Allocate some memories in SPIRAM first.

Try to allocate some WiFi and LWIP memories in SPIRAM first. If
    failed, try to allocate in internal RAM then.

components/esp32/Kconfig

@@ -127,6 +127,13 @@ config SPIRAM_MALLOC_ALWAYSINTERNAL
         than this size in internal memory, while allocations larger than this will be done from external RAM.
         If allocation from the preferred region fails, an attempt is made to allocate from the non-preferred
         region instead, so malloc() will not suddenly fail when either internal or external memory is full.
+        
+config WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST
+    bool "Try to allocate memories of WiFi and LWIP in SPIRAM firstly. If failed, allocate internal memory"
+    depends on SPIRAM_USE_CAPS_ALLOC || SPIRAM_USE_MALLOC
+    default "n"
+    help
+        Try to allocate memories of WiFi and LWIP in SPIRAM firstly. If failed, try to allocate internal memory then.
 
 config SPIRAM_MALLOC_RESERVE_INTERNAL
     int "Reserve this amount of bytes for data that specifically needs to be in DMA or internal memory"

components/esp32/include/esp_wifi_internal.h

@@ -121,6 +121,41 @@ esp_err_t esp_wifi_internal_reg_rxcb(wifi_interface_t ifx, wifi_rxcb_t fn);
   */
 esp_err_t esp_wifi_internal_set_sta_ip(void);
 
+/**
+  * @brief     Allocate a chunk of memory for WiFi driver
+  *
+  * @attention This API is not used for DMA memory allocation.
+  *
+  * @param     size_t size : Size, in bytes, of the amount of memory to allocate
+  *
+  * @return    A pointer to the memory allocated on success, NULL on failure
+  */
+void *wifi_malloc( size_t size );
+
+/**
+  * @brief     Reallocate a chunk of memory for WiFi driver
+  *
+  * @attention This API is not used for DMA memory allocation.
+  *
+  * @param     void * ptr  : Pointer to previously allocated memory, or NULL for a new allocation.
+  * @param     size_t size : Size, in bytes, of the amount of memory to allocate
+  *
+  * @return    A pointer to the memory allocated on success, NULL on failure
+  */
+void *wifi_realloc( void *ptr, size_t size );
+
+/**
+  * @brief     Callocate memory for WiFi driver
+  *
+  * @attention This API is not used for DMA memory allocation.
+  *
+  * @param     size_t n    : Number of continuing chunks of memory to allocate
+  * @param     size_t size : Size, in bytes, of the amount of memory to allocate
+  *
+  * @return    A pointer to the memory allocated on success, NULL on failure
+  */
+void *wifi_calloc( size_t n, size_t size );
+
 #ifdef __cplusplus
 }
 #endif

components/esp32/wifi_internal.c

@@ -0,0 +1,56 @@
+// Copyright 2015-2017 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.
+
+#include "esp_attr.h"
+#include "esp_heap_caps.h"
+#include "sdkconfig.h"
+
+/*
+ If CONFIG_WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST is enabled. Prefer to allocate a chunk of memory in SPIRAM firstly.
+ If failed, try to allocate it in internal memory then.
+ */
+IRAM_ATTR void *wifi_malloc( size_t size )
+{
+#if CONFIG_WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST
+    return heap_caps_malloc_prefer(size, 2, MALLOC_CAP_DEFAULT|MALLOC_CAP_SPIRAM, MALLOC_CAP_DEFAULT|MALLOC_CAP_INTERNAL);
+#else
+    return malloc(size);
+#endif
+}
+
+/*
+ If CONFIG_WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST is enabled. Prefer to allocate a chunk of memory in SPIRAM firstly.
+ If failed, try to allocate it in internal memory then.
+ */
+IRAM_ATTR void *wifi_realloc( void *ptr, size_t size )
+{
+#if CONFIG_WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST
+    return heap_caps_realloc_prefer(ptr, size, 2, MALLOC_CAP_DEFAULT|MALLOC_CAP_SPIRAM, MALLOC_CAP_DEFAULT|MALLOC_CAP_INTERNAL);
+#else
+    return realloc(ptr, size);
+#endif
+}
+
+/*
+ If CONFIG_WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST is enabled. Prefer to allocate a chunk of memory in SPIRAM firstly.
+ If failed, try to allocate it in internal memory then.
+ */
+IRAM_ATTR void *wifi_calloc( size_t n, size_t size )
+{
+#if CONFIG_WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST
+    return heap_caps_calloc_prefer(n, size, 2, MALLOC_CAP_DEFAULT|MALLOC_CAP_SPIRAM, MALLOC_CAP_DEFAULT|MALLOC_CAP_INTERNAL);
+#else
+    return calloc(n, size);
+#endif
+}