blackmagic/src/platforms/stm32/timing_stm32.c
Uwe Bonnes 1ca9f234f7 Infrastructure for setting maximum SWJ frequency.
Implement for BMP/firmware on STM32.
2020-12-12 18:33:09 +01:00

90 lines
2.3 KiB
C

/*
* This file is part of the Black Magic Debug project.
*
* Copyright (C) 2015 Gareth McMullin <gareth@blacksphere.co.nz>
*
* 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 "general.h"
#include "morse.h"
#include <libopencm3/cm3/systick.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/rcc.h>
uint8_t running_status;
static volatile uint32_t time_ms;
uint32_t swd_delay_cnt = 0;
void platform_timing_init(void)
{
/* Setup heartbeat timer */
systick_set_clocksource(STK_CSR_CLKSOURCE_AHB_DIV8);
/* Interrupt us at 10 Hz */
systick_set_reload(rcc_ahb_frequency / (8 * 10) );
/* SYSTICK_IRQ with low priority */
nvic_set_priority(NVIC_SYSTICK_IRQ, 14 << 4);
systick_interrupt_enable();
systick_counter_enable();
}
void platform_delay(uint32_t ms)
{
platform_timeout timeout;
platform_timeout_set(&timeout, ms);
while (!platform_timeout_is_expired(&timeout));
}
void sys_tick_handler(void)
{
if(running_status)
gpio_toggle(LED_PORT, LED_IDLE_RUN);
time_ms += 100;
SET_ERROR_STATE(morse_update());
}
uint32_t platform_time_ms(void)
{
return time_ms;
}
/* Assume some USED_SWD_CYCLES per clock
* and CYCLES_PER_CNT Cycles per delay loop cnt with 2 delay loops per clock
*/
/* Values for STM32F103 at 72 MHz */
#define USED_SWD_CYCLES 22
#define CYCLES_PER_CNT 10
void platform_max_frequency_set(uint32_t freq)
{
int divisor = rcc_ahb_frequency - USED_SWD_CYCLES * freq;
if (divisor < 0) {
swd_delay_cnt = 0;
return;
}
divisor /= 2;
swd_delay_cnt = divisor/(CYCLES_PER_CNT * freq);
if ((swd_delay_cnt * (CYCLES_PER_CNT * freq)) < (unsigned int)divisor)
swd_delay_cnt++;
}
uint32_t platform_max_frequency_get(void)
{
uint32_t ret = rcc_ahb_frequency;
ret /= USED_SWD_CYCLES + CYCLES_PER_CNT * swd_delay_cnt;
return ret;
}