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/* SPDX-License-Identifier: BSD-3-Clause */
#include <drivers/spi/tpm/tpm.h>
#include <security/tpm/tis.h>
#include <string.h>
#include <types.h>
#define CR50_BOARD_CFG_LOCKBIT_MASK 0x80000000U
#define CR50_BOARD_CFG_FEATUREBITS_MASK 0x3FFFFFFFU
#define CR50_BOARD_CFG_100US_READY_PULSE 0x00000001U
#define CR50_BOARD_CFG_VALUE \
(CONFIG(CR50_USE_LONG_INTERRUPT_PULSES) \
? CR50_BOARD_CFG_100US_READY_PULSE : 0)
enum cr50_register {
CR50_FW_VER_REG,
CR50_BOARD_CFG_REG,
};
#define CR50_FW_VER_REG_SPI (TPM_LOCALITY_0_SPI_BASE + 0xf90)
#define CR50_BOARD_CFG_REG_SPI (TPM_LOCALITY_0_SPI_BASE + 0xfe0)
#define CR50_FW_VER_REG_I2C 0x0f
#define CR50_BOARD_CFG_REG_I2C 0x1c
/* Return register address, which depends on the bus type, or -1 for error. */
static int get_reg_addr(enum cr50_register reg)
{
if (CONFIG(SPI_TPM)) {
switch (reg) {
case CR50_FW_VER_REG:
return CR50_FW_VER_REG_SPI;
case CR50_BOARD_CFG_REG:
return CR50_BOARD_CFG_REG_SPI;
default:
return -1;
}
}
if (CONFIG(I2C_TPM)) {
switch (reg) {
case CR50_FW_VER_REG:
return CR50_FW_VER_REG_I2C;
case CR50_BOARD_CFG_REG:
return CR50_BOARD_CFG_REG_I2C;
default:
return -1;
}
}
return -1;
}
static bool cr50_fw_supports_board_cfg(struct cr50_firmware_version *version)
{
/* Cr50 supports the CR50_BOARD_CFG register from version 0.5.5 / 0.6.5
* and onwards. */
if (version->epoch > 0 || version->major >= 7
|| (version->major >= 5 && version->minor >= 5))
return true;
printk(BIOS_INFO, "Cr50 firmware does not support CR50_BOARD_CFG, version: %d.%d.%d\n",
version->epoch, version->major, version->minor);
return false;
}
/*
* Expose method to read the CR50_BOARD_CFG register, will return zero if
* register not supported by Cr50 firmware.
*/
static uint32_t cr50_get_board_cfg(void)
{
struct cr50_firmware_version ver;
uint32_t value;
if (cr50_get_firmware_version(&ver) != CB_SUCCESS)
return 0;
if (!cr50_fw_supports_board_cfg(&ver))
return 0;
const enum cb_err ret = tis_vendor_read(get_reg_addr(CR50_BOARD_CFG_REG), &value,
sizeof(value));
if (ret != CB_SUCCESS) {
printk(BIOS_INFO, "Error reading from cr50\n");
return 0;
}
return value & CR50_BOARD_CFG_FEATUREBITS_MASK;
}
/**
* Set the BOARD_CFG register on the TPM chip to a particular compile-time constant value.
*/
enum cb_err cr50_set_board_cfg(void)
{
struct cr50_firmware_version ver;
enum cb_err ret;
uint32_t value;
if (cr50_get_firmware_version(&ver) != CB_SUCCESS)
return CB_ERR;
if (!cr50_fw_supports_board_cfg(&ver))
return CB_ERR;
/* Set the CR50_BOARD_CFG register, for e.g. asking cr50 to use longer ready pulses. */
ret = tis_vendor_read(get_reg_addr(CR50_BOARD_CFG_REG), &value, sizeof(value));
if (ret != CB_SUCCESS) {
printk(BIOS_INFO, "Error reading from cr50\n");
return CB_ERR;
}
if ((value & CR50_BOARD_CFG_FEATUREBITS_MASK) == CR50_BOARD_CFG_VALUE) {
printk(BIOS_INFO, "Current CR50_BOARD_CFG = 0x%08x, matches desired = 0x%08x\n",
value, CR50_BOARD_CFG_VALUE);
return CB_SUCCESS;
}
if (value & CR50_BOARD_CFG_LOCKBIT_MASK) {
/* The high bit is set, meaning that the Cr50 is already locked on a particular
* value for the register, but not the one we wanted. */
printk(BIOS_ERR, "Current CR50_BOARD_CFG = 0x%08x, does not match"
"desired = 0x%08x\n", value, CR50_BOARD_CFG_VALUE);
return CB_ERR;
}
printk(BIOS_INFO, "Current CR50_BOARD_CFG = 0x%08x, setting to 0x%08x\n",
value, CR50_BOARD_CFG_VALUE);
value = CR50_BOARD_CFG_VALUE;
ret = tis_vendor_write(get_reg_addr(CR50_BOARD_CFG_REG), &value, sizeof(value));
if (ret != CB_SUCCESS) {
printk(BIOS_ERR, "Error writing to cr50\n");
return ret;
}
return CB_SUCCESS;
}
bool cr50_is_long_interrupt_pulse_enabled(void)
{
return !!(cr50_get_board_cfg() & CR50_BOARD_CFG_100US_READY_PULSE);
}
static enum cb_err cr50_parse_fw_version(const char *version_str,
struct cr50_firmware_version *ver)
{
int epoch, major, minor;
char *number = strstr(version_str, " RW_A:");
if (!number)
number = strstr(version_str, " RW_B:");
if (!number)
return CB_ERR_ARG;
number += 6; /* Skip past the colon. */
epoch = skip_atoi(&number);
if (*number++ != '.')
return CB_ERR_ARG;
major = skip_atoi(&number);
if (*number++ != '.')
return CB_ERR_ARG;
minor = skip_atoi(&number);
ver->epoch = epoch;
ver->major = major;
ver->minor = minor;
return CB_SUCCESS;
}
enum cb_err cr50_get_firmware_version(struct cr50_firmware_version *version)
{
static struct cr50_firmware_version cr50_firmware_version;
if (cr50_firmware_version.epoch || cr50_firmware_version.major ||
cr50_firmware_version.minor)
goto success;
int chunk_count = 0;
size_t chunk_size = 50;
char version_str[301];
int addr = get_reg_addr(CR50_FW_VER_REG);
/*
* Does not really matter what's written, this just makes sure
* the version is reported from the beginning.
*/
tis_vendor_write(addr, &chunk_size, 1);
/*
* Read chunk_size bytes at a time, last chunk will be zero padded.
*/
do {
uint8_t *buf = (uint8_t *)version_str + chunk_count * chunk_size;
tis_vendor_read(addr, buf, chunk_size);
if (!version_str[++chunk_count * chunk_size - 1])
/* Zero padding detected: end of string. */
break;
/* Check if there is enough room for reading one more chunk. */
} while (chunk_count * chunk_size < sizeof(version_str) - chunk_size);
version_str[chunk_count * chunk_size] = '\0';
printk(BIOS_INFO, "Firmware version: %s\n", version_str);
if (cr50_parse_fw_version(version_str, &cr50_firmware_version) != CB_SUCCESS) {
printk(BIOS_ERR, "Did not recognize Cr50 version format\n");
return CB_ERR;
}
success:
*version = cr50_firmware_version;
return CB_SUCCESS;
}
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