GPL"); -- 2.7.4
