baremetal: Add WiFi AP example for ESP8266 MCU using GCC toolchain

This example implements the non-connectable WiFi access point
running on the ESP8266-WROOM-02 module:

 * https://www.espressif.com/sites/default/files/documentation/0c-esp-wroom-02_datasheet_en.pdf

For compilation of this module requires the GCC-based proprietary
(pre-compiled) ESP8266 NON-OS SDK:

 * https://github.com/espressif/ESP8266_NONOS_SDK

Change-Id: I035e9d8dc621d0981783008fe12af378ee9b02e6
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

8 files changed, 384 insertions, 0 deletions

diff --git a/examples/baremetal/baremetal.qbs b/examples/baremetal/baremetal.qbs
index 8cb9692f2..9d7e82ef8 100644
--- a/examples/baremetal/baremetal.qbs
+++ b/examples/baremetal/baremetal.qbs
@@ -61,5 +61,6 @@ Project {
         "cy7c68013a/cy7c68013a.qbs",
         "stm32f103/stm32f103.qbs",
         "pca10040/pca10040.qbs",
+        "esp8266/esp8266.qbs",
     ]
 }
diff --git a/examples/baremetal/esp8266/README.md b/examples/baremetal/esp8266/README.md
new file mode 100644
index 000000000..a9b4ef92d
--- /dev/null
+++ b/examples/baremetal/esp8266/README.md
@@ -0,0 +1,34 @@
+This example demonstrates how to build a bare-metal application using
+GCC toolchain for Espressif ESP8266-WROOM02 MCU.
+
+An application is designed to be flashed on the external SPI FLASH
+with the following parameters:
+
+ * SPI FLASH size: 16 MBit (2048 + 2048 KBytes)
+ * SPI FLASH mode: DIO
+ * SPI FLASH clock: 40 MHz
+ * SPI FLASH map type: 5
+
+An application is running as WiFi access point that discards all
+connection attempts, and has the following WiFi parameters:
+ * SSID: "HELLO FROM QBS"
+ * Authentication mode: "open"
+ * Beacon interval: 1000 milliseconds
+ * Channel number: 3
+
+An application requires the ESP8266 NON-OS SDK:
+
+ * https://github.com/espressif/ESP8266_NONOS_SDK
+
+the path to which should be set via the ESP8266_NON_OS_SDK_ROOT
+environment variable.
+
+To convert the ELF application to the final binary image (and also for
+re-program the ESP8266 MCU), you can use the open source 'esptool'
+utility (using the SPI FLASH parameters, provided above):
+
+ * https://github.com/espressif/esptool
+
+The following toolchains are supported:
+
+  * GNU ESP8266 Toolchain
diff --git a/examples/baremetal/esp8266/access-point/access-point.qbs b/examples/baremetal/esp8266/access-point/access-point.qbs
new file mode 100644
index 000000000..fd2890fbd
--- /dev/null
+++ b/examples/baremetal/esp8266/access-point/access-point.qbs
@@ -0,0 +1,30 @@
+import qbs
+
+CppApplication {
+    condition: qbs.toolchain.contains("gcc") && qbs.architecture === "xtensa"
+
+    Depends { name: "esp8266_sdk" }
+
+    cpp.cLanguageVersion: "c99"
+    cpp.positionIndependentCode: false
+
+    // This required because ESP8266 SDK includes this 'user_config.h' internally.
+    cpp.includePaths: ["."]
+
+    cpp.staticLibraries: [
+        "c",
+        "crypto",
+        "gcc",
+        "lwip",
+        "main",
+        "net80211",
+        "phy",
+        "pp",
+        "wpa"
+    ]
+
+    files: [
+        "user_config.h",
+        "user_main.c"
+    ]
+}
diff --git a/examples/baremetal/esp8266/access-point/user_config.h b/examples/baremetal/esp8266/access-point/user_config.h
new file mode 100644
index 000000000..307f93dd5
--- /dev/null
+++ b/examples/baremetal/esp8266/access-point/user_config.h
@@ -0,0 +1,62 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Denis Shienkov <denis.shienkov@gmail.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of Qbs.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef ESP8266_USER_CONFIG_H
+#define ESP8266_USER_CONFIG_H
+
+// From ESP8266 SDK.
+#include <user_interface.h>
+
+#define ESP_SSID_CFG                "HELLO FROM QBS\0"
+#define ESP_AUTO_MODE_CFG           (AUTH_OPEN)
+#define ESP_BEACON_INTERVAL_MS_CFG  (1000)
+#define ESP_CHANNEL_NO_CFG          (3)
+
+#endif // ESP8266_USER_CONFIG_H
diff --git a/examples/baremetal/esp8266/access-point/user_main.c b/examples/baremetal/esp8266/access-point/user_main.c
new file mode 100644
index 000000000..be2a8e92d
--- /dev/null
+++ b/examples/baremetal/esp8266/access-point/user_main.c
@@ -0,0 +1,105 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Denis Shienkov <denis.shienkov@gmail.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of Qbs.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "user_config.h"
+
+// From ESP8266 SDK.
+#include <osapi.h>
+
+static const partition_item_t esp_partitions[] = {
+    {SYSTEM_PARTITION_BOOTLOADER, ESP_PART_BL_ADDR, ESP_PART_BOOTLOADER_SIZE},
+    {SYSTEM_PARTITION_OTA_1, ESP_PART_APP1_ADDR, ESP_PART_APPLICATION_SIZE},
+    {SYSTEM_PARTITION_OTA_2, ESP_PART_APP2_ADDR, ESP_PART_APPLICATION_SIZE},
+    {SYSTEM_PARTITION_RF_CAL, ESP_PART_RF_CAL_ADDR, ESP_PART_RF_CAL_SIZE},
+    {SYSTEM_PARTITION_PHY_DATA, ESP_PART_PHY_DATA_ADDR, ESP_PART_PHY_DATA_SIZE},
+    {SYSTEM_PARTITION_SYSTEM_PARAMETER, ESP_PART_SYS_PARAM_ADDR, ESP_PART_SYS_PARAM_SIZE}
+};
+
+enum {
+    ESP_PART_COUNT = sizeof(esp_partitions) / sizeof(esp_partitions[0])
+};
+
+LOCAL void ICACHE_FLASH_ATTR user_init_done(void)
+{
+    os_printf("esp: initialization completed\n");
+}
+
+void ICACHE_FLASH_ATTR user_pre_init(void)
+{
+    const bool ok = system_partition_table_regist(esp_partitions, ESP_PART_COUNT, SPI_FLASH_SIZE_MAP);
+    if (!ok) {
+        os_printf("esp: partitions registration failed\n");
+        while (true);
+    }
+}
+
+void ICACHE_FLASH_ATTR user_init(void)
+{
+    os_printf("esp: SDK version: %s\n", system_get_sdk_version());
+    os_printf("esp: reset reason: %u\n", system_get_rst_info()->reason);
+
+    const bool ok = wifi_set_opmode(SOFTAP_MODE);
+    if (!ok) {
+        os_printf("esp: set softap mode failed\n");
+    } else {
+        struct softap_config ap_cfg = {0};
+        ap_cfg.authmode = ESP_AUTO_MODE_CFG;
+        ap_cfg.beacon_interval = ESP_BEACON_INTERVAL_MS_CFG;
+        ap_cfg.channel = ESP_CHANNEL_NO_CFG;
+        ap_cfg.max_connection = 0;
+        ap_cfg.ssid_hidden = false;
+        os_memcpy(&ap_cfg.ssid, ESP_SSID_CFG, sizeof(ESP_SSID_CFG));
+        const bool ok = wifi_softap_set_config(&ap_cfg);
+        if (!ok)
+            os_printf("esp: set softap configuration failed\n");
+    }
+
+    system_init_done_cb(user_init_done);
+}
diff --git a/examples/baremetal/esp8266/esp8266.qbs b/examples/baremetal/esp8266/esp8266.qbs
new file mode 100644
index 000000000..6056a33e0
--- /dev/null
+++ b/examples/baremetal/esp8266/esp8266.qbs
@@ -0,0 +1,59 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Denis Shienkov <denis.shienkov@gmail.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of Qbs.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import qbs
+
+Project {
+    name: "Examples for esp8266-wroom-02 board"
+    qbsSearchPaths: "qbs"
+    references: [
+        "access-point/access-point.qbs"
+    ]
+}
diff --git a/examples/baremetal/esp8266/qbs/imports/Esp8266SdkProbe.qbs b/examples/baremetal/esp8266/qbs/imports/Esp8266SdkProbe.qbs
new file mode 100644
index 000000000..faa8b1efd
--- /dev/null
+++ b/examples/baremetal/esp8266/qbs/imports/Esp8266SdkProbe.qbs
@@ -0,0 +1,25 @@
+import qbs.Environment
+import qbs.File
+import qbs.FileInfo
+import qbs.Probes
+
+Probes.PathProbe {
+    // Inputs.
+    environmentPaths: Environment.getEnv("ESP8266_NON_OS_SDK_ROOT")
+    // Outputs.
+    property string includesPath;
+    property string libsPath;
+    property string linkerScriptsPath;
+    configure: {
+        for (var i in environmentPaths) {
+            var rootPath = environmentPaths[i];
+            if (!File.exists(rootPath))
+                continue;
+            includesPath = FileInfo.joinPaths(rootPath, "include");
+            libsPath = FileInfo.joinPaths(rootPath, "lib");
+            linkerScriptsPath = FileInfo.joinPaths(rootPath, "ld");
+            found = true;
+            return;
+        }
+    }
+}
diff --git a/examples/baremetal/esp8266/qbs/modules/esp8266_sdk/Esp8266SdkModule.qbs b/examples/baremetal/esp8266/qbs/modules/esp8266_sdk/Esp8266SdkModule.qbs
new file mode 100644
index 000000000..ba7cbbe44
--- /dev/null
+++ b/examples/baremetal/esp8266/qbs/modules/esp8266_sdk/Esp8266SdkModule.qbs
@@ -0,0 +1,68 @@
+import qbs
+
+Module {
+    Depends { name: "cpp" }
+
+    Esp8266SdkProbe { id: esp_sdk_probe }
+
+    validate: {
+        if (!esp_sdk_probe.found)
+            throw "ESP8266 NON OS SDK not found. Please set the ESP8266_NON_OS_SDK_ROOT env variable."
+    }
+
+    cpp.systemIncludePaths: [esp_sdk_probe.includesPath]
+    cpp.libraryPaths: [esp_sdk_probe.libsPath]
+    cpp.driverFlags: ["-nostdlib"]
+
+    cpp.cFlags: [
+        "-Wpointer-arith",
+        "-Wundef",
+        "-fno-inline-functions",
+        "-mlongcalls",
+        "-mtext-section-literals",
+        "-ffunction-sections",
+        "-fdata-sections",
+        "-fno-builtin-printf",
+        "-fno-guess-branch-probability",
+        "-freorder-blocks-and-partition",
+        "-fno-cse-follow-jumps"
+    ]
+
+    cpp.linkerFlags: [
+        "--no-check-sections",
+        "--gc-sections",
+        "--start-group"
+    ]
+
+    cpp.defines: [
+        "ICACHE_FLASH",
+        "USE_OPTIMIZE_PRINTF",
+
+        // Target specific defines for the external 40MHz DIO
+        // SPI 16 Mbit FLASH (2048 KByte + 2048 KByte) FOTA.
+        "SPI_FLASH_SIZE_MAP=5",
+        "ESP_PART_BL_ADDR=0x000000",
+        "ESP_PART_APP1_ADDR=0x001000",
+        "ESP_PART_APP2_ADDR=0x101000",
+        "ESP_PART_RF_CAL_ADDR=0x1FB000",
+        "ESP_PART_PHY_DATA_ADDR=0x1FC000",
+        "ESP_PART_SYS_PARAM_ADDR=0x1FD000",
+        "ESP_PART_BOOTLOADER_SIZE=0x001000",
+        "ESP_PART_APPLICATION_SIZE=0x0E0000",
+        "ESP_PART_RF_CAL_SIZE=0x001000",
+        "ESP_PART_PHY_DATA_SIZE=0x001000",
+        "ESP_PART_SYS_PARAM_SIZE=0x003000"
+    ]
+
+    property string _linker_scripts_path: esp_sdk_probe.linkerScriptsPath + "/"
+
+    Group {
+        name: "ESP8266 Linker Scripts"
+        prefix: esp8266_sdk._linker_scripts_path + "/"
+        fileTags: ["linkerscript"]
+        files: [
+            "eagle.rom.addr.v6.ld",
+            "eagle.app.v6.new.2048.ld"
+        ]
+    }
+}