esp_ringbuf: fix default placement from flash to IRAM

In earlier change this component was decoupled from freertos and hence
regression was introduced which changed default placement to flash. Some
device drivers make use of ringbuffer while flash cache is being disabled
and hence default placement should instead be internal memory.

Closes: https://github.com/espressif/esp-idf/issues/2517

components/esp32/ld/esp32.common.ld

@@ -153,6 +153,7 @@ SECTIONS
     /* Code marked as runnning out of IRAM */
     _iram_text_start = ABSOLUTE(.);
     *(.iram1 .iram1.*)
+    *libesp_ringbuf.a:(.literal .text .literal.* .text.*)
     *libfreertos.a:(.literal .text .literal.* .text.*)
     *libheap.a:multi_heap.*(.literal .text .literal.* .text.*)
     *libheap.a:multi_heap_poisoning.*(.literal .text .literal.* .text.*)

components/esp_ringbuf/test/test_ringbuf.c

@@ -6,6 +6,7 @@
 #include "freertos/semphr.h"
 #include "freertos/ringbuf.h"
 #include "driver/timer.h"
+#include "esp_spi_flash.h"
 #include "unity.h"
 
 //Definitions used in multiple test cases
@@ -604,3 +605,22 @@ TEST_CASE("Test ring buffer SMP", "[freertos]")
     vSemaphoreDelete(rx_done);
     vSemaphoreDelete(tasks_done);
 }
+
+static IRAM_ATTR __attribute__((noinline)) bool iram_ringbuf_test()
+{
+    bool result = true;
+
+    spi_flash_guard_get()->start(); // Disables flash cache
+    RingbufHandle_t handle = xRingbufferCreate(CONT_DATA_TEST_BUFF_LEN, RINGBUF_TYPE_NOSPLIT);
+    result = result && (handle != NULL);
+    xRingbufferGetMaxItemSize(handle);
+    vRingbufferDelete(handle);
+    spi_flash_guard_get()->end(); // Re-enables flash cache
+
+    return result;
+}
+
+TEST_CASE("Test ringbuffer functions work with flash cache disabled", "[freertos]")
+{
+    TEST_ASSERT( iram_ringbuf_test() );
+}

components/freertos/component.mk

@@ -6,4 +6,4 @@ COMPONENT_ADD_LDFLAGS += -Wl,--undefined=uxTopUsedPriority
 COMPONENT_ADD_INCLUDEDIRS := include
 COMPONENT_PRIV_INCLUDEDIRS := include/freertos
 
-tasks.o event_groups.o timers.o queue.o ringbuf.o: CFLAGS += -D_ESP_FREERTOS_INTERNAL
+tasks.o event_groups.o timers.o queue.o: CFLAGS += -D_ESP_FREERTOS_INTERNAL