__flush_dcache_page
__flush_dcache_page((pfn + i) * PAGE_SIZE);
__flush_dcache_page(pfn << PAGE_SHIFT);
void __flush_dcache_page(void *addr, int flush_icache);
__flush_dcache_page(folio_address(folio) + i * PAGE_SIZE,
__flush_dcache_page(folio_address(folio) + i * PAGE_SIZE,
extern void __flush_dcache_page(unsigned long);
__flush_dcache_page((unsigned long)paddr);