From 07fdd6c1dd26fae3a1e0b93b3877483c87d81f2a Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Sun, 6 Oct 2024 15:00:11 -0400
Subject: abstract timer driver
---
src/main.zig | 7 ++++---
src/timer.zig | 38 +++++++++++++++++++++++++-------------
2 files changed, 29 insertions(+), 16 deletions(-)
diff --git a/src/main.zig b/src/main.zig
index deac169..d6a1aa4 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -6,12 +6,13 @@ const timer = @import("timer.zig");
const rcc: *[39]u32 = @ptrFromInt(0x40021000);
const gpioa = gpio.gpioa;
const gpioc = gpio.gpioc;
+const tick = timer.systick;
export fn _start() callconv(.C) noreturn {
cpu.interrupt_disable();
interrupt.initialize();
interrupt.register(.SVCall, svcall);
- timer.initialize(1000);
+ tick.initialize(1000);
cpu.interrupt_enable();
rcc[19] |= 5; // gpio a and c
@@ -21,8 +22,8 @@ export fn _start() callconv(.C) noreturn {
while (true) {
//asm volatile("svc 0");
gpioa.toggle(5);
- const next = timer.ticks() + 1000;
- while (timer.ticks() < next) {
+ const next = tick.ticks() + 1000;
+ while (tick.ticks() < next) {
asm volatile("nop");
}
}
diff --git a/src/timer.zig b/src/timer.zig
index 21151c7..b30cfcf 100644
--- a/src/timer.zig
+++ b/src/timer.zig
@@ -1,6 +1,6 @@
const interrupt = @import("interrupt.zig");
-const sys_tick_type = packed struct {
+const driver_armcortex = packed struct {
enable: u1,
tickint: u1,
unused: u30,
@@ -8,24 +8,36 @@ const sys_tick_type = packed struct {
rvr: u32,
cvr: u32,
calib: u32,
-};
-var sys_tick: *volatile sys_tick_type = @ptrFromInt(0xE000E010);
+ pub fn initialize(self: *driver_armcortex, freq: u32) void {
+ self.rvr = 4000000 / 8 / freq;
+ self.tickint = 1;
+ self.enable = 1;
+ }
-pub var ticks_raw: u32 = 0;
+};
-pub fn initialize(freq: u32) void {
- interrupt.register(.SysTick, tick);
- sys_tick.rvr = 4000000 / 8 / freq;
- sys_tick.tickint = 1;
- sys_tick.enable = 1;
-}
+var ticks_raw: u32 = 0;
fn tick() void {
ticks_raw += 1;
}
-pub fn ticks() u32 {
- return @atomicLoad(u32, &ticks_raw, .acquire);
-}
+const driver = struct {
+ const lld_type = driver_armcortex;
+
+ lld: *driver_armcortex,
+
+ pub fn initialize(self: driver, freq: u32) void {
+ interrupt.register(.SysTick, tick);
+ self.lld.initialize(freq);
+ }
+
+ pub fn ticks(self: driver) u32 {
+ _ = self;
+ return @atomicLoad(u32, &ticks_raw, .acquire);
+ }
+};
+
+pub const systick = driver { .lld = @ptrFromInt(0xE000E010) };
--
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