1 /* 2 * arch/sh/mm/ioremap.c 3 * 4 * Re-map IO memory to kernel address space so that we can access it. 5 * This is needed for high PCI addresses that aren't mapped in the 6 * 640k-1MB IO memory area on PC's 7 * 8 * (C) Copyright 1995 1996 Linus Torvalds 9 * (C) Copyright 2005, 2006 Paul Mundt 10 * 11 * This file is subject to the terms and conditions of the GNU General 12 * Public License. See the file "COPYING" in the main directory of this 13 * archive for more details. 14 */ 15 #include <linux/vmalloc.h> 16 #include <linux/module.h> 17 #include <linux/mm.h> 18 #include <linux/pci.h> 19 #include <linux/io.h> 20 #include <asm/page.h> 21 #include <asm/pgalloc.h> 22 #include <asm/addrspace.h> 23 #include <asm/cacheflush.h> 24 #include <asm/tlbflush.h> 25 #include <asm/mmu.h> 26 27 /* 28 * Remap an arbitrary physical address space into the kernel virtual 29 * address space. Needed when the kernel wants to access high addresses 30 * directly. 31 * 32 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 33 * have to convert them into an offset in a page-aligned mapping, but the 34 * caller shouldn't need to know that small detail. 35 */ 36 void __iomem *__ioremap(unsigned long phys_addr, unsigned long size, 37 unsigned long flags) 38 { 39 struct vm_struct * area; 40 unsigned long offset, last_addr, addr, orig_addr; 41 pgprot_t pgprot; 42 43 /* Don't allow wraparound or zero size */ 44 last_addr = phys_addr + size - 1; 45 if (!size || last_addr < phys_addr) 46 return NULL; 47 48 /* 49 * If we're on an SH7751 or SH7780 PCI controller, PCI memory is 50 * mapped at the end of the address space (typically 0xfd000000) 51 * in a non-translatable area, so mapping through page tables for 52 * this area is not only pointless, but also fundamentally 53 * broken. Just return the physical address instead. 54 * 55 * For boards that map a small PCI memory aperture somewhere in 56 * P1/P2 space, ioremap() will already do the right thing, 57 * and we'll never get this far. 58 */ 59 if (is_pci_memaddr(phys_addr) && is_pci_memaddr(last_addr)) 60 return (void __iomem *)phys_addr; 61 62 /* 63 * Don't allow anybody to remap normal RAM that we're using.. 64 */ 65 if (phys_addr < virt_to_phys(high_memory)) 66 return NULL; 67 68 /* 69 * Mappings have to be page-aligned 70 */ 71 offset = phys_addr & ~PAGE_MASK; 72 phys_addr &= PAGE_MASK; 73 size = PAGE_ALIGN(last_addr+1) - phys_addr; 74 75 /* 76 * Ok, go for it.. 77 */ 78 area = get_vm_area(size, VM_IOREMAP); 79 if (!area) 80 return NULL; 81 area->phys_addr = phys_addr; 82 orig_addr = addr = (unsigned long)area->addr; 83 84 #ifdef CONFIG_32BIT 85 /* 86 * First try to remap through the PMB once a valid VMA has been 87 * established. Smaller allocations (or the rest of the size 88 * remaining after a PMB mapping due to the size not being 89 * perfectly aligned on a PMB size boundary) are then mapped 90 * through the UTLB using conventional page tables. 91 * 92 * PMB entries are all pre-faulted. 93 */ 94 if (unlikely(size >= 0x1000000)) { 95 unsigned long mapped = pmb_remap(addr, phys_addr, size, flags); 96 97 if (likely(mapped)) { 98 addr += mapped; 99 phys_addr += mapped; 100 size -= mapped; 101 } 102 } 103 #endif 104 105 pgprot = __pgprot(pgprot_val(PAGE_KERNEL_NOCACHE) | flags); 106 if (likely(size)) 107 if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) { 108 vunmap((void *)orig_addr); 109 return NULL; 110 } 111 112 return (void __iomem *)(offset + (char *)orig_addr); 113 } 114 EXPORT_SYMBOL(__ioremap); 115 116 void __iounmap(void __iomem *addr) 117 { 118 unsigned long vaddr = (unsigned long __force)addr; 119 struct vm_struct *p; 120 121 if (PXSEG(vaddr) < P3SEG || is_pci_memaddr(vaddr)) 122 return; 123 124 #ifdef CONFIG_32BIT 125 /* 126 * Purge any PMB entries that may have been established for this 127 * mapping, then proceed with conventional VMA teardown. 128 * 129 * XXX: Note that due to the way that remove_vm_area() does 130 * matching of the resultant VMA, we aren't able to fast-forward 131 * the address past the PMB space until the end of the VMA where 132 * the page tables reside. As such, unmap_vm_area() will be 133 * forced to linearly scan over the area until it finds the page 134 * tables where PTEs that need to be unmapped actually reside, 135 * which is far from optimal. Perhaps we need to use a separate 136 * VMA for the PMB mappings? 137 * -- PFM. 138 */ 139 pmb_unmap(vaddr); 140 #endif 141 142 p = remove_vm_area((void *)(vaddr & PAGE_MASK)); 143 if (!p) { 144 printk(KERN_ERR "%s: bad address %p\n", __FUNCTION__, addr); 145 return; 146 } 147 148 kfree(p); 149 } 150 EXPORT_SYMBOL(__iounmap); 151