2 * linux/arch/arm/mm/ioremap.c
4 * Re-map IO memory to kernel address space so that we can access it.
6 * (C) Copyright 1995 1996 Linus Torvalds
8 * Hacked for ARM by Phil Blundell <philb@gnu.org>
9 * Hacked to allow all architectures to build, and various cleanups
12 * This allows a driver to remap an arbitrary region of bus memory into
13 * virtual space. One should *only* use readl, writel, memcpy_toio and
14 * so on with such remapped areas.
16 * Because the ARM only has a 32-bit address space we can't address the
17 * whole of the (physical) PCI space at once. PCI huge-mode addressing
18 * allows us to circumvent this restriction by splitting PCI space into
19 * two 2GB chunks and mapping only one at a time into processor memory.
20 * We use MMU protection domains to trap any attempt to access the bank
21 * that is not currently mapped. (This isn't fully implemented yet.)
23 #include <linux/module.h>
24 #include <linux/errno.h>
26 #include <linux/vmalloc.h>
29 #include <asm/cputype.h>
30 #include <asm/cacheflush.h>
31 #include <asm/mmu_context.h>
32 #include <asm/pgalloc.h>
33 #include <asm/tlbflush.h>
34 #include <asm/sizes.h>
36 #include <asm/mach/map.h>
40 * Used by ioremap() and iounmap() code to mark (super)section-mapped
41 * I/O regions in vm_struct->flags field.
43 #define VM_ARM_SECTION_MAPPING 0x80000000
45 static int remap_area_pte(pmd_t *pmd, unsigned long addr, unsigned long end,
46 unsigned long phys_addr, const struct mem_type *type)
48 pgprot_t prot = __pgprot(type->prot_pte);
51 pte = pte_alloc_kernel(pmd, addr);
59 set_pte_ext(pte, pfn_pte(phys_addr >> PAGE_SHIFT, prot),
61 phys_addr += PAGE_SIZE;
62 } while (pte++, addr += PAGE_SIZE, addr != end);
66 printk(KERN_CRIT "remap_area_pte: page already exists\n");
70 static inline int remap_area_pmd(pgd_t *pgd, unsigned long addr,
71 unsigned long end, unsigned long phys_addr,
72 const struct mem_type *type)
78 pmd = pmd_alloc(&init_mm, pgd, addr);
83 next = pmd_addr_end(addr, end);
84 ret = remap_area_pte(pmd, addr, next, phys_addr, type);
87 phys_addr += next - addr;
88 } while (pmd++, addr = next, addr != end);
92 static int remap_area_pages(unsigned long start, unsigned long pfn,
93 size_t size, const struct mem_type *type)
95 unsigned long addr = start;
96 unsigned long next, end = start + size;
97 unsigned long phys_addr = __pfn_to_phys(pfn);
102 pgd = pgd_offset_k(addr);
104 next = pgd_addr_end(addr, end);
105 err = remap_area_pmd(pgd, addr, next, phys_addr, type);
108 phys_addr += next - addr;
109 } while (pgd++, addr = next, addr != end);
115 void __check_kvm_seq(struct mm_struct *mm)
120 seq = init_mm.context.kvm_seq;
121 memcpy(pgd_offset(mm, VMALLOC_START),
122 pgd_offset_k(VMALLOC_START),
123 sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
124 pgd_index(VMALLOC_START)));
125 mm->context.kvm_seq = seq;
126 } while (seq != init_mm.context.kvm_seq);
131 * Section support is unsafe on SMP - If you iounmap and ioremap a region,
132 * the other CPUs will not see this change until their next context switch.
133 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
134 * which requires the new ioremap'd region to be referenced, the CPU will
135 * reference the _old_ region.
137 * Note that get_vm_area() allocates a guard 4K page, so we need to mask
138 * the size back to 1MB aligned or we will overflow in the loop below.
140 static void unmap_area_sections(unsigned long virt, unsigned long size)
142 unsigned long addr = virt, end = virt + (size & ~SZ_1M);
145 flush_cache_vunmap(addr, end);
146 pgd = pgd_offset_k(addr);
148 pmd_t pmd, *pmdp = pmd_offset(pgd, addr);
151 if (!pmd_none(pmd)) {
153 * Clear the PMD from the page table, and
154 * increment the kvm sequence so others
155 * notice this change.
157 * Note: this is still racy on SMP machines.
160 init_mm.context.kvm_seq++;
163 * Free the page table, if there was one.
165 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
166 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
171 } while (addr < end);
174 * Ensure that the active_mm is up to date - we want to
175 * catch any use-after-iounmap cases.
177 if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq)
178 __check_kvm_seq(current->active_mm);
180 flush_tlb_kernel_range(virt, end);
184 remap_area_sections(unsigned long virt, unsigned long pfn,
185 size_t size, const struct mem_type *type)
187 unsigned long addr = virt, end = virt + size;
191 * Remove and free any PTE-based mapping, and
192 * sync the current kernel mapping.
194 unmap_area_sections(virt, size);
196 pgd = pgd_offset_k(addr);
198 pmd_t *pmd = pmd_offset(pgd, addr);
200 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
201 pfn += SZ_1M >> PAGE_SHIFT;
202 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
203 pfn += SZ_1M >> PAGE_SHIFT;
204 flush_pmd_entry(pmd);
208 } while (addr < end);
214 remap_area_supersections(unsigned long virt, unsigned long pfn,
215 size_t size, const struct mem_type *type)
217 unsigned long addr = virt, end = virt + size;
221 * Remove and free any PTE-based mapping, and
222 * sync the current kernel mapping.
224 unmap_area_sections(virt, size);
226 pgd = pgd_offset_k(virt);
228 unsigned long super_pmd_val, i;
230 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
232 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
234 for (i = 0; i < 8; i++) {
235 pmd_t *pmd = pmd_offset(pgd, addr);
237 pmd[0] = __pmd(super_pmd_val);
238 pmd[1] = __pmd(super_pmd_val);
239 flush_pmd_entry(pmd);
245 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
246 } while (addr < end);
254 * Remap an arbitrary physical address space into the kernel virtual
255 * address space. Needed when the kernel wants to access high addresses
258 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
259 * have to convert them into an offset in a page-aligned mapping, but the
260 * caller shouldn't need to know that small detail.
262 * 'flags' are the extra L_PTE_ flags that you want to specify for this
263 * mapping. See <asm/pgtable.h> for more information.
266 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
269 const struct mem_type *type;
272 struct vm_struct * area;
275 * High mappings must be supersection aligned
277 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK))
280 type = get_mem_type(mtype);
285 * Page align the mapping size, taking account of any offset.
287 size = PAGE_ALIGN(offset + size);
289 area = get_vm_area(size, VM_IOREMAP);
292 addr = (unsigned long)area->addr;
295 if (DOMAIN_IO == 0 &&
296 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
297 cpu_is_xsc3()) && pfn >= 0x100000 &&
298 !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) {
299 area->flags |= VM_ARM_SECTION_MAPPING;
300 err = remap_area_supersections(addr, pfn, size, type);
301 } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
302 area->flags |= VM_ARM_SECTION_MAPPING;
303 err = remap_area_sections(addr, pfn, size, type);
306 err = remap_area_pages(addr, pfn, size, type);
309 vunmap((void *)addr);
313 flush_cache_vmap(addr, addr + size);
314 return (void __iomem *) (offset + addr);
316 EXPORT_SYMBOL(__arm_ioremap_pfn);
319 __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
321 unsigned long last_addr;
322 unsigned long offset = phys_addr & ~PAGE_MASK;
323 unsigned long pfn = __phys_to_pfn(phys_addr);
326 * Don't allow wraparound or zero size
328 last_addr = phys_addr + size - 1;
329 if (!size || last_addr < phys_addr)
332 return __arm_ioremap_pfn(pfn, offset, size, mtype);
334 EXPORT_SYMBOL(__arm_ioremap);
336 void __iounmap(volatile void __iomem *io_addr)
338 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
340 struct vm_struct **p, *tmp;
342 unsigned int section_mapping = 0;
346 * If this is a section based mapping we need to handle it
347 * specially as the VM subsystem does not know how to handle
348 * such a beast. We need the lock here b/c we need to clear
349 * all the mappings before the area can be reclaimed
352 write_lock(&vmlist_lock);
353 for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
354 if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
355 if (tmp->flags & VM_ARM_SECTION_MAPPING) {
357 unmap_area_sections((unsigned long)tmp->addr,
365 write_unlock(&vmlist_lock);
368 if (!section_mapping)
371 EXPORT_SYMBOL(__iounmap);