rom: add header guards in rom/opi_flash.h, fix error in rom/spi_flash.h

components/esp_rom/include/esp32s2beta/rom/opi_flash.h

@@ -10,6 +10,10 @@
 #include <stdint.h>
 #include "spi_flash.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
     uint16_t cmd;                /*!< Command value */
     uint16_t cmdBitLen;          /*!< Command byte length*/
@@ -288,4 +292,8 @@ esp_rom_spiflash_result_t esp_rom_opiflash_write(int spi_num, esp_rom_spiflash_r
 void esp_rom_opiflash_set_mode(int spi_num, esp_rom_spiflash_read_mode_t cur_mode, esp_rom_spiflash_read_mode_t target_mode);
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif

components/esp_rom/include/esp32s2beta/rom/spi_flash.h

@@ -15,6 +15,10 @@
 #ifndef _ROM_SPI_FLASH_H_
 #define _ROM_SPI_FLASH_H_
 
+#ifndef CONFIG_IDF_TARGET_ESP32S2BETA
+#error This file should only be included for ESP32-S2 target
+#endif
+
 #include <stdint.h>
 #include <stdbool.h>