interrupts: Fix clock cycle calculation

2 files changed, 2 insertions, 4 deletions

diff --git a/src/interrupts.zig b/src/interrupts.zig
index 5e642bd..efde552 100644
--- a/src/interrupts.zig
+++ b/src/interrupts.zig
@@ -102,9 +102,6 @@ export fn handleTrap(epc: usize, tval: usize, cause_bits: usize, hart_id: usize,
         switch (@as(AsyncCause, @enumFromInt(cause.num))) {
             .supervisor_software => w.print("Hart {d}: Software interrupt\r\n", .{hart_id}) catch while (true) {},
             .supervisor_timer => {
-                time.interruptInMillis(null, process.schedule_interval_millis) catch |err| {
-                    std.debug.panic("Hart {d}: Unable to set interrupt timer: {any}", .{ hart_id, err });
-                };
                 schedule() catch |err| {
                     std.debug.panic("Hart {d}: Unable to schedule next process: {any}", .{ hart_id, err });
                 };
@@ -268,6 +265,7 @@ export fn supervisorTrapVector() align(4) callconv(.Naked) noreturn {
 
 fn schedule() !noreturn {
     if (process.next()) |next| {
+        try time.interruptInMillis(null, process.schedule_interval_millis);
         process.switchTo(next);
     }
 
diff --git a/src/sbi/time.zig b/src/sbi/time.zig
index c0d9069..4700191 100644
--- a/src/sbi/time.zig
+++ b/src/sbi/time.zig
@@ -43,7 +43,7 @@ pub fn interruptInMillis(dt: ?*const fdt.Tree, millis: u64) !void {
         frequency = std.mem.readInt(u32, frequency_prop[0..@sizeOf(u32)], .big);
     } else return Error.TimebaseFrequencyPropTooShort;
 
-    const cycles = millis / 1000 * frequency;
+    const cycles = frequency / 1000 * millis;
 
     try setTimer(stime + cycles);
 }