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core: Improve Serial implements #206

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130 changes: 72 additions & 58 deletions cores/arduino/zephyrSerial.cpp
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Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
/*
* Copyright (c) 2022 Dhruva Gole
* Copyright (c) Arduino s.r.l. and/or its affiliated companies
*
* SPDX-License-Identifier: Apache-2.0
*/
Expand All @@ -9,6 +10,7 @@

#include <api/HardwareSerial.h>
#include <zephyrSerial.h>
#include <Arduino.h>

namespace {

Expand Down Expand Up @@ -58,10 +60,14 @@ void arduino::ZephyrSerial::begin(unsigned long baud, uint16_t conf) {
.flow_ctrl = UART_CFG_FLOW_CTRL_NONE,
};

uart->ops.init(uart);
_reinit_if_needed();

uart_configure(uart, &config);
uart_irq_callback_user_data_set(uart, arduino::ZephyrSerial::IrqDispatch, this);
k_sem_take(&rx.sem, K_FOREVER);
ring_buf_reset(&rx.ringbuf);
k_sem_give(&rx.sem);

uart_irq_rx_enable(uart);
}

Expand All @@ -72,10 +78,6 @@ void arduino::ZephyrSerial::IrqHandler() {

(void)uart_irq_update(uart);

if (ring_buf_size_get(&tx.ringbuf) == 0) {
uart_irq_tx_disable(uart);
}

k_sem_take(&rx.sem, K_NO_WAIT);
while (uart_irq_rx_ready(uart) && ((length = uart_fifo_read(uart, buf, sizeof(buf))) > 0)) {
length = min(sizeof(buf), static_cast<size_t>(length));
Comment thread
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Expand All @@ -88,6 +90,11 @@ void arduino::ZephyrSerial::IrqHandler() {
k_sem_give(&rx.sem);

k_sem_take(&tx.sem, K_NO_WAIT);

if (ring_buf_size_get(&tx.ringbuf) == 0) {
uart_irq_tx_disable(uart);
}
Comment on lines 92 to +96

@soburi soburi Jul 5, 2026

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Considering addressing this in arduino/ArduinoCore-zephyr.


while (uart_irq_tx_ready(uart) && ((length = ring_buf_size_get(&tx.ringbuf)) > 0)) {
length = min(sizeof(buf), static_cast<size_t>(length));
ring_buf_peek(&tx.ringbuf, &buf[0], length);
Expand All @@ -103,6 +110,7 @@ void arduino::ZephyrSerial::IrqHandler() {
}

void arduino::ZephyrSerial::IrqDispatch(const struct device *dev, void *data) {
(void)dev; // unused
reinterpret_cast<ZephyrSerial *>(data)->IrqHandler();
}

Expand All @@ -116,87 +124,93 @@ int arduino::ZephyrSerial::available() {
return ret;
}

int arduino::ZephyrSerial::availableForWrite() {
int ret;

k_sem_take(&tx.sem, K_FOREVER);
ret = ring_buf_space_get(&tx.ringbuf);
k_sem_give(&tx.sem);

return ret;
}

int arduino::ZephyrSerial::peek() {
uint8_t data;

k_sem_take(&rx.sem, K_FOREVER);
ring_buf_peek(&rx.ringbuf, &data, 1);
uint32_t cb_ret = ring_buf_peek(&rx.ringbuf, &data, 1);
k_sem_give(&rx.sem);

return data;
return cb_ret ? data : -1;
}

int arduino::ZephyrSerial::read() {
uint8_t data;

k_sem_take(&rx.sem, K_FOREVER);
ring_buf_get(&rx.ringbuf, &data, 1);
uint32_t cb_ret = ring_buf_get(&rx.ringbuf, &data, 1);
k_sem_give(&rx.sem);

return data;
return cb_ret ? data : -1;
}

size_t arduino::ZephyrSerial::write(const uint8_t *buffer, size_t size) {
int ret;
size_t idx = 0;

k_sem_take(&tx.sem, K_FOREVER);
ret = ring_buf_put(&tx.ringbuf, buffer, size);
k_sem_give(&tx.sem);

if (ret < 0) {
return 0;
while (1) {
Comment thread
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k_sem_take(&tx.sem, K_FOREVER);
auto ret = ring_buf_put(&tx.ringbuf, &buffer[idx], size - idx);
k_sem_give(&tx.sem);
if (ret < 0) {
return 0;
}
idx += ret;
if (ret == 0) {
uart_irq_tx_enable(uart);
yield();
}
if (idx == size) {
break;
}
}

uart_irq_tx_enable(uart);

return ret;
return size;
}

#if DT_NODE_HAS_PROP(DT_PATH(zephyr_user), serials)
arduino::ZephyrSerial Serial(DEVICE_DT_GET(DT_PHANDLE_BY_IDX(DT_PATH(zephyr_user), serials, 0)));
#if (DT_PROP_LEN(DT_PATH(zephyr_user), serials) > 1)
#define ARDUINO_SERIAL_DEFINED_0 1

#define DECL_SERIAL_0(n, p, i)
#define DECL_SERIAL_N(n, p, i) \
arduino::ZephyrSerial Serial##i(DEVICE_DT_GET(DT_PHANDLE_BY_IDX(n, p, i)));
#define DECLARE_SERIAL_N(n, p, i) \
COND_CODE_1(ARDUINO_SERIAL_DEFINED_##i, (DECL_SERIAL_0(n, p, i)), (DECL_SERIAL_N(n, p, i)))

#define CALL_EVENT_0(n, p, i)
#define CALL_EVENT_N(n, p, i) \
if (_CONCAT(Serial, i).available()) \
_CONCAT(_CONCAT(serial, i), Event)();
#define CALL_SERIALEVENT_N(n, p, i) \
COND_CODE_1(ARDUINO_SERIAL_DEFINED_##i, (CALL_EVENT_0(n, p, i)), (CALL_EVENT_N(n, p, i)));

#define DECL_EVENT_0(n, p, i)
#define DECL_EVENT_N(n, p, i) \
__attribute__((weak)) void serial##i##Event() { \
void arduino::ZephyrSerial::flush() {
while (ring_buf_size_get(&tx.ringbuf) > 0) {
k_yield();
}
#define DECLARE_SERIALEVENT_N(n, p, i) \
COND_CODE_1(ARDUINO_SERIAL_DEFINED_##i, (DECL_EVENT_0(n, p, i)), (DECL_EVENT_N(n, p, i)));

DT_FOREACH_PROP_ELEM(DT_PATH(zephyr_user), serials, DECLARE_SERIAL_N)
#endif // PROP_LEN(serials) > 1
#elif DT_NODE_HAS_STATUS(DT_NODELABEL(arduino_serial), okay)
/* If serials node is not defined, tries to use arduino_serial */
arduino::ZephyrSerial Serial(DEVICE_DT_GET(DT_NODELABEL(arduino_serial)));
#else
arduino::ZephyrSerialStub Serial;
while (uart_irq_tx_complete(uart) == 0) {
k_yield();
}
}

#if DT_NODE_HAS_PROP(DT_PATH(zephyr_user), serials)
#define DEFINE_SERIAL_N(n, p, i) \
arduino::ZephyrSerial ZARD_SERIAL_NAME(i)(DEVICE_DT_GET(DT_PHANDLE_BY_IDX(n, p, i)));
DT_FOREACH_PROP_ELEM(DT_PATH(zephyr_user), serials, DEFINE_SERIAL_N)

#elif DT_NODE_HAS_STATUS_OKAY(DT_NODELABEL(arduino_serial))
arduino::ZephyrSerial ZARD_SERIAL_NAME(0)(DEVICE_DT_GET(DT_NODELABEL(arduino_serial)));
#endif

__attribute__((weak)) void serialEvent() {
}
#if (DT_PROP_LEN(DT_PATH(zephyr_user), serials) > 1)
DT_FOREACH_PROP_ELEM(DT_PATH(zephyr_user), serials, DECLARE_SERIALEVENT_N)
#if ZARD_FIRST_SERIAL_IS_STUB
arduino::ZephyrSerialStub Serial;
#endif

void arduino::serialEventRun(void) {
if (Serial.available()) {
serialEvent();
#define DEFINE_WEAK_SERIALEVENT_N(n, s) \
__attribute__((weak)) void CONCAT(serial, ZARD_SERIAL_STEM(n), Event)() { \
}
#if (DT_PROP_LEN(DT_PATH(zephyr_user), serials) > 1)
DT_FOREACH_PROP_ELEM(DT_PATH(zephyr_user), serials, CALL_SERIALEVENT_N)
#endif

#define CALL_SERIALEVENT_N(n, s) \
if (ZARD_SERIAL_NAME(n).available()) \
CONCAT(serial, ZARD_SERIAL_STEM(n), Event)();

LISTIFY(ZARD_GENERIC_SERIAL_COUNT, DEFINE_WEAK_SERIALEVENT_N, ())

void arduino::serialEventRun(void) {
LISTIFY(ZARD_GENERIC_SERIAL_COUNT, CALL_SERIALEVENT_N, ())
}
116 changes: 96 additions & 20 deletions cores/arduino/zephyrSerial.h
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,24 +1,25 @@
/*
* Copyright (c) 2022 Dhruva Gole
* Copyright (c) Arduino s.r.l. and/or its affiliated companies
*
* SPDX-License-Identifier: Apache-2.0
*/

#pragma once

#include <zephyr/sys/ring_buffer.h>

#include <Arduino.h>
#include <zephyr/kernel.h>
#include <api/HardwareSerial.h>

namespace arduino {

class ZephyrSerialStub : public HardwareSerial {
public:
void begin(unsigned long baudRate) {
void begin(__attribute__((unused)) unsigned long baudRate) {
}

void begin(unsigned long baudrate, uint16_t config) {
void begin(__attribute__((unused)) unsigned long baudrate,
__attribute__((unused)) uint16_t config) {
}

void end() {
Expand Down Expand Up @@ -72,8 +73,7 @@ class ZephyrSerial : public HardwareSerial {
begin(baudrate, SERIAL_8N1);
}

void flush() {
}
void flush();

void end() {
#ifdef CONFIG_DEVICE_DEINIT_SUPPORT
Expand All @@ -89,41 +89,117 @@ class ZephyrSerial : public HardwareSerial {
return write(&data, 1);
}

using Print::write; // pull in write(str) and write(buf, size) from Print
int available();
int availableForWrite();
int peek();
int read();

operator bool() {
return true;
}

friend class SerialUSB_;

protected:
void IrqHandler();
static void IrqDispatch(const struct device *dev, void *data);

const struct device *uart;
ZephyrSerialBuffer<CONFIG_ARDUINO_API_SERIAL_BUFFER_SIZE> tx;
ZephyrSerialBuffer<CONFIG_ARDUINO_API_SERIAL_BUFFER_SIZE> rx;

virtual void _reinit_if_needed() {
uart->ops.init(uart);
}
};

} // namespace arduino

/* Return the index of it if matched, oterwise return an empty string. */
#define ZARD_SERIAL_MATCH(n, p, i, node) \
COND_CODE_1(DT_SAME_NODE(DT_PHANDLE_BY_IDX(n, p, i), node), (i), ())

/* Only matched device returns non-empty value, so the overall expansion is
* matched device's index.
*/
#define ZARD_SERIAL_INDEXOF(node) \
DT_FOREACH_PROP_ELEM_VARGS(DT_PATH(zephyr_user), serials, ZARD_SERIAL_MATCH, node)

/* Serial object associated with the Zephyr console. */
#define ARDUINO_CONSOLE_SERIAL ZARD_SERIAL_NAME(ZARD_SERIAL_INDEXOF(DT_CHOSEN(zephyr_console)))

/* Serial object associated with the first HW serial (usually on D0/D1). */
#define ARDUINO_HARDWARE_SERIAL ZARD_SERIAL_NAME(0)

#if DT_NODE_HAS_PROP(DT_PATH(zephyr_user), cdc_acm_serial)
/* Devicetree requires a SerialUSB object for 'Serial'. */
#define ZARD_SKIP_FIRST_SERIAL 1
#if (CONFIG_USB_CDC_ACM || CONFIG_USBD_CDC_ACM_CLASS)
/* SerialUSB can be compiled in the project. */
#define ZARD_FIRST_SERIAL_IS_SERIALUSB 1
#else
/* SerialUSB is required but no driver was enabled for the USB CDC ACM device.
* Define a stub Serial object to avoid build errors.
*/
#define ZARD_FIRST_SERIAL_IS_STUB 1
#endif
#endif

#if DT_NODE_HAS_PROP(DT_PATH(zephyr_user), arduino_router_serial)
/* If the board has an arduino,router-serial node, and the currently used
* library has the support, then the 'Serial' object is actually the same as
* the Monitor object in the Arduino_RouterBridge library.
*/
#define ZARD_SKIP_FIRST_SERIAL 1
#define ZARD_FIRST_SERIAL_IS_ARDUINO_ROUTER 1
#define ARDUINO_ROUTER_PHANDLE DT_PROP(DT_PATH(zephyr_user), arduino_router_serial)
#define ARDUINO_ROUTER_SERIAL ZARD_SERIAL_NAME(ZARD_SERIAL_INDEXOF(ARDUINO_ROUTER_PHANDLE))
#endif

/* Name of a Serial object for a given index. */
#define ZARD_SERIAL_NAME(n) CONCAT(Serial, ZARD_SERIAL_STEM(n))

/*
* Determine the number of generic ZephyrSerial objects to instantiate.
*/

#if DT_NODE_HAS_PROP(DT_PATH(zephyr_user), serials)
extern arduino::ZephyrSerial Serial;
#if (DT_PROP_LEN(DT_PATH(zephyr_user), serials) > 1)
#define SERIAL_DEFINED_0 1
#define EXTERN_SERIAL_N(i) extern arduino::ZephyrSerial Serial##i;
#define DECLARE_EXTERN_SERIAL_N(n, p, i) COND_CODE_1(SERIAL_DEFINED_##i, (), (EXTERN_SERIAL_N(i)))

/* Declare Serial1, Serial2, ... */
DT_FOREACH_PROP_ELEM(DT_PATH(zephyr_user), serials, DECLARE_EXTERN_SERIAL_N)

#undef DECLARE_EXTERN_SERIAL_N
#undef EXTERN_SERIAL_N
#undef SERIAL_DEFINED_0
/* The array property; the total number is the length of the array. */
#define ZARD_GENERIC_SERIAL_COUNT DT_PROP_LEN(DT_PATH(zephyr_user), serials)

#elif DT_NODE_HAS_STATUS_OKAY(DT_NODELABEL(arduino_serial))
/* A single node with compatible "arduino,serial" is present. */
#define ZARD_GENERIC_SERIAL_COUNT 1

#elif ZARD_SKIP_FIRST_SERIAL
/* Only a special Serial is present. */
#define ZARD_GENERIC_SERIAL_COUNT 0

#else
/* Neither 'serials' property, nor 'arduino,serial' node, nor a special Serial
* is present. Define a stub Serial object to avoid build errors.
*/
#define ZARD_GENERIC_SERIAL_COUNT 0
#define ZARD_SKIP_FIRST_SERIAL 1
#define ZARD_FIRST_SERIAL_IS_STUB 1
#endif
#elif DT_NODE_HAS_STATUS(DT_NODELABEL(arduino_serial), okay)
extern arduino::ZephyrSerial Serial;

#if ZARD_SKIP_FIRST_SERIAL
// Map index 0 to 'Serial1', index 1 to 'Serial2', etc.
#define ZARD_SERIAL_STEM(i) UTIL_INC(i)
#else
// Map index 0 to 'Serial', index 1 to 'Serial1', etc.
#define ZARD_SERIAL_STEM(i) COND_CODE_0(i, (), (i))
#endif

#if ZARD_FIRST_SERIAL_IS_STUB
extern arduino::ZephyrSerialStub Serial;
#endif

#if ZARD_GENERIC_SERIAL_COUNT > 0
/* Declare all generic ZephyrSerial objects */
#define DECLARE_SERIAL_N(n, s) extern arduino::ZephyrSerial ZARD_SERIAL_NAME(n);
LISTIFY(ZARD_GENERIC_SERIAL_COUNT, DECLARE_SERIAL_N, ())
#undef DECLARE_SERIAL_N
#endif
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