docs: record v1.1.1 dirty-network recovery design

Document the AT+BAUD flow in the debug guide, including U0/U1 data-port mapping and the save/reset behavior required for USART2/USART3 baud changes.

App/tcp_client.c

@@ -17,7 +17,10 @@ typedef struct {
     uint8_t rx_ring[TCP_CLIENT_RX_BUFFER_SIZE];
     uint16_t rx_head;
     uint16_t rx_tail;
+    struct pbuf *hold_pbuf;
+    uint16_t hold_offset;
     uint32_t next_retry_ms;
+    uint32_t connect_start_ms;
     uint8_t index;
     tcp_client_instance_config_t config;
     tcp_client_status_t status;
@@ -30,10 +33,95 @@ static uint16_t ring_free(uint16_t head, uint16_t tail, uint16_t size)
     return (head >= tail) ? (uint16_t)(size - head + tail - 1u) : (uint16_t)(tail - head - 1u);
 }
 
+static uint16_t ring_used(uint16_t head, uint16_t tail, uint16_t size)
+{
+    return (head >= tail) ? (uint16_t)(head - tail) : (uint16_t)(size - tail + head);
+}
+
+static bool tick_reached(uint32_t now, uint32_t deadline)
+{
+    return ((int32_t)(now - deadline) >= 0);
+}
+
+static void tcp_client_reset_rx_state(tcp_client_ctx_t *ctx)
+{
+    if (ctx == NULL) {
+        return;
+    }
+    if (ctx->hold_pbuf != NULL) {
+        pbuf_free(ctx->hold_pbuf);
+        ctx->hold_pbuf = NULL;
+    }
+    ctx->hold_offset = 0u;
+    ctx->rx_head = 0u;
+    ctx->rx_tail = 0u;
+}
+
+static void tcp_client_abort_connect_timeout(tcp_client_ctx_t *ctx, uint32_t now)
+{
+    if (ctx == NULL) {
+        return;
+    }
+
+    if (ctx->pcb != NULL) {
+        tcp_arg(ctx->pcb, NULL);
+        tcp_recv(ctx->pcb, NULL);
+        tcp_sent(ctx->pcb, NULL);
+        tcp_err(ctx->pcb, NULL);
+        tcp_client_reset_rx_state(ctx);
+        tcp_abort(ctx->pcb);
+        ctx->pcb = NULL;
+    } else {
+        tcp_client_reset_rx_state(ctx);
+    }
+
+    ctx->connect_start_ms = 0u;
+    ctx->status.state = TCP_CLIENT_STATE_DISCONNECTED;
+    ctx->status.errors++;
+    ctx->status.connect_timeout_count++;
+    ctx->next_retry_ms = now + ctx->config.reconnect_interval_ms;
+}
+
+static void tcp_client_fill_ring_from_pbuf(tcp_client_ctx_t *ctx)
+{
+    struct pbuf *q;
+    uint16_t offset;
+
+    if (ctx == NULL || ctx->hold_pbuf == NULL) {
+        return;
+    }
+
+    q = ctx->hold_pbuf;
+    offset = ctx->hold_offset;
+    while (q != NULL && offset >= q->len) {
+        offset = (uint16_t)(offset - q->len);
+        q = q->next;
+    }
+
+    while (q != NULL) {
+        const uint8_t *src = (const uint8_t *)q->payload;
+        for (uint16_t i = offset; i < q->len; ++i) {
+            if (ring_free(ctx->rx_head, ctx->rx_tail, TCP_CLIENT_RX_BUFFER_SIZE) == 0u) {
+                ctx->hold_offset = (uint16_t)(ctx->hold_offset + i - offset);
+                return;
+            }
+            ctx->rx_ring[ctx->rx_head] = src[i];
+            ctx->rx_head = (uint16_t)((ctx->rx_head + 1u) % TCP_CLIENT_RX_BUFFER_SIZE);
+            ctx->status.rx_bytes++;
+        }
+        ctx->hold_offset = (uint16_t)(ctx->hold_offset + q->len - offset);
+        offset = 0u;
+        q = q->next;
+    }
+
+    pbuf_free(ctx->hold_pbuf);
+    ctx->hold_pbuf = NULL;
+    ctx->hold_offset = 0u;
+}
+
 static err_t tcp_client_on_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
 {
     tcp_client_ctx_t *ctx = (tcp_client_ctx_t *)arg;
-    struct pbuf *q;
 
     if (ctx == NULL) {
         if (p != NULL) {
@@ -54,26 +142,22 @@ static err_t tcp_client_on_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p,
         tcp_err(pcb, NULL);
         tcp_abort(pcb);
         ctx->pcb = NULL;
+        ctx->connect_start_ms = 0u;
         ctx->status.state = TCP_CLIENT_STATE_DISCONNECTED;
         ctx->next_retry_ms = HAL_GetTick() + ctx->config.reconnect_interval_ms;
         return ERR_ABRT;
     }
 
-    for (q = p; q != NULL; q = q->next) {
-        const uint8_t *src = (const uint8_t *)q->payload;
-        for (uint16_t i = 0; i < q->len; ++i) {
-            if (ring_free(ctx->rx_head, ctx->rx_tail, TCP_CLIENT_RX_BUFFER_SIZE) == 0u) {
-                ctx->status.errors++;
-                break;
-            }
-            ctx->rx_ring[ctx->rx_head] = src[i];
-            ctx->rx_head = (uint16_t)((ctx->rx_head + 1u) % TCP_CLIENT_RX_BUFFER_SIZE);
-            ctx->status.rx_bytes++;
-        }
+    if (ctx->hold_pbuf != NULL) {
+        ctx->status.errors++;
+        return ERR_MEM;
     }
 
-    tcp_recved(pcb, p->tot_len);
+    pbuf_ref(p);
+    ctx->hold_pbuf = p;
+    ctx->hold_offset = 0u;
     pbuf_free(p);
+    tcp_client_fill_ring_from_pbuf(ctx);
     return ERR_OK;
 }
 
@@ -93,7 +177,9 @@ static void tcp_client_on_err(void *arg, err_t err)
     if (ctx == NULL) {
         return;
     }
+    tcp_client_reset_rx_state(ctx);
     ctx->pcb = NULL;
+    ctx->connect_start_ms = 0u;
     ctx->status.state = TCP_CLIENT_STATE_DISCONNECTED;
     ctx->status.errors++;
     ctx->next_retry_ms = HAL_GetTick() + ctx->config.reconnect_interval_ms;
@@ -109,6 +195,7 @@ static err_t tcp_client_on_connected(void *arg, struct tcp_pcb *pcb, err_t err)
     }
     if (err != ERR_OK) {
         ctx->pcb = NULL;
+        ctx->connect_start_ms = 0u;
         ctx->status.state = TCP_CLIENT_STATE_DISCONNECTED;
         ctx->status.errors++;
         ctx->next_retry_ms = HAL_GetTick() + ctx->config.reconnect_interval_ms;
@@ -116,6 +203,7 @@ static err_t tcp_client_on_connected(void *arg, struct tcp_pcb *pcb, err_t err)
     }
 
     ctx->pcb = pcb;
+    ctx->connect_start_ms = 0u;
     ctx->status.state = TCP_CLIENT_STATE_CONNECTED;
     tcp_nagle_disable(pcb);
     tcp_arg(pcb, ctx);
@@ -175,6 +263,7 @@ int tcp_client_connect(uint8_t instance)
         if (err != ERR_OK) {
             tcp_abort(pcb);
             ctx->status.state = TCP_CLIENT_STATE_DISCONNECTED;
+            ctx->connect_start_ms = 0u;
             ctx->status.errors++;
             ctx->next_retry_ms = HAL_GetTick() + ctx->config.reconnect_interval_ms;
             return -1;
@@ -188,6 +277,7 @@ int tcp_client_connect(uint8_t instance)
              ctx->config.remote_ip[3]);
 
     ctx->status.state = TCP_CLIENT_STATE_CONNECTING;
+    ctx->connect_start_ms = HAL_GetTick();
     tcp_arg(pcb, ctx);
     tcp_err(pcb, tcp_client_on_err);
     err = tcp_connect(pcb, &remote_addr, ctx->config.remote_port, tcp_client_on_connected);
@@ -195,6 +285,7 @@ int tcp_client_connect(uint8_t instance)
         tcp_err(pcb, NULL);
         tcp_abort(pcb);
         ctx->status.state = TCP_CLIENT_STATE_DISCONNECTED;
+        ctx->connect_start_ms = 0u;
         ctx->status.errors++;
         ctx->next_retry_ms = HAL_GetTick() + ctx->config.reconnect_interval_ms;
         return -1;
@@ -213,6 +304,7 @@ int tcp_client_disconnect(uint8_t instance)
     }
     ctx = &g_clients[instance];
     if (ctx->pcb != NULL) {
+        tcp_client_reset_rx_state(ctx);
         tcp_arg(ctx->pcb, NULL);
         tcp_recv(ctx->pcb, NULL);
         tcp_sent(ctx->pcb, NULL);
@@ -220,9 +312,9 @@ int tcp_client_disconnect(uint8_t instance)
         tcp_abort(ctx->pcb);
         ctx->pcb = NULL;
     }
+    ctx->connect_start_ms = 0u;
     ctx->status.state = TCP_CLIENT_STATE_DISCONNECTED;
-    ctx->rx_head = 0u;
-    ctx->rx_tail = 0u;
+    tcp_client_reset_rx_state(ctx);
     return 0;
 }
 
@@ -272,13 +364,71 @@ int tcp_client_recv(uint8_t instance, uint8_t *data, uint16_t max_len)
         return -1;
     }
     ctx = &g_clients[instance];
+    tcp_client_fill_ring_from_pbuf(ctx);
     while (copied < max_len && ctx->rx_tail != ctx->rx_head) {
         data[copied++] = ctx->rx_ring[ctx->rx_tail];
         ctx->rx_tail = (uint16_t)((ctx->rx_tail + 1u) % TCP_CLIENT_RX_BUFFER_SIZE);
     }
+    if (copied > 0u && ctx->pcb != NULL) {
+        tcp_recved(ctx->pcb, copied);
+    }
     return (int)copied;
 }
 
+uint16_t tcp_client_rx_available(uint8_t instance)
+{
+    if (instance >= TCP_CLIENT_INSTANCE_COUNT) {
+        return 0u;
+    }
+    tcp_client_fill_ring_from_pbuf(&g_clients[instance]);
+    return ring_used(g_clients[instance].rx_head, g_clients[instance].rx_tail, TCP_CLIENT_RX_BUFFER_SIZE);
+}
+
+uint16_t tcp_client_peek(uint8_t instance, uint8_t *data, uint16_t max_len)
+{
+    uint16_t copied = 0u;
+    uint16_t tail;
+    tcp_client_ctx_t *ctx;
+
+    if (instance >= TCP_CLIENT_INSTANCE_COUNT || data == NULL || max_len == 0u) {
+        return 0u;
+    }
+
+    ctx = &g_clients[instance];
+    tcp_client_fill_ring_from_pbuf(ctx);
+    tail = ctx->rx_tail;
+    while (copied < max_len && tail != ctx->rx_head) {
+        data[copied++] = ctx->rx_ring[tail];
+        tail = (uint16_t)((tail + 1u) % TCP_CLIENT_RX_BUFFER_SIZE);
+    }
+    return copied;
+}
+
+void tcp_client_drop(uint8_t instance, uint16_t len)
+{
+    tcp_client_ctx_t *ctx;
+    uint16_t acked = 0u;
+
+    if (instance >= TCP_CLIENT_INSTANCE_COUNT || len == 0u) {
+        return;
+    }
+
+    ctx = &g_clients[instance];
+    while (acked < len) {
+        tcp_client_fill_ring_from_pbuf(ctx);
+        if (ctx->rx_tail == ctx->rx_head) {
+            break;
+        }
+        while (acked < len && ctx->rx_tail != ctx->rx_head) {
+            ctx->rx_tail = (uint16_t)((ctx->rx_tail + 1u) % TCP_CLIENT_RX_BUFFER_SIZE);
+            acked++;
+        }
+    }
+    if (acked > 0u && ctx->pcb != NULL) {
+        tcp_recved(ctx->pcb, acked);
+    }
+}
+
 bool tcp_client_is_connected(uint8_t instance)
 {
     return (instance < TCP_CLIENT_INSTANCE_COUNT) &&
@@ -299,13 +449,17 @@ void tcp_client_poll(void)
 
     for (uint8_t i = 0; i < TCP_CLIENT_INSTANCE_COUNT; ++i) {
         tcp_client_ctx_t *ctx = &g_clients[i];
+        tcp_client_fill_ring_from_pbuf(ctx);
         if (!ctx->config.enabled || !ctx->config.auto_reconnect || tcp_client_is_connected(i)) {
             continue;
         }
         if ((ctx->pcb != NULL) && (ctx->status.state == TCP_CLIENT_STATE_CONNECTING)) {
+            if ((uint32_t)(now - ctx->connect_start_ms) >= TCP_CLIENT_CONNECT_TIMEOUT_MS) {
+                tcp_client_abort_connect_timeout(ctx, now);
+            }
             continue;
         }
-        if (now >= ctx->next_retry_ms) {
+        if (tick_reached(now, ctx->next_retry_ms)) {
             ctx->status.reconnect_count++;
             ctx->next_retry_ms = now + ctx->config.reconnect_interval_ms;
             (void)tcp_client_connect(i);

App/tcp_client.h

@@ -14,8 +14,9 @@ extern "C" {
 #endif
 
 #define TCP_CLIENT_INSTANCE_COUNT      2u
-#define TCP_CLIENT_RX_BUFFER_SIZE      512u
+#define TCP_CLIENT_RX_BUFFER_SIZE      480u
 #define TCP_CLIENT_RECONNECT_DELAY_MS  3000u
+#define TCP_CLIENT_CONNECT_TIMEOUT_MS  10000u
 
 typedef enum {
     TCP_CLIENT_STATE_IDLE = 0,
@@ -39,6 +40,7 @@ typedef struct {
     uint32_t rx_bytes;
     uint32_t tx_bytes;
     uint32_t reconnect_count;
+    uint32_t connect_timeout_count;
     uint32_t errors;
 } tcp_client_status_t;
 
@@ -48,6 +50,9 @@ int tcp_client_connect(uint8_t instance);
 int tcp_client_disconnect(uint8_t instance);
 int tcp_client_send(uint8_t instance, const uint8_t *data, uint16_t len);
 int tcp_client_recv(uint8_t instance, uint8_t *data, uint16_t max_len);
+uint16_t tcp_client_rx_available(uint8_t instance);
+uint16_t tcp_client_peek(uint8_t instance, uint8_t *data, uint16_t max_len);
+void tcp_client_drop(uint8_t instance, uint16_t len);
 bool tcp_client_is_connected(uint8_t instance);
 void tcp_client_get_status(uint8_t instance, tcp_client_status_t *status);
 void tcp_client_poll(void);

App/tcp_server.c

@@ -18,6 +18,8 @@ typedef struct {
     uint8_t rx_ring[TCP_SERVER_RX_BUFFER_SIZE];
     uint16_t rx_head;
     uint16_t rx_tail;
+    struct pbuf *hold_pbuf;
+    uint16_t hold_offset;
     uint8_t index;
     tcp_server_instance_config_t config;
     tcp_server_status_t status;
@@ -30,10 +32,65 @@ static uint16_t ring_free(uint16_t head, uint16_t tail, uint16_t size)
     return (head >= tail) ? (uint16_t)(size - head + tail - 1u) : (uint16_t)(tail - head - 1u);
 }
 
+static uint16_t ring_used(uint16_t head, uint16_t tail, uint16_t size)
+{
+    return (head >= tail) ? (uint16_t)(head - tail) : (uint16_t)(size - tail + head);
+}
+
+static void tcp_server_reset_rx_state(tcp_server_ctx_t *ctx)
+{
+    if (ctx == NULL) {
+        return;
+    }
+    if (ctx->hold_pbuf != NULL) {
+        pbuf_free(ctx->hold_pbuf);
+        ctx->hold_pbuf = NULL;
+    }
+    ctx->hold_offset = 0u;
+    ctx->rx_head = 0u;
+    ctx->rx_tail = 0u;
+}
+
+static void tcp_server_fill_ring_from_pbuf(tcp_server_ctx_t *ctx)
+{
+    struct pbuf *q;
+    uint16_t offset;
+
+    if (ctx == NULL || ctx->hold_pbuf == NULL) {
+        return;
+    }
+
+    q = ctx->hold_pbuf;
+    offset = ctx->hold_offset;
+    while (q != NULL && offset >= q->len) {
+        offset = (uint16_t)(offset - q->len);
+        q = q->next;
+    }
+
+    while (q != NULL) {
+        const uint8_t *src = (const uint8_t *)q->payload;
+        for (uint16_t i = offset; i < q->len; ++i) {
+            if (ring_free(ctx->rx_head, ctx->rx_tail, TCP_SERVER_RX_BUFFER_SIZE) == 0u) {
+                ctx->hold_offset = (uint16_t)(ctx->hold_offset + i - offset);
+                return;
+            }
+            ctx->rx_ring[ctx->rx_head] = src[i];
+            ctx->rx_head = (uint16_t)((ctx->rx_head + 1u) % TCP_SERVER_RX_BUFFER_SIZE);
+            ctx->status.rx_bytes++;
+        }
+        ctx->hold_offset = (uint16_t)(ctx->hold_offset + q->len - offset);
+        offset = 0u;
+        q = q->next;
+    }
+
+    pbuf_free(ctx->hold_pbuf);
+    ctx->hold_pbuf = NULL;
+    ctx->hold_offset = 0u;
+}
+
 static err_t tcp_server_on_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
 {
     tcp_server_ctx_t *ctx = (tcp_server_ctx_t *)arg;
-    struct pbuf *q;
 
     if (ctx == NULL) {
         if (p != NULL) {
@@ -58,21 +115,16 @@ static err_t tcp_server_on_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p,
         return ERR_ABRT;
     }
 
-    for (q = p; q != NULL; q = q->next) {
-        const uint8_t *src = (const uint8_t *)q->payload;
-        for (uint16_t i = 0; i < q->len; ++i) {
-            if (ring_free(ctx->rx_head, ctx->rx_tail, TCP_SERVER_RX_BUFFER_SIZE) == 0u) {
-                ctx->status.errors++;
-                break;
-            }
-            ctx->rx_ring[ctx->rx_head] = src[i];
-            ctx->rx_head = (uint16_t)((ctx->rx_head + 1u) % TCP_SERVER_RX_BUFFER_SIZE);
-            ctx->status.rx_bytes++;
-        }
+    if (ctx->hold_pbuf != NULL) {
+        ctx->status.errors++;
+        return ERR_MEM;
     }
 
-    tcp_recved(pcb, p->tot_len);
+    pbuf_ref(p);
+    ctx->hold_pbuf = p;
+    ctx->hold_offset = 0u;
     pbuf_free(p);
+    tcp_server_fill_ring_from_pbuf(ctx);
     return ERR_OK;
 }
 
@@ -92,6 +144,7 @@ static void tcp_server_on_err(void *arg, err_t err)
     if (ctx == NULL) {
         return;
     }
+    tcp_server_reset_rx_state(ctx);
     ctx->client_pcb = NULL;
     ctx->status.state = ctx->config.enabled ? TCP_SERVER_STATE_LISTENING : TCP_SERVER_STATE_IDLE;
     ctx->status.errors++;
@@ -193,6 +246,7 @@ int tcp_server_stop(uint8_t instance)
     ctx = &g_servers[instance];
 
     if (ctx->client_pcb != NULL) {
+        tcp_server_reset_rx_state(ctx);
         tcp_arg(ctx->client_pcb, NULL);
         tcp_recv(ctx->client_pcb, NULL);
         tcp_sent(ctx->client_pcb, NULL);
@@ -210,8 +264,7 @@ int tcp_server_stop(uint8_t instance)
     }
 
     ctx->status.state = TCP_SERVER_STATE_IDLE;
-    ctx->rx_head = 0u;
-    ctx->rx_tail = 0u;
+    tcp_server_reset_rx_state(ctx);
     return 0;
 }
 
@@ -262,13 +315,66 @@ int tcp_server_recv(uint8_t instance, uint8_t *data, uint16_t max_len)
         return -1;
     }
     ctx = &g_servers[instance];
+    tcp_server_fill_ring_from_pbuf(ctx);
     while (copied < max_len && ctx->rx_tail != ctx->rx_head) {
         data[copied++] = ctx->rx_ring[ctx->rx_tail];
         ctx->rx_tail = (uint16_t)((ctx->rx_tail + 1u) % TCP_SERVER_RX_BUFFER_SIZE);
     }
+    if (copied > 0u && ctx->client_pcb != NULL) {
+        tcp_recved(ctx->client_pcb, copied);
+    }
     return (int)copied;
 }
 
+uint16_t tcp_server_rx_available(uint8_t instance)
+{
+    if (instance >= TCP_SERVER_INSTANCE_COUNT) {
+        return 0u;
+    }
+    tcp_server_fill_ring_from_pbuf(&g_servers[instance]);
+    return ring_used(g_servers[instance].rx_head, g_servers[instance].rx_tail, TCP_SERVER_RX_BUFFER_SIZE);
+}
+
+uint16_t tcp_server_peek(uint8_t instance, uint8_t *data, uint16_t max_len)
+{
+    uint16_t copied = 0u;
+    uint16_t tail;
+    tcp_server_ctx_t *ctx;
+
+    if (instance >= TCP_SERVER_INSTANCE_COUNT || data == NULL || max_len == 0u) {
+        return 0u;
+    }
+
+    ctx = &g_servers[instance];
+    tcp_server_fill_ring_from_pbuf(ctx);
+    tail = ctx->rx_tail;
+    while (copied < max_len && tail != ctx->rx_head) {
+        data[copied++] = ctx->rx_ring[tail];
+        tail = (uint16_t)((tail + 1u) % TCP_SERVER_RX_BUFFER_SIZE);
+    }
+    return copied;
+}
+
+void tcp_server_drop(uint8_t instance, uint16_t len)
+{
+    tcp_server_ctx_t *ctx;
+    uint16_t dropped = 0u;
+
+    if (instance >= TCP_SERVER_INSTANCE_COUNT || len == 0u) {
+        return;
+    }
+
+    ctx = &g_servers[instance];
+    while (dropped < len && ctx->rx_tail != ctx->rx_head) {
+        ctx->rx_tail = (uint16_t)((ctx->rx_tail + 1u) % TCP_SERVER_RX_BUFFER_SIZE);
+        dropped++;
+    }
+    if (dropped > 0u && ctx->client_pcb != NULL) {
+        tcp_recved(ctx->client_pcb, dropped);
+    }
+    tcp_server_fill_ring_from_pbuf(ctx);
+}
+
 bool tcp_server_is_connected(uint8_t instance)
 {
     return (instance < TCP_SERVER_INSTANCE_COUNT) && (g_servers[instance].client_pcb != NULL);
@@ -280,3 +386,10 @@ void tcp_server_get_status(uint8_t instance, tcp_server_status_t *status)
         *status = g_servers[instance].status;
     }
 }
+
+void tcp_server_poll(void)
+{
+    for (uint8_t i = 0; i < TCP_SERVER_INSTANCE_COUNT; ++i) {
+        tcp_server_fill_ring_from_pbuf(&g_servers[i]);
+    }
+}

App/tcp_server.h

@@ -14,7 +14,7 @@ extern "C" {
 #endif
 
 #define TCP_SERVER_INSTANCE_COUNT    2u
-#define TCP_SERVER_RX_BUFFER_SIZE    512u
+#define TCP_SERVER_RX_BUFFER_SIZE    480u
 
 typedef enum {
     TCP_SERVER_STATE_IDLE = 0,
@@ -42,8 +42,12 @@ int tcp_server_start(uint8_t instance);
 int tcp_server_stop(uint8_t instance);
 int tcp_server_send(uint8_t instance, const uint8_t *data, uint16_t len);
 int tcp_server_recv(uint8_t instance, uint8_t *data, uint16_t max_len);
+uint16_t tcp_server_rx_available(uint8_t instance);
+uint16_t tcp_server_peek(uint8_t instance, uint8_t *data, uint16_t max_len);
+void tcp_server_drop(uint8_t instance, uint16_t len);
 bool tcp_server_is_connected(uint8_t instance);
 void tcp_server_get_status(uint8_t instance, tcp_server_status_t *status);
+void tcp_server_poll(void);
 
 #ifdef __cplusplus
 }

App/uart_trans.c

@@ -281,6 +281,14 @@ uint16_t uart_trans_write(uart_channel_t channel, const uint8_t *data, uint16_t
     return written;
 }
 
+uint16_t uart_trans_tx_free(uart_channel_t channel)
+{
+    if (channel >= UART_CHANNEL_MAX) {
+        return 0u;
+    }
+    return ring_free(g_channels[channel].tx_head, g_channels[channel].tx_tail, UART_TX_RING_BUFFER_SIZE);
+}
+
 void uart_trans_get_stats(uart_channel_t channel, uart_stats_t *stats)
 {
     if (channel < UART_CHANNEL_MAX && stats != NULL) {

App/uart_trans.h

@@ -55,6 +55,7 @@ void uart_trans_poll(void);
 uint16_t uart_trans_rx_available(uart_channel_t channel);
 uint16_t uart_trans_read(uart_channel_t channel, uint8_t *data, uint16_t max_len);
 uint16_t uart_trans_write(uart_channel_t channel, const uint8_t *data, uint16_t len);
+uint16_t uart_trans_tx_free(uart_channel_t channel);
 void uart_trans_get_stats(uart_channel_t channel, uart_stats_t *stats);
 void uart_trans_reset_stats(uart_channel_t channel);
 void uart_trans_idle_handler(uart_channel_t channel);

Core/Src/main.c

@@ -35,10 +35,11 @@
 
 /* Private define ------------------------------------------------------------*/
 /* USER CODE BEGIN PD */
-#define LED_PIN             GPIO_PIN_13
-#define LED_PORT            GPIOC
-#define APP_ROUTE_BUFFER_SIZE 256u
-#define STACK_GUARD_WORD     0xA5A5A5A5u
+#define LED_PIN                     GPIO_PIN_13
+#define LED_PORT                    GPIOC
+#define APP_ROUTE_BUFFER_SIZE       256u
+#define APP_TCP_TO_UART_CHUNK_SIZE  128u
+#define STACK_GUARD_WORD            0xA5A5A5A5u
 #define APP_HEALTH_CHECK_INTERVAL_MS 5000u
 /* USER CODE END PD */
 
@@ -67,6 +68,8 @@ static void App_RouteTcpTraffic(void);
 static void StackGuard_Init(void);
 static void StackGuard_Check(void);
 static bool App_SendToUart(uint8_t uart_index, uint8_t src_id, uint8_t dst_mask, const uint8_t *data, uint16_t len);
+static uint16_t App_SendTcpPayloadToUartRaw(uint8_t uart_index, const uint8_t *data, uint16_t len);
+static bool App_SendTcpPayloadToUartMux(uint8_t uart_index, uint8_t src_id, uint8_t dst_mask, const uint8_t *data, uint16_t len);
 static bool App_SendTcpServerPayload(uint8_t instance, const uint8_t *data, uint16_t len);
 static bool App_SendTcpClientPayload(uint8_t instance, const uint8_t *data, uint16_t len);
 /* USER CODE END PFP */
@@ -146,6 +149,19 @@ static void BootDiag_ReportCh390(void)
                       cfg->net.mask[0], cfg->net.mask[1], cfg->net.mask[2], cfg->net.mask[3],
                       cfg->net.gw[0], cfg->net.gw[1], cfg->net.gw[2], cfg->net.gw[3],
                       cfg->mux_mode);
+    SEGGER_RTT_printf(0,
+                      "ETH rx ok=%u drop=%u pbuf_fail=%u filt=%u ipv6=%u udp=%u igmp=%u lldp=%u other_eth=%u other_ipv4=%u last=0x%04X\r\n",
+                      (unsigned int)diag.rx_packets_ok,
+                      (unsigned int)diag.rx_packets_drop,
+                      (unsigned int)diag.rx_pbuf_alloc_failed,
+                      (unsigned int)diag.rx_filtered_frames,
+                      (unsigned int)diag.rx_filtered_ipv6,
+                      (unsigned int)diag.rx_filtered_udp,
+                      (unsigned int)diag.rx_filtered_igmp,
+                      (unsigned int)diag.rx_filtered_lldp,
+                      (unsigned int)diag.rx_filtered_other_eth,
+                      (unsigned int)diag.rx_filtered_other_ipv4,
+                      diag.last_eth_type);
 }
 
 static void App_ConfigureLinks(const device_config_t *cfg)
@@ -296,35 +312,159 @@ static bool App_SendToUart(uint8_t uart_index, uint8_t src_id, uint8_t dst_mask,
     }
 }
 
+static uint16_t App_SendTcpPayloadToUartRaw(uint8_t uart_index, const uint8_t *data, uint16_t len)
+{
+    uart_channel_t channel = (uart_index == LINK_UART_U1) ? UART_CHANNEL_U1 : UART_CHANNEL_U0;
+    return uart_trans_write(channel, data, len);
+}
+
+static bool App_SendTcpPayloadToUartMux(uint8_t uart_index, uint8_t src_id, uint8_t dst_mask, const uint8_t *data, uint16_t len)
+{
+    uart_channel_t channel = (uart_index == LINK_UART_U1) ? UART_CHANNEL_U1 : UART_CHANNEL_U0;
+    uint8_t frame[APP_TCP_TO_UART_CHUNK_SIZE + 6u];
+    uint16_t frame_len = 0u;
+
+    if (len == 0u || len > APP_TCP_TO_UART_CHUNK_SIZE) {
+        return false;
+    }
+    if (uart_trans_tx_free(channel) < (uint16_t)(len + 6u)) {
+        return false;
+    }
+    if (!uart_mux_encode_frame(src_id, dst_mask, data, len, frame, &frame_len, sizeof(frame))) {
+        return false;
+    }
+    return uart_trans_write(channel, frame, frame_len) == frame_len;
+}
+
 static void App_RouteTcpTraffic(void)
 {
     const device_config_t *cfg = config_get();
-    uint8_t buffer[APP_ROUTE_BUFFER_SIZE];
+    uint8_t buffer[APP_TCP_TO_UART_CHUNK_SIZE];
 
     for (uint8_t i = 0; i < TCP_SERVER_INSTANCE_COUNT; ++i) {
-        int rc = tcp_server_recv(i, buffer, sizeof(buffer));
-        if (rc > 0) {
+        uint16_t available = tcp_server_rx_available(i);
+        if (available > 0u) {
             uint8_t link_index = (i == 0u) ? CONFIG_LINK_S1 : CONFIG_LINK_S2;
-            if (!App_SendToUart(cfg->links[link_index].uart,
-                                config_link_index_to_endpoint(link_index),
-                                config_uart_index_to_endpoint(cfg->links[link_index].uart),
-                                buffer,
-                                (uint16_t)rc)) {
-                return;
+            uint8_t uart_index = cfg->links[link_index].uart;
+            uint8_t src_id = config_link_index_to_endpoint(link_index);
+            uint8_t dst_mask = config_uart_index_to_endpoint(uart_index);
+            uart_channel_t channel = (uart_index == LINK_UART_U1) ? UART_CHANNEL_U1 : UART_CHANNEL_U0;
+
+            if (cfg->mux_mode == MUX_MODE_FRAME) {
+                uint16_t tx_free = uart_trans_tx_free(channel);
+                uint16_t payload_len;
+                if (tx_free <= 6u) {
+                    return;
+                }
+                payload_len = available;
+                if (payload_len > APP_TCP_TO_UART_CHUNK_SIZE) {
+                    payload_len = APP_TCP_TO_UART_CHUNK_SIZE;
+                }
+                if (payload_len > (uint16_t)(tx_free - 6u)) {
+                    payload_len = (uint16_t)(tx_free - 6u);
+                }
+                if (payload_len == 0u) {
+                    return;
+                }
+                payload_len = tcp_server_peek(i, buffer, payload_len);
+                if (payload_len == 0u) {
+                    continue;
+                }
+                if (!App_SendTcpPayloadToUartMux(uart_index, src_id, dst_mask, buffer, payload_len)) {
+                    return;
+                }
+                tcp_server_drop(i, payload_len);
+            } else {
+                uint16_t chunk = available;
+                uint16_t tx_free = uart_trans_tx_free(channel);
+                uint16_t written;
+                if (tx_free == 0u) {
+                    return;
+                }
+                if (chunk > APP_TCP_TO_UART_CHUNK_SIZE) {
+                    chunk = APP_TCP_TO_UART_CHUNK_SIZE;
+                }
+                if (chunk > tx_free) {
+                    chunk = tx_free;
+                }
+                if (chunk == 0u) {
+                    return;
+                }
+                chunk = tcp_server_peek(i, buffer, chunk);
+                if (chunk == 0u) {
+                    continue;
+                }
+                written = App_SendTcpPayloadToUartRaw(uart_index, buffer, chunk);
+                if (written > 0u) {
+                    tcp_server_drop(i, written);
+                }
+                if (written < chunk) {
+                    return;
+                }
             }
         }
     }
 
     for (uint8_t i = 0; i < TCP_CLIENT_INSTANCE_COUNT; ++i) {
-        int rc = tcp_client_recv(i, buffer, sizeof(buffer));
-        if (rc > 0) {
+        uint16_t available = tcp_client_rx_available(i);
+        if (available > 0u) {
             uint8_t link_index = (i == 0u) ? CONFIG_LINK_C1 : CONFIG_LINK_C2;
-            if (!App_SendToUart(cfg->links[link_index].uart,
-                                config_link_index_to_endpoint(link_index),
-                                config_uart_index_to_endpoint(cfg->links[link_index].uart),
-                                buffer,
-                                (uint16_t)rc)) {
-                return;
+            uint8_t uart_index = cfg->links[link_index].uart;
+            uint8_t src_id = config_link_index_to_endpoint(link_index);
+            uint8_t dst_mask = config_uart_index_to_endpoint(uart_index);
+            uart_channel_t channel = (uart_index == LINK_UART_U1) ? UART_CHANNEL_U1 : UART_CHANNEL_U0;
+
+            if (cfg->mux_mode == MUX_MODE_FRAME) {
+                uint16_t tx_free = uart_trans_tx_free(channel);
+                uint16_t payload_len;
+                if (tx_free <= 6u) {
+                    return;
+                }
+                payload_len = available;
+                if (payload_len > APP_TCP_TO_UART_CHUNK_SIZE) {
+                    payload_len = APP_TCP_TO_UART_CHUNK_SIZE;
+                }
+                if (payload_len > (uint16_t)(tx_free - 6u)) {
+                    payload_len = (uint16_t)(tx_free - 6u);
+                }
+                if (payload_len == 0u) {
+                    return;
+                }
+                payload_len = tcp_client_peek(i, buffer, payload_len);
+                if (payload_len == 0u) {
+                    continue;
+                }
+                if (!App_SendTcpPayloadToUartMux(uart_index, src_id, dst_mask, buffer, payload_len)) {
+                    return;
+                }
+                tcp_client_drop(i, payload_len);
+            } else {
+                uint16_t chunk = available;
+                uint16_t tx_free = uart_trans_tx_free(channel);
+                uint16_t written;
+                if (tx_free == 0u) {
+                    return;
+                }
+                if (chunk > APP_TCP_TO_UART_CHUNK_SIZE) {
+                    chunk = APP_TCP_TO_UART_CHUNK_SIZE;
+                }
+                if (chunk > tx_free) {
+                    chunk = tx_free;
+                }
+                if (chunk == 0u) {
+                    return;
+                }
+                chunk = tcp_client_peek(i, buffer, chunk);
+                if (chunk == 0u) {
+                    continue;
+                }
+                written = App_SendTcpPayloadToUartRaw(uart_index, buffer, chunk);
+                if (written > 0u) {
+                    tcp_client_drop(i, written);
+                }
+                if (written < chunk) {
+                    return;
+                }
             }
         }
     }
@@ -510,6 +650,7 @@ static void App_Poll(void)
     sys_check_timeouts();
     App_StopLinksIfNeeded();
     App_StartLinksIfNeeded();
+    tcp_server_poll();
     tcp_client_poll();
     uart_trans_poll();
     StackGuard_Check();

Drivers/CH390/ch390_runtime.c

@@ -22,11 +22,18 @@ static uint8_t ch390_runtime_drain_rx(struct netif *netif, uint8_t max_frames)
 {
     struct pbuf *p;
     uint8_t drained = 0u;
+    uint8_t rx_ready;
 
     while (drained < max_frames) {
         p = ch390_runtime_input_frame(netif);
         if (p == NULL) {
-            break;
+            ch390_read_reg(CH390_MRCMDX);
+            rx_ready = ch390_read_reg(CH390_MRCMDX);
+            if ((rx_ready & CH390_PKT_RDY) == 0u) {
+                break;
+            }
+            drained++;
+            continue;
         }
         ch390_runtime_dispatch_frame(netif, p);
         drained++;
@@ -49,7 +56,179 @@ static uint8_t g_link_restart_pending;
 #define HEALTH_FAIL_SHIFT             4u
 #define HEALTH_FAIL_MASK              0xF0u
 
+#define CH390_RX_FILTER_ENABLE             1u
+#define CH390_RX_PREFIX_LEN                38u
+#define CH390_ETH_HEADER_LEN               14u
+#define CH390_IPV4_MIN_HEADER_LEN          20u
+#define CH390_ETH_TYPE_IPV4                0x0800u
+#define CH390_ETH_TYPE_ARP                 0x0806u
+#define CH390_ETH_TYPE_VLAN                0x8100u
+#define CH390_ETH_TYPE_IPV6                0x86DDu
+#define CH390_ETH_TYPE_QINQ                0x88A8u
+#define CH390_ETH_TYPE_LLDP                0x88CCu
+#define CH390_IP_PROTO_ICMP                1u
+#define CH390_IP_PROTO_IGMP                2u
+#define CH390_IP_PROTO_TCP                 6u
+#define CH390_IP_PROTO_UDP                 17u
+
+typedef enum {
+    CH390_RX_ACCEPT = 0,
+    CH390_RX_DROP_MALFORMED,
+    CH390_RX_DROP_IPV6,
+    CH390_RX_DROP_LLDP,
+    CH390_RX_DROP_UDP,
+    CH390_RX_DROP_IGMP,
+    CH390_RX_DROP_OTHER_ETH,
+    CH390_RX_DROP_OTHER_IPV4
+} ch390_rx_filter_result_t;
+
 static bool ch390_mac_address_valid(const uint8_t *mac);
+static ch390_rx_filter_result_t ch390_runtime_filter_frame(const uint8_t *prefix, uint16_t frame_len, uint16_t prefix_len);
+static void ch390_runtime_count_filtered_frame(ch390_rx_filter_result_t result);
+static void ch390_runtime_copy_prefix_to_pbuf(struct pbuf *p, const uint8_t *prefix, uint16_t prefix_len);
+static void ch390_runtime_read_remaining_to_pbuf(struct pbuf *p, uint16_t offset);
+
+static ch390_rx_filter_result_t ch390_runtime_filter_frame(const uint8_t *prefix, uint16_t frame_len, uint16_t prefix_len)
+{
+    uint16_t eth_type;
+    uint16_t l2_header_len = CH390_ETH_HEADER_LEN;
+    uint16_t ip_offset;
+    uint8_t ip_version;
+    uint8_t ip_ihl;
+    uint8_t ip_proto;
+
+    if ((prefix == NULL) || (frame_len < CH390_ETH_HEADER_LEN) || (prefix_len < CH390_ETH_HEADER_LEN)) {
+        return CH390_RX_DROP_MALFORMED;
+    }
+
+    eth_type = (uint16_t)(((uint16_t)prefix[12] << 8) | prefix[13]);
+    g_diag.last_eth_type = eth_type;
+
+    if ((eth_type == CH390_ETH_TYPE_VLAN) || (eth_type == CH390_ETH_TYPE_QINQ)) {
+        if ((frame_len < (CH390_ETH_HEADER_LEN + 4u)) || (prefix_len < (CH390_ETH_HEADER_LEN + 4u))) {
+            return CH390_RX_DROP_MALFORMED;
+        }
+        l2_header_len = (uint16_t)(CH390_ETH_HEADER_LEN + 4u);
+        eth_type = (uint16_t)(((uint16_t)prefix[16] << 8) | prefix[17]);
+        g_diag.last_eth_type = eth_type;
+    }
+
+    if (eth_type == CH390_ETH_TYPE_ARP) {
+        g_diag.rx_arp_frames++;
+        return CH390_RX_ACCEPT;
+    }
+
+    if (eth_type == CH390_ETH_TYPE_IPV6) {
+        return CH390_RX_DROP_IPV6;
+    }
+
+    if (eth_type == CH390_ETH_TYPE_LLDP) {
+        return CH390_RX_DROP_LLDP;
+    }
+
+    if (eth_type != CH390_ETH_TYPE_IPV4) {
+        return CH390_RX_DROP_OTHER_ETH;
+    }
+
+    ip_offset = l2_header_len;
+    if ((frame_len < (uint16_t)(ip_offset + CH390_IPV4_MIN_HEADER_LEN)) ||
+        (prefix_len < (uint16_t)(ip_offset + CH390_IPV4_MIN_HEADER_LEN))) {
+        return CH390_RX_DROP_MALFORMED;
+    }
+
+    ip_version = (uint8_t)(prefix[ip_offset] >> 4);
+    ip_ihl = (uint8_t)(prefix[ip_offset] & 0x0Fu);
+    if ((ip_version != 4u) || (ip_ihl < 5u)) {
+        return CH390_RX_DROP_MALFORMED;
+    }
+
+    ip_proto = prefix[ip_offset + 9u];
+    g_diag.rx_ip_frames++;
+
+    if (ip_proto == CH390_IP_PROTO_ICMP) {
+        g_diag.rx_ipv4_icmp_frames++;
+        return CH390_RX_ACCEPT;
+    }
+
+    if (ip_proto == CH390_IP_PROTO_TCP) {
+        g_diag.rx_ipv4_tcp_frames++;
+        return CH390_RX_ACCEPT;
+    }
+
+    if (ip_proto == CH390_IP_PROTO_UDP) {
+        g_diag.rx_ipv4_udp_frames++;
+        return CH390_RX_DROP_UDP;
+    }
+
+    if (ip_proto == CH390_IP_PROTO_IGMP) {
+        g_diag.rx_filtered_igmp++;
+        return CH390_RX_DROP_IGMP;
+    }
+
+    return CH390_RX_DROP_OTHER_IPV4;
+}
+
+static void ch390_runtime_count_filtered_frame(ch390_rx_filter_result_t result)
+{
+    g_diag.rx_filtered_frames++;
+    switch (result) {
+    case CH390_RX_DROP_MALFORMED:
+        g_diag.rx_filtered_malformed++;
+        break;
+    case CH390_RX_DROP_IPV6:
+        g_diag.rx_filtered_ipv6++;
+        break;
+    case CH390_RX_DROP_LLDP:
+        g_diag.rx_filtered_lldp++;
+        break;
+    case CH390_RX_DROP_UDP:
+        g_diag.rx_filtered_udp++;
+        break;
+    case CH390_RX_DROP_IGMP:
+        break;
+    case CH390_RX_DROP_OTHER_ETH:
+        g_diag.rx_filtered_other_eth++;
+        break;
+    case CH390_RX_DROP_OTHER_IPV4:
+        g_diag.rx_filtered_other_ipv4++;
+        break;
+    case CH390_RX_ACCEPT:
+    default:
+        break;
+    }
+}
+
+static void ch390_runtime_copy_prefix_to_pbuf(struct pbuf *p, const uint8_t *prefix, uint16_t prefix_len)
+{
+    struct pbuf *q;
+    uint16_t copied = 0u;
+
+    for (q = p; (q != NULL) && (copied < prefix_len); q = q->next) {
+        uint16_t chunk = (uint16_t)(prefix_len - copied);
+        if (chunk > q->len) {
+            chunk = q->len;
+        }
+        memcpy(q->payload, &prefix[copied], chunk);
+        copied = (uint16_t)(copied + chunk);
+    }
+}
+
+static void ch390_runtime_read_remaining_to_pbuf(struct pbuf *p, uint16_t offset)
+{
+    struct pbuf *q;
+    uint16_t skipped = 0u;
+
+    for (q = p; q != NULL; q = q->next) {
+        if (skipped >= offset) {
+            ch390_read_mem((uint8_t *)q->payload, q->len);
+        } else if ((uint16_t)(skipped + q->len) > offset) {
+            uint16_t in_chunk_offset = (uint16_t)(offset - skipped);
+            uint16_t read_len = (uint16_t)(q->len - in_chunk_offset);
+            ch390_read_mem(&((uint8_t *)q->payload)[in_chunk_offset], read_len);
+        }
+        skipped = (uint16_t)(skipped + q->len);
+    }
+}
 
 static uint8_t ch390_runtime_is_restart_pending(void)
 {
@@ -154,12 +333,14 @@ struct pbuf *ch390_runtime_input_frame(struct netif *netif)
 {
     struct ethernetif *ethernetif = (struct ethernetif *)netif->state;
     struct pbuf *p = NULL;
-    struct pbuf *q;
     uint16_t len;
     uint16_t frame_len;
+    uint16_t prefix_len;
     uint8_t rcr;
     uint8_t rx_ready;
     uint8_t rx_header[4];
+    uint8_t frame_prefix[CH390_RX_PREFIX_LEN];
+    ch390_rx_filter_result_t filter_result;
     ch390_read_reg(CH390_MRCMDX);
     rx_ready = ch390_read_reg(CH390_MRCMDX);
 
@@ -196,6 +377,23 @@ struct pbuf *ch390_runtime_input_frame(struct netif *netif)
     }
 
     ethernetif->rx_len = frame_len;
+    prefix_len = frame_len;
+    if (prefix_len > CH390_RX_PREFIX_LEN) {
+        prefix_len = CH390_RX_PREFIX_LEN;
+    }
+    ch390_read_mem(frame_prefix, prefix_len);
+
+#if CH390_RX_FILTER_ENABLE
+    filter_result = ch390_runtime_filter_frame(frame_prefix, frame_len, prefix_len);
+    if (filter_result != CH390_RX_ACCEPT) {
+        ch390_drop_packet((uint16_t)(frame_len - prefix_len));
+        LINK_STATS_INC(link.drop);
+        g_diag.rx_packets_drop++;
+        ch390_runtime_count_filtered_frame(filter_result);
+        return NULL;
+    }
+#endif
+
     len = ethernetif->rx_len;
 #if ETH_PAD_SIZE
     len += ETH_PAD_SIZE;
@@ -206,9 +404,8 @@ struct pbuf *ch390_runtime_input_frame(struct netif *netif)
 #if ETH_PAD_SIZE
         pbuf_remove_header(p, ETH_PAD_SIZE);
 #endif
-        for (q = p; q != NULL; q = q->next) {
-            ch390_read_mem((uint8_t *)q->payload, q->len);
-        }
+        ch390_runtime_copy_prefix_to_pbuf(p, frame_prefix, prefix_len);
+        ch390_runtime_read_remaining_to_pbuf(p, prefix_len);
 #if ETH_PAD_SIZE
         pbuf_add_header(p, ETH_PAD_SIZE);
 #endif
@@ -218,10 +415,11 @@ struct pbuf *ch390_runtime_input_frame(struct netif *netif)
         g_diag.last_frame_len = frame_len;
         g_diag.last_payload_len = p->tot_len;
     } else {
-        ch390_drop_packet(ethernetif->rx_len);
+        ch390_drop_packet((uint16_t)(frame_len - prefix_len));
         LINK_STATS_INC(link.memerr);
         LINK_STATS_INC(link.drop);
         g_diag.rx_packets_drop++;
+        g_diag.rx_pbuf_alloc_failed++;
     }
 
     return p;

Drivers/CH390/ch390_runtime.h

@@ -38,8 +38,20 @@ typedef struct {
     uint32_t rx_packets_drop;
     uint32_t tx_packets_ok;
     uint32_t tx_packets_timeout;
+    uint32_t rx_pbuf_alloc_failed;
+    uint32_t rx_filtered_frames;
+    uint32_t rx_filtered_ipv6;
+    uint32_t rx_filtered_udp;
+    uint32_t rx_filtered_igmp;
+    uint32_t rx_filtered_lldp;
+    uint32_t rx_filtered_other_eth;
+    uint32_t rx_filtered_other_ipv4;
+    uint32_t rx_filtered_malformed;
     uint32_t rx_arp_frames;
     uint32_t rx_ip_frames;
+    uint32_t rx_ipv4_icmp_frames;
+    uint32_t rx_ipv4_tcp_frames;
+    uint32_t rx_ipv4_udp_frames;
     uint32_t rx_other_frames;
     uint32_t rx_unicast_self_frames;
     uint32_t rx_broadcast_frames;

MDK-ARM/keil-build-viewer-record.txt

@@ -1,7 +1,7 @@
       Code (inc. data)   RO Data    RW Data    ZI Data      Debug   Object Name
        632          0          0          0          0          0   ch390.o
        616          0         64          0          0          0   ch390_interface.o
-      2050          0         85          6         88          0   ch390_runtime.o
+      2546          0         85          6        136          0   ch390_runtime.o
       3958          0        591          8       1240          0   config.o
          8          0          0          0          0          0   def.o
        124          0          0          0          0          0   dma.o
@@ -17,7 +17,7 @@
        778          0          0          2          0          0   ip4.o
         46          0          4          0          0          0   ip4_addr.o
         44          0          0          0         12          0   iwdg.o
-      2842          0        185         12        272          0   main.o
+      3264          0        300         12        272          0   main.o
        828          0          0         12       4115          0   mem.o
        196          0        244         32       6464          0   memp.o
        582          0          0         12          0          0   netif.o
@@ -43,13 +43,13 @@
        490          0          0          0          0          0   stm32f1xx_it.o
          2          0         24          4          0          0   system_stm32f1xx.o
       3474          0        193         32          0          0   tcp.o
-      1232          0          0          0       1120          0   tcp_client.o
+      1734          0          0          0       1088          0   tcp_client.o
       3684          0          0         36         20          0   tcp_in.o
       3862          0          0          0          0          0   tcp_out.o
-       986          0          0          0       1104          0   tcp_server.o
+      1364          0          0          0       1048          0   tcp_server.o
        164          0          0          0         72          0   tim.o
        374          0         16         12          0          0   timeouts.o
-      1538          0          0          0       2936          0   uart_trans.o
+      1590          0          0          0       2936          0   uart_trans.o
        816          0          0          0        624          0   usart.o
 Object Totals
 
@@ -57,8 +57,8 @@ Memory Map of the image
 
 	Load Region LR_IROM1 
 
-		Execution Region ER_IROM1 (Exec base: 0x08000000, Size: 0x0000D72C, Max: 0x00010000, END)
+		Execution Region ER_IROM1 (Exec base: 0x08000000, Size: 0x0000DED8, Max: 0x00010000, END)
 
-		Execution Region RW_IRAM1 (Exec base: 0x20000000, Size: 0x00005000, Max: 0x00005000, END)
+		Execution Region RW_IRAM1 (Exec base: 0x20000000, Size: 0x00004FD8, Max: 0x00005000, END)
 
 Image component sizes

工程调试指南.md

@@ -225,11 +225,21 @@
 5. `AT+MUX?`
 6. `AT+NET=...`
 7. `AT+NET?`
-8. `AT+LINK=...`
-9. `AT+LINK?`
-10. `AT+SAVE`
-11. `AT+RESET`
-12. `AT+DEFAULT`
+8. `AT+BAUD=...`
+9. `AT+BAUD?`
+10. `AT+LINK=...`
+11. `AT+LINK?`
+12. `AT+SAVE`
+13. `AT+RESET`
+14. `AT+DEFAULT`
+
+其中与数据串口相关的固定映射为：
+
+1. `U0 = USART2`
+2. `U1 = USART3`
+3. `AT+BAUD=U0,<baud>` / `AT+BAUD=U1,<baud>` 只更新当前运行配置记录
+4. 新波特率不会立即重初始化 `USART2/USART3`，必须执行 `AT+SAVE` + `AT+RESET` 后按保存值生效
+5. 当前代码接受的波特率范围为 `1200 ~ 921600`
 
 ### 6.2 现场关键规则
 
@@ -238,6 +248,7 @@
 1. 当前现场验证时，配置命令必须保证以换行完成帧。
 2. 若主机侧发送方式不对，现象会很像“配置口完全无响应”。
 3. 因此，配置口不响应时，第一优先级不是改 parser，而是先验证主机端发送格式与接线。
+4. `BAUD` 类命令若查询值已变化，但 `USART2/USART3` 现场波特率尚未变化，不应立即归因为命令无效，应先确认是否已经执行 `AT+SAVE` 与 `AT+RESET`。
 
 ### 6.3 最小验证步骤
 
@@ -247,13 +258,16 @@
 2. 先发 `AT`
 3. 再发 `AT+QUERY`
 4. 再发 `AT+NET?`
-5. 再发 `AT+LINK?`
-6. 修改一个最小参数，例如：
-   - `AT+MUX=1`
-7. 执行：
-   - `AT+SAVE`
-   - `AT+RESET`
-8. 复位后再次查询，确认配置是否保留
+5. 再发 `AT+BAUD?`
+6. 再发 `AT+LINK?`
+7. 修改一个最小参数，例如：
+    - `AT+MUX=1`
+    - 或 `AT+BAUD=U1,38400`
+8. 执行：
+    - `AT+SAVE`
+    - `AT+RESET`
+9. 复位后再次查询，确认配置是否保留
+10. 若本轮验证的是 `AT+BAUD`，还应同步用上位机重新按新波特率连接 `USART2/USART3`，确认数据口实际生效
 
 ### 6.4 持久化失败时怎么查
 
@@ -488,12 +502,15 @@ Keil MDK-ARM 构建 0 Error(s), 0 Warning(s)。Flash 52.7 KB / 64.0 KB (82.5%)
 
 在 CH390 发生 TX timeout 并触发 `ch390_runtime_emergency_reset()` 后，芯片寄存器访问恢复正常，`VID` 可读、PHY 链路也可能保持 `up`，但 TCP 业务流量仍可能长时间不恢复，表现为“芯片还活着，但网络像失联一样，通常只能重启恢复”。
 
+在后续实现收敛中，又确认仅依赖单次 VID 异常或单次 TX busy 即立刻 reset 过于激进，容易把瞬时抖动误判为芯片失活，因此当前代码已经演化为“带阈值的恢复策略”。
+
 #### 根因
 
 `ch390_runtime_emergency_reset()` 旧实现仅执行 `ch390_software_reset()`、`ch390_default_config()` 与 `diag` 刷新，缺少 cold init 里已有的两层恢复语义：
 
 1. **MAC 对齐未恢复**：旧代码没有重新写回 CH390 `PAR`，也没有把硬件 MAC 重新同步到 `netif->hwaddr`。若软件复位后 CH390 的 MAC 过滤状态与 lwIP 侧缓存身份不一致，现象会表现为寄存器可访问、链路仍在，但单播业务流量不通。
 2. **上层链路回收未触发**：TX-timeout 路径直接调用 `ch390_runtime_emergency_reset()`，没有保证 `App_StopLinksIfNeeded()` / `App_StartLinksIfNeeded()` 观察到一次有效的 link-down 周期，导致旧 TCP client/server 状态可能跨芯片复位残留，业务层没有完成重建。
+3. **恢复策略缺少抖动抑制**：若仅凭单次 TX busy 或单次 VID 异常立即 reset，容易在瞬时总线/链路抖动下过度恢复，放大业务扰动，因此当前实现增加了连续失败阈值和失败计数清零逻辑。
 
 #### 修复内容
 
@@ -505,12 +522,40 @@ Keil MDK-ARM 构建 0 Error(s), 0 Warning(s)。Flash 52.7 KB / 64.0 KB (82.5%)
 | `Drivers/CH390/ch390_runtime.c` | emergency reset 成功后清 `g_ch390_irq_pending` 并置位 `g_link_restart_pending` | 避免复位前遗留中断状态影响恢复 |
 | `Drivers/CH390/ch390_runtime.c` | `ch390_runtime_check_link()` 增加一次性 hold-down 逻辑 | 保证主循环至少看到一次 link-down，从而触发 app 层 stop/start 回收重建 |
 | `Drivers/CH390/ch390_runtime.c` | TX-timeout 与 health-check 两条 reset 路径统一传入 `netif` | 让两类恢复路径都走同一套 MAC 重同步与链路重建语义 |
+| `Drivers/CH390/ch390_runtime.c` | 为 TX timeout 与 health-check 增加连续失败阈值 | 降低瞬时抖动导致的过度 reset 风险 |
+
+#### 当前实现语义（以源码为准）
+
+1. **TX timeout 阈值**
+   - 单次判定条件：`CH390_TCR.TXREQ` busy-wait 持续超过 `10 ms`
+   - 连续阈值：累计 `6` 次后才触发 `ch390_runtime_emergency_reset()`
+   - 只要有一次成功发送，`g_tx_consecutive_timeout` 立即清零，因此该阈值针对的是**连续失败**，不是累计历史失败次数。
+
+2. **health-check 阈值**
+   - `VID` 单次读到 `0x0000` / `0xFFFF` 并不会立即 reset。
+   - 只有连续 `3` 次异常 VID 才触发 emergency reset。
+   - 若 `g_ch390_ready == 0`，则 health-check 会直接尝试 reset，不再等待 VID 连续计数。
+
+3. **restart-pending 的单次语义**
+   - emergency reset 成功后会置位 restart-pending。
+   - 下一次 `ch390_runtime_check_link()` 先强制执行一次 `netif_set_link_down()`，随后立即清除此标志并提前返回。
+   - 该设计用于保证主循环至少看到一次有效的 logical link-down，从而沿用现有 `App_StopLinksIfNeeded()` / `App_StartLinksIfNeeded()` 路径回收并重建 TCP links。
+
+4. **内部计数与状态**
+   - `g_chip_reset_count`：记录 emergency reset 尝试次数，饱和递增到 `0xFF`。
+   - `g_tx_consecutive_timeout`：记录连续 TX busy 超时次数；成功发送或进入 reset 路径后清零。
+   - health-check 连续失败计数当前与 `g_link_restart_pending` 共用一个状态字节的高位 nibble 存储；当 VID 恢复正常、达到 reset 阈值或 emergency reset 成功时会清零。
+
+5. **失败路径差异**
+   - 只有当 emergency reset 完成后 `g_diag.id_valid` 仍然有效，才会置位 restart-pending 并进入后续 app recycle 语义。
+   - 若 reset 后芯片仍不响应，则仅记录失败并返回，不会伪装成可恢复状态。
 
 #### 预期结果
 
 1. CH390 发生 emergency reset 后，硬件 MAC、`netif->hwaddr` 与当前业务身份重新对齐。
 2. 即使物理网线始终保持连接，主循环仍会在后续 poll 中观察到一次有效 link-down，并按既有 `App_StopLinksIfNeeded()` / `App_StartLinksIfNeeded()` 路径回收并重建 TCP links。
-3. 复位后的恢复语义与 cold init 更接近，不再停留在“芯片寄存器恢复正常，但业务流量仍死掉”的半恢复状态。
+3. 恢复策略对瞬时异常更保守：只有连续超时或连续 VID 异常达到阈值才会触发 reset，降低误触发恢复的概率。
+4. 复位后的恢复语义与 cold init 更接近，不再停留在“芯片寄存器恢复正常，但业务流量仍死掉”的半恢复状态。
 
 #### 构建验证
 

项目技术实现.md

@@ -184,6 +184,117 @@ EN,LPORT,RIP,RPORT,UART
 2. 统一受 `LINK[idx]` 配置驱动
 3. 由调度层决定实例与 UART 的数据交换路径
 
+### 6.4 `v1.1.0` 低 RAM TCP 背压修复
+
+`v1.1.0` 起，`TCP -> UART` 路径补充如下实现约束，用于解决“TCP 接收过快、UART 发送过慢时本地缓存被冲垮”的问题，同时尽量不新增静态 RAM：
+
+1. 继续复用 `tcp_server` / `tcp_client` 现有 `RX ring`，不为每个连接新增独立的大块 pending payload 缓冲。
+2. `tcp_server_on_recv()` / `tcp_client_on_recv()` 不再在回调内立即 `tcp_recved()`。
+3. lwIP 交来的 `pbuf` 在回调中通过 `pbuf_ref()` 转为应用持有，再释放回调上下文的原始引用；后续由应用在主循环中继续把数据泵入 `RX ring`，最终在消费完成后释放。
+4. 当 `RX ring` 暂时装不下时，剩余数据保留在 `hold_pbuf + hold_offset` 中，等待主循环下一轮继续搬运。
+5. 只有当数据真正从 `TCP RX ring` 被 `drop` 掉，也就是已经被下游 `UART` 接收进入发送路径时，才调用 `tcp_recved()` 释放 TCP 接收窗口。
+
+这样做的效果是：
+
+1. `UART` 慢时，TCP 窗口不会继续无条件放大。
+2. 对端发送速度会被 lwIP 接收窗口自然压制。
+3. 修复点建立在已有 ring 与主循环调度之上，不引入 `FreeRTOS` 或新的大块静态缓存。
+
+#### RAW 与 MUX 的分流规则
+
+在 `v1.1.0` 中，`TCP` 侧拿到的都是纯 payload，因此 `TCP` 背压逻辑在 `RAW` 与 `MUX` 两种模式下共用到 `UART commit` 之前：
+
+1. `RAW` 模式：
+   - 主循环先查看 `uart_trans_tx_free()`
+   - 再按 `min(tcp_available, tx_free, APP_TCP_TO_UART_CHUNK_SIZE)` 从 TCP ring `peek`
+   - `uart_trans_write()` 实际写入多少，就 `drop + tcp_recved` 多少
+2. `MUX` 模式：
+   - `TCP` payload 本身不带帧头尾
+   - 只有当 `UART TX free >= payload_len + 6` 时，才在栈上临时编码一帧并一次性写入 `UART TX ring`
+   - 只有整帧成功入队后，才按原始 payload 长度执行 `drop + tcp_recved`
+
+该设计保证：
+
+1. `RAW` 模式允许流式逐步提交
+2. `MUX` 模式保持“单个 UART 输出帧必须完整入队”的语义
+3. `TCP` 接收窗口始终以真实下游消费进度为准，而不是以“回调里已经 memcpy 到本地”作为提交点
+
+#### RAM 与 chunk 策略
+
+为给新增的 `hold_pbuf / hold_offset` 状态字段让位，并进一步降低单轮转发压力，`v1.1.0` 同步采用以下策略：
+
+1. 新增 `APP_TCP_TO_UART_CHUNK_SIZE = 128`
+2. `TCP_SERVER_RX_BUFFER_SIZE` 从 `512` 调整为 `480`
+3. `TCP_CLIENT_RX_BUFFER_SIZE` 从 `512` 调整为 `480`
+
+设计意图：
+
+1. 利用更小的单次转发块提升主循环调度颗粒度
+2. 让 `MUX` 模式下 `payload + 6` 更容易完整进入 `UART TX ring`
+3. 在静态 RAM 已接近上限时，为少量新状态字段回收空间
+
+#### 构建基线
+
+`v1.1.0` 以 `MDK-ARM/TCP2UART.uvprojx` 的 `TCP2UART` Target 为构建验收基线。
+
+当前一次通过的参考结果：
+
+1. `errors = 0`
+2. `warnings = 0`
+3. `flash_bytes = 56544`
+4. `ram_bytes = 20376`
+
+该结果说明修复后工程仍满足 `STM32F103R8T6` 的 `20KB RAM` 上限，但余量已经很小；后续若继续增加功能，应优先考虑复用现有缓冲与状态，而不是增加新的静态大数组。
+
+### 6.3 客户现场脏网络恢复增强
+
+客户现场换 PC 后曾出现设备持续 ARP、`ping` 不通、TCP Client 不恢复的现象。抓包显示故障前后存在 IPv6、DHCPv6、mDNS、IGMP、LLDP 等与当前业务无关的网络噪声；当前固件为静态 IPv4、TCP2UART 与 ICMP 诊断模型，不依赖 UDP、IPv6、DHCP 或多播发现。
+
+本阶段采用低 RAM 优先的恢复策略，不先扩大 `PBUF_POOL_SIZE`，而是在更靠近入口的位置减少无关帧对 lwIP pool 的占用：
+
+1. `TCP Client CONNECTING` 增加应用层超时：
+   - `TCP_CLIENT_CONNECT_TIMEOUT_MS = 10000`
+   - `tcp_connect()` 返回 `ERR_OK` 后记录 `connect_start_ms`
+   - `tcp_client_poll()` 发现 `CONNECTING` 超过超时时间后，注销回调、`tcp_abort()` 当前 PCB、释放 `hold_pbuf`，再按原有 `reconnect_interval_ms` 重连
+   - `tcp_client_status_t.connect_timeout_count` 记录发生次数
+2. `CH390` RX 入口增加 `pre-pbuf` 协议过滤：
+   - 在 `pbuf_alloc(PBUF_RAW, ..., PBUF_POOL)` 之前先读取以太网头与最小 IPv4 头
+   - 允许进入 lwIP 的协议限定为 `ARP`、`IPv4 ICMP`、`IPv4 TCP`
+   - 默认丢弃 `IPv6`、`IPv4 UDP`、`IPv4 IGMP`、`LLDP`、未知 EtherType 与畸形头
+   - 丢弃帧只跳过 CH390 RX FIFO 剩余字节，不分配 pbuf
+3. 软件 MAC 过滤暂不启用：
+   - 第一版只做协议层过滤，避免误杀广播 ARP 或未来硬件过滤策略变化
+   - 目的 MAC 相关判断保留为后续可选增强
+
+新增 CH390 诊断字段用于现场判断是否仍存在资源压力：
+
+1. `rx_pbuf_alloc_failed`
+2. `rx_filtered_frames`
+3. `rx_filtered_ipv6`
+4. `rx_filtered_udp`
+5. `rx_filtered_igmp`
+6. `rx_filtered_lldp`
+7. `rx_filtered_other_eth`
+8. `rx_filtered_other_ipv4`
+9. `rx_filtered_malformed`
+10. `rx_ipv4_icmp_frames`
+11. `rx_ipv4_tcp_frames`
+12. `rx_ipv4_udp_frames`
+
+验收口径：
+
+1. 正常 `ARP / ping / TCP Server / TCP Client` 功能不受影响
+2. 客户脏网络中的 IPv6、UDP、IGMP、LLDP 噪声不会进入 lwIP pbuf pool
+3. 若远端 TCP Server 不监听或静默丢 SYN，TCP Client 不再永久停留在 `CONNECTING`
+4. 若过滤后 `rx_pbuf_alloc_failed` 仍持续增长，再评估从无关功能中回收 RAM 并调整 `PBUF_POOL_SIZE`
+
+本阶段 Keil 构建验收结果：
+
+1. `errors = 0`
+2. `warnings = 0`
+3. `flash_bytes = 57404`
+4. `ram_bytes = 20440`
+
 ## 七、主循环实现方向
 
 主循环仍保持裸机轮询风格：