1 /* 2 * OpenRISC ioremap.c 3 * 4 * Linux architectural port borrowing liberally from similar works of 5 * others. All original copyrights apply as per the original source 6 * declaration. 7 * 8 * Modifications for the OpenRISC architecture: 9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> 10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 18 #include <linux/vmalloc.h> 19 #include <linux/io.h> 20 #include <asm/pgalloc.h> 21 #include <asm/kmap_types.h> 22 #include <asm/fixmap.h> 23 #include <asm/bug.h> 24 #include <asm/pgtable.h> 25 #include <linux/sched.h> 26 #include <asm/tlbflush.h> 27 28 extern int mem_init_done; 29 30 static unsigned int fixmaps_used __initdata; 31 32 /* 33 * Remap an arbitrary physical address space into the kernel virtual 34 * address space. Needed when the kernel wants to access high addresses 35 * directly. 36 * 37 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 38 * have to convert them into an offset in a page-aligned mapping, but the 39 * caller shouldn't need to know that small detail. 40 */ 41 void __iomem *__ref 42 __ioremap(phys_addr_t addr, unsigned long size, pgprot_t prot) 43 { 44 phys_addr_t p; 45 unsigned long v; 46 unsigned long offset, last_addr; 47 struct vm_struct *area = NULL; 48 49 /* Don't allow wraparound or zero size */ 50 last_addr = addr + size - 1; 51 if (!size || last_addr < addr) 52 return NULL; 53 54 /* 55 * Mappings have to be page-aligned 56 */ 57 offset = addr & ~PAGE_MASK; 58 p = addr & PAGE_MASK; 59 size = PAGE_ALIGN(last_addr + 1) - p; 60 61 if (likely(mem_init_done)) { 62 area = get_vm_area(size, VM_IOREMAP); 63 if (!area) 64 return NULL; 65 v = (unsigned long)area->addr; 66 } else { 67 if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS) 68 return NULL; 69 v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used); 70 fixmaps_used += (size >> PAGE_SHIFT); 71 } 72 73 if (ioremap_page_range(v, v + size, p, prot)) { 74 if (likely(mem_init_done)) 75 vfree(area->addr); 76 else 77 fixmaps_used -= (size >> PAGE_SHIFT); 78 return NULL; 79 } 80 81 return (void __iomem *)(offset + (char *)v); 82 } 83 EXPORT_SYMBOL(__ioremap); 84 85 void iounmap(void *addr) 86 { 87 /* If the page is from the fixmap pool then we just clear out 88 * the fixmap mapping. 89 */ 90 if (unlikely((unsigned long)addr > FIXADDR_START)) { 91 /* This is a bit broken... we don't really know 92 * how big the area is so it's difficult to know 93 * how many fixed pages to invalidate... 94 * just flush tlb and hope for the best... 95 * consider this a FIXME 96 * 97 * Really we should be clearing out one or more page 98 * table entries for these virtual addresses so that 99 * future references cause a page fault... for now, we 100 * rely on two things: 101 * i) this code never gets called on known boards 102 * ii) invalid accesses to the freed areas aren't made 103 */ 104 flush_tlb_all(); 105 return; 106 } 107 108 return vfree((void *)(PAGE_MASK & (unsigned long)addr)); 109 } 110 EXPORT_SYMBOL(iounmap); 111 112 /** 113 * OK, this one's a bit tricky... ioremap can get called before memory is 114 * initialized (early serial console does this) and will want to alloc a page 115 * for its mapping. No userspace pages will ever get allocated before memory 116 * is initialized so this applies only to kernel pages. In the event that 117 * this is called before memory is initialized we allocate the page using 118 * the memblock infrastructure. 119 */ 120 121 pte_t __ref *pte_alloc_one_kernel(struct mm_struct *mm) 122 { 123 pte_t *pte; 124 125 if (likely(mem_init_done)) { 126 pte = (pte_t *)get_zeroed_page(GFP_KERNEL); 127 } else { 128 pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 129 if (!pte) 130 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 131 __func__, PAGE_SIZE, PAGE_SIZE); 132 } 133 134 return pte; 135 } 136