feat: 支持 DBCN

- 一个简单的支持非阻塞读写的 16550 驱动

Signed-off-by: YdrMaster <[email protected]>

Author: YdrMaster

Cargo.lock

@@ -23,7 +23,6 @@ rustsbi = { git = "https://github.com/rustsbi/rustsbi", rev = "91cfa36", feature
 sbi-spec = { version = "0.0.5", features = ["legacy"] }
 riscv = "0.10.1"
 spin = "0.9"
-uart_16550 = "0.2"
 rcore-console = "0.0.0"
 aclint = "0.0.0"
 sifive-test-device = "0.0.0"

rustsbi-qemu/Cargo.toml

@@ -1,6 +1,6 @@
 #![allow(unused)]
 
-use crate::UART;
+use crate::uart16550;
 use core::ops::Range;
 use rustsbi::{spec::binary::SbiRet, Console, Physical};
 use spin::Once;
@@ -22,11 +22,12 @@ impl Console for DBCN {
         let start = bytes.phys_addr_lo();
         let end = start + bytes.num_bytes();
         if self.0.contains(&start) && self.0.contains(&(end - 1)) {
-            let mut uart = UART.lock();
-            let uart = unsafe { uart.assume_init_mut() };
+            let uart = uart16550::UART.lock();
             for ptr in start..end {
-                let c = ptr as *const u8;
-                unsafe { uart.send(c.read_volatile()) };
+                let c = unsafe { (ptr as *const u8).read_volatile() };
+                if !uart.get().write(c) {
+                    return SbiRet::success(ptr - start);
+                }
             }
             SbiRet::success(bytes.num_bytes())
         } else {
@@ -38,11 +39,13 @@ impl Console for DBCN {
         let start = bytes.phys_addr_lo();
         let end = start + bytes.num_bytes();
         if self.0.contains(&start) && self.0.contains(&(end - 1)) {
-            let mut uart = UART.lock();
-            let uart = unsafe { uart.assume_init_mut() };
+            let uart = uart16550::UART.lock();
             for ptr in start..end {
-                let c = ptr as *mut u8;
-                unsafe { c.write_volatile(uart.receive()) };
+                if let Some(c) = uart.get().read() {
+                    unsafe { (ptr as *mut u8).write_volatile(c) };
+                } else {
+                    return SbiRet::success(ptr - start);
+                }
             }
             SbiRet::success(bytes.num_bytes())
         } else {
@@ -52,9 +55,11 @@ impl Console for DBCN {
 
     #[inline]
     fn write_byte(&self, byte: u8) -> SbiRet {
-        let mut uart = UART.lock();
-        let uart = unsafe { uart.assume_init_mut() };
-        uart.send(byte);
-        SbiRet::success(0)
+        let uart = uart16550::UART.lock();
+        loop {
+            if uart.get().write(byte) {
+                return SbiRet::success(0);
+            }
+        }
     }
 }

rustsbi-qemu/src/dbcn.rs

@@ -11,6 +11,7 @@ mod qemu_test;
 mod riscv_spec;
 mod trap_stack;
 mod trap_vec;
+mod uart16550;
 
 mod constants {
     /// 特权软件入口。
@@ -35,10 +36,9 @@ use device_tree::BoardInfo;
 use fast_trap::{FastContext, FastResult};
 use riscv_spec::*;
 use rustsbi::{spec::binary::SbiRet, RustSBI};
-use spin::{Mutex, Once};
+use spin::Once;
 use trap_stack::{local_hsm, local_remote_hsm, remote_hsm};
 use trap_vec::trap_vec;
-use uart_16550::MmioSerialPort;
 
 /// 入口。
 ///
@@ -83,7 +83,7 @@ extern "C" fn rust_main(hartid: usize, opaque: usize) {
         // 解析设备树
         let board_info = BOARD_INFO.call_once(|| device_tree::parse(opaque));
         // 初始化外设
-        *UART.lock() = MaybeUninit::new(unsafe { MmioSerialPort::new(board_info.uart.start) });
+        uart16550::init(board_info.uart.start);
         rcore_console::init_console(&Console);
         rcore_console::set_log_level(option_env!("LOG"));
         clint::init(board_info.clint.start);
@@ -120,7 +120,7 @@ extern "C" fn rust_main(hartid: usize, opaque: usize) {
                     .with_timer(&clint::Clint)
                     .with_hsm(Hsm)
                     .with_reset(qemu_test::get())
-                    // .with_console(dbcn::get())
+                    .with_console(dbcn::get())
                     .build(),
             );
         }
@@ -262,10 +262,14 @@ extern "C" fn fast_handler(
                                 ret.error = 0;
                                 ret.value = a1;
                             }
-                            legacy::LEGACY_CONSOLE_GETCHAR => {
-                                ret.error = unsafe { UART.lock().assume_init_mut() }.receive() as _;
-                                ret.value = a1;
-                            }
+                            legacy::LEGACY_CONSOLE_GETCHAR => loop {
+                                let uart = uart16550::UART.lock();
+                                if let Some(c) = uart.get().read() {
+                                    ret.error = c as _;
+                                    ret.value = a1;
+                                    break;
+                                }
+                            },
                             _ => {}
                         }
                     }
@@ -316,20 +320,23 @@ struct Supervisor {
 }
 
 struct Console;
-static UART: Mutex<MaybeUninit<MmioSerialPort>> = Mutex::new(MaybeUninit::uninit());
 
 impl rcore_console::Console for Console {
     #[inline]
     fn put_char(&self, c: u8) {
-        unsafe { UART.lock().assume_init_mut() }.send(c);
+        let uart = uart16550::UART.lock();
+        while !uart.get().write(c) {
+            core::hint::spin_loop();
+        }
     }
 
     #[inline]
     fn put_str(&self, s: &str) {
-        let mut uart = UART.lock();
-        let uart = unsafe { uart.assume_init_mut() };
+        let uart = uart16550::UART.lock();
         for c in s.bytes() {
-            uart.send(c);
+            while !uart.get().write(c) {
+                core::hint::spin_loop();
+            }
         }
     }
 }
@@ -343,8 +350,7 @@ type FixedRustSBI<'a> = RustSBI<
     Hsm,
     &'a qemu_test::QemuTest,
     Infallible,
-    Infallible,
-    // &'a dbcn::DBCN,
+    &'a dbcn::DBCN,
 >;
 
 struct Hsm;