[NUC472/M453] Fix serial error with sync/async calls interlaced

Serial implementation uses different vector handlers for sync/async calls respectively. The issue can be reproduced with the following flow:
1. Register sync mode callback with Serial.attach().
2. Sync call with Serial.putc()/getc().
3. Change to async call with Serial.write()/read().
4. Change back to sync call with Serial.putc()/getc().
Now, vector handller is still for async mode, not for sync mode.

To fix it:
1. Introduce internal function serial_enable_interrupt() for both sync/async vector handler enable/disable.
   Original HAL function serial_irq_set() is reduced to call it for sync mode vector handler enable/disable.
2. Introduce internal function serial_rollback_interrupt() to roll back sync mode vector handler at end of async transfer.

Author: ccli8

targets/TARGET_NUVOTON/TARGET_M451/TARGET_NUMAKER_PFM_M453/objects.h

@@ -61,6 +61,7 @@ struct serial_s {
     void        (*vec)(void);
     uint32_t    irq_handler;
     uint32_t    irq_id;
+    uint32_t    irq_en;
     uint32_t    inten_msk;
 
     // Async transfer related fields

targets/TARGET_NUVOTON/TARGET_M451/serial_api.c

@@ -24,6 +24,7 @@
 #include "PeripheralPins.h"
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
+#include <string.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -61,6 +62,8 @@ static void uart_dma_handler_rx(uint32_t id, uint32_t event);
 
 static void serial_tx_enable_interrupt(serial_t *obj, uint32_t address, uint8_t enable);
 static void serial_rx_enable_interrupt(serial_t *obj, uint32_t address, uint8_t enable);
+static void serial_enable_interrupt(serial_t *obj, SerialIrq irq, uint32_t enable);
+static void serial_rollback_interrupt(serial_t *obj, SerialIrq irq);
 static int serial_write_async(serial_t *obj);
 static int serial_read_async(serial_t *obj);
 
@@ -159,7 +162,7 @@ void serial_init(serial_t *obj, PinName tx, PinName rx)
 
     const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->serial.uart);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
     struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
 
@@ -186,6 +189,7 @@ void serial_init(serial_t *obj, PinName tx, PinName rx)
     serial_format(obj, 8, ParityNone, 1);
 
     obj->serial.vec = var->vec;
+    obj->serial.irq_en = 0;
 
 #if DEVICE_SERIAL_ASYNCH
     obj->serial.dma_usage_tx = DMA_USAGE_NEVER;
@@ -212,7 +216,7 @@ void serial_free(serial_t *obj)
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->serial.uart);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
     struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
 
@@ -329,7 +333,7 @@ void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id)
 
     const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->serial.uart);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
     obj->serial.irq_handler = (uint32_t) handler;
     obj->serial.irq_id = id;
@@ -340,51 +344,18 @@ void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id)
 
 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
 {
-    if (enable) {
-        const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
-        MBED_ASSERT(modinit != NULL);
-        MBED_ASSERT(modinit->modname == obj->serial.uart);
-    
-        NVIC_SetVector(modinit->irq_n, (uint32_t) obj->serial.vec);
-        NVIC_EnableIRQ(modinit->irq_n);
-        
-        struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
-        // Multiple serial S/W objects for single UART H/W module possibly.
-        // Bind serial S/W object to UART H/W module as interrupt is enabled.
-        var->obj = obj;
-        
-        switch (irq) {
-            // NOTE: Setting inten_msk first to avoid race condition
-            case RxIrq:
-                obj->serial.inten_msk = obj->serial.inten_msk | (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk);
-                UART_ENABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk));
-                break;
-            case TxIrq:
-                obj->serial.inten_msk = obj->serial.inten_msk | UART_INTEN_THREIEN_Msk;
-                UART_ENABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), UART_INTEN_THREIEN_Msk);
-                break;
-        }
-    } else { // disable
-        switch (irq) {
-            case RxIrq:
-                UART_DISABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk));
-                obj->serial.inten_msk = obj->serial.inten_msk & ~(UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk);
-                break;
-            case TxIrq:
-                UART_DISABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), UART_INTEN_THREIEN_Msk);
-                obj->serial.inten_msk = obj->serial.inten_msk & ~UART_INTEN_THREIEN_Msk;
-                break;
-        }
-    }
+    obj->serial.irq_en = enable;
+    serial_enable_interrupt(obj, irq, enable);
 }
 
 int serial_getc(serial_t *obj)
 {
-    // TODO: Fix every byte access requires accompaniness of one interrupt. This degrades performance much.    
+    // TODO: Fix every byte access requires accompaniment of one interrupt. This has side effect of performance degradation.
     while (! serial_readable(obj));
     int c = UART_READ(((UART_T *) NU_MODBASE(obj->serial.uart)));
 
-    // Simulate clear of the interrupt flag
+    // NOTE: On Nuvoton targets, no H/W IRQ to match TxIrq/RxIrq.
+    //       Simulation of TxIrq/RxIrq requires the call to Serial::putc()/Serial::getc() respectively. 
     if (obj->serial.inten_msk & (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk)) {
         UART_ENABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk));
     }
@@ -394,11 +365,12 @@ int serial_getc(serial_t *obj)
 
 void serial_putc(serial_t *obj, int c)
 {
-    // TODO: Fix every byte access requires accompaniness of one interrupt. This degrades performance much.
+    // TODO: Fix every byte access requires accompaniment of one interrupt. This has side effect of performance degradation.
     while (! serial_writable(obj));
     UART_WRITE(((UART_T *) NU_MODBASE(obj->serial.uart)), c);
 
-    // Simulate clear of the interrupt flag
+    // NOTE: On Nuvoton targets, no H/W IRQ to match TxIrq/RxIrq.
+    //       Simulation of TxIrq/RxIrq requires the call to Serial::putc()/Serial::getc() respectively. 
     if (obj->serial.inten_msk & UART_INTEN_THREIEN_Msk) {
         UART_ENABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), UART_INTEN_THREIEN_Msk);
     }
@@ -500,7 +472,7 @@ int serial_tx_asynch(serial_t *obj, const void *tx, size_t tx_length, uint8_t tx
         // DMA way
         const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
         MBED_ASSERT(modinit != NULL);
-        MBED_ASSERT(modinit->modname == obj->serial.uart);
+        MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
         PDMA_T *pdma_base = dma_modbase();
 
@@ -563,7 +535,7 @@ void serial_rx_asynch(serial_t *obj, void *rx, size_t rx_length, uint8_t rx_widt
         // DMA way
         const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
         MBED_ASSERT(modinit != NULL);
-        MBED_ASSERT(modinit->modname == obj->serial.uart);
+        MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
         PDMA_T *pdma_base = dma_modbase();
 
@@ -612,10 +584,8 @@ void serial_tx_abort_asynch(serial_t *obj)
     }
 
     // Necessary for both interrupt way and DMA way
-    serial_irq_set(obj, TxIrq, 0);
-    // FIXME: more complete abort operation
-    //UART_HAL_DisableTransmitter(obj->serial.serial.address);
-    //UART_HAL_FlushTxFifo(obj->serial.serial.address);
+    serial_enable_interrupt(obj, TxIrq, 0);
+    serial_rollback_interrupt(obj, TxIrq);
 }
 
 void serial_rx_abort_asynch(serial_t *obj)
@@ -633,20 +603,30 @@ void serial_rx_abort_asynch(serial_t *obj)
     }
 
     // Necessary for both interrupt way and DMA way
-    serial_irq_set(obj, RxIrq, 0);
-    // FIXME: more complete abort operation
-    //UART_HAL_DisableReceiver(obj->serial.serial.address);
-    //UART_HAL_FlushRxFifo(obj->serial.serial.address);
+    serial_enable_interrupt(obj, RxIrq, 0);
+    serial_rollback_interrupt(obj, RxIrq);
 }
 
 uint8_t serial_tx_active(serial_t *obj)
 {
-    return serial_is_irq_en(obj, TxIrq);
+    // NOTE: Judge by serial_is_irq_en(obj, TxIrq) doesn't work with sync/async modes interleaved. Change with TX FIFO empty flag.
+    const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
+    
+    struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;    
+    return (obj->serial.vec == var->vec_async);
 }
 
 uint8_t serial_rx_active(serial_t *obj)
 {
-    return serial_is_irq_en(obj, RxIrq);
+    // NOTE: Judge by serial_is_irq_en(obj, RxIrq) doesn't work with sync/async modes interleaved. Change with RX FIFO empty flag.
+    const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
+    
+    struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;    
+    return (obj->serial.vec == var->vec_async);
 }
 
 int serial_irq_handler_asynch(serial_t *obj)
@@ -886,7 +866,7 @@ static int serial_write_async(serial_t *obj)
 {   
     const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->serial.uart);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
     UART_T *uart_base = (UART_T *) NU_MODBASE(obj->serial.uart);
 
@@ -938,7 +918,7 @@ static int serial_read_async(serial_t *obj)
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->serial.uart);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
     uint32_t rx_fifo_busy = (((UART_T *) NU_MODBASE(obj->serial.uart))->FIFOSTS & UART_FIFOSTS_RXPTR_Msk) >> UART_FIFOSTS_RXPTR_Pos;
     //uint32_t rx_fifo_free = ((struct nu_uart_var *) modinit->var)->fifo_size_rx - rx_fifo_busy;
@@ -1013,28 +993,81 @@ static void serial_tx_enable_interrupt(serial_t *obj, uint32_t handler, uint8_t
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->serial.uart);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
     // Necessary for both interrupt way and DMA way
     struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
     // With our own async vector, tx/rx handlers can be different.
     obj->serial.vec = var->vec_async;
     obj->serial.irq_handler_tx_async = (void (*)(void)) handler;
-    serial_irq_set(obj, TxIrq, enable);
+    serial_enable_interrupt(obj, TxIrq, enable);
 }
 
 static void serial_rx_enable_interrupt(serial_t *obj, uint32_t handler, uint8_t enable)
 {
     const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
     MBED_ASSERT(modinit != NULL);
-    MBED_ASSERT(modinit->modname == obj->serial.uart);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
 
     // Necessary for both interrupt way and DMA way
     struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
     // With our own async vector, tx/rx handlers can be different.
     obj->serial.vec = var->vec_async;
     obj->serial.irq_handler_rx_async = (void (*) (void)) handler;
-    serial_irq_set(obj, RxIrq, enable);
+    serial_enable_interrupt(obj, RxIrq, enable);
+}
+
+static void serial_enable_interrupt(serial_t *obj, SerialIrq irq, uint32_t enable)
+{
+    if (enable) {
+        const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
+        MBED_ASSERT(modinit != NULL);
+        MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
+    
+        NVIC_SetVector(modinit->irq_n, (uint32_t) obj->serial.vec);
+        NVIC_EnableIRQ(modinit->irq_n);
+        
+        struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
+        // Multiple serial S/W objects for single UART H/W module possibly.
+        // Bind serial S/W object to UART H/W module as interrupt is enabled.
+        var->obj = obj;
+        
+        switch (irq) {
+            // NOTE: Setting inten_msk first to avoid race condition
+            case RxIrq:
+                obj->serial.inten_msk = obj->serial.inten_msk | (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk);
+                UART_ENABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk));
+                break;
+            case TxIrq:
+                obj->serial.inten_msk = obj->serial.inten_msk | UART_INTEN_THREIEN_Msk;
+                UART_ENABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), UART_INTEN_THREIEN_Msk);
+                break;
+        }
+    }
+    else { // disable
+        switch (irq) {
+            case RxIrq:
+                UART_DISABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), (UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk));
+                obj->serial.inten_msk = obj->serial.inten_msk & ~(UART_INTEN_RDAIEN_Msk | UART_INTEN_RXTOIEN_Msk);
+                break;
+            case TxIrq:
+                UART_DISABLE_INT(((UART_T *) NU_MODBASE(obj->serial.uart)), UART_INTEN_THREIEN_Msk);
+                obj->serial.inten_msk = obj->serial.inten_msk & ~UART_INTEN_THREIEN_Msk;
+                break;
+        }
+    }
+}
+
+static void serial_rollback_interrupt(serial_t *obj, SerialIrq irq)
+{
+    const struct nu_modinit_s *modinit = get_modinit(obj->serial.uart, uart_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == (int) obj->serial.uart);
+    
+    struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
+    
+    obj->serial.vec = var->vec;
+    serial_enable_interrupt(obj, irq, obj->serial.irq_en);
 }
 
 static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch)

targets/TARGET_NUVOTON/TARGET_NUC472/TARGET_NUMAKER_PFM_NUC472/objects.h

@@ -61,6 +61,7 @@ struct serial_s {
     void        (*vec)(void);
     uint32_t    irq_handler;
     uint32_t    irq_id;
+    uint32_t    irq_en;
     uint32_t    inten_msk;
 
     // Async transfer related fields