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mirror of https://github.com/trezor/trezor-firmware.git synced 2024-11-26 17:38:39 +00:00
trezor-firmware/core/embed/trezorhal/stm32.c
2021-06-23 16:40:45 +02:00

96 lines
3.5 KiB
C

/*
* This file is part of the Trezor project, https://trezor.io/
*
* Copyright (c) SatoshiLabs
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include STM32_HAL_H
#include "rng.h"
const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0,
1, 2, 3, 4, 6, 7, 8, 9};
const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4};
#ifdef STM32F427xx
#define CORE_CLOCK_MHZ 168U
#elif STM32F405xx
#define CORE_CLOCK_MHZ 120U
#else
#error Unsupported MCU
#endif
uint32_t SystemCoreClock = CORE_CLOCK_MHZ * 1000000U;
#pragma GCC optimize( \
"no-stack-protector") // applies to all functions in this file
void SystemInit(void) {
// set flash wait states for an increasing HCLK frequency -- reference RM0090
// section 3.5.1
FLASH->ACR = FLASH_ACR_LATENCY_5WS;
// wait until the new wait state config takes effect -- per section 3.5.1
// guidance
while ((FLASH->ACR & FLASH_ACR_LATENCY) != FLASH_ACR_LATENCY_5WS)
;
// configure main PLL; assumes HSE is 8 MHz; this should evaluate to
// 0x27402a04 -- reference RM0090 section 7.3.2
RCC->PLLCFGR =
(RCC_PLLCFGR_RST_VALUE & ~RCC_PLLCFGR_PLLQ & ~RCC_PLLCFGR_PLLSRC &
~RCC_PLLCFGR_PLLP & ~RCC_PLLCFGR_PLLN & ~RCC_PLLCFGR_PLLM) |
(7U << RCC_PLLCFGR_PLLQ_Pos) // Q = 7
| RCC_PLLCFGR_PLLSRC_HSE // PLLSRC = HSE
| (0U << RCC_PLLCFGR_PLLP_Pos) // P = 2 (two bits, 00 means PLLP = 2)
| (CORE_CLOCK_MHZ << RCC_PLLCFGR_PLLN_Pos) // N = CORE_CLOCK_MHZ
| (4U << RCC_PLLCFGR_PLLM_Pos); // M = 4
// enable spread spectrum clock for main PLL
RCC->SSCGR = RCC_SSCGR_SSCGEN | (44 << RCC_SSCGR_INCSTEP_Pos) |
(250 << RCC_SSCGR_MODPER_Pos);
// enable clock security system, HSE clock, and main PLL
RCC->CR |= RCC_CR_CSSON | RCC_CR_HSEON | RCC_CR_PLLON;
// wait until PLL and HSE ready
while ((RCC->CR & (RCC_CR_PLLRDY | RCC_CR_HSERDY)) !=
(RCC_CR_PLLRDY | RCC_CR_HSERDY))
;
// APB2=2, APB1=4, AHB=1, system clock = main PLL
const uint32_t cfgr = RCC_CFGR_PPRE2_DIV2 | RCC_CFGR_PPRE1_DIV4 |
RCC_CFGR_HPRE_DIV1 | RCC_CFGR_SW_PLL;
RCC->CFGR = cfgr;
// wait until PLL is system clock and also verify that the pre-scalers were
// set
while (RCC->CFGR != (RCC_CFGR_SWS_PLL | cfgr))
;
// turn off the HSI as it is now unused (it will be turned on again
// automatically if a clock security failure occurs)
RCC->CR &= ~RCC_CR_HSION;
// wait until ths HSI is off
while ((RCC->CR & RCC_CR_HSION) == RCC_CR_HSION)
;
// init the TRNG peripheral
rng_init();
// set CP10 and CP11 to enable full access to the fpu coprocessor; ARMv7-M
// Architecture Reference Manual section B3.2.20
SCB->CPACR |= ((3U << 22) | (3U << 20));
}
// from util.s
extern void shutdown_privileged(void);
void PVD_IRQHandler(void) {
TIM1->CCR1 = 0; // turn off display backlight
shutdown_privileged();
}