drivers/st/bsec/bsec2.c

/*
 * Copyright (c) 2017-2024, STMicroelectronics - All Rights Reserved
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <limits.h>

#include <arch_helpers.h>
#include <common/debug.h>
#include <drivers/st/bsec.h>
#include <drivers/st/bsec2_reg.h>
#include <lib/mmio.h>
#include <lib/spinlock.h>
#include <libfdt.h>

#include <platform_def.h>

#define BSEC_IP_VERSION_1_1	U(0x11)
#define BSEC_IP_VERSION_2_0	U(0x20)
#define BSEC_IP_ID_2		U(0x100032)

/*
 * IP configuration
 */
#define BSEC_OTP_MASK			GENMASK(4, 0)
#define BSEC_OTP_BANK_SHIFT		5
#define BSEC_TIMEOUT_VALUE		U(0xFFFF)

#define OTP_ACCESS_SIZE (round_up(OTP_MAX_SIZE, __WORD_BIT) / __WORD_BIT)

static uint32_t otp_nsec_access[OTP_ACCESS_SIZE] __maybe_unused;

static uint32_t bsec_shadow_register(uint32_t otp);
static uint32_t bsec_power_safmem(bool power);
static uint32_t bsec_get_version(void);
static uint32_t bsec_get_id(void);
static uint32_t bsec_get_status(void);
static uint32_t bsec_read_permanent_lock(uint32_t otp, bool *value);

/* BSEC access protection */
static spinlock_t bsec_spinlock;

static void bsec_lock(void)
{
	if (stm32mp_lock_available()) {
		spin_lock(&bsec_spinlock);
	}
}

static void bsec_unlock(void)
{
	if (stm32mp_lock_available()) {
		spin_unlock(&bsec_spinlock);
	}
}

static bool is_otp_invalid_mode(void)
{
	bool ret = ((bsec_get_status() & BSEC_OTP_STATUS_INVALID) == BSEC_OTP_STATUS_INVALID);

	if (ret) {
		ERROR("OTP mode is OTP-INVALID\n");
	}

	return ret;
}

#if defined(IMAGE_BL32)
static int bsec_get_dt_node(struct dt_node_info *info)
{
	int node;

	node = dt_get_node(info, -1, DT_BSEC_COMPAT);
	if (node < 0) {
		return -FDT_ERR_NOTFOUND;
	}

	return node;
}

static void enable_non_secure_access(uint32_t otp)
{
	otp_nsec_access[otp / __WORD_BIT] |= BIT(otp % __WORD_BIT);

	if (bsec_shadow_register(otp) != BSEC_OK) {
		panic();
	}
}

static bool non_secure_can_access(uint32_t otp)
{
	return (otp_nsec_access[otp / __WORD_BIT] &
		BIT(otp % __WORD_BIT)) != 0U;
}

static void bsec_dt_otp_nsec_access(void *fdt, int bsec_node)
{
	int bsec_subnode;

	fdt_for_each_subnode(bsec_subnode, fdt, bsec_node) {
		const fdt32_t *cuint;
		uint32_t otp;
		uint32_t i;
		uint32_t size;
		uint32_t offset;
		uint32_t length;

		cuint = fdt_getprop(fdt, bsec_subnode, "reg", NULL);
		if (cuint == NULL) {
			panic();
		}

		offset = fdt32_to_cpu(*cuint);
		cuint++;
		length = fdt32_to_cpu(*cuint);

		otp = offset / sizeof(uint32_t);

		if (otp < STM32MP1_UPPER_OTP_START) {
			unsigned int otp_end = round_up(offset + length,
						       sizeof(uint32_t)) /
					       sizeof(uint32_t);

			if (otp_end > STM32MP1_UPPER_OTP_START) {
				/*
				 * OTP crosses Lower/Upper boundary, consider
				 * only the upper part.
				 */
				otp = STM32MP1_UPPER_OTP_START;
				length -= (STM32MP1_UPPER_OTP_START *
					   sizeof(uint32_t)) - offset;
				offset = STM32MP1_UPPER_OTP_START *
					 sizeof(uint32_t);

				WARN("OTP crosses Lower/Upper boundary\n");
			} else {
				continue;
			}
		}

		if ((fdt_getprop(fdt, bsec_subnode,
				 "st,non-secure-otp", NULL)) == NULL) {
			continue;
		}

		if (((offset % sizeof(uint32_t)) != 0U) ||
		    ((length % sizeof(uint32_t)) != 0U)) {
			ERROR("Unaligned non-secure OTP\n");
			panic();
		}

		size = length / sizeof(uint32_t);

		for (i = otp; i < (otp + size); i++) {
			enable_non_secure_access(i);
		}
	}
}

static void bsec_late_init(void)
{
	void *fdt;
	int node;
	struct dt_node_info bsec_info;

	if (fdt_get_address(&fdt) == 0) {
		EARLY_ERROR("%s: DT not found\n", __func__);
		panic();
	}

	node = bsec_get_dt_node(&bsec_info);
	if (node < 0) {
		EARLY_ERROR("%s: BSEC node not found\n", __func__);
		panic();
	}

	assert(bsec_info.base == BSEC_BASE);

	bsec_dt_otp_nsec_access(fdt, node);
}
#endif

static uint32_t otp_bank_offset(uint32_t otp)
{
	assert(otp <= STM32MP1_OTP_MAX_ID);

	return ((otp & ~BSEC_OTP_MASK) >> BSEC_OTP_BANK_SHIFT) *
	       sizeof(uint32_t);
}

static uint32_t otp_bit_mask(uint32_t otp)
{
	return BIT(otp & BSEC_OTP_MASK);
}

/*
 * bsec_check_error: check BSEC error status.
 * otp: OTP number.
 * check_disturbed: check only error (false),
 *	or error and disturbed status (true).
 * return value: BSEC_OK if no error.
 */
static uint32_t bsec_check_error(uint32_t otp, bool check_disturbed)
{
	uint32_t bit = otp_bit_mask(otp);
	uint32_t bank = otp_bank_offset(otp);

	if ((mmio_read_32(BSEC_BASE + BSEC_ERROR_OFF + bank) & bit) != 0U) {
		return BSEC_ERROR;
	}

	if (!check_disturbed) {
		return BSEC_OK;
	}

	if ((mmio_read_32(BSEC_BASE + BSEC_DISTURBED_OFF + bank) & bit) != 0U) {
		return BSEC_DISTURBED;
	}

	return BSEC_OK;
}

/*
 * bsec_probe: initialize BSEC driver.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_probe(void)
{
	uint32_t version;
	uint32_t id;

	if (is_otp_invalid_mode()) {
		EARLY_ERROR("%s: otp_invalid_mod\n", __func__);
		return BSEC_ERROR;
	}

	version = bsec_get_version();
	id = bsec_get_id();

	if (((version != BSEC_IP_VERSION_1_1) &&
	     (version != BSEC_IP_VERSION_2_0)) ||
	    (id != BSEC_IP_ID_2)) {
		EARLY_ERROR("%s: version = 0x%x, id = 0x%x\n", __func__, version, id);
		panic();
	}

#if defined(IMAGE_BL32)
	bsec_late_init();
#endif
	return BSEC_OK;
}

/*
 * bsec_shadow_register: copy SAFMEM OTP to BSEC data.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
static uint32_t bsec_shadow_register(uint32_t otp)
{
	uint32_t result;
	bool value;
	bool power_up = false;

	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	result = bsec_read_sr_lock(otp, &value);
	if (result != BSEC_OK) {
		ERROR("BSEC: %u Sticky-read bit read Error %u\n", otp, result);
		return result;
	}

	if (value) {
		VERBOSE("BSEC: OTP %u is locked and will not be refreshed\n",
			otp);
	}

	if ((bsec_get_status() & BSEC_OTP_STATUS_PWRON) == 0U) {
		result = bsec_power_safmem(true);

		if (result != BSEC_OK) {
			return result;
		}

		power_up = true;
	}

	bsec_lock();

	mmio_write_32(BSEC_BASE + BSEC_OTP_CTRL_OFF, otp | BSEC_READ);

	while ((bsec_get_status() & BSEC_OTP_STATUS_BUSY) != 0U) {
		;
	}

	result = bsec_check_error(otp, true);

	bsec_unlock();

	if (power_up) {
		if (bsec_power_safmem(false) != BSEC_OK) {
			panic();
		}
	}

	return result;
}

/*
 * bsec_read_otp: read an OTP data value.
 * val: read value.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_read_otp(uint32_t *val, uint32_t otp)
{
	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	*val = mmio_read_32(BSEC_BASE + BSEC_OTP_DATA_OFF +
			    (otp * sizeof(uint32_t)));

	return BSEC_OK;
}

/*
 * bsec_write_otp: write value in BSEC data register.
 * val: value to write.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_write_otp(uint32_t val, uint32_t otp)
{
	uint32_t result;
	bool value;

	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	result = bsec_read_sw_lock(otp, &value);
	if (result != BSEC_OK) {
		ERROR("BSEC: %u Sticky-write bit read Error %u\n", otp, result);
		return result;
	}

	if (value) {
		VERBOSE("BSEC: OTP %u is locked and write will be ignored\n",
			otp);
	}

	/* Ensure integrity of each register access sequence */
	bsec_lock();

	mmio_write_32(BSEC_BASE + BSEC_OTP_DATA_OFF +
		      (otp * sizeof(uint32_t)), val);

	bsec_unlock();

	return result;
}

/*
 * bsec_program_otp: program a bit in SAFMEM after the prog.
 *	The OTP data is not refreshed.
 * val: value to program.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_program_otp(uint32_t val, uint32_t otp)
{
	uint32_t result;
	bool power_up = false;
	bool sp_lock;
	bool perm_lock;

	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	result = bsec_read_sp_lock(otp, &sp_lock);
	if (result != BSEC_OK) {
		ERROR("BSEC: %u Sticky-prog bit read Error %u\n", otp, result);
		return result;
	}

	result = bsec_read_permanent_lock(otp, &perm_lock);
	if (result != BSEC_OK) {
		ERROR("BSEC: %u permanent bit read Error %u\n", otp, result);
		return result;
	}

	if (sp_lock || perm_lock) {
		WARN("BSEC: OTP locked, prog will be ignored\n");
		return BSEC_PROG_FAIL;
	}

	if ((mmio_read_32(BSEC_BASE + BSEC_OTP_LOCK_OFF) & GPLOCK_LOCK_MASK) != 0U) {
		WARN("BSEC: GPLOCK activated, prog will be ignored\n");
	}

	if ((bsec_get_status() & BSEC_OTP_STATUS_PWRON) == 0U) {
		result = bsec_power_safmem(true);

		if (result != BSEC_OK) {
			return result;
		}

		power_up = true;
	}

	bsec_lock();

	mmio_write_32(BSEC_BASE + BSEC_OTP_WRDATA_OFF, val);

	mmio_write_32(BSEC_BASE + BSEC_OTP_CTRL_OFF, otp | BSEC_WRITE);

	while ((bsec_get_status() & BSEC_OTP_STATUS_BUSY) != 0U) {
		;
	}

	if ((bsec_get_status() & BSEC_OTP_STATUS_PROGFAIL) != 0U) {
		result = BSEC_PROG_FAIL;
	} else {
		result = bsec_check_error(otp, true);
	}

	bsec_unlock();

	if (power_up) {
		if (bsec_power_safmem(false) != BSEC_OK) {
			panic();
		}
	}

	return result;
}

/*
 * bsec_permanent_lock_otp: permanent lock of OTP in SAFMEM.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
#if defined(IMAGE_BL32)
uint32_t bsec_permanent_lock_otp(uint32_t otp)
{
	uint32_t result;
	bool power_up = false;
	uint32_t data;
	uint32_t addr;

	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	if ((bsec_get_status() & BSEC_OTP_STATUS_PWRON) == 0U) {
		result = bsec_power_safmem(true);

		if (result != BSEC_OK) {
			return result;
		}

		power_up = true;
	}

	if (otp < STM32MP1_UPPER_OTP_START) {
		addr = otp >> ADDR_LOWER_OTP_PERLOCK_SHIFT;
		data = DATA_LOWER_OTP_PERLOCK_BIT <<
		       ((otp & DATA_LOWER_OTP_PERLOCK_MASK) << 1U);
	} else {
		addr = (otp >> ADDR_UPPER_OTP_PERLOCK_SHIFT) + 2U;
		data = DATA_UPPER_OTP_PERLOCK_BIT <<
		       (otp & DATA_UPPER_OTP_PERLOCK_MASK);
	}

	bsec_lock();

	mmio_write_32(BSEC_BASE + BSEC_OTP_WRDATA_OFF, data);

	mmio_write_32(BSEC_BASE + BSEC_OTP_CTRL_OFF,
		      addr | BSEC_WRITE | BSEC_LOCK);

	while ((bsec_get_status() & BSEC_OTP_STATUS_BUSY) != 0U) {
		;
	}

	if ((bsec_get_status() & BSEC_OTP_STATUS_PROGFAIL) != 0U) {
		result = BSEC_PROG_FAIL;
	} else {
		result = bsec_check_error(otp, false);
	}

	bsec_unlock();

	if (power_up) {
		if (bsec_power_safmem(false) != BSEC_OK) {
			panic();
		}
	}

	return result;
}
#endif

/*
 * bsec_read_debug_conf: return debug configuration register value.
 */
uint32_t bsec_read_debug_conf(void)
{
	return mmio_read_32(BSEC_BASE + BSEC_DEN_OFF);
}

/*
 * bsec_write_scratch: write value in scratch register.
 * val: value to write.
 * return value: none.
 */
void bsec_write_scratch(uint32_t val)
{
#if defined(IMAGE_BL32)
	if (is_otp_invalid_mode()) {
		return;
	}

	bsec_lock();
	mmio_write_32(BSEC_BASE + BSEC_SCRATCH_OFF, val);
	bsec_unlock();
#else
	mmio_write_32(BSEC_BASE + BSEC_SCRATCH_OFF, val);
#endif
}

/*
 * bsec_get_status: return status register value.
 */
static uint32_t bsec_get_status(void)
{
	return mmio_read_32(BSEC_BASE + BSEC_OTP_STATUS_OFF);
}

/*
 * bsec_get_version: return BSEC version register value.
 */
static uint32_t bsec_get_version(void)
{
	return mmio_read_32(BSEC_BASE + BSEC_IPVR_OFF) & BSEC_IPVR_MSK;
}

/*
 * bsec_get_id: return BSEC ID register value.
 */
static uint32_t bsec_get_id(void)
{
	return mmio_read_32(BSEC_BASE + BSEC_IP_ID_OFF);
}

/*
 * bsec_set_sr_lock: set shadow-read lock.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_set_sr_lock(uint32_t otp)
{
	uint32_t bank = otp_bank_offset(otp);
	uint32_t otp_mask = otp_bit_mask(otp);

	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	bsec_lock();
	mmio_write_32(BSEC_BASE + BSEC_SRLOCK_OFF + bank, otp_mask);
	bsec_unlock();

	return BSEC_OK;
}

/*
 * bsec_read_sr_lock: read shadow-read lock.
 * otp: OTP number.
 * value: read value (true or false).
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_read_sr_lock(uint32_t otp, bool *value)
{
	uint32_t bank = otp_bank_offset(otp);
	uint32_t otp_mask = otp_bit_mask(otp);
	uint32_t bank_value;

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	bank_value = mmio_read_32(BSEC_BASE + BSEC_SRLOCK_OFF + bank);

	*value = ((bank_value & otp_mask) != 0U);

	return BSEC_OK;
}

/*
 * bsec_set_sw_lock: set shadow-write lock.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_set_sw_lock(uint32_t otp)
{
	uint32_t bank = otp_bank_offset(otp);
	uint32_t otp_mask = otp_bit_mask(otp);

	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	bsec_lock();
	mmio_write_32(BSEC_BASE + BSEC_SWLOCK_OFF + bank, otp_mask);
	bsec_unlock();

	return BSEC_OK;
}

/*
 * bsec_read_sw_lock: read shadow-write lock.
 * otp: OTP number.
 * value: read value (true or false).
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_read_sw_lock(uint32_t otp, bool *value)
{
	uint32_t bank = otp_bank_offset(otp);
	uint32_t otp_mask = BIT(otp & BSEC_OTP_MASK);
	uint32_t bank_value;

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	bank_value = mmio_read_32(BSEC_BASE + BSEC_SWLOCK_OFF + bank);

	*value = ((bank_value & otp_mask) != 0U);

	return BSEC_OK;
}

/*
 * bsec_set_sp_lock: set shadow-program lock.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_set_sp_lock(uint32_t otp)
{
	uint32_t bank = otp_bank_offset(otp);
	uint32_t otp_mask = otp_bit_mask(otp);

	if (is_otp_invalid_mode()) {
		return BSEC_ERROR;
	}

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	bsec_lock();
	mmio_write_32(BSEC_BASE + BSEC_SPLOCK_OFF + bank, otp_mask);
	bsec_unlock();

	return BSEC_OK;
}

/*
 * bsec_read_sp_lock: read shadow-program lock.
 * otp: OTP number.
 * value: read value (true or false).
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_read_sp_lock(uint32_t otp, bool *value)
{
	uint32_t bank = otp_bank_offset(otp);
	uint32_t otp_mask = BIT(otp & BSEC_OTP_MASK);
	uint32_t bank_value;

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	bank_value = mmio_read_32(BSEC_BASE + BSEC_SPLOCK_OFF + bank);

	*value = ((bank_value & otp_mask) != 0U);

	return BSEC_OK;
}

/*
 * bsec_read_permanent_lock: Read permanent lock status.
 * otp: OTP number.
 * value: read value (true or false).
 * return value: BSEC_OK if no error.
 */
static uint32_t bsec_read_permanent_lock(uint32_t otp, bool *value)
{
	uint32_t bank = otp_bank_offset(otp);
	uint32_t otp_mask = otp_bit_mask(otp);
	uint32_t bank_value;

	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	bank_value = mmio_read_32(BSEC_BASE + BSEC_WRLOCK_OFF + bank);

	*value = ((bank_value & otp_mask) != 0U);

	return BSEC_OK;
}

/*
 * bsec_power_safmem: Activate or deactivate SAFMEM power.
 * power: true to power up, false to power down.
 * return value: BSEC_OK if no error.
 */
static uint32_t bsec_power_safmem(bool power)
{
	uint32_t register_val;
	uint32_t timeout = BSEC_TIMEOUT_VALUE;

	bsec_lock();

	register_val = mmio_read_32(BSEC_BASE + BSEC_OTP_CONF_OFF);

	if (power) {
		register_val |= BSEC_CONF_POWER_UP_MASK;
	} else {
		register_val &= ~BSEC_CONF_POWER_UP_MASK;
	}

	mmio_write_32(BSEC_BASE + BSEC_OTP_CONF_OFF, register_val);

	if (power) {
		while (((bsec_get_status() & BSEC_OTP_STATUS_PWRON) == 0U) &&
		       (timeout != 0U)) {
			timeout--;
		}
	} else {
		while (((bsec_get_status() & BSEC_OTP_STATUS_PWRON) != 0U) &&
		       (timeout != 0U)) {
			timeout--;
		}
	}

	bsec_unlock();

	if (timeout == 0U) {
		return BSEC_TIMEOUT;
	}

	return BSEC_OK;
}

/*
 * bsec_shadow_read_otp: Load OTP from SAFMEM and provide its value.
 * val: read value.
 * otp: OTP number.
 * return value: BSEC_OK if no error.
 */
uint32_t bsec_shadow_read_otp(uint32_t *val, uint32_t otp)
{
	uint32_t result;

	result = bsec_shadow_register(otp);
	if (result != BSEC_OK) {
		ERROR("BSEC: %u Shadowing Error %u\n", otp, result);
		return result;
	}

	result = bsec_read_otp(val, otp);
	if (result != BSEC_OK) {
		ERROR("BSEC: %u Read Error %u\n", otp, result);
	}

	return result;
}

#if defined(IMAGE_BL32)
/*
 * bsec_check_nsec_access_rights: check non-secure access rights to target OTP.
 * otp: OTP number.
 * return value: BSEC_OK if authorized access.
 */
uint32_t bsec_check_nsec_access_rights(uint32_t otp)
{
	if (otp > STM32MP1_OTP_MAX_ID) {
		return BSEC_INVALID_PARAM;
	}

	if (otp >= STM32MP1_UPPER_OTP_START) {
		if (!non_secure_can_access(otp)) {
			return BSEC_ERROR;
		}
	}

	return BSEC_OK;
}
#endif

uint32_t bsec_get_secure_state(void)
{
	uint32_t status = bsec_get_status();
	uint32_t result = BSEC_STATE_INVALID;
	uint32_t otp_enc_id __maybe_unused;
	uint32_t otp_bit_len __maybe_unused;
	int res __maybe_unused;

	if ((status & BSEC_OTP_STATUS_INVALID) != 0U) {
		result = BSEC_STATE_INVALID;
	} else {
		if ((status & BSEC_OTP_STATUS_SECURE) != 0U) {
			if (stm32mp_check_closed_device() == STM32MP_CHIP_SEC_CLOSED) {
				result = BSEC_STATE_SEC_CLOSED;
			} else {
				result = BSEC_STATE_SEC_OPEN;
			}
		} else {
			/* OTP modes OPEN1 and OPEN2 are not supported */
			result = BSEC_STATE_INVALID;
		}
	}

	return result;
}