esp_rom: Add initial ESP32-C3 support

From internal commit 7761d6e8

components/esp_rom/include/esp32c3/rom/esp_flash.h

@@ -0,0 +1,54 @@
+// Copyright 2020 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 "esp_err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Note: Most of esp_flash APIs in ROM are compatible with headers in ESP-IDF, this function
+   just adds ROM-specific parts
+*/
+
+struct spi_flash_chip_t;
+typedef struct esp_flash_t esp_flash_t;
+
+/* Structure to wrap "global" data used by esp_flash in ROM */
+typedef struct {
+    /* Default SPI flash chip, ie main chip attached to the MCU
+       This chip is used if the 'chip' argument passed to esp_flash_xxx API functions is ever NULL
+    */
+    esp_flash_t *default_chip;
+
+    /* Global API OS notification start/end/chip_check functions
+
+       These are used by ROM if no other host functions are configured.
+    */
+    struct {
+        esp_err_t (*start)(esp_flash_t *chip);
+        esp_err_t (*end)(esp_flash_t *chip, esp_err_t err);
+        esp_err_t (*chip_check)(esp_flash_t **inout_chip);
+    } api_funcs;
+} esp_flash_rom_global_data_t;
+
+/** Access a pointer to the global data used by the ROM spi_flash driver
+ */
+esp_flash_rom_global_data_t *esp_flash_get_rom_global_data(void);
+
+#ifdef __cplusplus
+}
+#endif