From ce199326a184aa4953a35ff3ef0e16088b6591f7 Mon Sep 17 00:00:00 2001
From: Tomer27cz <tomer19cz@gmail.com>
Date: Fri, 23 Jan 2026 21:04:55 +0100
Subject: [PATCH] Improve UART locking and fallback read logic

Refactored XT211Uart to handle cases where the lock is not initialized, preventing null dereference. Added fallback to base read_array for non-hardware UARTs in read_array_quick_, improving compatibility with BLE-backed UARTs.
---
 components/xt211/xt211_uart.h | 41 +++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/components/xt211/xt211_uart.h b/components/xt211/xt211_uart.h
index 591cb8c..f1c2ab8 100644
--- a/components/xt211/xt211_uart.h
+++ b/components/xt211/xt211_uart.h
@@ -85,13 +85,19 @@ class XT211Uart final : public uart::ESP8266UartComponent {
 class XT211Uart final : public uart::IDFUARTComponent {
  public:
   XT211Uart(uart::IDFUARTComponent &uart)
-      : uart_(uart), iuart_num_(uart.*(&XT211Uart::uart_num_)), ilock_(uart.*(&XT211Uart::lock_)) {}
+      : uart_(uart), iuart_num_(uart.*(&XT211Uart::uart_num_)) {}
 
   // Reconfigure baudrate
   void update_baudrate(uint32_t baudrate) {
-    xSemaphoreTake(ilock_, portMAX_DELAY);
-    uart_set_baudrate(iuart_num_, baudrate);
-    xSemaphoreGive(ilock_);
+    auto &lock = uart_.*(&XT211Uart::lock_);
+    if (lock != nullptr) {
+      xSemaphoreTake(lock, portMAX_DELAY);
+      uart_set_baudrate(iuart_num_, baudrate);
+      xSemaphoreGive(lock);
+    } else {
+      // Lock not initialized yet, just set baudrate without locking
+      uart_set_baudrate(iuart_num_, baudrate);
+    }
   }
 
   bool read_one_byte(uint8_t *data) { return read_array_quick_(data, 1); }
@@ -115,23 +121,40 @@ class XT211Uart final : public uart::IDFUARTComponent {
     size_t length_to_read = len;
     if (!this->check_read_timeout_quick_(len))
       return false;
-    xSemaphoreTake(this->ilock_, portMAX_DELAY);
+
+    auto &lock = uart_.*(&XT211Uart::lock_);
+    bool locked = false;
+    if (lock != nullptr) {
+      xSemaphoreTake(lock, portMAX_DELAY);
+      locked = true;
+    }
+
     if (this->has_peek_) {
       length_to_read--;
       *data = this->peek_byte_;
       data++;
       this->has_peek_ = false;
     }
-    if (length_to_read > 0)
-      uart_read_bytes(this->iuart_num_, data, length_to_read, 20 / portTICK_PERIOD_MS);
-    xSemaphoreGive(this->ilock_);
+    if (length_to_read > 0) {
+      // If no valid hardware UART, fall back to base read_array (e.g., BLE-backed UART)
+      if (this->iuart_num_ < UART_NUM_0 || this->iuart_num_ >= UART_NUM_MAX) {
+        if (!uart_.read_array(data, length_to_read)) {
+          return false;
+        }
+      } else {
+        uart_read_bytes(this->iuart_num_, data, length_to_read, 20 / portTICK_PERIOD_MS);
+      }
+    }
+
+    if (locked) {
+      xSemaphoreGive(lock);
+    }
 
     return true;
   }
 
   uart::IDFUARTComponent &uart_;
   uart_port_t iuart_num_;
-  SemaphoreHandle_t &ilock_;
 };
 #endif