commit 621c3fa7e60bd46123980e938e3e9342b6ab4f3b
from: Aleksey Ryndin <continue@to.any-key.press>
date: Thu Mar 02 12:53:23 2023 UTC

UART recv implementation

commit - f9977d5b1ec596532f80fbeb1a112024f8f6d43f
commit + 621c3fa7e60bd46123980e938e3e9342b6ab4f3b
blob - 24f15702cdb5ba0ca3a48174cca2ef20f7d0f547
blob + 349071597c6fca19429942fb86deeb6f1892a6f6
--- Makefile
+++ Makefile
@@ -12,9 +12,11 @@ BOARD		= virt
 ASFLAGS		= -target ${TARGET}
 ASFILES		= boot.o
 
-CXXFLAGS	= -target ${TARGET} -Wall -Wextra -nostdlib -fno-exceptions
+CXXFLAGS	= -target ${TARGET}
+CXXFLAGS        +=-Wall -Wextra -Werror
+CXXFLAGS        +=-nostdlib -fno-exceptions -std=c++11
 CXXFLAGS	+=-ffreestanding -mgeneral-regs-only
-CXXFLAGS	+=-Iinclude -std=c++11
+CXXFLAGS	+=-Iinclude
 CXXFILES	= kernel.cc uart_${BOARD}.cc
 
 OBJS		= ${ASFILES:.S=.o} ${CXXFILES:.cc=.o}
blob - 66a22a047beaacf08b00ea31812c9be3b8d2076a
blob + 60bb64a260ae9b8f384a0d42559ad7c8bbd90448
--- kernel.cc
+++ kernel.cc
@@ -10,13 +10,25 @@ void
 uart_send_string(const char *szContent)
 {
     const char *szCurrent = szContent;
-    while (*szCurrent) {
+    while (*szCurrent)
+    {
         Board::Uart::send(*szCurrent);
         ++szCurrent;
     }
 }
 
 
+void
+uart_echo_test_mode()
+{
+    uart_send_string("UART echo test mode\r\n> ");
+    for (; ; )
+    {
+        Board::Uart::send(Board::Uart::recv());
+    }
+}
+
+
 } // anonymous namespace 
 
 
@@ -27,6 +39,5 @@ kernel_entry_point()
     Board::Uart::initialize();
     uart_send_string("Squat entry point\r\n");
 
-    for (; ; )
-        ;
+    uart_echo_test_mode();
 }
blob - 74896d01b6a78d7f2a5bd6bb89926a2e82b31c27
blob + 7663a12da52749a2f572dedb6a5cbed5c08869f6
--- uart_virt.cc
+++ uart_virt.cc
@@ -23,6 +23,7 @@ void initialize()
     Pl011::ControlRegister ControlRegister;
     ControlRegister.m_u.m_Bits.m_UartEnable = 1;
     ControlRegister.m_u.m_Bits.m_TransmitEnable = 1;
+    ControlRegister.m_u.m_Bits.m_ReceiveEnable = 1;
     Hw::write32(UART_BASE + Pl011::CONTROL_REGISTER, ControlRegister.m_u.m_nValue);
 }
 
@@ -42,7 +43,13 @@ void send(uint8_t nValue)
 
 uint8_t recv()
 {
-    return 0;
+    for (; ; )
+    {
+        Pl011::FlagRegister FlagRegister{Hw::read32(UART_BASE + Pl011::FLAG_REGISTER)};
+        if (!FlagRegister.m_u.m_Bits.m_ReceiveFifoEmpty)
+            break;
+    }
+    return Hw::read32(UART_BASE + Pl011::DATA_REGISTER) & 0xff;
 }