API to temporarily enable/disable FileHandles

UNITTESTS/stubs/UARTSerial_stub.cpp

@@ -120,6 +120,16 @@ void UARTSerial::tx_irq(void)
 {
 }
 
+int UARTSerial::enable_input(bool enabled)
+{
+    return 0;
+}
+
+int UARTSerial::enable_output(bool enabled)
+{
+    return 0;
+}
+
 void UARTSerial::wait_ms(uint32_t millisec)
 {
 

drivers/UARTSerial.cpp

@@ -32,11 +32,13 @@ UARTSerial::UARTSerial(PinName tx, PinName rx, int baud) :
     SerialBase(tx, rx, baud),
     _blocking(true),
     _tx_irq_enabled(false),
-    _rx_irq_enabled(true),
+    _rx_irq_enabled(false),
+    _tx_enabled(true),
+    _rx_enabled(true),
     _dcd_irq(NULL)
 {
     /* Attatch IRQ routines to the serial device. */
-    SerialBase::attach(callback(this, &UARTSerial::rx_irq), RxIrq);
+    enable_rx_irq();
 }
 
 UARTSerial::~UARTSerial()
@@ -188,11 +190,10 @@ ssize_t UARTSerial::write(const void *buffer, size_t length)
         }
 
         core_util_critical_section_enter();
-        if (!_tx_irq_enabled) {
+        if (_tx_enabled && !_tx_irq_enabled) {
             UARTSerial::tx_irq();                // only write to hardware in one place
             if (!_txbuf.empty()) {
-                SerialBase::attach(callback(this, &UARTSerial::tx_irq), TxIrq);
-                _tx_irq_enabled = true;
+                enable_tx_irq();
             }
         }
         core_util_critical_section_exit();
@@ -231,11 +232,10 @@ ssize_t UARTSerial::read(void *buffer, size_t length)
     }
 
     core_util_critical_section_enter();
-    if (!_rx_irq_enabled) {
+    if (_rx_enabled && !_rx_irq_enabled) {
         UARTSerial::rx_irq();               // only read from hardware in one place
         if (!_rxbuf.full()) {
-            SerialBase::attach(callback(this, &UARTSerial::rx_irq), RxIrq);
-            _rx_irq_enabled = true;
+            enable_rx_irq();
         }
     }
     core_util_critical_section_exit();
@@ -314,8 +314,7 @@ void UARTSerial::rx_irq(void)
     }
 
     if (_rx_irq_enabled && _rxbuf.full()) {
-        SerialBase::attach(NULL, RxIrq);
-        _rx_irq_enabled = false;
+        disable_rx_irq();
     }
 
     /* Report the File handler that data is ready to be read from the buffer. */
@@ -337,8 +336,7 @@ void UARTSerial::tx_irq(void)
     }
 
     if (_tx_irq_enabled && _txbuf.empty()) {
-        SerialBase::attach(NULL, TxIrq);
-        _tx_irq_enabled = false;
+        disable_tx_irq();
     }
 
     /* Report the File handler that data can be written to peripheral. */
@@ -347,6 +345,69 @@ void UARTSerial::tx_irq(void)
     }
 }
 
+/* These are all called from critical section */
+void UARTSerial::enable_rx_irq()
+{
+    SerialBase::attach(callback(this, &UARTSerial::rx_irq), RxIrq);
+    _rx_irq_enabled = true;
+}
+
+void UARTSerial::disable_rx_irq()
+{
+    SerialBase::attach(NULL, RxIrq);
+    _rx_irq_enabled = false;
+}
+
+void UARTSerial::enable_tx_irq()
+{
+    SerialBase::attach(callback(this, &UARTSerial::tx_irq), TxIrq);
+    _tx_irq_enabled = true;
+}
+
+void UARTSerial::disable_tx_irq()
+{
+    SerialBase::attach(NULL, TxIrq);
+    _tx_irq_enabled = false;
+}
+
+int UARTSerial::enable_input(bool enabled)
+{
+    core_util_critical_section_enter();
+    if (_rx_enabled != enabled) {
+        if (enabled) {
+            UARTSerial::rx_irq();
+            if (!_rxbuf.full()) {
+                enable_rx_irq();
+            }
+        } else {
+            disable_rx_irq();
+        }
+        _rx_enabled = enabled;
+    }
+    core_util_critical_section_exit();
+
+    return 0;
+}
+
+int UARTSerial::enable_output(bool enabled)
+{
+    core_util_critical_section_enter();
+    if (_tx_enabled != enabled) {
+        if (enabled) {
+            UARTSerial::tx_irq();
+            if (!_txbuf.empty()) {
+                enable_tx_irq();
+            }
+        } else {
+            disable_tx_irq();
+        }
+        _tx_enabled = enabled;
+    }
+    core_util_critical_section_exit();
+
+    return 0;
+}
+
 void UARTSerial::wait_ms(uint32_t millisec)
 {
     /* wait_ms implementation for RTOS spins until exact microseconds - we

drivers/UARTSerial.h

@@ -152,6 +152,36 @@ class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UA
         return _blocking;
     }
 
+    /** Enable or disable input
+     *
+     * Control enabling of device for input. This is primarily intended
+     * for temporary power-saving; the overall ability of the device to operate for
+     * input and/or output may be fixed at creation time, but this call can
+     * allow input to be temporarily disabled to permit power saving without
+     * losing device state.
+     *
+     *  @param enabled      true to enable input, false to disable.
+     *
+     *  @return             0 on success
+     *  @return             Negative error code on failure
+     */
+    virtual int enable_input(bool enabled);
+
+    /** Enable or disable output
+     *
+     * Control enabling of device for output. This is primarily intended
+     * for temporary power-saving; the overall ability of the device to operate for
+     * input and/or output may be fixed at creation time, but this call can
+     * allow output to be temporarily disabled to permit power saving without
+     * losing device state.
+     *
+     *  @param enabled      true to enable output, false to disable.
+     *
+     *  @return             0 on success
+     *  @return             Negative error code on failure
+     */
+    virtual int enable_output(bool enabled);
+
     /** Register a callback on state change of the file.
      *
      *  The specified callback will be called on state changes such as when
@@ -242,6 +272,11 @@ class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UA
     /** Unbuffered write - invoked when write called from critical section */
     ssize_t write_unbuffered(const char *buf_ptr, size_t length);
 
+    void enable_rx_irq();
+    void disable_rx_irq();
+    void enable_tx_irq();
+    void disable_tx_irq();
+
     /** Software serial buffers
      *  By default buffer size is 256 for TX and 256 for RX. Configurable through mbed_app.json
      */
@@ -255,6 +290,8 @@ class UARTSerial : private SerialBase, public FileHandle, private NonCopyable<UA
     bool _blocking;
     bool _tx_irq_enabled;
     bool _rx_irq_enabled;
+    bool _tx_enabled;
+    bool _rx_enabled;
     InterruptIn *_dcd_irq;
 
     /** Device Hanged up

platform/FileHandle.h

@@ -220,6 +220,42 @@ class FileHandle : private NonCopyable<FileHandle> {
         return true;
     }
 
+    /** Enable or disable input
+     *
+     * Control enabling of device for input. This is primarily intended
+     * for temporary power-saving; the overall ability of the device to operate for
+     * input and/or output may be fixed at creation time, but this call can
+     * allow input to be temporarily disabled to permit power saving without
+     * losing device state.
+     *
+     *  @param enabled      true to enable input, false to disable.
+     *
+     *  @return             0 on success
+     *  @return             Negative error code on failure
+     */
+    virtual int enable_input(bool enabled)
+    {
+        return -EINVAL;
+    }
+
+    /** Enable or disable output
+     *
+     * Control enabling of device for output. This is primarily intended
+     * for temporary power-saving; the overall ability of the device to operate for
+     * input and/or output may be fixed at creation time, but this call can
+     * allow output to be temporarily disabled to permit power saving without
+     * losing device state.
+     *
+     *  @param enabled      true to enable output, false to disable.
+     *
+     *  @return             0 on success
+     *  @return             Negative error code on failure
+     */
+    virtual int enable_output(bool enabled)
+    {
+        return -EINVAL;
+    }
+
     /** Check for poll event flags
      * You can use or ignore the input parameter. You can return all events
      * or check just the events listed in events.

platform/mbed_retarget.cpp

@@ -290,7 +290,7 @@ static FileHandle *get_console(int fd)
 }
 
 /* Deal with the fact C library may not _open descriptors 0, 1, 2 - auto bind */
-static FileHandle *get_fhc(int fd)
+FileHandle *mbed::mbed_file_handle(int fd)
 {
     if (fd >= OPEN_MAX) {
         return NULL;
@@ -490,13 +490,13 @@ extern "C" FILEHANDLE PREFIX(_open)(const char *name, int openflags)
     /* Use the posix convention that stdin,out,err are filehandles 0,1,2.
      */
     if (std::strcmp(name, __stdin_name) == 0) {
-        get_fhc(STDIN_FILENO);
+        mbed_file_handle(STDIN_FILENO);
         return STDIN_FILENO;
     } else if (std::strcmp(name, __stdout_name) == 0) {
-        get_fhc(STDOUT_FILENO);
+        mbed_file_handle(STDOUT_FILENO);
         return STDOUT_FILENO;
     } else if (std::strcmp(name, __stderr_name) == 0) {
-        get_fhc(STDERR_FILENO);
+        mbed_file_handle(STDERR_FILENO);
         return STDERR_FILENO;
     }
 #endif
@@ -555,7 +555,7 @@ extern "C" int PREFIX(_close)(FILEHANDLE fh)
 
 extern "C" int close(int fildes)
 {
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     filehandles[fildes] = NULL;
     if (fhc == NULL) {
         errno = EBADF;
@@ -667,7 +667,7 @@ extern "C" int PREFIX(_write)(FILEHANDLE fh, const unsigned char *buffer, unsign
 extern "C" ssize_t write(int fildes, const void *buf, size_t length)
 {
 
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -761,8 +761,7 @@ extern "C" int PREFIX(_read)(FILEHANDLE fh, unsigned char *buffer, unsigned int
 
 extern "C" ssize_t read(int fildes, void *buf, size_t length)
 {
-
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -789,7 +788,7 @@ extern "C" int _isatty(FILEHANDLE fh)
 
 extern "C" int isatty(int fildes)
 {
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return 0;
@@ -828,7 +827,7 @@ int _lseek(FILEHANDLE fh, int offset, int whence)
 
 extern "C" off_t lseek(int fildes, off_t offset, int whence)
 {
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -844,7 +843,7 @@ extern "C" off_t lseek(int fildes, off_t offset, int whence)
 
 extern "C" int ftruncate(int fildes, off_t length)
 {
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -868,7 +867,7 @@ extern "C" int PREFIX(_ensure)(FILEHANDLE fh)
 
 extern "C" int fsync(int fildes)
 {
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -886,7 +885,7 @@ extern "C" int fsync(int fildes)
 #ifdef __ARMCC_VERSION
 extern "C" long PREFIX(_flen)(FILEHANDLE fh)
 {
-    FileHandle *fhc = get_fhc(fh);
+    FileHandle *fhc = mbed_file_handle(fh);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -936,7 +935,7 @@ extern "C" int _fstat(int fh, struct stat *st)
 
 extern "C" int fstat(int fildes, struct stat *st)
 {
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -949,7 +948,7 @@ extern "C" int fstat(int fildes, struct stat *st)
 
 extern "C" int fcntl(int fildes, int cmd, ...)
 {
-    FileHandle *fhc = get_fhc(fildes);
+    FileHandle *fhc = mbed_file_handle(fildes);
     if (fhc == NULL) {
         errno = EBADF;
         return -1;
@@ -994,7 +993,7 @@ extern "C" int poll(struct pollfd fds[], nfds_t nfds, int timeout)
     for (nfds_t n = 0; n < nfds; n++) {
         // Underlying FileHandle poll returns POLLNVAL if given NULL, so
         // we don't need to take special action.
-        fhs[n].fh = get_fhc(fds[n].fd);
+        fhs[n].fh = mbed_file_handle(fds[n].fd);
         fhs[n].events = fds[n].events;
     }
     int ret = poll(fhs, nfds, timeout);