ar100: Support for ar100 (#6054)

Add files to support AR100

Signed-off-by: Elias Bakken <elias@iagent.no>

src/ar100/timer.c

@@ -0,0 +1,52 @@
+// Timer functions for ar100
+//
+// Copyright (C) 2020-2021  Elias Bakken <elias@iagent.no>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "timer.h"
+#include "board/timer_irq.h"
+#include "board/misc.h"
+
+volatile static uint32_t timer_compare;
+static uint8_t interrupt_seen;
+
+uint8_t timer_interrupt_pending(void){
+    if(interrupt_seen){
+      return 0;
+    }
+    if(timer_is_before(mfspr(SPR_TICK_TTCR_ADDR), timer_compare)){
+      return 0;
+    }
+
+    return 1;
+}
+void timer_clear_interrupt(void){
+    interrupt_seen = 1;
+}
+// Set the next timer wake up time
+void timer_set(uint32_t value){
+    timer_compare = value;
+    interrupt_seen = 0;
+}
+
+// Return the current time (in absolute clock ticks).
+uint32_t timer_read_time(void){
+    return mfspr(SPR_TICK_TTCR_ADDR);
+}
+
+void timer_reset(void){
+    mtspr(SPR_TICK_TTCR_ADDR, 0);
+}
+
+// Activate timer dispatch as soon as possible
+void timer_kick(void){
+    timer_set(timer_read_time() + 50);
+}
+
+void timer_init(void){
+    interrupt_seen = 1;
+    mtspr(SPR_TICK_TTMR_ADDR, 3<<30); // continous
+    timer_kick();
+}
+DECL_INIT(timer_init);