Finish the arch section for LoongArch in OSTD

ostd/src/arch/loongarch/mod.rs

@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: MPL-2.0
+
+//! Platform-specific code for the LoongArch platform.
+
+pub mod boot;
+pub(crate) mod cpu;
+pub mod device;
+mod io;
+pub(crate) mod iommu;
+pub(crate) mod irq;
+pub(crate) mod mm;
+pub(crate) mod pci;
+pub mod qemu;
+pub(crate) mod serial;
+pub(crate) mod task;
+pub mod timer;
+pub mod trap;
+
+#[cfg(feature = "cvm_guest")]
+pub(crate) fn init_cvm_guest() {
+    // Unimplemented, no-op
+}
+
+pub(crate) unsafe fn late_init_on_bsp() {
+    // SAFETY: This function is called in the boot context of the BSP.
+    unsafe { trap::init() };
+
+    let io_mem_builder = io::construct_io_mem_allocator_builder();
+
+    // SAFETY: We're on the BSP and we're ready to boot all APs.
+    unsafe { crate::boot::smp::boot_all_aps() };
+
+    // SAFETY:
+    // 1. All the system device memory have been removed from the builder.
+    // 2. LoongArch platforms does not have port I/O.
+    unsafe { crate::io::init(io_mem_builder) };
+
+    let _ = pci::init();
+}
+
+pub(crate) unsafe fn init_on_ap() {
+    unimplemented!()
+}
+
+pub(crate) fn interrupts_ack(irq_number: usize) {
+    unimplemented!()
+}
+
+/// Returns the frequency of TSC. The unit is Hz.
+pub fn tsc_freq() -> u64 {
+    loongArch64::time::get_timer_freq() as _
+}
+
+/// Reads the current value of the processor’s time-stamp counter (TSC).
+pub fn read_tsc() -> u64 {
+    loongArch64::time::Time::read() as _
+}
+
+/// Reads a hardware generated 64-bit random value.
+///
+/// Returns None if no random value was generated.
+pub fn read_random() -> Option<u64> {
+    // FIXME: Implement a hardware random number generator on LoongArch platforms.
+    None
+}
+
+pub(crate) fn enable_cpu_features() {}