trezor-mcu/setup.c

/*
 * This file is part of the TREZOR project, https://trezor.io/
 *
 * Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <libopencm3/cm3/mpu.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/cm3/scb.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/spi.h>
#include <libopencm3/stm32/rng.h>

#include "rng.h"
#include "layout.h"
#include "util.h"

uint32_t __stack_chk_guard;

static inline void __attribute__((noreturn)) fault_handler(const char *line1) {
	layoutDialog(&bmp_icon_error, NULL, NULL, NULL, line1, "detected.", NULL, "Please unplug", "the device.", NULL);
	for (;;) {} // loop forever
}

void __attribute__((noreturn)) __stack_chk_fail(void) {
	fault_handler("Stack smashing");
}

void nmi_handler(void)
{
	// Clock Security System triggered NMI
	if ((RCC_CIR & RCC_CIR_CSSF) != 0) {
		fault_handler("Clock instability");
	}
}

void hard_fault_handler(void) {
	fault_handler("Hard fault");
}

void mem_manage_handler(void) {
	fault_handler("Memory fault");
}

void setup(void)
{
	// set SCB_CCR STKALIGN bit to make sure 8-byte stack alignment on exception entry is in effect.
	// This is not strictly necessary for the current TREZOR system.
	// This is here to comply with guidance from section 3.3.3 "Binary compatibility with other Cortex processors"
	// of the ARM Cortex-M3 Processor Technical Reference Manual.
	// According to section 4.4.2 and 4.4.7 of the "STM32F10xxx/20xxx/21xxx/L1xxxx Cortex-M3 programming manual",
	// STM32F2 series MCUs are r2p0 and always have this bit set on reset already.
	SCB_CCR |= SCB_CCR_STKALIGN;

	// setup clock
	struct rcc_clock_scale clock = rcc_hse_8mhz_3v3[RCC_CLOCK_3V3_120MHZ];
	rcc_clock_setup_hse_3v3(&clock);

	// enable GPIO clock - A (oled), B(oled), C (buttons)
	rcc_periph_clock_enable(RCC_GPIOA);
	rcc_periph_clock_enable(RCC_GPIOB);
	rcc_periph_clock_enable(RCC_GPIOC);

	// enable SPI clock
	rcc_periph_clock_enable(RCC_SPI1);

	// enable RNG
	rcc_periph_clock_enable(RCC_RNG);
	RNG_CR |= RNG_CR_RNGEN;
	// to be extra careful and heed the STM32F205xx Reference manual, Section 20.3.1
	// we don't use the first random number generated after setting the RNGEN bit in setup
	random32();

	// enable CSS (Clock Security System)
	RCC_CR |= RCC_CR_CSSON;

	// set GPIO for buttons
	gpio_mode_setup(GPIOC, GPIO_MODE_INPUT, GPIO_PUPD_PULLUP, GPIO2 | GPIO5);

	// set GPIO for OLED display
	gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO4);
	gpio_mode_setup(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO0 | GPIO1);

	// enable SPI 1 for OLED display
	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO5 | GPIO7);
	gpio_set_af(GPIOA, GPIO_AF5, GPIO5 | GPIO7);

//	spi_disable_crc(SPI1);
	spi_init_master(SPI1, SPI_CR1_BAUDRATE_FPCLK_DIV_8, SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE, SPI_CR1_CPHA_CLK_TRANSITION_1, SPI_CR1_DFF_8BIT, SPI_CR1_MSBFIRST);
	spi_enable_ss_output(SPI1);
//	spi_enable_software_slave_management(SPI1);
//	spi_set_nss_high(SPI1);
//	spi_clear_mode_fault(SPI1);
	spi_enable(SPI1);

	// enable OTG_FS
	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO10);
	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO11 | GPIO12);
	gpio_set_af(GPIOA, GPIO_AF10, GPIO10 | GPIO11 | GPIO12);

	// enable OTG FS clock
	rcc_periph_clock_enable(RCC_OTGFS);
	// clear USB OTG_FS peripheral dedicated RAM
	memset_reg((void *) 0x50020000, (void *) 0x50020500, 0);
}

void setupApp(void)
{
	// for completeness, disable RNG peripheral interrupts for old bootloaders that had
	// enabled them in RNG control register (the RNG interrupt was never enabled in the NVIC)
	RNG_CR &= ~RNG_CR_IE;
	// the static variables in random32 are separate between the bootloader and firmware.
	// therefore, they need to be initialized here so that we can be sure to avoid dupes.
	// this is to try to comply with STM32F205xx Reference manual - Section 20.3.1:
	// "Each subsequent generated random number has to be compared with the previously generated
	// number. The test fails if any two compared numbers are equal (continuous random number generator test)."
	random32();

	// enable CSS (Clock Security System)
	RCC_CR |= RCC_CR_CSSON;

	// hotfix for old bootloader
	gpio_mode_setup(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_NONE, GPIO9);
	spi_init_master(SPI1, SPI_CR1_BAUDRATE_FPCLK_DIV_8, SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE, SPI_CR1_CPHA_CLK_TRANSITION_1, SPI_CR1_DFF_8BIT, SPI_CR1_MSBFIRST);

	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO10);
	gpio_set_af(GPIOA, GPIO_AF10, GPIO10);
}

#define MPU_RASR_SIZE_32KB  (0x0EUL << MPU_RASR_SIZE_LSB)
#define MPU_RASR_SIZE_64KB  (0x0FUL << MPU_RASR_SIZE_LSB)
#define MPU_RASR_SIZE_128KB (0x10UL << MPU_RASR_SIZE_LSB)
#define MPU_RASR_SIZE_256KB (0x11UL << MPU_RASR_SIZE_LSB)
#define MPU_RASR_SIZE_512MB (0x1CUL << MPU_RASR_SIZE_LSB)

// http://infocenter.arm.com/help/topic/com.arm.doc.dui0552a/BABDJJGF.html
#define MPU_RASR_ATTR_FLASH  (MPU_RASR_ATTR_C)
#define MPU_RASR_ATTR_SRAM   (MPU_RASR_ATTR_C | MPU_RASR_ATTR_S)
#define MPU_RASR_ATTR_PERIPH (MPU_RASR_ATTR_B | MPU_RASR_ATTR_S)

#define FLASH_BASE	(0x08000000U)
#define SRAM_BASE	(0x20000000U)

// Never use in bootloader! Disables access to PPB (including MPU, NVIC, SCB)
void mpu_config(void)
{
	// Disable MPU
	MPU_CTRL = 0;

	// Bootloader (0x08000000 - 0x08007FFF, 32 KiB, read-only, execute never)
	MPU_RBAR = FLASH_BASE | MPU_RBAR_VALID | (0 << MPU_RBAR_REGION_LSB);
	MPU_RASR = MPU_RASR_ENABLE | MPU_RASR_ATTR_FLASH | MPU_RASR_SIZE_32KB | MPU_RASR_ATTR_AP_PRO_URO | MPU_RASR_ATTR_XN;

	// Metadata (0x08008000 - 0x0800FFFF, 32 KiB, read-write, execute never)
	MPU_RBAR = FLASH_BASE | 0x8000 | MPU_RBAR_VALID | (1 << MPU_RBAR_REGION_LSB);
	MPU_RASR = MPU_RASR_ENABLE | MPU_RASR_ATTR_FLASH | MPU_RASR_SIZE_32KB | MPU_RASR_ATTR_AP_PRW_URW | MPU_RASR_ATTR_XN;

	// Firmware (0x08010000 - 0x0807FFFF, 64 + 3 * 128 KiB = 64 + 128 + 256 KiB = 448 KiB, read-only)
	MPU_RBAR = FLASH_BASE | 0x10000 | MPU_RBAR_VALID | (2 << MPU_RBAR_REGION_LSB);
	MPU_RASR = MPU_RASR_ENABLE | MPU_RASR_ATTR_FLASH | MPU_RASR_SIZE_64KB | MPU_RASR_ATTR_AP_PRO_URO;
	MPU_RBAR = FLASH_BASE | 0x20000 | MPU_RBAR_VALID | (3 << MPU_RBAR_REGION_LSB);
	MPU_RASR = MPU_RASR_ENABLE | MPU_RASR_ATTR_FLASH | MPU_RASR_SIZE_128KB | MPU_RASR_ATTR_AP_PRO_URO;
	MPU_RBAR = FLASH_BASE | 0x40000 | MPU_RBAR_VALID | (4 << MPU_RBAR_REGION_LSB);
	MPU_RASR = MPU_RASR_ENABLE | MPU_RASR_ATTR_FLASH | MPU_RASR_SIZE_256KB | MPU_RASR_ATTR_AP_PRO_URO;

	// SRAM (0x20000000 - 0x2001FFFF, read-write, execute never)
	MPU_RBAR = SRAM_BASE | MPU_RBAR_VALID | (5 << MPU_RBAR_REGION_LSB);
	MPU_RASR = MPU_RASR_ENABLE | MPU_RASR_ATTR_SRAM | MPU_RASR_SIZE_128KB | MPU_RASR_ATTR_AP_PRW_URW | MPU_RASR_ATTR_XN;

	// Peripherals (0x40000000 - 0x5FFFFFFF, read-write, execute never)
	MPU_RBAR = PERIPH_BASE | MPU_RBAR_VALID | (6 << MPU_RBAR_REGION_LSB);
	MPU_RASR = MPU_RASR_ENABLE | MPU_RASR_ATTR_PERIPH | MPU_RASR_SIZE_512MB | MPU_RASR_ATTR_AP_PRW_URW | MPU_RASR_ATTR_XN;

	// Enable MPU
	MPU_CTRL = MPU_CTRL_ENABLE;

	// Enable memory fault handler
	SCB_SHCSR |= SCB_SHCSR_MEMFAULTENA;

	__asm__ volatile("dsb");
	__asm__ volatile("isb");

	// Switch to unprivileged software execution to prevent access to MPU
	set_mode_unprivileged();
}