1 files changed, 86 insertions, 0 deletions
diff --git a/code/fe310/eos/timer.c b/code/fe310/eos/timer.c
new file mode 100644
index 0000000..0a07ed9
--- /dev/null
+++ b/code/fe310/eos/timer.c
@@ -0,0 +1,86 @@
+#include <stddef.h>
+#include <stdio.h>
+
+#include "encoding.h"
+#include "platform.h"
+#include "event.h"
+#include "timer.h"
+
+#define MIN(X, Y)               (((X) < (Y)) ? (X) : (Y))
+#define MAX(X, Y)               (((X) > (Y)) ? (X) : (Y))
+
+static eos_timer_fptr_t timer_ext_handler = NULL;
+volatile uint64_t timer_next = 0;
+volatile uint64_t timer_next_evt = 0;
+
+void handle_m_time_interrupt(void) {
+    volatile uint64_t *mtime = (uint64_t *) (CLINT_CTRL_ADDR + CLINT_MTIME);
+    volatile uint64_t *mtimecmp = (uint64_t *) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
+    uint64_t now = *mtime;
+
+    if (timer_next && (timer_next <= now)) {
+        uint32_t next = timer_ext_handler();
+        if (next) {
+            timer_next = now + next;
+        } else {
+            timer_next = 0;
+        }
+    }
+    if (timer_next_evt && (timer_next_evt <= now)) {
+        eos_evtq_push(EOS_EVT_TIMER, NULL, 0);
+        timer_next_evt = 0;
+    }
+    *mtimecmp = (timer_next && timer_next_evt) ? MIN(timer_next, timer_next_evt) : (timer_next ? timer_next : timer_next_evt);
+    if (*mtimecmp == 0) clear_csr(mie, MIP_MTIP);
+}
+
+void eos_timer_init(void) {
+    volatile uint64_t *mtimecmp = (uint64_t *) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
+    *mtimecmp = 0;
+    clear_csr(mie, MIP_MTIP);
+}
+
+void eos_timer_set(uint32_t tick, unsigned char is_evt) {
+    volatile uint64_t *mtime = (uint64_t *) (CLINT_CTRL_ADDR + CLINT_MTIME);
+    volatile uint64_t *mtimecmp = (uint64_t *) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
+
+    clear_csr(mstatus, MSTATUS_MIE);
+
+    uint64_t now = *mtime;
+    uint64_t then = *mtimecmp;
+    uint64_t next = now + tick;
+    if (is_evt) {
+        if ((timer_next_evt == 0) || (next < timer_next_evt)) timer_next_evt = next;
+        next = timer_next ? MIN(timer_next, timer_next_evt) : timer_next_evt;
+    } else if (timer_ext_handler) {
+        if ((timer_next == 0) || (next < timer_next)) timer_next = next;
+        next = timer_next_evt ? MIN(timer_next, timer_next_evt) : timer_next;
+    }
+    if ((then == 0) || (next < then)) *mtimecmp = next;
+    if (then == 0) set_csr(mie, MIP_MTIP);
+
+    set_csr(mstatus, MSTATUS_MIE);
+}
+
+void eos_timer_clear(unsigned char is_evt) {
+    volatile uint64_t *mtimecmp = (uint64_t *) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
+
+    clear_csr(mstatus, MSTATUS_MIE);
+
+    if (is_evt) {
+        timer_next_evt = 0;
+        *mtimecmp = timer_next;
+    } else {
+        timer_next = 0;
+        *mtimecmp = timer_next_evt;
+    }
+    if (*mtimecmp == 0) clear_csr(mie, MIP_MTIP);
+
+    set_csr(mstatus, MSTATUS_MIE);
+}
+
+void eos_timer_set_handler(eos_timer_fptr_t handler) {
+    clear_csr(mstatus, MSTATUS_MIE);
+    timer_ext_handler = handler;
+    set_csr(mstatus, MSTATUS_MIE);
+}