On Sat, Aug 20, 2022 at 08:31:15AM +0800, Baoquan He wrote: > +void __iomem *arch_ioremap(phys_addr_t phys_addr, size_t size, unsigned long prot); Please avoid the overly long lines. I also wonder if we just want a common definition with a __weak default instead of duplicating it in many arch headers. > + ioaddr = arch_ioremap(phys_addr, size, prot); > + if (IS_ERR(ioaddr)) > + return NULL; > + else if (ioaddr) > + return ioaddr; No need for the else here.