sync(template): 回合 capsule_mb 通用驱动修复

- uart_ring_buffer: PRIMASK 位检查从 ==0 改为 &0x1 修正
- i2c: 新增 i2c_read_raw() 无子地址读函数
- 全局: volatile 统一替换为 __IO (CMSIS 风格)

Src/uart_ring_buffer.c

@@ -8,10 +8,10 @@
 #include "uart_ring_buffer.h"
 #include "gd32e23x.h"
 
-static volatile uint8_t uart_rx_buffer[UART_RX_BUFFER_SIZE];
-static volatile uint8_t write_index = 0;
-static volatile uint8_t read_index = 0;
-static volatile uint32_t dropped_bytes = 0;
+static __IO uint8_t uart_rx_buffer[UART_RX_BUFFER_SIZE];
+static __IO uint8_t write_index = 0;
+static __IO uint8_t read_index = 0;
+static __IO uint32_t dropped_bytes = 0;
 
 static inline uint32_t irq_save(void) {
     uint32_t primask = __get_PRIMASK();
@@ -20,7 +20,7 @@ static inline uint32_t irq_save(void) {
 }
 
 static inline void irq_restore(uint32_t primask) {
-    if (primask == 0U) {
+    if ((primask & 0x1) == 0) {
         __enable_irq();
     }
 }
@@ -44,9 +44,9 @@ static void uart_ring_buffer_reset_state(void) {
  * @ingroup RingBuffer
  */
 void uart_ring_buffer_init(void) {
-    uint32_t irq_key = irq_save();
+    uint32_t primask = irq_save();
     uart_ring_buffer_reset_state();
-    irq_restore(irq_key);
+    irq_restore(primask);
 }
 
 /**
@@ -105,9 +105,9 @@ bool uart_ring_buffer_put(uint8_t data) {
  * @ingroup RingBuffer
  */
 void uart_ring_buffer_clear(void) {
-    uint32_t irq_key = irq_save();
+    uint32_t primask = irq_save();
     uart_ring_buffer_reset_state();
-    irq_restore(irq_key);
+    irq_restore(primask);
 }
 
 /**