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 int ioremap_page(unsigned long virt, unsigned long phys,
46 const struct mem_type *mtype)
48 return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
49 __pgprot(mtype->prot_pte));
51 EXPORT_SYMBOL(ioremap_page);
53 void __check_kvm_seq(struct mm_struct *mm)
58 seq = init_mm.context.kvm_seq;
59 memcpy(pgd_offset(mm, VMALLOC_START),
60 pgd_offset_k(VMALLOC_START),
61 sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
62 pgd_index(VMALLOC_START)));
63 mm->context.kvm_seq = seq;
64 } while (seq != init_mm.context.kvm_seq);
69 * Section support is unsafe on SMP - If you iounmap and ioremap a region,
70 * the other CPUs will not see this change until their next context switch.
71 * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
72 * which requires the new ioremap'd region to be referenced, the CPU will
73 * reference the _old_ region.
75 * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
76 * mask the size back to 1MB aligned or we will overflow in the loop below.
78 static void unmap_area_sections(unsigned long virt, unsigned long size)
80 unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
83 flush_cache_vunmap(addr, end);
84 pgd = pgd_offset_k(addr);
86 pmd_t pmd, *pmdp = pmd_offset(pgd, addr);
91 * Clear the PMD from the page table, and
92 * increment the kvm sequence so others
95 * Note: this is still racy on SMP machines.
98 init_mm.context.kvm_seq++;
101 * Free the page table, if there was one.
103 if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
104 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
109 } while (addr < end);
112 * Ensure that the active_mm is up to date - we want to
113 * catch any use-after-iounmap cases.
115 if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq)
116 __check_kvm_seq(current->active_mm);
118 flush_tlb_kernel_range(virt, end);
122 remap_area_sections(unsigned long virt, unsigned long pfn,
123 size_t size, const struct mem_type *type)
125 unsigned long addr = virt, end = virt + size;
129 * Remove and free any PTE-based mapping, and
130 * sync the current kernel mapping.
132 unmap_area_sections(virt, size);
134 pgd = pgd_offset_k(addr);
136 pmd_t *pmd = pmd_offset(pgd, addr);
138 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
139 pfn += SZ_1M >> PAGE_SHIFT;
140 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
141 pfn += SZ_1M >> PAGE_SHIFT;
142 flush_pmd_entry(pmd);
146 } while (addr < end);
152 remap_area_supersections(unsigned long virt, unsigned long pfn,
153 size_t size, const struct mem_type *type)
155 unsigned long addr = virt, end = virt + size;
159 * Remove and free any PTE-based mapping, and
160 * sync the current kernel mapping.
162 unmap_area_sections(virt, size);
164 pgd = pgd_offset_k(virt);
166 unsigned long super_pmd_val, i;
168 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
170 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
172 for (i = 0; i < 8; i++) {
173 pmd_t *pmd = pmd_offset(pgd, addr);
175 pmd[0] = __pmd(super_pmd_val);
176 pmd[1] = __pmd(super_pmd_val);
177 flush_pmd_entry(pmd);
183 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
184 } while (addr < end);
190 void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
191 unsigned long offset, size_t size, unsigned int mtype, void *caller)
193 const struct mem_type *type;
196 struct vm_struct * area;
199 * High mappings must be supersection aligned
201 if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK))
205 * Don't allow RAM to be mapped - this causes problems with ARMv6+
207 if (WARN_ON(pfn_valid(pfn)))
210 type = get_mem_type(mtype);
215 * Page align the mapping size, taking account of any offset.
217 size = PAGE_ALIGN(offset + size);
219 area = get_vm_area_caller(size, VM_IOREMAP, caller);
222 addr = (unsigned long)area->addr;
225 if (DOMAIN_IO == 0 &&
226 (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
227 cpu_is_xsc3()) && pfn >= 0x100000 &&
228 !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) {
229 area->flags |= VM_ARM_SECTION_MAPPING;
230 err = remap_area_supersections(addr, pfn, size, type);
231 } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
232 area->flags |= VM_ARM_SECTION_MAPPING;
233 err = remap_area_sections(addr, pfn, size, type);
236 err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
237 __pgprot(type->prot_pte));
240 vunmap((void *)addr);
244 flush_cache_vmap(addr, addr + size);
245 return (void __iomem *) (offset + addr);
248 void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size,
249 unsigned int mtype, void *caller)
251 unsigned long last_addr;
252 unsigned long offset = phys_addr & ~PAGE_MASK;
253 unsigned long pfn = __phys_to_pfn(phys_addr);
256 * Don't allow wraparound or zero size
258 last_addr = phys_addr + size - 1;
259 if (!size || last_addr < phys_addr)
262 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
267 * Remap an arbitrary physical address space into the kernel virtual
268 * address space. Needed when the kernel wants to access high addresses
271 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
272 * have to convert them into an offset in a page-aligned mapping, but the
273 * caller shouldn't need to know that small detail.
276 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
279 return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
280 __builtin_return_address(0));
282 EXPORT_SYMBOL(__arm_ioremap_pfn);
285 __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
287 return __arm_ioremap_caller(phys_addr, size, mtype,
288 __builtin_return_address(0));
290 EXPORT_SYMBOL(__arm_ioremap);
293 * Remap an arbitrary physical address space into the kernel virtual
294 * address space as memory. Needed when the kernel wants to execute
295 * code in external memory. This is needed for reprogramming source
296 * clocks that would affect normal memory for example. Please see
297 * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
300 __arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached)
307 mtype = MT_MEMORY_NONCACHED;
309 return __arm_ioremap_caller(phys_addr, size, mtype,
310 __builtin_return_address(0));
313 void __iounmap(volatile void __iomem *io_addr)
315 void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
317 struct vm_struct **p, *tmp;
320 * If this is a section based mapping we need to handle it
321 * specially as the VM subsystem does not know how to handle
322 * such a beast. We need the lock here b/c we need to clear
323 * all the mappings before the area can be reclaimed
326 write_lock(&vmlist_lock);
327 for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
328 if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
329 if (tmp->flags & VM_ARM_SECTION_MAPPING) {
330 unmap_area_sections((unsigned long)tmp->addr,
336 write_unlock(&vmlist_lock);
341 EXPORT_SYMBOL(__iounmap);