1 files changed, 118 insertions, 0 deletions
diff --git a/kernel/timer.cc b/kernel/timer.cc
new file mode 100644
index 0000000..3cf03cf
--- /dev/null
+++ b/kernel/timer.cc
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+#include <lume/timer.h>
+#include <lume/fdt.h>
+#include <lume/sched.h>
+#include <arch/cpu.h>
+#include <arch/sbi.h>
+
+#include <kernel/sync/spinlock.h>
+
+uint64 g_jiffies = 0;
+static uint64 g_timer_freq = 10000000;
+static uint64 g_tick_interval = 0;
+
+static list_node g_timer_list;
+static Spinlock g_timer_lock;
+
+
+void add_timer(TimerList* timer) {
+    LockGuard guard(g_timer_lock);
+    
+    list_node* pos;
+    list_for_each(pos, &g_timer_list) {
+        TimerList* t = list_entry<TimerList, &TimerList::entry>(pos);
+        if (t->expires > timer->expires) {
+            break;
+        }
+    }
+    
+    timer->entry.prev = pos->prev;
+    timer->entry.next = pos;
+    pos->prev->next = &timer->entry;
+    pos->prev = &timer->entry;
+}
+
+int del_timer(TimerList* timer) {
+    LockGuard guard(g_timer_lock);
+    if (timer->entry.next != nullptr && timer->entry.next != &timer->entry) {
+        timer->entry.prev->next = timer->entry.next;
+        timer->entry.next->prev = timer->entry.prev;
+        timer->entry.init();
+        return 1;
+    }
+    return 0;
+}
+
+int mod_timer(TimerList* timer, uint64 expires) {
+    int ret = del_timer(timer);
+    timer->expires = expires;
+    add_timer(timer);
+    return ret;
+}
+
+static void run_timers() {
+    g_timer_lock.acquire();
+    
+    while (!g_timer_list.is_empty()) {
+        TimerList* t = list_entry<TimerList, &TimerList::entry>(g_timer_list.next);
+        if (t->expires > g_jiffies) {
+            break;
+        }
+        
+        t->entry.prev->next = t->entry.next;
+        t->entry.next->prev = t->entry.prev;
+        t->entry.init();
+        
+        g_timer_lock.release();
+        t->function(t);
+        g_timer_lock.acquire();
+    }
+    
+    g_timer_lock.release();
+}
+
+static void timer_set_next() {
+    arch::sbi::set_timer(arch::cpu::read_time() + g_tick_interval);
+}
+
+void timer_init() {
+    DeviceNode* cpus = fdt_get_node_by_path("/cpus");
+    if (cpus) {
+        g_timer_freq = cpus->get_prop_u32("timebase-frequency", g_timer_freq);
+    }
+    
+    // Default 100 Hz (10ms per tick)
+    g_tick_interval = g_timer_freq / 100;
+    
+    g_timer_lock.init("timer_list");
+    g_timer_list.init();
+    
+    timer_set_next();
+
+    arch::cpu::timer_intr_on();
+}
+
+
+void timer_init_ap() {
+    timer_set_next();
+    arch::cpu::timer_intr_on();
+}
+
+extern "C" uint32 bsp_hart_id;
+
+void timer_tick() {
+    if (arch::cpu::id() == bsp_hart_id) {
+        g_jiffies++;
+        run_timers();
+    }
+
+    timer_set_next();
+    sched_tick();
+}
+
+
+uint64 timer_get_freq() {
+    return g_timer_freq;
+}