Support wired network interfaces (W5500, W5100, ENC28J60) (#1703)

Enable use of wired Ethernet modules as first-class LWIP citizens.  All
networking classes like MDNS, WebServer, HTTPClient, WiFiClient, and OTA
can use a wired Ethernet adapter just like built-in WiFi.

Two examples updated to show proper use.

Uses the Async Context support built into the Pico SDK.  When running on the
Pico  it will use the CYW43 async instance.

Uses modified wired Ethernet drivers, thanks Nicholas Humfrey!

Note, the classic, non-LWIP integrated `Ethernet` and related libraries
should still work fine (but not be able to use WebServer/HTTPS/etc.)

Fixes #775

README.md

@@ -202,6 +202,7 @@ The installed tools include a version of OpenOCD (in the pqt-openocd directory)
 * Bluetooth on the PicoW (Classic and BLE) with Keyboard, Mouse, Joystick, and Virtual Serial
 * Generic Arduino USB Serial, Keyboard, Joystick, and Mouse emulation
 * WiFi (Pico W)
+* Ethernet (Wired W5500, W5100, ENC28J60)
 * HTTP client and server (WebServer)
 * SSL/TLS/HTTPS
 * Over-the-Air (OTA) upgrades

cores/rp2040/lwip_wrap.cpp

@@ -18,6 +18,7 @@
     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
+#include <Arduino.h>
 #include <pico/mutex.h>
 #include <lwip/pbuf.h>
 #include <lwip/udp.h>
@@ -26,20 +27,61 @@
 #include <lwip/raw.h>
 #include <lwip/timeouts.h>
 #include <pico/cyw43_arch.h>
+#include <pico/mutex.h>
+#include <sys/lock.h>
+
+#if !defined(ARDUINO_RASPBERRY_PI_PICO_W)
+extern void ethernet_arch_lwip_begin() __attribute__((weak));
+extern void ethernet_arch_lwip_end() __attribute__((weak));
+
+auto_init_recursive_mutex(__lwipMutex); // Only for non-PicoW case
+#endif
 
 class LWIPMutex {
 public:
     LWIPMutex() {
-        cyw43_arch_lwip_begin();
+#if defined(ARDUINO_RASPBERRY_PI_PICO_W)
+        if (rp2040.isPicoW()) {
+            cyw43_arch_lwip_begin();
+            return;
+        }
+#else
+        if (ethernet_arch_lwip_begin) {
+            ethernet_arch_lwip_begin();
+        } else {
+            recursive_mutex_enter_blocking(&__lwipMutex);
+        }
+#endif
     }
 
     ~LWIPMutex() {
-        cyw43_arch_lwip_end();
+#if defined(ARDUINO_RASPBERRY_PI_PICO_W)
+        if (rp2040.isPicoW()) {
+            cyw43_arch_lwip_end();
+            return;
+        }
+#else
+        if (ethernet_arch_lwip_end) {
+            ethernet_arch_lwip_end();
+        } else {
+            recursive_mutex_exit(&__lwipMutex);
+        }
+#endif
     }
 };
 
 extern "C" {
 
+    // Avoid calling lwip_init multiple times
+    extern void __real_lwip_init();
+    void __wrap_lwip_init() {
+        static bool initted = false;
+        if (!initted) {
+            __real_lwip_init();
+            initted = true;
+        }
+    }
+
     extern u8_t __real_pbuf_header(struct pbuf *p, s16_t header_size);
     u8_t __wrap_pbuf_header(struct pbuf *p, s16_t header_size) {
         LWIPMutex m;

docs/ethernet.rst

@@ -0,0 +1,139 @@
+EthernetLWIP (Wired Ethernet) Support
+=====================================
+
+Wired Ethernet interfaces are supported for all the internal networking
+libraries (``WiFiClient``, ``WiFiClientSecure``, ``WiFiServer``,
+``WiFiServerSecure``, ``WiFiUDP``, ``WebServer``, ``Updater``,
+``HTTPClient``, etc.).
+
+Using these wired interfaces is very similar to using the Pico-W WiFi
+so most examples in the core only require minor modifications to use
+a wired interface.
+
+Supported Wired Ethernet Modules
+--------------------------------
+
+* Wiznet W5100
+
+* Wiznet W5500
+
+* ENC28J60
+
+
+Enabling Wired Ethernet
+-----------------------
+
+Simply replace the WiFi include at the top with:
+
+.. code:: cpp
+
+    #include <W5500lwIP.h> // Or W5100lwIP.h or ENC28J60.h
+    
+
+And add a global Ethernet object of the same type:
+
+.. code:: cpp
+
+    Wiznet5500lwIP eth(1); // Parameter is the Chip Select pin
+
+In your ``setup()`` you may adjust the SPI pins you're using to
+match your hardware (be sure they are legal for the RP2040!), or
+skip this if you're using the default ones:
+
+.. code:: cpp
+
+    void setup() {
+        SPI.setRX(0);
+        SPI.setCS(1);
+        SPI.setSCK(2);
+        SPI.setTX(3);
+        ....
+    }
+
+And finally replace the ``WiFi.begin()`` and ``WiFi.connected()``
+calls with ``eth.begin()`` and ``eth.connected()``:
+
+.. code:: cpp
+
+    void setup() {
+        ....
+        // WiFi.begin(SSID, PASS)
+        eth.begin();
+        
+        //while (!WiFi.connected()) {
+        while (!eth.connected()) {
+            Serial.print(".");
+        }
+
+        Serial.print("IP address: ");
+        //Serial.println(WiFi.localIP());
+        Serial.println(eth.localIP());
+
+        ....
+    }
+
+Adjusting LWIP Polling
+----------------------
+
+LWIP operates in a polling mode for the wired Ethernet devices.  By default it will run
+every 20ms, meaning that on average it will take half that time (10ms) before a packet
+received in the Ethernet module is received and operated upon by the Pico.  This gives
+very low CPU utilization but in some cases this latency can affect performance.
+
+Adding a call to ``lwipPollingPeriod(XXX)`` (where ``XXXX`` is the polling period in
+milliseconds) can adjust this setting on the fly.  Note that if you set it too low, the
+Pico may not have enough time to service the Ethernet port before the timer fires again,
+leading to a lock up and hang.
+
+
+Adjusting SPI Speed
+-------------------
+
+By default a 4MHz clock will be used to clock data into and out of the Ethernet module.
+Depending on the module and your wiring, a higher SPI clock may increase performance (but
+too high of a clock will cause communications problems or hangs).
+
+This value may be adjusted using the ``eth.setSPISpeed(hz)`` call **before** starting the
+device.  (You may also use custom ``SPISettings`` instead via ``eth.setSPISettings(spis)```)
+
+For example, to set the W5500 to use a 30MHZ clock:
+
+.. code:: cpp
+
+    #include <W5500lwIP.h>
+    Wiznet5500lwIP eth(1);
+
+    void setup() {
+        eth.setSPISpeed(30000000);
+        lwipPollingPeriod(3);
+        ...
+        eth.begin();
+        ...
+    }
+
+
+Example Code
+------------
+
+The following examples allow switching between WiFi and Ethernet:
+
+* ``WebServer/AdvancedWebServer``
+
+* ``HTTPClient/BasicHTTPSClient``
+
+Caveats
+-------
+
+The same restrictions for ``WiFi`` apply to these Ethernet classes, namely:
+
+* Only core 0 may run any networking related code.
+
+* In FreeRTOS, only the ``setup`` and ``loop`` task can call networking libraries, not any tasks.
+
+Special Thanks
+--------------
+
+* LWIPEthernet classes come from the ESP8266 Arduino team
+
+* Individual Ethernet drivers were written by Nicholas Humfrey
+

docs/index.rst

@@ -50,6 +50,7 @@ For the latest version, always check https://github.com/earlephilhower/arduino-p
    FreeRTOS SMP (multicore) <freertos>
 
    WiFi (Pico-W Support) <wifi>
+   Ethernet (Wired) <ethernet>
    WiFiClient <wificlient>
    WiFiServer <wifiserver>
    WiFiUDP <wifiudp>

lib/platform_wrap.txt

@@ -152,6 +152,8 @@
 -Wl,--wrap=realloc
 -Wl,--wrap=free
 
+-Wl,--wrap=lwip_init
+
 -Wl,--wrap=pbuf_header
 -Wl,--wrap=pbuf_free
 -Wl,--wrap=pbuf_alloc

libraries/HTTPClient/examples/BasicHttpsClient/BasicHttpsClient.ino

@@ -6,7 +6,19 @@
 */
 
 #include <Arduino.h>
+
+
+// Example works with either Wired or WiFi Ethernet, define one of these values to 1, other to 0
+#define USE_WIFI 1
+#define USE_WIRED 0
+
+#if USE_WIFI
 #include <WiFi.h>
+#elif USE_WIRED
+#include <W5500lwIP.h> // Or W5100lwIP.h or ENC28J60lwIP.h
+Wiznet5500lwIP eth(1 /* chip select */); // or Wiznet5100lwIP or ENC28J60lwIP
+#endif
+
 #include <HTTPClient.h>
 
 #ifndef STASSID
@@ -34,8 +46,33 @@ void setup() {
     delay(1000);
   }
 
+#if USE_WIFI
   WiFi.mode(WIFI_STA);
   WiFiMulti.addAP(ssid, pass);
+#elif USE_WIRED
+  // Set up SPI pinout to match your HW
+  SPI.setRX(0);
+  SPI.setCS(1);
+  SPI.setSCK(2);
+  SPI.setTX(3);
+
+  // Start the Ethernet port
+  if (!eth.begin()) {
+    Serial.println("No wired Ethernet hardware detected. Check pinouts, wiring.");
+    while (1) {
+      delay(1000);
+    }
+  }
+
+  // Wait for connection
+  while (eth.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.print("IP address: ");
+  Serial.println(eth.localIP());
+#endif
+
 }
 
 const char *jigsaw_cert = R"EOF(
@@ -74,8 +111,12 @@ N6K5xrmaof185pVCxACPLc/BoKyUwMeC8iXCm00=
 static int cnt = 0;
 
 void loop() {
-  // wait for WiFi connection
-  if ((WiFiMulti.run() == WL_CONNECTED)) {
+#if USE_WIFI
+ // wait for WiFi connection
+ if ((WiFiMulti.run() == WL_CONNECTED)) {
+#elif USE_WIRED
+ if (eth.connected()) {
+#endif
     HTTPClient https;
     switch (cnt) {
       case 0:

libraries/WebServer/examples/AdvancedWebServer/AdvancedWebServer.ino

@@ -28,7 +28,17 @@
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
+// Example works with either Wired or WiFi Ethernet, define one of these values to 1, other to 0
+#define USE_WIFI 1
+#define USE_WIRED 0
+
+#if USE_WIFI
 #include <WiFi.h>
+#elif USE_WIRED
+#include <W5500lwIP.h> // Or W5100lwIP.h or ENC28J60lwIP.h
+Wiznet5500lwIP eth(1 /* chip select */); // or Wiznet5100lwIP or ENC28J60lwIP
+#endif
+
 #include <WiFiClient.h>
 #include <WebServer.h>
 #include <LEAmDNS.h>
@@ -58,13 +68,13 @@ void handleRoot() {
   temp.printf("<html>\
   <head>\
     <meta http-equiv='refresh' content='5'/>\
-    <title>Pico-W Demo</title>\
+    <title>" BOARD_NAME " Demo</title>\
     <style>\
       body { background-color: #cccccc; font-family: Arial, Helvetica, Sans-Serif; Color: #000088; }\
     </style>\
   </head>\
   <body>\
-    <h1>Hello from the Pico W!</h1>\
+    <h1>Hello from the " BOARD_NAME "!</h1>\
     <p>Uptime: %02d:%02d:%02d</p>\
     <p>Free Memory: %d</p>\
     <p>Page Count: %d</p>\
@@ -117,6 +127,8 @@ void setup(void) {
   pinMode(led, OUTPUT);
   digitalWrite(led, 0);
   Serial.begin(115200);
+
+#if USE_WIFI
   WiFi.mode(WIFI_STA);
   WiFi.begin(ssid, password);
   Serial.println("");
@@ -130,8 +142,32 @@ void setup(void) {
   Serial.println("");
   Serial.print("Connected to ");
   Serial.println(ssid);
+
   Serial.print("IP address: ");
   Serial.println(WiFi.localIP());
+#elif USE_WIRED
+  // Set up SPI pinout to match your HW
+  SPI.setRX(0);
+  SPI.setCS(1);
+  SPI.setSCK(2);
+  SPI.setTX(3);
+
+  // Start the Ethernet port
+  if (!eth.begin()) {
+    Serial.println("No wired Ethernet hardware detected. Check pinouts, wiring.");
+    while (1) {
+      delay(1000);
+    }
+  }
+
+  // Wait for connection
+  while (eth.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.print("IP address: ");
+  Serial.println(eth.localIP());
+#endif
 
   if (MDNS.begin("picow")) {
     Serial.println("MDNS responder started");

libraries/WiFi/examples/WiFiClient/WiFiClient.ino

@@ -61,7 +61,7 @@ void loop() {
   // This will send a string to the server
   Serial.println("sending data to server");
   if (client.connected()) {
-    client.println("hello from ESP8266");
+    client.println("hello from RP2040");
   }
 
   // wait for data to be available