/* * (C) Copyright 1995 1996 Linus Torvalds * (C) Copyright 2012 Regents of the University of California * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation, version 2. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/export.h> #include <linux/mm.h> #include <linux/vmalloc.h> #include <linux/io.h> #include <asm/pgtable.h> /* * Remap an arbitrary physical address space into the kernel virtual * address space. Needed when the kernel wants to access high addresses * directly. * * NOTE! We need to allow non-page-aligned mappings too: we will obviously * have to convert them into an offset in a page-aligned mapping, but the * caller shouldn't need to know that small detail. */ static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size, pgprot_t prot, void *caller) { phys_addr_t last_addr; unsigned long offset, vaddr; struct vm_struct *area; /* Disallow wrap-around or zero size */ last_addr = addr + size - 1; if (!size || last_addr < addr) return NULL; /* Page-align mappings */ offset = addr & (~PAGE_MASK); addr -= offset; size = PAGE_ALIGN(size + offset); area = get_vm_area_caller(size, VM_IOREMAP, caller); if (!area) return NULL; vaddr = (unsigned long)area->addr; if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) { free_vm_area(area); return NULL; } return (void __iomem *)(vaddr + offset); } /* * ioremap - map bus memory into CPU space * @offset: bus address of the memory * @size: size of the resource to map * * ioremap performs a platform specific sequence of operations to * make bus memory CPU accessible via the readb/readw/readl/writeb/ * writew/writel functions and the other mmio helpers. The returned * address is not guaranteed to be usable directly as a virtual * address. * * Must be freed with iounmap. */ void __iomem *ioremap(phys_addr_t offset, unsigned long size) { return __ioremap_caller(offset, size, PAGE_KERNEL, __builtin_return_address(0)); } EXPORT_SYMBOL(ioremap); /** * iounmap - Free a IO remapping * @addr: virtual address from ioremap_* * * Caller must ensure there is only one unmapping for the same pointer. */ void iounmap(volatile void __iomem *addr) { vunmap((void *)((unsigned long)addr & PAGE_MASK)); } EXPORT_SYMBOL(iounmap);