feat(loader): support load kernel and dtb from flash

Signed-off-by: tfx2001 <tfx2001@outlook.com>

src/loader.rs

@@ -0,0 +1,55 @@
+use crate::{DTB_LOAD_ADDRESS, SUPERVISOR_ENTRY};
+
+#[derive(PartialEq)]
+enum BlobType {
+    Kernel,
+    Dts,
+}
+struct BlobInfo {
+    type_: BlobType,
+    start: usize,
+    length: usize,
+}
+/// # Blob Info Table
+///
+/// | Name   | Begin      | Length |
+/// |--------|------------|--------|
+/// | Kernel | 0x80040000 | 2 MB   |
+/// | DTS    | 0x80240000 | 16 KB  |
+///
+const BLOB_TABLE: &'static [BlobInfo] = &[
+    BlobInfo {
+        type_: BlobType::Kernel,
+        // Keep 256 KB for SBI firmware.
+        start: 0x80040000,
+        length: 2 * 1024 * 1024,
+    },
+    BlobInfo {
+        type_: BlobType::Dts,
+        start: 0x80240000,
+        length: 16 * 1024,
+    },
+];
+
+impl BlobInfo {
+    unsafe fn load(&self, load_address: *mut u8) {
+        let src: &[u8] = core::slice::from_raw_parts(self.start as *mut _, self.length);
+        let dst: &mut [u8] = core::slice::from_raw_parts_mut(load_address, self.length);
+        dst.copy_from_slice(src);
+    }
+}
+
+pub unsafe fn load_test_kernel() {
+    let info: &BlobInfo = &BLOB_TABLE[0];
+    assert!(info.type_ == BlobType::Kernel);
+    assert!(info.start + info.length <= BLOB_TABLE[1].start);
+
+    info.load(SUPERVISOR_ENTRY as *mut u8);
+}
+
+pub unsafe fn load_dtb() {
+    let info: &BlobInfo = &BLOB_TABLE[1];
+    assert!(info.type_ == BlobType::Dts);
+
+    info.load(DTB_LOAD_ADDRESS as *mut u8);
+}

src/main.rs

@@ -5,13 +5,16 @@
 
 mod board;
 mod extension;
+mod loader;
 mod pmp;
 mod riscv_spec;
 mod trap;
 mod trap_stack;
 mod constants {
     /// 特权软件入口。
-    pub(crate) const SUPERVISOR_ENTRY: usize = 0x0108_0000;
+    pub(crate) const SUPERVISOR_ENTRY: usize = 0x4000_0000;
+    /// 设备树加载地址。
+    pub(crate) const DTB_LOAD_ADDRESS: usize = 0x4020_0000;
     /// 每个硬件线程设置 16KiB 栈空间。
     pub(crate) const LEN_STACK_PER_HART: usize = 16 * 1024;
 }
@@ -21,21 +24,13 @@ use core::arch::asm;
 use constants::*;
 use trap_stack::local_hsm;
 
-const TEST_KERNEL: &'static [u8] = include_bytes!("kernel.bin");
-
 /// 特权软件信息。
 #[derive(Debug)]
 struct Supervisor {
     start_addr: usize,
     opaque: usize,
 }
 
-fn load_test_kernel() {
-    let dst: &mut [u8] =
-        unsafe { core::slice::from_raw_parts_mut(SUPERVISOR_ENTRY as *mut u8, TEST_KERNEL.len()) };
-    dst.copy_from_slice(TEST_KERNEL);
-}
-
 #[hpm_rt::entry]
 fn main() -> ! {
     let hartid = riscv::register::mhartid::read();
@@ -65,14 +60,19 @@ fn main() -> ! {
     pmp::print_pmps();
     // 设置陷入栈
     trap_stack::prepare_for_trap();
-    // 加载内核
-    load_test_kernel();
+    unsafe {
+        // 加载内核
+        loader::load_test_kernel();
+        // 加载设备树
+        loader::load_dtb()
+    };
     // 设置内核入口
     local_hsm().prepare(Supervisor {
         start_addr: SUPERVISOR_ENTRY,
-        opaque: Default::default(),
+        opaque: DTB_LOAD_ADDRESS,
     });
     // 准备启动调度
+    println!("\nStarting kernel ...\n");
     unsafe {
         asm!("csrw mideleg,    {}", in(reg) !0);
         asm!("csrw medeleg,    {}", in(reg) !0);