1/* 2 * Re-map IO memory to kernel address space so that we can access it. 3 * Needed for memory-mapped I/O devices mapped outside our normal DRAM 4 * window (that is, all memory-mapped I/O devices). 5 * 6 * Copyright (C) 1995,1996 Linus Torvalds 7 * 8 * Meta port based on CRIS-port by Axis Communications AB 9 */ 10 11#include <linux/vmalloc.h> 12#include <linux/io.h> 13#include <linux/export.h> 14#include <linux/slab.h> 15#include <linux/mm.h> 16 17#include <asm/pgtable.h> 18 19/* 20 * Remap an arbitrary physical address space into the kernel virtual 21 * address space. Needed when the kernel wants to access high addresses 22 * directly. 23 * 24 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 25 * have to convert them into an offset in a page-aligned mapping, but the 26 * caller shouldn't need to know that small detail. 27 */ 28void __iomem *__ioremap(unsigned long phys_addr, size_t size, 29 unsigned long flags) 30{ 31 unsigned long addr; 32 struct vm_struct *area; 33 unsigned long offset, last_addr; 34 pgprot_t prot; 35 36 /* Don't allow wraparound or zero size */ 37 last_addr = phys_addr + size - 1; 38 if (!size || last_addr < phys_addr) 39 return NULL; 40 41 /* Custom region addresses are accessible and uncached by default. */ 42 if (phys_addr >= LINSYSCUSTOM_BASE && 43 phys_addr < (LINSYSCUSTOM_BASE + LINSYSCUSTOM_LIMIT)) 44 return (__force void __iomem *) phys_addr; 45 46 /* 47 * Mappings have to be page-aligned 48 */ 49 offset = phys_addr & ~PAGE_MASK; 50 phys_addr &= PAGE_MASK; 51 size = PAGE_ALIGN(last_addr+1) - phys_addr; 52 prot = __pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_DIRTY | 53 _PAGE_ACCESSED | _PAGE_KERNEL | _PAGE_CACHE_WIN0 | 54 flags); 55 56 /* 57 * Ok, go for it.. 58 */ 59 area = get_vm_area(size, VM_IOREMAP); 60 if (!area) 61 return NULL; 62 area->phys_addr = phys_addr; 63 addr = (unsigned long) area->addr; 64 if (ioremap_page_range(addr, addr + size, phys_addr, prot)) { 65 vunmap((void *) addr); 66 return NULL; 67 } 68 return (__force void __iomem *) (offset + (char *)addr); 69} 70EXPORT_SYMBOL(__ioremap); 71 72void __iounmap(void __iomem *addr) 73{ 74 struct vm_struct *p; 75 76 if ((__force unsigned long)addr >= LINSYSCUSTOM_BASE && 77 (__force unsigned long)addr < (LINSYSCUSTOM_BASE + 78 LINSYSCUSTOM_LIMIT)) 79 return; 80 81 p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr)); 82 if (unlikely(!p)) { 83 pr_err("iounmap: bad address %p\n", addr); 84 return; 85 } 86 87 kfree(p); 88} 89EXPORT_SYMBOL(__iounmap); 90