From 8701c881cf81ba730584e54d870c22568edea8e0 Mon Sep 17 00:00:00 2001
From: Rodrigo Garcia <rodrigo.garcia@espressif.com>
Date: Sun, 27 Nov 2022 17:09:41 -0300
Subject: [PATCH 1/4] Improves UART reading performance
---
cores/esp32/HardwareSerial.cpp | 19 ++++++-------------
cores/esp32/esp32-hal-uart.c | 28 ++++++++++++++++++++++++++++
cores/esp32/esp32-hal-uart.h | 1 +
3 files changed, 35 insertions(+), 13 deletions(-)
diff --git a/cores/esp32/HardwareSerial.cpp b/cores/esp32/HardwareSerial.cpp
index 049c24a74d5..96fbb82cdc5 100644
--- a/cores/esp32/HardwareSerial.cpp
+++ b/cores/esp32/HardwareSerial.cpp
@@ -450,10 +450,12 @@ int HardwareSerial::peek(void)
int HardwareSerial::read(void)
{
- if(available()) {
- return uartRead(_uart);
+ uint8_t c = 0;
+ if (uartReadBytes(_uart, &c, 1, 0) == 1) {
+ return c;
+ } else {
+ return -1;
}
- return -1;
}
// read characters into buffer
@@ -462,16 +464,7 @@ int HardwareSerial::read(void)
// the buffer is NOT null terminated.
size_t HardwareSerial::read(uint8_t *buffer, size_t size)
{
- size_t avail = available();
- if (size < avail) {
- avail = size;
- }
- size_t count = 0;
- while(count < avail) {
- *buffer++ = uartRead(_uart);
- count++;
- }
- return count;
+ return uartReadBytes(_uart, buffer, size, 0);
}
void HardwareSerial::flush(void)
diff --git a/cores/esp32/esp32-hal-uart.c b/cores/esp32/esp32-hal-uart.c
index e4b24a112f5..5ad7ba13a9c 100644
--- a/cores/esp32/esp32-hal-uart.c
+++ b/cores/esp32/esp32-hal-uart.c
@@ -326,6 +326,34 @@ uint32_t uartAvailableForWrite(uart_t* uart)
return available;
}
+size_t uartReadBytes(uart_t* uart, uint8_t *buffer, size_t size, uint32_t timeout_ms)
+{
+ if(uart == NULL || size == 0 || buffer == NULL) {
+ return 0;
+ }
+
+ size_t bytes_read = 0;
+
+ UART_MUTEX_LOCK();
+
+ if (uart->has_peek) {
+ uart->has_peek = false;
+ *buffer++ = uart->peek_byte;
+ size--;
+ bytes_read = 1;
+ }
+
+ if (size > 0) {
+ int len = uart_read_bytes(uart->num, buffer, size, pdMS_TO_TICKS(timeout_ms));
+ if (len < 0) len = 0; // error reading UART
+ bytes_read += len;
+ }
+
+
+ UART_MUTEX_UNLOCK();
+ return bytes_read;
+}
+
uint8_t uartRead(uart_t* uart)
{
diff --git a/cores/esp32/esp32-hal-uart.h b/cores/esp32/esp32-hal-uart.h
index ffb0a3f027a..8e6e7ec4a1b 100644
--- a/cores/esp32/esp32-hal-uart.h
+++ b/cores/esp32/esp32-hal-uart.h
@@ -69,6 +69,7 @@ void uartGetEventQueue(uart_t* uart, QueueHandle_t *q);
uint32_t uartAvailable(uart_t* uart);
uint32_t uartAvailableForWrite(uart_t* uart);
+size_t uartReadBytes(uart_t* uart, uint8_t *buffer, size_t size, uint32_t timeout_ms);
uint8_t uartRead(uart_t* uart);
uint8_t uartPeek(uart_t* uart);
From e0723028494de5ad6349a039bdd5a190fc5c61ab Mon Sep 17 00:00:00 2001
From: Rodrigo Garcia <rodrigo.garcia@espressif.com>
Date: Sun, 4 Dec 2022 10:44:58 -0300
Subject: [PATCH 2/4] overrides Stream::readBytes()
---
cores/esp32/HardwareSerial.cpp | 6 ++++++
cores/esp32/HardwareSerial.h | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/cores/esp32/HardwareSerial.cpp b/cores/esp32/HardwareSerial.cpp
index 96fbb82cdc5..7b8ee993581 100644
--- a/cores/esp32/HardwareSerial.cpp
+++ b/cores/esp32/HardwareSerial.cpp
@@ -467,6 +467,12 @@ size_t HardwareSerial::read(uint8_t *buffer, size_t size)
return uartReadBytes(_uart, buffer, size, 0);
}
+// Overrides Stream::readBytes() to be faster using IDF
+size_t HardwareSerial::readBytes(uint8_t *buffer, size_t length)
+{
+ return uartReadBytes(_uart, buffer, length, (uint32_t)getTimeout());
+}
+
void HardwareSerial::flush(void)
{
uartFlush(_uart);
diff --git a/cores/esp32/HardwareSerial.h b/cores/esp32/HardwareSerial.h
index 0c673c1483f..24b1421311b 100644
--- a/cores/esp32/HardwareSerial.h
+++ b/cores/esp32/HardwareSerial.h
@@ -118,6 +118,12 @@ class HardwareSerial: public Stream
{
return read((uint8_t*) buffer, size);
}
+ // Overrides Stream::readBytes() to be faster using IDF
+ size_t readBytes(uint8_t *buffer, size_t length);
+ size_t readBytes(char *buffer, size_t length)
+ {
+ return readBytes((char *) buffer, length);
+ }
void flush(void);
void flush( bool txOnly);
size_t write(uint8_t);
From 6ef09b6a4e13f65b268117ce8356a660d9683ba1 Mon Sep 17 00:00:00 2001
From: Rodrigo Garcia <rodrigo.garcia@espressif.com>
Date: Tue, 6 Dec 2022 16:42:48 -0300
Subject: [PATCH 3/4] fixes override signature
---
cores/esp32/HardwareSerial.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/cores/esp32/HardwareSerial.h b/cores/esp32/HardwareSerial.h
index 24b1421311b..d5f9c7c1a7b 100644
--- a/cores/esp32/HardwareSerial.h
+++ b/cores/esp32/HardwareSerial.h
@@ -122,7 +122,7 @@ class HardwareSerial: public Stream
size_t readBytes(uint8_t *buffer, size_t length);
size_t readBytes(char *buffer, size_t length)
{
- return readBytes((char *) buffer, length);
+ return readBytes((uint8_t *) buffer, length);
}
void flush(void);
void flush( bool txOnly);
From d37a199ebe23ff0f4eb7b923687490780c23ae42 Mon Sep 17 00:00:00 2001
From: Rodrigo Garcia <rodrigo.garcia@espressif.com>
Date: Tue, 6 Dec 2022 16:57:06 -0300
Subject: [PATCH 4/4] adds some IDF error return conditions
---
cores/esp32/esp32-hal-uart.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/cores/esp32/esp32-hal-uart.c b/cores/esp32/esp32-hal-uart.c
index 5ad7ba13a9c..cad9ce7d9c2 100644
--- a/cores/esp32/esp32-hal-uart.c
+++ b/cores/esp32/esp32-hal-uart.c
@@ -354,7 +354,8 @@ size_t uartReadBytes(uart_t* uart, uint8_t *buffer, size_t size, uint32_t timeou
return bytes_read;
}
-
+// DEPRICATED but the original code will be kepts here as future reference when a final solution
+// to the UART driver is defined in the use case of reading byte by byte from UART.
uint8_t uartRead(uart_t* uart)
{
if(uart == NULL) {
@@ -370,7 +371,7 @@ uint8_t uartRead(uart_t* uart)
} else {
int len = uart_read_bytes(uart->num, &c, 1, 20 / portTICK_RATE_MS);
- if (len == 0) {
+ if (len <= 0) { // includes negative return from IDF in case of error
c = 0;
}
}
@@ -378,6 +379,7 @@ uint8_t uartRead(uart_t* uart)
return c;
}
+
uint8_t uartPeek(uart_t* uart)
{
if(uart == NULL) {
@@ -391,7 +393,7 @@ uint8_t uartPeek(uart_t* uart)
c = uart->peek_byte;
} else {
int len = uart_read_bytes(uart->num, &c, 1, 20 / portTICK_RATE_MS);
- if (len == 0) {
+ if (len <= 0) { // includes negative return from IDF in case of error
c = 0;
} else {
uart->has_peek = true;