fix: harden ch390 recovery primitives

Drivers/CH390/CH390.c

@@ -12,6 +12,25 @@
 #include "CH390.h"
 #include "CH390_Interface.h"
 
+#define CH390_EPCR_POLL_LIMIT 100000u
+
+static int ch390_wait_epcr_ready(void)
+{
+    uint32_t poll_count = CH390_EPCR_POLL_LIMIT;
+
+    while ((ch390_read_reg(CH390_EPCR) & 0x01u) != 0u)
+    {
+        if (poll_count == 0u)
+        {
+            ch390_write_reg(CH390_EPCR, 0x00u);
+            return -1;
+        }
+        --poll_count;
+    }
+
+    return 0;
+}
+
 void ch390_probe_rx_header(uint8_t *head)
 {
     if (head == 0)
@@ -22,6 +41,46 @@ void ch390_probe_rx_header(uint8_t *head)
     ch390_read_mem(head, 4);
 }
 
+int ch390_peek_packet(uint8_t *rx_status, uint16_t *rx_len)
+{
+    uint8_t nsr;
+    uint8_t header[4];
+    uint16_t mrr;
+
+    if (rx_status != 0)
+    {
+        *rx_status = 0u;
+    }
+
+    if (rx_len != 0)
+    {
+        *rx_len = 0u;
+    }
+
+    nsr = ch390_read_reg(CH390_NSR);
+    if ((nsr & NSR_RXRDY) == 0u)
+    {
+        return 0;
+    }
+
+    mrr = (uint16_t)ch390_read_mrrl() | ((uint16_t)ch390_read_mrrh() << 8);
+    ch390_read_mem(header, 4);
+    ch390_write_reg(CH390_MRRL, (uint8_t)(mrr & 0xffu));
+    ch390_write_reg(CH390_MRRH, (uint8_t)((mrr >> 8) & 0xffu));
+
+    if (rx_status != 0)
+    {
+        *rx_status = header[1];
+    }
+
+    if (rx_len != 0)
+    {
+        *rx_len = (uint16_t)header[2] | ((uint16_t)header[3] << 8);
+    }
+
+    return 1;
+}
+
 /**
  * @name ch390_receive_packet
  * @brief Receive packet
@@ -125,6 +184,16 @@ void ch390_drop_packet(uint16_t len)
     ch390_write_reg(CH390_MRRH, (mdr >> 8) & 0xff);
 }
 
+void ch390_rx_reset(void)
+{
+    uint8_t rcr = ch390_read_reg(CH390_RCR);
+
+    ch390_write_reg(CH390_RCR, (uint8_t)(rcr & (uint8_t)(~RCR_RXEN)));
+    ch390_write_reg(CH390_NSR, NSR_RXOV);
+    ch390_write_reg(CH390_ISR, (uint8_t)(ISR_ROS | ISR_ROO | ISR_PR));
+    ch390_write_reg(CH390_RCR, (uint8_t)(rcr | RCR_RXEN));
+}
+
 /**
  * @name ch390_read_phy
  * @brief Read PHY register
@@ -135,7 +204,10 @@ uint16_t ch390_read_phy(uint8_t reg)
     ch390_write_reg(CH390_EPAR, CH390_PHY | reg);
     // Chose PHY, send read command
     ch390_write_reg(CH390_EPCR, EPCR_ERPRR | EPCR_EPOS);
-    while(ch390_read_reg(CH390_EPCR) & 0x01);
+    if (ch390_wait_epcr_ready() != 0)
+    {
+        return 0xFFFFu;
+    }
     // Clear read command
     ch390_write_reg(CH390_EPCR, 0x00);
     return (ch390_read_reg(CH390_EPDRH) << 8) |
@@ -155,7 +227,10 @@ void ch390_write_phy(uint8_t reg, uint16_t value)
     ch390_write_reg(CH390_EPDRH, ((value >> 8) & 0xff)); // High byte
     // Chose PHY, send write command
     ch390_write_reg(CH390_EPCR, 0x0A);
-    while(ch390_read_reg(CH390_EPCR) & 0x01);
+    if (ch390_wait_epcr_ready() != 0)
+    {
+        return;
+    }
     // Clear write command
     ch390_write_reg(CH390_EPCR, 0x00);
 }
@@ -173,7 +248,10 @@ void ch390_write_eeprom(uint8_t reg, uint16_t value)
     ch390_write_reg(CH390_EPDRH, ((value >> 8) & 0xff)); // High byte
     // Chose EEPROM, send write command
     ch390_write_reg(CH390_EPCR, EPCR_ERPRW);
-    while(ch390_read_reg(CH390_EPCR) & 0x01);
+    if (ch390_wait_epcr_ready() != 0)
+    {
+        return;
+    }
     // Clear write command
     ch390_write_reg(CH390_EPCR, 0x00);
 }

Drivers/CH390/CH390.h

@@ -657,6 +657,21 @@ int ch390_runtime_link_up_from_status(const struct ch390_runtime_status *status)
  */
 void ch390_probe_rx_header(uint8_t *head);
 
+/**
+ * @name ch390_peek_packet
+ * @brief Peek current RX header without consuming the packet.
+ * @param rx_status - Output abnormal status while receiving packet
+ * @param rx_len - Output packet length from RX header
+ * @return 0: no packet pending  1: header sampled
+ */
+int ch390_peek_packet(uint8_t *rx_status, uint16_t *rx_len);
+
+/**
+ * @name ch390_rx_reset
+ * @brief Repair RX datapath after overflow/corruption without full chip reset.
+ */
+void ch390_rx_reset(void);
+
 /**
  * @name ch390_runtime_receive_packet
  * @brief Runtime RX entry point for packet receive