Add a UART keyboard and mouse driver

.editorconfig

@@ -2,7 +2,7 @@ root = true
 
 [*]
 charset = utf-8
-indent_size = 4
+indent_size = 2
 indent_style = space
 trim_trailing_whitespace = true
 insert_final_newline = true

README.md

@@ -24,6 +24,15 @@ cmake -S . -Bbuild -DGCC_PREFIX=aarch64-linux-gnu- --toolchain=cmake/GCCToolchai
 make -j -C build kernel-img
 ```
 
+Or (for Clang):
+```shell
+# Change -17 by whatever version of Clang is installed on your system (or use nothing to call `clang` as is).
+cmake -S . -Bbuild -DCLANG_SUFFIX=-17 --toolchain=cmake/ClangToolchain.cmake
+make -j -C build kernel-img
+```
+
+You should specify `-DTARGET_QEMU=ON` when configuring CMake if you intend to build an image for QEMU.
+
 ## Testing the kernel
 
 You can either run the kernel on real Raspberry PI (at least version 3 required) hardware.
@@ -43,7 +52,24 @@ Then to run the kernel, just type:
 
 ```shell
 # You may need to change qemu-system-aarch64 by whatever is QEMU for aarch64 is named on your computer.
-qemu-system-aarch64 -M raspi3b -serial stdio -kernel build/kernel/kernel8.img -dtb doc/DeviceTree/pi3.dtb -device loader,file=build/binfs/fs.img,addr=0x18000000,force-raw=on
+qemu-system-aarch64 \
+    -M raspi3b \
+    -serial pipe:/tmp/uart-input \
+    -serial stdio \
+    -kernel build/kernel/kernel8.img \
+    -dtb doc/DeviceTree/pi3.dtb \
+    -device loader,file=build/binuser/fs.img,addr=0x18000000,force-raw=on
+```
+and launch `python tools/uart-input-server.py` (for the UART keyboard and mouse driver).
+
+If you don't want to use the UART keyboard and mouse driver (you will probably need to modify kernel.cpp):
+```shell
+qemu-system-aarch64 \
+    -M raspi3b \
+    -serial stdio \
+    -kernel build/kernel/kernel8.img \
+    -dtb doc/DeviceTree/pi3.dtb \
+    -device loader,file=build/binuser/fs.img,addr=0x18000000,force-raw=on
 ```
 
 ## The userspace file structure

kernel/CMakeLists.txt

@@ -82,8 +82,8 @@ add_executable(kernel
         hardware/ps2_keyboard.cpp
         hardware/ps2_keyboard.hpp
 
-        hardware/ps2_keyboard.cpp
-        hardware/ps2_keyboard.hpp
+        hardware/uart_keyboard.cpp
+        hardware/uart_keyboard.hpp
 
         # IRQ
         hardware/irq/bcm2837_irq_manager.hpp
@@ -160,6 +160,12 @@ add_executable(kernel
         wm/data/pika_icon.hpp
         wm/data/pika_icon.cpp
 
+        # Input management
+        input/keyboard_input.hpp
+        input/keyboard_input.cpp
+        input/mouse_input.hpp
+        input/mouse_input.cpp
+
         # Filesystem
         fs/filesystem.hpp
         fs/filesystem.cpp

kernel/boot/startup.cpp

@@ -96,7 +96,7 @@ extern "C" void _startup(uintptr_t dtb) {
   GPIO::init();
 
   // Try to initialize UART early as possible.
-  UART log(1000000);  // Set to a High Baud-rate, otherwise UART is THE bottleneck :/
+  UART log(1000000, "uart1", /* irqs= */false);  // Set to a High Baud-rate, otherwise UART is THE bottleneck :/
   libk::register_logger(log);
 
   // Set up the System Timer

kernel/hardware/kernel_dt.cpp

@@ -211,7 +211,7 @@ uintptr_t KernelDT::convert_soc_address(uintptr_t soc_address) {
 uintptr_t KernelDT::force_get_device_address(libk::StringView device) {
   uintptr_t device_address;
   if (!KernelDT::get_device_address(device, &device_address)) {
-    LOG_ERROR("Unable to retrieved {} address.", device);
+    LOG_ERROR("Unable to retrieve {} address.", device);
     libk::panic("Kernel Device Tree Fatal Error.");
   }
 

kernel/hardware/ps2_keyboard.cpp

@@ -256,6 +256,8 @@ void init() {
   GPIO::set_event_callback(CLOCK_PIN, &gpio_clock_handler);
 
   GPIO::set_falling_edge_async_detect(CLOCK_PIN, true);
+
+  LOG_INFO("PS/2 keyboard driver initialized");
 }
 
 void set_on_event(Event ev) {

kernel/hardware/uart.cpp

@@ -6,55 +6,59 @@
 #include "hardware/mailbox.hpp"
 #include "kernel_dt.hpp"
 
-/** UART0 Data Register (size: 32) */
+/** UART Data Register (size: 32) */
 static inline constexpr int UART_DR = 0x0;
 
-/** UART0 Flag Register (size: 32) */
+/** UART Flag Register (size: 32) */
 static inline constexpr int UART_FR = 0x18;
 
-/** UART0 Integer Baud rate divisor (size: 32) */
+/** UART Integer Baud rate divisor (size: 32) */
 static inline constexpr int UART_IBRD = 0x24;
 
-/** UART0 Fractional Baud rate divisor (size: 32) */
+/** UART Fractional Baud rate divisor (size: 32) */
 static inline constexpr int UART_FBRD = 0x28;
 
-/** UART0 Line Control Register (size: 32) */
+/** UART Line Control Register (size: 32) */
 static inline constexpr int UART_LCRH = 0x2c;
 
-/** UART0 Control Register (size: 32) */
+/** UART Control Register (size: 32) */
 static inline constexpr int UART_CR = 0x30;
 
-/** UART0 Interrupt FIFO Level Select Register (size: 32) */
+/** UART Interrupt FIFO Level Select Register (size: 32) */
 // static inline constexpr int UART_IFLS = 0x34;
 
-/** UART0 Interrupt Mask Set Clear Register (size: 32) */
-// static inline constexpr int UART_IMSC = 0x38;
+/** UART Interrupt Mask Set Clear Register (size: 32) */
+static inline constexpr int UART_IMSC = 0x38;
 
-/** UART0 Raw Interrupt Status Register (size: 32) */
+/** UART Raw Interrupt Status Register (size: 32) */
 // static inline constexpr int UART_RIS = 0x3c;
 
-/** UART0 Masked Interrupt Status Register (size: 32) */
+/** UART Masked Interrupt Status Register (size: 32) */
 // static inline constexpr int UART_MIS = 0x40;
 
-/** UART0 Interrupt Clear Register (size: 32) */
+/** UART Interrupt Clear Register (size: 32) */
 // static inline constexpr int UART_ICR = 0x44;
 
-/** UART0 DMA Control Register (size: 32) */
+/** UART DMA Control Register (size: 32) */
 // static inline constexpr int UART_DMACR = 0x48;
 
-/** UART0 Test Control Register (size: 32) */
+/** UART Test Control Register (size: 32) */
 // static inline constexpr int UART_ITCR = 0x80;
 
-/** UART0 Integration Test Input Register (size: 32) */
+/** UART Integration Test Input Register (size: 32) */
 // static inline constexpr int UART_ITIP = 0x84;
 
-/** UART0 Integration Test Output Register (size: 32) */
+/** UART Integration Test Output Register (size: 32) */
 // static inline constexpr int UART_ITOP = 0x88;
 
-/** UART0 Test Data Register (size: 32) */
+/** UART Test Data Register (size: 32) */
 // static inline constexpr int UART_TDR = 0x8c;
 
-UART::UART(uint32_t baud_rate) : _uart_base(KernelDT::force_get_device_address("uart0")) {
+UART::UART(uint32_t baud_rate, libk::StringView name, bool enabling_irqs)
+    : _uart_base(KernelDT::force_get_device_address(name)) {
+  // We don't yet support IRQs for UART1 (UART1 is a bit different from the others).
+  KASSERT(!enabling_irqs || name != "uart1");
+
   // Get the UART Clock
   uint32_t uart_clock = Device::get_clock_rate(Device::UART);
 
@@ -78,11 +82,24 @@ UART::UART(uint32_t baud_rate) : _uart_base(KernelDT::force_get_device_address("
 
   // Enable UART0, receive & transfer part of UART.
   libk::write32(_uart_base + UART_CR, (1 << 0) | (1 << 8) | (1 << 9));
+
+  if (enabling_irqs) {
+    // Enable IRQs
+    libk::write32(_uart_base + UART_IMSC, (1 << 1) | (1 << 4));
+  }
+}
+
+bool UART::is_fifo_empty() const {
+  return (libk::read32(_uart_base + UART_FR) & (1 << 4)) != 0;
+}
+
+bool UART::is_fifo_full() const {
+  return (libk::read32(_uart_base + UART_FR) & (1 << 5)) != 0;
 }
 
 void UART::write_one(char value) const {
   // Wait for UART to become ready to transmit.
-  while ((libk::read32(_uart_base + UART_FR) & (1 << 5)) != 0) {
+  while (is_fifo_full()) {
     libk::yield();
   }
 
@@ -91,7 +108,7 @@ void UART::write_one(char value) const {
 
 char UART::read_one() const {
   // Wait for UART to have received something.
-  while ((libk::read32(_uart_base + UART_FR) & (1 << 4)) != 0) {
+  while (is_fifo_empty()) {
     libk::yield();
   }
 

kernel/hardware/uart.hpp

@@ -24,7 +24,12 @@ class UART : public libk::Logger {
    *  - 1500000 [Tested]
    *  - 2000000 [Tested]
    */
-  explicit UART(uint32_t baud_rate);
+  explicit UART(uint32_t baud_rate, libk::StringView name = "uart0", bool enabling_irqs = false);
+
+  /** Returns true if the UART FIFO is empty (aka cannot read anymore from it). */
+  [[nodiscard]] bool is_fifo_empty() const;
+  /** Returns true if the UART FIFO is full (aka cannot write anymore to it). */
+  [[nodiscard]] bool is_fifo_full() const;
 
   /** Writes the given @a value into this UART. */
   void write_one(char value) const;

kernel/hardware/uart_keyboard.cpp

@@ -0,0 +1,71 @@
+#include "uart_keyboard.hpp"
+#include "hardware/irq/irq_lists.hpp"
+#include "hardware/irq/irq_manager.hpp"
+#include "input/keyboard_input.hpp"
+#include "input/mouse_input.hpp"
+
+namespace UARTKeyboard {
+UART* keyboard_uart = nullptr;
+
+void init(UART* uart) {
+  KASSERT(uart != nullptr);
+  keyboard_uart = uart;
+
+  IRQManager::register_irq_handler(
+      VC_UART,
+      [](void*) {
+        if (keyboard_uart->is_fifo_empty())
+          return;
+
+        uint8_t header = (uint8_t)keyboard_uart->read_one();
+
+        switch (header & 0xF) {
+          case 0x1:  // mouse move
+          {
+            uint8_t dx_mag = (uint8_t)keyboard_uart->read_one();
+            uint8_t dy_mag = (uint8_t)keyboard_uart->read_one();
+
+            int16_t dx = dx_mag;
+            int16_t dy = dy_mag;
+
+            if ((header & (1 << 4)) != 0)
+              dx = -dx;
+            if ((header & (1 << 5)) != 0)
+              dy = -dy;
+
+            MouseSystem::notify_hardware_move_event(dx, dy);
+          } break;
+          case 0x2:  // mouse click
+          {
+            uint8_t button = (uint8_t)keyboard_uart->read_one();
+          } break;
+          case 0x3:  // mouse scroll
+          {
+            uint8_t dx_mag = (uint8_t)keyboard_uart->read_one();
+            uint8_t dy_mag = (uint8_t)keyboard_uart->read_one();
+
+            int16_t dx = dx_mag;
+            int16_t dy = dy_mag;
+
+            if (header & (1 << 4) != 0)
+              dx = -dx;
+            if (header & (1 << 5) != 0)
+              dy = -dy;
+
+            MouseSystem::notify_hardware_scroll_event(dx, dy);
+          } break;
+          case 0x4:  // key press/release
+          {
+            uint16_t key;
+            keyboard_uart->read((char*)&key, sizeof(key));
+
+            bool is_pressed = (header & (1 << 4)) != 0;
+            KeyboardSystem::notify_hardware_event((sys_key_code_t)key, is_pressed);
+          } break;
+        }
+      },
+      nullptr);
+
+  LOG_INFO("UART keyboard & mouse driver initialized");
+}
+}  // namespace UARTKeyboard

kernel/hardware/uart_keyboard.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include <cstdint>
+#include "hardware/uart.hpp"
+
+namespace UARTKeyboard {
+void init(UART* uart);
+}  // namespace UARTKeyboard