sdmmc_mem_read_block_subr
error = sdmmc_mem_read_block_subr(sf, NULL, blkno + i,
error = sdmmc_mem_read_block_subr(sf, NULL, blkno,
error = sdmmc_mem_read_block_subr(sf, sc->sc_dmap, blkno, data,
int sdmmc_mem_read_block_subr(struct sdmmc_function *, bus_dmamap_t,