1 files changed, 101 insertions, 20 deletions

diff --git a/app/platform/stm32f0-gcc/uart.cpp b/app/platform/stm32f0-gcc/uart.cpp
index 0fa6527..4d9bf5f 100644
--- a/app/platform/stm32f0-gcc/uart.cpp
+++ b/app/platform/stm32f0-gcc/uart.cpp
@@ -1,33 +1,114 @@
 #include "uart.h"
+#include "ring_buffer.h"
 
-size_t UARTWrite(USART_TypeDef* uart, const void *data, size_t nbytes)
+#if defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wold-style-cast"
+#endif
+
+struct UART
+{
+    USART_TypeDef* usart;
+    RingBuffer<uint8_t> rx_buffer;
+    RingBuffer<uint8_t> tx_buffer;
+};
+
+static constexpr size_t kUART1RxBufferSize = 100;
+static constexpr size_t kUART1TxBufferSize = 256;
+static constexpr size_t kUART3RxBufferSize = 256;
+static constexpr size_t kUART3TxBufferSize = 256;
+static constexpr size_t kUART4RxBufferSize = 100;
+static constexpr size_t kUART4TxBufferSize = 100;
+static uint8_t g_uart1_rx_buffer[kUART1RxBufferSize]{};
+static uint8_t g_uart1_tx_buffer[kUART1TxBufferSize]{};
+static uint8_t g_uart3_rx_buffer[kUART3RxBufferSize]{};
+static uint8_t g_uart3_tx_buffer[kUART3TxBufferSize]{};
+static uint8_t g_uart4_rx_buffer[kUART4RxBufferSize]{};
+static uint8_t g_uart4_tx_buffer[kUART4TxBufferSize]{};
+
+UART g_uart1{
+    USART1,
+    RingBuffer<uint8_t>(g_uart1_rx_buffer, kUART1RxBufferSize),
+    RingBuffer<uint8_t>(g_uart1_tx_buffer, kUART1TxBufferSize),
+};
+UART g_uart3{
+    USART3,
+    RingBuffer<uint8_t>(g_uart3_rx_buffer, kUART3RxBufferSize),
+    RingBuffer<uint8_t>(g_uart3_tx_buffer, kUART3TxBufferSize),
+};
+UART g_uart4{
+    USART4,
+    RingBuffer<uint8_t>(g_uart4_rx_buffer, kUART4RxBufferSize),
+    RingBuffer<uint8_t>(g_uart4_tx_buffer, kUART4TxBufferSize),
+};
+
+static constexpr Min(size_t a, size_t b) { return (a >= b) ? a : b; }
+
+size_t UARTWrite(UART* uart, const void *buf, size_t nbytes)
+{
+    if (uart == nullptr || buf == nullptr) return 0;
+    const size_t size = Min(nbytes, uart->tx_buffer.Free());
+    if (size == 0) return 0;
+    uart->tx_buffer.Push(reinterpret_cast<const uint8_t*>(buf), size);
+    uart->usart->CR1 |= USART_CR1_TXEIE;
+    return size;
+}
+
+size_t UARTWriteDirect(UART* uart, const void *buf, size_t nbytes)
 {
-    if (uart == nullptr) return 0;
-    (void) data;
-    (void) nbytes;
-    return 0;
+    if (uart == nullptr || buf == nullptr) return 0;
+    const uint8_t *data = reinterpret_cast<const uint8_t *>(buf);
+    // TODO disable interrupts here
+    for (size_t i = 0; i < nbytes; i++) {
+        while (!(uart->usart->ISR & USART_ISR_TXE));
+        uart->usart->TDR = data[i];
+    }
+    // TODO restore (not just enable) interrupts here
+    return nbytes;
 }
 
-size_t UARTWriteDirect(USART_TypeDef* uart, const void *data, size_t nbytes)
+size_t UARTRead(UART* uart, void *buf, size_t nbytes)
 {
-    if (uart == nullptr) return 0;
-    (void) data;
-    (void) nbytes;
-    return 0;
+    if (uart == nullptr || buf == nullptr) return 0;
+    const size_t size = Min(nbytes, uart->rx_buffer.Occupied());
+    uart->rx_buffer.Pop(reinterpret_cast<uint8_t*>(buf), size);
+    return size;
 }
 
-size_t UARTRead(USART_TypeDef* uart, void *data, size_t nbytes)
+size_t UARTReadDirect(UART* uart, void *buf, size_t nbytes)
 {
-    if (uart == nullptr) return 0;
-    (void) data;
-    (void) nbytes;
-    return 0;
+    if (uart == nullptr || buf == nullptr) return 0;
+    uint8_t *data = reinterpret_cast<uint8_t *>(buf);
+    // TODO disable interrupts here
+    for (size_t i = 0; i < nbytes; i++) {
+        while (!(uart->usart->ISR & USART_ISR_RXNE));
+        data[i] = uart->usart->RDR;
+    }
+    // TODO restore (not just enable) interrupts here
+    return nbytes;
 }
 
-size_t UARTReadDirect(USART_TypeDef* uart, void *data, size_t nbytes)
+void UARTHandleInterrupt(UART* uart)
 {
-    if (uart == nullptr) return 0;
-    (void) data;
-    (void) nbytes;
-    return 0;
+    volatile USART_TypeDef* usart_regs = uart->usart;
+    const uint32_t cr1 = usart_regs->CR1;
+    if ((cr1 & USART_CR1_UE) == 0)
+        return;
+    for (int _ = 0; _ < 256; _++) {
+        const uint32_t isr = usart_regs->ISR;
+        const bool rxne = isr & USART_ISR_RXNE;
+        const bool txe = isr & USART_ISR_TXE;
+        if (!rxne && !txe)
+            break;
+        if (rxne) {
+            uart->rx_buffer.Push(usart_regs->RDR);
+        }
+        if (txe) {
+            if (!uart->tx_buffer.IsEmpty()) {
+                usart_regs->TDR = uart->tx_buffer.Pop();
+            } else {
+                usart_regs->CR1 &= ~USART_CR1_TXEIE;
+            }
+        }
+    }
 }