sdmmc: add peripheral driver and protocol layer

components/driver/sdmmc_private.h

@@ -0,0 +1,44 @@
+// Copyright 2015-2016 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 <stdint.h>
+#include <stddef.h>
+#include "esp_err.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/queue.h"
+#include "soc/sdmmc_struct.h"
+
+typedef struct {
+    uint32_t sdmmc_status;      ///< masked SDMMC interrupt status
+    uint32_t dma_status;        ///< masked DMA interrupt status
+} sdmmc_event_t;
+
+void sdmmc_host_reset();
+
+esp_err_t sdmmc_host_start_command(int slot, sdmmc_hw_cmd_t cmd, uint32_t arg);
+
+esp_err_t sdmmc_host_wait_for_event(int tick_count, sdmmc_event_t* out_event);
+
+void sdmmc_host_dma_prepare(sdmmc_desc_t* desc, size_t block_size, size_t data_size);
+
+void sdmmc_host_dma_stop();
+
+void sdmmc_host_dma_resume();
+
+esp_err_t sdmmc_host_transaction_handler_init();
+
+void sdmmc_host_transaction_handler_deinit();
+