Diff: drivers/UARTSerial.cpp

Revision:

168:e84263d55307

Child:

169:9672193075cf

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/UARTSerial.cpp	Wed Jun 21 17:46:44 2017 +0100
@@ -0,0 +1,265 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if DEVICE_SERIAL
+
+#include <errno.h>
+#include "UARTSerial.h"
+#include "platform/mbed_poll.h"
+#include "platform/mbed_wait_api.h"
+
+namespace mbed {
+
+UARTSerial::UARTSerial(PinName tx, PinName rx, int baud) :
+        SerialBase(tx, rx, baud),
+        _blocking(true),
+        _tx_irq_enabled(false),
+        _dcd_irq(NULL)
+{
+    /* Attatch IRQ routines to the serial device. */
+    SerialBase::attach(callback(this, &UARTSerial::rx_irq), RxIrq);
+}
+
+UARTSerial::~UARTSerial()
+{
+    delete _dcd_irq;
+}
+
+void UARTSerial::dcd_irq()
+{
+    wake();
+}
+
+void UARTSerial::set_data_carrier_detect(PinName dcd_pin, bool active_high)
+{
+     delete _dcd_irq;
+    _dcd_irq = NULL;
+
+    if (dcd_pin != NC) {
+        _dcd_irq = new InterruptIn(dcd_pin);
+        if (active_high) {
+            _dcd_irq->fall(callback(this, &UARTSerial::dcd_irq));
+        } else {
+            _dcd_irq->rise(callback(this, &UARTSerial::dcd_irq));
+        }
+    }
+}
+
+int UARTSerial::close()
+{
+    /* Does not let us pass a file descriptor. So how to close ?
+     * Also, does it make sense to close a device type file descriptor*/
+    return 0;
+}
+
+int UARTSerial::isatty()
+{
+    return 1;
+
+}
+
+off_t UARTSerial::seek(off_t offset, int whence)
+{
+    /*XXX lseek can be done theoratically, but is it sane to mark positions on a dynamically growing/shrinking
+     * buffer system (from an interrupt context) */
+    return -ESPIPE;
+}
+
+int UARTSerial::sync()
+{
+    lock();
+
+    while (!_txbuf.empty()) {
+        unlock();
+        // Doing better than wait would require TxIRQ to also do wake() when becoming empty. Worth it?
+        wait_ms(1);
+        lock();
+    }
+
+    unlock();
+
+    return 0;
+}
+
+void UARTSerial::sigio(Callback<void()> func) {
+    core_util_critical_section_enter();
+    _sigio_cb = func;
+    if (_sigio_cb) {
+        short current_events = poll(0x7FFF);
+        if (current_events) {
+            _sigio_cb();
+        }
+    }
+    core_util_critical_section_exit();
+}
+
+ssize_t UARTSerial::write(const void* buffer, size_t length)
+{
+    size_t data_written = 0;
+    const char *buf_ptr = static_cast<const char *>(buffer);
+
+    lock();
+
+    while (_txbuf.full()) {
+        if (!_blocking) {
+            unlock();
+            return -EAGAIN;
+        }
+        unlock();
+        wait_ms(1); // XXX todo - proper wait, WFE for non-rtos ?
+        lock();
+    }
+
+    while (data_written < length && !_txbuf.full()) {
+        _txbuf.push(*buf_ptr++);
+        data_written++;
+    }
+
+    core_util_critical_section_enter();
+    if (!_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;
+        }
+    }
+    core_util_critical_section_exit();
+
+    unlock();
+
+    return data_written;
+}
+
+ssize_t UARTSerial::read(void* buffer, size_t length)
+{
+    size_t data_read = 0;
+
+    char *ptr = static_cast<char *>(buffer);
+
+    lock();
+
+    while (_rxbuf.empty()) {
+        if (!_blocking) {
+            unlock();
+            return -EAGAIN;
+        }
+        unlock();
+        wait_ms(1);  // XXX todo - proper wait, WFE for non-rtos ?
+        lock();
+    }
+
+    while (data_read < length && !_rxbuf.empty()) {
+        _rxbuf.pop(*ptr++);
+        data_read++;
+    }
+
+    unlock();
+
+    return data_read;
+}
+
+bool UARTSerial::hup() const
+{
+    return _dcd_irq && _dcd_irq->read() != 0;
+}
+
+void UARTSerial::wake()
+{
+    if (_sigio_cb) {
+        _sigio_cb();
+    }
+}
+
+short UARTSerial::poll(short events) const {
+
+    short revents = 0;
+    /* Check the Circular Buffer if space available for writing out */
+
+
+    if (!_rxbuf.empty()) {
+        revents |= POLLIN;
+    }
+
+    /* POLLHUP and POLLOUT are mutually exclusive */
+    if (hup()) {
+        revents |= POLLHUP;
+    } else if (!_txbuf.full()) {
+        revents |= POLLOUT;
+    }
+
+    /*TODO Handle other event types */
+
+    return revents;
+}
+
+void UARTSerial::lock(void)
+{
+    _mutex.lock();
+}
+
+void UARTSerial::unlock(void)
+{
+    _mutex.unlock();
+}
+
+void UARTSerial::rx_irq(void)
+{
+    bool was_empty = _rxbuf.empty();
+
+    /* Fill in the receive buffer if the peripheral is readable
+     * and receive buffer is not full. */
+    while (SerialBase::readable()) {
+        char data = SerialBase::_base_getc();
+        if (!_rxbuf.full()) {
+            _rxbuf.push(data);
+        } else {
+            /* Drop - can we report in some way? */
+        }
+    }
+
+    /* Report the File handler that data is ready to be read from the buffer. */
+    if (was_empty && !_rxbuf.empty()) {
+        wake();
+    }
+}
+
+// Also called from write to start transfer
+void UARTSerial::tx_irq(void)
+{
+    bool was_full = _txbuf.full();
+
+    /* Write to the peripheral if there is something to write
+     * and if the peripheral is available to write. */
+    while (!_txbuf.empty() && SerialBase::writeable()) {
+        char data;
+        _txbuf.pop(data);
+        SerialBase::_base_putc(data);
+    }
+
+    if (_tx_irq_enabled && _txbuf.empty()) {
+        SerialBase::attach(NULL, TxIrq);
+        _tx_irq_enabled = false;
+    }
+
+    /* Report the File handler that data can be written to peripheral. */
+    if (was_full && !_txbuf.full() && !hup()) {
+        wake();
+    }
+}
+
+} //namespace mbed
+
+#endif //DEVICE_SERIAL