Fix serial corruption due to deep sleep

Prevent deep sleep when there is still any character being transmitted on the UART.
This allows tickless to be safely enabled.

targets/TARGET_NUVOTON/TARGET_M2351/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -87,6 +88,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1171,4 +1174,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_M2351/sleep.c

@@ -22,9 +22,14 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
 
 #if defined (__ARM_FEATURE_CMSE) && (__ARM_FEATURE_CMSE == 3U)
 
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
+
 /**
  * Enter idle mode, in which just CPU is halted.
  */
@@ -42,6 +47,12 @@ void hal_sleep(void)
 __NONSECURE_ENTRY
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/TARGET_M451/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -83,6 +84,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1088,4 +1091,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_M451/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/TARGET_M480/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -87,6 +88,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1145,4 +1148,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_M480/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/TARGET_NANO100/serial_api.c

@@ -18,13 +18,14 @@
 
 #if DEVICE_SERIAL
 
-#include <string.h>
 #include "cmsis.h"
 #include "mbed_error.h"
 #include "mbed_assert.h"
 #include "PeripheralPins.h"
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
+#include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -76,6 +77,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -990,4 +993,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_NANO100/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();

targets/TARGET_NUVOTON/TARGET_NUC472/serial_api.c

@@ -25,6 +25,7 @@
 #include "nu_modutil.h"
 #include "nu_bitutil.h"
 #include <string.h>
+#include <stdbool.h>
 
 #if DEVICE_SERIAL_ASYNCH
 #include "dma_api.h"
@@ -87,6 +88,8 @@ static void serial_check_dma_usage(DMAUsage *dma_usage, int *dma_ch);
 static int serial_is_irq_en(serial_t *obj, SerialIrq irq);
 #endif
 
+bool serial_can_deep_sleep(void);
+
 static struct nu_uart_var uart0_var = {
     .ref_cnt            =   0,
     .obj                =   NULL,
@@ -1136,4 +1139,23 @@ static int serial_is_irq_en(serial_t *obj, SerialIrq irq)
 }
 
 #endif  // #if DEVICE_SERIAL_ASYNCH
+
+bool serial_can_deep_sleep(void)
+{
+    bool sleep_allowed = 1;
+    const struct nu_modinit_s *modinit = uart_modinit_tab;
+    while (modinit->var != NULL) {
+        struct nu_uart_var *uart_var = (struct nu_uart_var *) modinit->var;
+        UART_T *uart_base = (UART_T *) NU_MODBASE(modinit->modname);
+        if (uart_var->ref_cnt > 0) {
+            if (!UART_IS_TX_EMPTY(uart_base)) {
+                sleep_allowed = 0;
+                break;
+            }
+        }
+        modinit++;
+    }
+    return sleep_allowed;
+}
+
 #endif  // #if DEVICE_SERIAL

targets/TARGET_NUVOTON/TARGET_NUC472/sleep.c

@@ -22,6 +22,11 @@
 #include "device.h"
 #include "objects.h"
 #include "PeripheralPins.h"
+#include <stdbool.h>
+
+#if DEVICE_SERIAL
+bool serial_can_deep_sleep(void);
+#endif
 
 /**
  * Enter idle mode, in which just CPU is halted.
@@ -38,6 +43,12 @@ void hal_sleep(void)
  */
 void hal_deepsleep(void)
 {
+#if DEVICE_SERIAL
+    if (!serial_can_deep_sleep()) {
+        return;
+    }
+#endif
+
     SYS_UnlockReg();
     CLK_PowerDown();
     SYS_LockReg();