Add pico-w5500 example

Makefile

@@ -12,7 +12,7 @@ VCFLAGS = /nologo /W3 /O2 /MD /I. $(DEFS) $(TFLAGS)
 IPV6 ?= 1
 ASAN ?= -fsanitize=address,undefined,alignment -fno-sanitize-recover=all -fno-omit-frame-pointer -fno-common
 ASAN_OPTIONS ?= detect_leaks=1
-EXAMPLES := $(dir $(wildcard examples/*/Makefile)) $(wildcard examples/stm32/nucleo-*)
+EXAMPLES := $(dir $(wildcard examples/*/Makefile)) $(wildcard examples/stm32/nucleo-*) $(wildcard examples/rp2040/*)
 PREFIX ?= /usr/local
 VERSION ?= $(shell cut -d'"' -f2 src/version.h)
 COMMON_CFLAGS ?= $(C_WARN) $(WARN) $(INCS) $(DEFS) -DMG_ENABLE_IPV6=$(IPV6) $(TFLAGS)

examples/rp2040/pico-w5500/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.13)
+include(pico-sdk/pico_sdk_init.cmake)
+
+project(example)
+pico_sdk_init()
+
+add_executable(example main.c mongoose.c)
+target_link_libraries(example pico_stdlib hardware_spi)
+pico_add_extra_outputs(example)
+
+# Enable USB output. Comment out in order to use UART
+pico_enable_stdio_usb(example 1)
+pico_enable_stdio_uart(example 0)
+
+# Mongoose build flags
+add_definitions(-DMG_ARCH=MG_ARCH_NEWLIB)
+add_definitions(-DMG_ENABLE_MIP=1)
+add_definitions(-DMG_ENABLE_CUSTOM_MILLIS=1)

examples/rp2040/pico-w5500/Makefile

@@ -0,0 +1,13 @@
+SDK_VERSION ?= 1.4.0
+SDK_REPO ?= https://github.com/raspberrypi/pico-sdk
+
+all example build: pico-sdk
+	test -d build || mkdir build
+	cd build && cmake .. && make
+
+pico-sdk:
+	git clone --depth 1 -b $(SDK_VERSION) $(SDK_REPO) $@
+	cd $@ && git submodule update --init
+
+clean:
+	rm -rf pico-sdk build

examples/rp2040/pico-w5500/README.md

@@ -0,0 +1,57 @@
+# RP2040 with W5500 Ethernet module
+
+This repository demonstrates how to use RP2040 with W5500 Ethernet module,
+to implement networking. In this example, a very simple HTTP server is
+implemented. See [other examples](../..) for more functionality.
+
+## RP2040 Pico wiring
+
+The W5500 module uses SPI for communication. The following pins are used
+by this example (modify `main.c` if you use a different pinout):
+
+```c
+enum { LED = 25, SPI_CS = 17, SPI_CLK = 18, SPI_TX = 19, SPI_RX = 16 };
+```
+
+On a breadboard, it might look like this:
+
+![](images/wiring.png)
+
+## Pinout reference
+
+![](images/pinout.png)
+
+## Build and run
+
+Clone Mongoose repo, go to this example, and build it:
+
+```sh
+git clone https://github.com/cesanta/mongoose
+cd mongoose/examples/ro2040/pico-w5500
+make
+```
+
+The above will make a firmware in `build/example.uf2`. Reboot your Pico
+board in bootloader mode, and copy `example.uf2` to the RPI disk.
+
+Attach serial console. Then, plug in Ethernet cable:
+
+```
+$ cu -l /dev/cu.usb* -s 115200
+4653 2 main.c:79:main                   Ethernet: down
+520b 2 main.c:79:main                   Ethernet: down
+5dc3 2 main.c:79:main                   Ethernet: down
+6593 1 mongoose.c:6757:onstatechange    Link up
+659a 3 mongoose.c:6840:tx_dhcp_discover DHCP discover sent
+667b 3 mongoose.c:6723:arp_cache_add    ARP cache: added 192.168.0.1 @ 90:5c:44:55:19:8b
+667d 2 mongoose.c:6749:onstatechange    READY, IP: 192.168.0.24
+667e 2 mongoose.c:6750:onstatechange           GW: 192.168.0.1
+6680 2 mongoose.c:6752:onstatechange           Lease: 86062 sec
+697b 2 main.c:79:main                   Ethernet: up
+7533 2 main.c:79:main                   Ethernet: up
+```
+
+Note the aquired IP address printed. Run a browser, and type that IP address
+in the address field. You should see an "ok" message in a browser:
+
+![](images/browser.png)

examples/rp2040/pico-w5500/main.c

@@ -0,0 +1,85 @@
+// Copyright (c) 2023 Cesanta Software Limited
+// All rights reserved
+
+#include <stdio.h>
+#include <string.h>
+#include "hardware/spi.h"
+#include "pico/stdlib.h"
+
+#include "mongoose.h"
+
+enum { LED = 25, SPI_CS = 17, SPI_CLK = 18, SPI_TX = 19, SPI_RX = 16 };  // Pins
+enum { STATUS_TIMER_MS = 3000, BLINK_TIMER_MS = 250 };  // Timeouts
+
+static void spi_begin(void *spi) {
+  gpio_put(SPI_CS, 0);
+}
+
+static void spi_end(void *spi) {
+  gpio_put(SPI_CS, 1);
+}
+
+static uint8_t spi_txn(void *spi, uint8_t byte) {
+  uint8_t result = 0;
+  spi_write_read_blocking(spi0, &byte, &result, 1);
+  // MG_INFO(("%x -> %x", byte, result));
+  return result;
+}
+
+uint64_t mg_millis(void) {
+  return to_ms_since_boot(get_absolute_time());
+}
+
+static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
+  if (ev == MG_EV_HTTP_MSG) {
+    mg_http_reply(c, 200, "", "ok\n");
+  }
+}
+
+int main(void) {
+  stdio_init_all();
+  MG_INFO(("Starting ..."));
+
+  // Init LED
+  gpio_init(LED);
+  gpio_set_dir(LED, GPIO_OUT);
+
+  // Init SPI pins
+  uint r = spi_init(spi0, 500 * 1000);
+  MG_INFO(("r = %x\n", r));
+  gpio_set_function(SPI_RX, GPIO_FUNC_SPI);   // MISO
+  gpio_set_function(SPI_TX, GPIO_FUNC_SPI);   // MOSI
+  gpio_set_function(SPI_CLK, GPIO_FUNC_SPI);  // CLK
+  gpio_init(SPI_CS);                          // CS
+  gpio_set_dir(SPI_CS, GPIO_OUT);             // Set CS it to output
+  gpio_put(SPI_CS, 1);                        // And drive CS high (inactive)
+
+  // Init Mongoose
+  struct mip_spi spi = {NULL, spi_begin, spi_end, spi_txn};
+  struct mip_if mif = {.mac = {2, 0, 1, 2, 3, 5},
+                       .driver = &mip_driver_w5500,
+                       .driver_data = &spi};
+  struct mg_mgr mgr;                                 // Declare event manager
+  mg_mgr_init(&mgr);                                 // Init event manager
+  mg_log_set(MG_LL_DEBUG);                           // Set DEBUG log level
+  mip_init(&mgr, &mif);                              // Init TCP/IP stack
+  mg_http_listen(&mgr, "http://0.0.0.0", fn, NULL);  // HTTP listener
+
+  bool led_on = false;                         // Initial LED state
+  uint64_t status_timer = 0, blink_timer = 0;  // Initial timer expirations
+
+  // Infinite event manager loop
+  for (;;) {
+    if (mg_timer_expired(&blink_timer, BLINK_TIMER_MS, mg_millis())) {
+      led_on = !led_on;                              // Flip LED state
+      if (mip_driver_w5500.up(&mif)) led_on = true;  // Always on if Eth up
+      gpio_put(LED, led_on);                         // Set LED
+    }
+    if (mg_timer_expired(&status_timer, STATUS_TIMER_MS, mg_millis())) {
+      MG_INFO(("Ethernet: %s", mip_driver_w5500.up(&mif) ? "up" : "down"));
+    }
+    mg_mgr_poll(&mgr, 1);
+  }
+
+  return 0;
+}

examples/rp2040/pico-w5500/mongoose.c

@@ -0,0 +1 @@
+../../../mongoose.c

examples/rp2040/pico-w5500/mongoose.h

@@ -0,0 +1 @@
+../../../mongoose.h