Update IDF to a0468b2 (#2108)

* Update IDF to a0468b2

* add missing ld file

* Fix PIO builds and change coex policy

tools/sdk/include/protocomm/protocomm_httpd.h

@@ -0,0 +1,73 @@
+// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <protocomm.h>
+
+#define PROTOCOMM_HTTPD_DEFAULT_CONFIG() {   \
+    .port           = 80,                    \
+    .stack_size     = 4096,                  \
+    .task_priority  = tskIDLE_PRIORITY + 5,  \
+}
+
+/**
+ * @brief   Config parameters for protocomm HTTP server
+ */
+typedef struct {
+    uint16_t port;          /*!< Port on which the http server will listen */
+
+    /**
+     * Stack size of server task, adjusted depending
+     * upon stack usage of endpoint handler
+     */
+    size_t   stack_size;
+    unsigned task_priority; /*!< Priority of server task */
+} protocomm_httpd_config_t;
+
+/**
+ * @brief   Start HTTPD protocomm transport
+ *
+ * This API internally creates a framework to allow endpoint registration and security
+ * configuration for the protocomm.
+ *
+ * @note    This is a singleton. ie. Protocomm can have multiple instances, but only
+ *          one instance can be bound to an HTTP transport layer.
+ *
+ * @param[in] pc        Protocomm instance pointer obtained from protocomm_new()
+ * @param[in] config    Pointer to config structure for initialising HTTP server
+ *
+ * @return
+ *  - ESP_OK : Server started succefully
+ *  - ESP_ERR_INVALID_ARG : Null arguments
+ *  - ESP_ERR_NOT_SUPPORTED : Transport layer bound to another protocomm instance
+ *  - ESP_ERR_INVALID_STATE : Transport layer already bound to this protocomm instance
+ *  - ESP_ERR_NO_MEM : Memory allocation for server resource failed
+ *  - ESP_ERR_HTTPD_* : HTTP server error on start
+ */
+esp_err_t protocomm_httpd_start(protocomm_t *pc, const protocomm_httpd_config_t *config);
+
+/**
+ * @brief   Stop HTTPD protocomm transport
+ *
+ * This API cleans up the HTTPD transport protocomm and frees all the handlers registered
+ * with the protocomm.
+ *
+ * @param[in] pc    Same protocomm instance that was passed to protocomm_httpd_start()
+ *
+ * @return
+ *  - ESP_OK : Server stopped succefully
+ *  - ESP_ERR_INVALID_ARG : Null / incorrect protocomm instance pointer
+ */
+esp_err_t protocomm_httpd_stop(protocomm_t *pc);