Function esp_rom_spiflash_read

pub unsafe extern "C" fn esp_rom_spiflash_read(
    src_addr: u32,
    data: *const u32,
    len: u32,
) -> i32

Read Data from Flash via ROM code, you should Erase it yourself if need.

src_addr should be 4 bytes aligned. len should be 4 bytes aligned.