James Hogan | 373cd78 | 2012-10-09 10:54:17 +0100 | [diff] [blame] | 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 | */ |
| 28 | void __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 | } |
| 70 | EXPORT_SYMBOL(__ioremap); |
| 71 | |
| 72 | void __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 | } |
| 89 | EXPORT_SYMBOL(__iounmap); |