1/* 2 * linux/arch/unicore32/mm/ioremap.c 3 * 4 * Code specific to PKUnity SoC and UniCore ISA 5 * 6 * Copyright (C) 2001-2010 GUAN Xue-tao 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * 13 * Re-map IO memory to kernel address space so that we can access it. 14 * 15 * This allows a driver to remap an arbitrary region of bus memory into 16 * virtual space. One should *only* use readl, writel, memcpy_toio and 17 * so on with such remapped areas. 18 * 19 * Because UniCore only has a 32-bit address space we can't address the 20 * whole of the (physical) PCI space at once. PCI huge-mode addressing 21 * allows us to circumvent this restriction by splitting PCI space into 22 * two 2GB chunks and mapping only one at a time into processor memory. 23 * We use MMU protection domains to trap any attempt to access the bank 24 * that is not currently mapped. (This isn't fully implemented yet.) 25 */ 26#include <linux/module.h> 27#include <linux/errno.h> 28#include <linux/mm.h> 29#include <linux/vmalloc.h> 30#include <linux/io.h> 31 32#include <asm/cputype.h> 33#include <asm/cacheflush.h> 34#include <asm/mmu_context.h> 35#include <asm/pgalloc.h> 36#include <asm/tlbflush.h> 37#include <asm/sizes.h> 38 39#include <mach/map.h> 40#include "mm.h" 41 42/* 43 * Used by ioremap() and iounmap() code to mark (super)section-mapped 44 * I/O regions in vm_struct->flags field. 45 */ 46#define VM_UNICORE_SECTION_MAPPING 0x80000000 47 48int ioremap_page(unsigned long virt, unsigned long phys, 49 const struct mem_type *mtype) 50{ 51 return ioremap_page_range(virt, virt + PAGE_SIZE, phys, 52 __pgprot(mtype->prot_pte)); 53} 54EXPORT_SYMBOL(ioremap_page); 55 56/* 57 * Section support is unsafe on SMP - If you iounmap and ioremap a region, 58 * the other CPUs will not see this change until their next context switch. 59 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs 60 * which requires the new ioremap'd region to be referenced, the CPU will 61 * reference the _old_ region. 62 * 63 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to 64 * mask the size back to 4MB aligned or we will overflow in the loop below. 65 */ 66static void unmap_area_sections(unsigned long virt, unsigned long size) 67{ 68 unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1)); 69 pgd_t *pgd; 70 71 flush_cache_vunmap(addr, end); 72 pgd = pgd_offset_k(addr); 73 do { 74 pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr); 75 76 pmd = *pmdp; 77 if (!pmd_none(pmd)) { 78 /* 79 * Clear the PMD from the page table, and 80 * increment the kvm sequence so others 81 * notice this change. 82 * 83 * Note: this is still racy on SMP machines. 84 */ 85 pmd_clear(pmdp); 86 87 /* 88 * Free the page table, if there was one. 89 */ 90 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) 91 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd)); 92 } 93 94 addr += PGDIR_SIZE; 95 pgd++; 96 } while (addr < end); 97 98 flush_tlb_kernel_range(virt, end); 99} 100 101static int 102remap_area_sections(unsigned long virt, unsigned long pfn, 103 size_t size, const struct mem_type *type) 104{ 105 unsigned long addr = virt, end = virt + size; 106 pgd_t *pgd; 107 108 /* 109 * Remove and free any PTE-based mapping, and 110 * sync the current kernel mapping. 111 */ 112 unmap_area_sections(virt, size); 113 114 pgd = pgd_offset_k(addr); 115 do { 116 pmd_t *pmd = pmd_offset((pud_t *)pgd, addr); 117 118 set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect)); 119 pfn += SZ_4M >> PAGE_SHIFT; 120 flush_pmd_entry(pmd); 121 122 addr += PGDIR_SIZE; 123 pgd++; 124 } while (addr < end); 125 126 return 0; 127} 128 129void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn, 130 unsigned long offset, size_t size, unsigned int mtype, void *caller) 131{ 132 const struct mem_type *type; 133 int err; 134 unsigned long addr; 135 struct vm_struct *area; 136 137 /* 138 * High mappings must be section aligned 139 */ 140 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK)) 141 return NULL; 142 143 /* 144 * Don't allow RAM to be mapped 145 */ 146 if (pfn_valid(pfn)) { 147 printk(KERN_WARNING "BUG: Your driver calls ioremap() on\n" 148 "system memory. This leads to architecturally\n" 149 "unpredictable behaviour, and ioremap() will fail in\n" 150 "the next kernel release. Please fix your driver.\n"); 151 WARN_ON(1); 152 } 153 154 type = get_mem_type(mtype); 155 if (!type) 156 return NULL; 157 158 /* 159 * Page align the mapping size, taking account of any offset. 160 */ 161 size = PAGE_ALIGN(offset + size); 162 163 area = get_vm_area_caller(size, VM_IOREMAP, caller); 164 if (!area) 165 return NULL; 166 addr = (unsigned long)area->addr; 167 168 if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { 169 area->flags |= VM_UNICORE_SECTION_MAPPING; 170 err = remap_area_sections(addr, pfn, size, type); 171 } else 172 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn), 173 __pgprot(type->prot_pte)); 174 175 if (err) { 176 vunmap((void *)addr); 177 return NULL; 178 } 179 180 flush_cache_vmap(addr, addr + size); 181 return (void __iomem *) (offset + addr); 182} 183 184void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size, 185 unsigned int mtype, void *caller) 186{ 187 unsigned long last_addr; 188 unsigned long offset = phys_addr & ~PAGE_MASK; 189 unsigned long pfn = __phys_to_pfn(phys_addr); 190 191 /* 192 * Don't allow wraparound or zero size 193 */ 194 last_addr = phys_addr + size - 1; 195 if (!size || last_addr < phys_addr) 196 return NULL; 197 198 return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller); 199} 200 201/* 202 * Remap an arbitrary physical address space into the kernel virtual 203 * address space. Needed when the kernel wants to access high addresses 204 * directly. 205 * 206 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 207 * have to convert them into an offset in a page-aligned mapping, but the 208 * caller shouldn't need to know that small detail. 209 */ 210void __iomem * 211__uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, 212 unsigned int mtype) 213{ 214 return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, 215 __builtin_return_address(0)); 216} 217EXPORT_SYMBOL(__uc32_ioremap_pfn); 218 219void __iomem * 220__uc32_ioremap(unsigned long phys_addr, size_t size) 221{ 222 return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE, 223 __builtin_return_address(0)); 224} 225EXPORT_SYMBOL(__uc32_ioremap); 226 227void __iomem * 228__uc32_ioremap_cached(unsigned long phys_addr, size_t size) 229{ 230 return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE_CACHED, 231 __builtin_return_address(0)); 232} 233EXPORT_SYMBOL(__uc32_ioremap_cached); 234 235void __uc32_iounmap(volatile void __iomem *io_addr) 236{ 237 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); 238 struct vm_struct **p, *tmp; 239 240 /* 241 * If this is a section based mapping we need to handle it 242 * specially as the VM subsystem does not know how to handle 243 * such a beast. We need the lock here b/c we need to clear 244 * all the mappings before the area can be reclaimed 245 * by someone else. 246 */ 247 write_lock(&vmlist_lock); 248 for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { 249 if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) { 250 if (tmp->flags & VM_UNICORE_SECTION_MAPPING) { 251 unmap_area_sections((unsigned long)tmp->addr, 252 tmp->size); 253 } 254 break; 255 } 256 } 257 write_unlock(&vmlist_lock); 258 259 vunmap(addr); 260} 261EXPORT_SYMBOL(__uc32_iounmap); 262