[feat] Serial output

kernel/main.cpp

@@ -3,22 +3,53 @@
 #include <graphics/context.h>
 #include <graphics/draw.h>
 #include <fonts/pixel_font.h>
+#include <serial.h>
 
-extern "C" void kernel_main() {
-    EFI_GUID gop_guid = {0x9042a9de, 0x23dc, 0x4a38, {0x96, 0xfb, 0x7a, 0xde, 0xd0, 0x80, 0x51, 0x6a}};
-
+inline void init_gop() {
+    EFI_GUID gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
     EFI_GRAPHICS_OUTPUT_PROTOCOL *GOP;
     uefi_call_wrapper((void*)ST->BootServices->SetWatchdogTimer, 4, 0, 0, 0, NULL);
     uefi_call_wrapper((void*)ST->BootServices->LocateProtocol, 3, &gop_guid, NULL, (void **)&GOP);
-
     gfx_init(GOP);
+}
+
+inline void init_serial() {
+    EFI_SERIAL_IO_PROTOCOL *SerialIo = NULL;
+    EFI_GUID gEfiSerialIoProtocolGuid = EFI_SERIAL_IO_PROTOCOL_GUID;
+    EFI_HANDLE *SerialHandles = NULL;
+    UINTN NumSerials = 0;
+    EFI_STATUS status = uefi_call_wrapper((void*)ST->BootServices->LocateHandleBuffer, 5,
+        ByProtocol,
+        &gEfiSerialIoProtocolGuid,
+        NULL,
+        &NumSerials,
+        &SerialHandles
+    );
+    if (status == EFI_SUCCESS && NumSerials > 0) {
+        status = uefi_call_wrapper((void*)ST->BootServices->HandleProtocol, 3,
+            SerialHandles[0], &gEfiSerialIoProtocolGuid, (void **)&SerialIo);
+        if (status == EFI_SUCCESS) {
+            serial_init(SerialIo);
+        }
+    }
+    if (SerialHandles) {
+        ST->BootServices->FreePool(SerialHandles);
+    }
+}
+
+extern "C" void kernel_main() {
+    init_gop();
+    init_serial();
 
     uefi_call_wrapper((void*)ST->ConOut->SetCursorPosition, 3, ST->ConOut, 0, 5);
     uefi_call_wrapper((void*)ST->ConOut->OutputString, 2, ST->ConOut, L"Kernel is running!\n");
 
     uefi_call_wrapper((void*)ST->ConOut->ClearScreen, 1, ST->ConOut);
+    serial_write("\n\n"); // 防止和前面串了
 
     // pf_print_char('k', 10, 10);
     pf_print("Welcome to Sylva OS!", 10, 10);
+    serial_write("Hello from serial!\n");
+    serial_write("Hello from serial line 2!");
     while (1);
 }

kernel/serial.cpp

@@ -0,0 +1,40 @@
+#include <serial.h>
+#include <efilib.h>
+
+serial_context g_serial;
+
+void serial_init(EFI_SERIAL_IO_PROTOCOL *SerialIo) {
+    g_serial.SerialIo = SerialIo;
+    uefi_call_wrapper((void*)SerialIo->Reset, 1, SerialIo);
+}
+
+void serial_write_char(char c) {
+    if (!g_serial.SerialIo) {
+        uefi_call_wrapper((void*)ST->ConOut->OutputString, 2, ST->ConOut, L"serial: null io\n");
+        return;
+    }
+    UINTN size = 1;
+    EFI_STATUS status = uefi_call_wrapper((void*)g_serial.SerialIo->Write, 3, g_serial.SerialIo, &size, &c);
+    if (status != EFI_SUCCESS) {
+        uefi_call_wrapper((void*)ST->ConOut->OutputString, 2, ST->ConOut, L"serial: write failed\n");
+    }
+}
+
+void serial_write(const char *str) {
+    if (!g_serial.SerialIo) {
+        uefi_call_wrapper((void*)ST->ConOut->OutputString, 2, ST->ConOut, L"serial: null io\n");
+        return;
+    }
+    while (*str) {
+        serial_write_char(*str++);
+    }
+}
+
+char serial_read_char() {
+    if (!g_serial.SerialIo) return 0;
+    char c = 0;
+    UINTN size = 1;
+    EFI_STATUS status = uefi_call_wrapper((void*)g_serial.SerialIo->Read, 3, g_serial.SerialIo, &size, &c);
+    if (status != EFI_SUCCESS || size == 0) return 0;
+    return c;
+}