From 77eda9fcb74c2d75e65f87a153e4256bffd8f54b Mon Sep 17 00:00:00 2001
From: Harald Welte <laforge@osmocom.org>
Date: Sun, 28 Mar 2021 12:16:21 +0200
Subject: [PATCH] rfdn: add systick

---
 projects/rfdsatt/attenuator.c |  2 +-
 projects/rfdsatt/rfdsatt.c    | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/projects/rfdsatt/attenuator.c b/projects/rfdsatt/attenuator.c
index 5a45bea..0bf03d5 100644
--- a/projects/rfdsatt/attenuator.c
+++ b/projects/rfdsatt/attenuator.c
@@ -12,7 +12,7 @@
 static const struct attenuator_cfg *g_att_cfg;
 static struct attenuator_state **g_att_state;
 
-static void delay()
+static void delay(void)
 {
 	volatile uint32_t i;
 	for (i = 0; i < 10000; i++) { }
diff --git a/projects/rfdsatt/rfdsatt.c b/projects/rfdsatt/rfdsatt.c
index a25411c..7d10f8d 100644
--- a/projects/rfdsatt/rfdsatt.c
+++ b/projects/rfdsatt/rfdsatt.c
@@ -20,10 +20,39 @@
 #include <libopencm3/stm32/rcc.h>
 #include <libopencm3/stm32/gpio.h>
 #include <libopencm3/stm32/usart.h>
+#include <libopencm3/stm32/i2c.h>
+#include <libopencm3/cm3/nvic.h>
+#include <libopencm3/cm3/systick.h>
+
+#include "attenuator.h"
+#include "misc.h"
+
+volatile uint32_t jiffies;
+
+void sys_tick_handler(void)
+{
+	jiffies++;
+}
+
+/* busy wait specified number of ms */
+void msleep(uint32_t delay)
+{
+	uint32_t wake = jiffies + delay;
+	do {
+	} while (wake > jiffies);
+}
+
 
 static void clock_setup(void)
 {
 	rcc_clock_setup_in_hsi_out_48mhz();
+	/* HCLK=48MHz; ADC=6MHz; APB1=24MHz; APB2=48MHz; USB=48MHz */
+
+	/* tick rate of 1ms */
+	systick_set_reload(48000);
+	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
+	systick_counter_enable();
+	systick_interrupt_enable();
 
 	/* Enable GPIOC clock. */
 	rcc_periph_clock_enable(RCC_GPIOA);