87 lines
4.5 KiB
C
87 lines
4.5 KiB
C
/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** USB DFU bootloader
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* @file bootloader.c
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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*/
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/* standard libraries */
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#include <stdint.h> // standard integer types
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#include <stdbool.h> // boolean types
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/* STM32 (including CM3) libraries */
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#include <libopencm3/cm3/scb.h> // vector table definition
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#include <libopencm3/stm32/rcc.h> // clock utilities
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#include <libopencm3/stm32/gpio.h> // GPIO utilities
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/* own libraries */
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#include "global.h" // board definitions
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#include "usb_dfu.h" // USB DFU utilities
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/** bootloader entry point */
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void main(void);
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void main(void)
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{
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// check of DFU mode is forced
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bool dfu_force = false; // to remember if DFU mode is forced
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// check if a soft boot has been used
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if (0==(RCC_CSR&0xfc000000)) { // no reset flag present -> this was a soft reset using csr_reset_core(), very probably to start the DFU mode
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dfu_force = true;
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} else { // check if the force DFU mode input is set
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// disable SWJ pin to use as GPIO
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#if (GPIO(B)==GPIO(DFU_FORCE_PORT)) && (GPIO(4)==GPIO(DFU_FORCE_PIN))
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gpio_primary_remap(AFIO_MAPR_SWJ_CFG_FULL_SWJ_NO_JNTRST, 0);
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#elif ((GPIO(B)==GPIO(DFU_FORCE_PORT)) && (GPIO(3)==GPIO(DFU_FORCE_PIN))) || ((GPIO(A)==GPIO(DFU_FORCE_PORT)) && (GPIO(15)==GPIO(DFU_FORCE_PIN)))
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gpio_primary_remap(AFIO_MAPR_SWJ_CFG_JTAG_OFF_SW_ON, 0);
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#elif ((GPIO(A)==GPIO(DFU_FORCE_PORT)) && (GPIO(14)==GPIO(DFU_FORCE_PIN))) || ((GPIO(A)==GPIO(DFU_FORCE_PORT)) && (GPIO(13)==GPIO(DFU_FORCE_PIN)))
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gpio_primary_remap(AFIO_MAPR_SWJ_CFG_JTAG_OFF_SW_OFF, 0);
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#endif
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rcc_periph_clock_enable(RCC_GPIO(DFU_FORCE_PORT)); // enable clock for GPIO domain
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gpio_set_mode(GPIO(DFU_FORCE_PORT), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO(DFU_FORCE_PIN)); // set GPIO to input
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// pull on the opposite of the expected value
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#if (DFU_FORCE_VALUE==1)
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gpio_clear(GPIO(DFU_FORCE_PORT), GPIO(DFU_FORCE_PIN)); // pull down to be able to detect when tied to high
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if (gpio_get(GPIO(DFU_FORCE_PORT), GPIO(DFU_FORCE_PIN))) { // check if output is set to the value to force DFU mode
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#else
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gpio_set(GPIO(DFU_FORCE_PORT), GPIO(DFU_FORCE_PIN)); // pull up to be able to detect when tied to low
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if (0==gpio_get(GPIO(DFU_FORCE_PORT), GPIO(DFU_FORCE_PIN))) { // check if output is set to the value to force DFU mode
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#endif
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dfu_force = true; // DFU mode forced
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}
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}
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// start application if valid
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/* the application starts with the vector table
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* the first entry in the vector table is the initial stack pointer (SP) address
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* the stack will be placed in RAM
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* on STM32F1xx SRAM begins at 0x2000 0000, and on STM32F103x8 there is 20KB of RAM (0x5000).
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* since the stack grown "downwards" it should start at the end of the RAM: 0x2000 5000
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* if the SP is not in this range (e.g. flash has been erased) there is no valid application
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* the second entry in the vector table is the reset address, corresponding to the application start
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*/
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volatile uint32_t* application = &__application_beginning; // get the value of the application address symbol (use a register instead on the stack since the stack pointer will be changed)
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if (!dfu_force && (((*application)&0xFFFE0000)==0x20000000)) { // application at address seems valid
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SCB_VTOR = (volatile uint32_t)(application); // set vector table to application vector table (store at the beginning of the application)
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__asm__ volatile ("MSR msp,%0" : :"r"(*application)); // set stack pointer to address provided in the beginning of the application (loaded into a register first)
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(*(void(**)(void))(application + 1))(); // start application (by jumping to the reset function which address is stored as second entry of the vector table)
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}
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rcc_clock_setup_in_hse_8mhz_out_72mhz(); // start main clock
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board_setup(); // setup board to control LED
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led_on(); // indicate bootloader started
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usb_dfu_setup(); // setup USB DFU for firmware upload
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usb_dfu_start(); // run DFU mode
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}
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