[rust] set clock speed to 1008 MHz on sun20iw1 platform

Signed-off-by: Zhouqi Jiang <luojia@hust.edu.cn>

board/100ask-d1-h-rs/src/main.rs

@@ -2,13 +2,16 @@
 #![no_main]
 
 use panic_halt as _;
-use syterkit::{clock_dump, entry, println, show_banner, Clocks, Peripherals};
+use syterkit::{clock_dump, clock_init, entry, println, show_banner, Clocks, Peripherals};
 
 #[entry]
 fn main(p: Peripherals, _c: Clocks) {
     // Display the bootloader banner.
     show_banner();
 
+    // Initialize system clocks. // TODO: built-in in `entry` macro
+    clock_init(&p.ccu);
+
     // Initialize the DRAM.
     let dram_size = syterkit::mctl::init(&p.ccu);
     println!("DRAM size: {}M 🐏", dram_size);

rust/src/lib.rs

@@ -14,7 +14,7 @@ pub use allwinner_hal::ccu::Clocks;
 pub use syterkit_macros::entry;
 
 #[cfg(feature = "sun20iw1")]
-pub use soc::sun20iw1::{clock_dump, Peripherals};
+pub use soc::sun20iw1::{clock_dump, clock_init, Peripherals};
 
 /// Print SyterKit banner.
 pub fn show_banner() {

rust/src/soc/sun20iw1.rs

@@ -45,6 +45,27 @@ impl<'a> Peripherals<'a> {
     }
 }
 
+/// Initialize clock configurations.
+pub fn clock_init(ccu: &CCU) {
+    // TODO rewrite accordding to function `set_pll_cpux_axi` in src/drivers/sun20iw1/sys-clk.c
+    unsafe {
+        ccu.cpu_axi_config
+            .modify(|val| val.set_clock_source(CpuClockSource::PllPeri1x))
+    };
+    unsafe {
+        ccu.pll_cpu_control.modify(|val| val.set_pll_n(42 - 1));
+        ccu.pll_cpu_control.modify(|val| val.disable_lock());
+        ccu.pll_cpu_control.modify(|val| val.enable_lock())
+    };
+    while !ccu.pll_cpu_control.read().is_locked() {
+        core::hint::spin_loop();
+    }
+    unsafe {
+        ccu.cpu_axi_config
+            .modify(|val| val.set_clock_source(CpuClockSource::PllCpu));
+    };
+}
+
 /// Dump information about the system clocks.
 pub fn clock_dump(ccu: &CCU) {
     let cpu_clock_source = ccu.cpu_axi_config.read().clock_source();