// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2014-2021 Nuvoton Technology corporation * Copyright (C) 2019-2022 Infineon Technologies AG * * This device driver implements the TPM interface as defined in the TCG PC * Client Platform TPM Profile (PTP) Specification for TPM 2.0 v1.04 * Revision 14. * * It is based on the tpm_tis_spi device driver. */ #include <linux/i2c.h> #include <linux/crc-ccitt.h> #include "tpm_tis_core.h" /* TPM registers */ #define TPM_I2C_LOC_SEL … #define TPM_I2C_ACCESS … #define TPM_I2C_INTERFACE_CAPABILITY … #define TPM_I2C_DEVICE_ADDRESS … #define TPM_I2C_DATA_CSUM_ENABLE … #define TPM_DATA_CSUM … #define TPM_I2C_DID_VID … #define TPM_I2C_RID … /* TIS-compatible register address to avoid clash with TPM_ACCESS (0x00) */ #define TPM_LOC_SEL … /* Mask to extract the I2C register from TIS register addresses */ #define TPM_TIS_REGISTER_MASK … /* Default Guard Time of 250µs until interface capability register is read */ #define GUARD_TIME_DEFAULT_MIN … #define GUARD_TIME_DEFAULT_MAX … /* Guard Time of 250µs after I2C slave NACK */ #define GUARD_TIME_ERR_MIN … #define GUARD_TIME_ERR_MAX … /* Guard Time bit masks; SR is repeated start, RW is read then write, etc. */ #define TPM_GUARD_TIME_SR_MASK … #define TPM_GUARD_TIME_RR_MASK … #define TPM_GUARD_TIME_RW_MASK … #define TPM_GUARD_TIME_WR_MASK … #define TPM_GUARD_TIME_WW_MASK … #define TPM_GUARD_TIME_MIN_MASK … #define TPM_GUARD_TIME_MIN_SHIFT … /* Masks with bits that must be read zero */ #define TPM_ACCESS_READ_ZERO … #define TPM_INT_ENABLE_ZERO … #define TPM_STS_READ_ZERO … #define TPM_INTF_CAPABILITY_ZERO … #define TPM_I2C_INTERFACE_CAPABILITY_ZERO … struct tpm_tis_i2c_phy { … }; static inline struct tpm_tis_i2c_phy * to_tpm_tis_i2c_phy(struct tpm_tis_data *data) { … } /* * tpm_tis_core uses the register addresses as defined in Table 19 "Allocation * of Register Space for FIFO TPM Access" of the TCG PC Client PTP * Specification. In order for this code to work together with tpm_tis_core, * those addresses need to mapped to the registers defined for I2C TPMs in * Table 51 "I2C-TPM Register Overview". * * For most addresses this can be done by simply stripping off the locality * information from the address. A few addresses need to be mapped explicitly, * since the corresponding I2C registers have been moved around. TPM_LOC_SEL is * only defined for I2C TPMs and is also mapped explicitly here to distinguish * it from TPM_ACCESS(0). * * Locality information is ignored, since this driver assumes exclusive access * to the TPM and always uses locality 0. */ static u8 tpm_tis_i2c_address_to_register(u32 addr) { … } static int tpm_tis_i2c_retry_transfer_until_ack(struct tpm_tis_data *data, struct i2c_msg *msg) { … } /* Check that bits which must be read zero are not set */ static int tpm_tis_i2c_sanity_check_read(u8 reg, u16 len, u8 *buf) { … } static int tpm_tis_i2c_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len, u8 *result, enum tpm_tis_io_mode io_mode) { … } static int tpm_tis_i2c_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len, const u8 *value, enum tpm_tis_io_mode io_mode) { … } static int tpm_tis_i2c_verify_crc(struct tpm_tis_data *data, size_t len, const u8 *value) { … } /* * Guard Time: * After each I2C operation, the TPM might require the master to wait. * The time period is vendor-specific and must be read from the * TPM_I2C_INTERFACE_CAPABILITY register. * * Before the Guard Time is read (or after the TPM failed to send an I2C NACK), * a Guard Time of 250µs applies. * * Various flags in the same register indicate if a guard time is needed: * - SR: <I2C read with repeated start> <guard time> <I2C read> * - RR: <I2C read> <guard time> <I2C read> * - RW: <I2C read> <guard time> <I2C write> * - WR: <I2C write> <guard time> <I2C read> * - WW: <I2C write> <guard time> <I2C write> * * See TCG PC Client PTP Specification v1.04, 8.1.10 GUARD_TIME */ static int tpm_tis_i2c_init_guard_time(struct tpm_tis_i2c_phy *phy) { … } 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 = …; static int tpm_tis_i2c_probe(struct i2c_client *dev) { … } static void tpm_tis_i2c_remove(struct i2c_client *client) { … } static const struct i2c_device_id tpm_tis_i2c_id[] = …; MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_id); #ifdef CONFIG_OF static const struct of_device_id of_tis_i2c_match[] = …; MODULE_DEVICE_TABLE(of, of_tis_i2c_match); #endif static struct i2c_driver tpm_tis_i2c_driver = …; module_i2c_driver(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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