1 /* 2 * Copyright (c) 2025, Arm Limited. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #include <drivers/delay_timer.h> 8 #include <drivers/gpio.h> 9 #include <drivers/tpm/tpm2_slb9670/slb9670_gpio.h> 10 11 /* 12 * Infineon SLB9670 Chip Reset Parameters 13 */ 14 #define t_WRST 2 /* Warm Reset Time (us) */ 15 #define t_RSTIN 60 /* Reset Inactive Time (ms) */ 16 17 /* 18 * RPi3 GPIO pin configuration for TPM via bit-bang SPI 19 * References: https://pinout.xyz/pinout/spi 20 * - docs/design_documents/measured_boot_dtpm_poc.rst 21 */ 22 const struct gpio_spi_config tpm_rpi3_gpio_data = { .cs_gpio = 7, 23 .sclk_gpio = 11, 24 .mosi_gpio = 10, 25 .miso_gpio = 9, 26 .reset_gpio = 24, 27 .spi_mode = 0, 28 .spi_max_clock = 1000000 }; 29 30 /* 31 * When RST is asserted at certain points in time, then this 32 * triggers the TPM's security functions, in the case where 33 * multiple resets need to be asserted, there must be a wait 34 * of at least t_RSTIN between the resets 35 * 36 * In most cases this is not needed since RST is only being asserted 37 * once, ie for TPM initialization at the beginning of TFA. 38 */ 39 void tpm2_slb9670_reset_chip(const struct gpio_spi_config *tpm_gpio_data) 40 { 41 /* 42 * since we don't know the value of the pin before it was init to 1 43 * it is best to assume the state was 0, and account for that by 44 * adding an initial RST inactive delay 45 */ 46 mdelay(t_RSTIN); 47 /* pull #RST pin to active low for 2us */ 48 gpio_set_value(tpm_gpio_data->reset_gpio, 0); 49 udelay(t_WRST); 50 /* wait 60ms after warm reset before sending TPM commands */ 51 gpio_set_value(tpm_gpio_data->reset_gpio, 1); 52 mdelay(t_RSTIN); 53 } 54 55 /* 56 * init GPIO pins for the Infineon slb9670 TPM 57 */ 58 void tpm2_slb9670_gpio_init(const struct gpio_spi_config *tpm_gpio_data) 59 { 60 gpio_set_value(tpm_gpio_data->reset_gpio, 1); 61 gpio_set_direction(tpm_gpio_data->reset_gpio, GPIO_DIR_OUT); 62 } 63 64 const struct gpio_spi_config *tpm2_slb9670_get_config(void) 65 { 66 return &tpm_rpi3_gpio_data; 67 } 68