/* * linux/arch/arm/mm/ioremap.c * * Re-map IO memory to kernel address space so that we can access it. * * (C) Copyright 1995 1996 Linus Torvalds * * Hacked for ARM by Phil Blundell <philb@gnu.org> * Hacked to allow all architectures to build, and various cleanups * by Russell King * * This allows a driver to remap an arbitrary region of bus memory into * virtual space. One should *only* use readl, writel, memcpy_toio and * so on with such remapped areas. * * Because the ARM only has a 32-bit address space we can't address the * whole of the (physical) PCI space at once. PCI huge-mode addressing * allows us to circumvent this restriction by splitting PCI space into * two 2GB chunks and mapping only one at a time into processor memory. * We use MMU protection domains to trap any attempt to access the bank * that is not currently mapped. (This isn't fully implemented yet.) */ #include <linux/module.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/vmalloc.h> #include <asm/cacheflush.h> #include <asm/io.h> #include <asm/mmu_context.h> #include <asm/pgalloc.h> #include <asm/tlbflush.h> #include <asm/sizes.h> #include <asm/mach/map.h> #include "mm.h" /* * Used by ioremap() and iounmap() code to mark (super)section-mapped * I/O regions in vm_struct->flags field. */ #define VM_ARM_SECTION_MAPPING 0x80000000 static int remap_area_pte(pmd_t *pmd, unsigned long addr, unsigned long end, unsigned long phys_addr, const struct mem_type *type) { pgprot_t prot = __pgprot(type->prot_pte); pte_t *pte; pte = pte_alloc_kernel(pmd, addr); if (!pte) return -ENOMEM; do { if (!pte_none(*pte)) goto bad; set_pte_ext(pte, pfn_pte(phys_addr >> PAGE_SHIFT, prot), type->prot_pte_ext); phys_addr += PAGE_SIZE; } while (pte++, addr += PAGE_SIZE, addr != end); return 0; bad: printk(KERN_CRIT "remap_area_pte: page already exists\n"); BUG(); } static inline int remap_area_pmd(pgd_t *pgd, unsigned long addr, unsigned long end, unsigned long phys_addr, const struct mem_type *type) { unsigned long next; pmd_t *pmd; int ret = 0; pmd = pmd_alloc(&init_mm, pgd, addr); if (!pmd) return -ENOMEM; do { next = pmd_addr_end(addr, end); ret = remap_area_pte(pmd, addr, next, phys_addr, type); if (ret) return ret; phys_addr += next - addr; } while (pmd++, addr = next, addr != end); return ret; } static int remap_area_pages(unsigned long start, unsigned long pfn, size_t size, const struct mem_type *type) { unsigned long addr = start; unsigned long next, end = start + size; unsigned long phys_addr = __pfn_to_phys(pfn); pgd_t *pgd; int err = 0; BUG_ON(addr >= end); pgd = pgd_offset_k(addr); do { next = pgd_addr_end(addr, end); err = remap_area_pmd(pgd, addr, next, phys_addr, type); if (err) break; phys_addr += next - addr; } while (pgd++, addr = next, addr != end); return err; } void __check_kvm_seq(struct mm_struct *mm) { unsigned int seq; do { seq = init_mm.context.kvm_seq; memcpy(pgd_offset(mm, VMALLOC_START), pgd_offset_k(VMALLOC_START), sizeof(pgd_t) * (pgd_index(VMALLOC_END) - pgd_index(VMALLOC_START))); mm->context.kvm_seq = seq; } while (seq != init_mm.context.kvm_seq); } #ifndef CONFIG_SMP /* * Section support is unsafe on SMP - If you iounmap and ioremap a region, * the other CPUs will not see this change until their next context switch. * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs * which requires the new ioremap'd region to be referenced, the CPU will * reference the _old_ region. * * Note that get_vm_area() allocates a guard 4K page, so we need to mask * the size back to 1MB aligned or we will overflow in the loop below. */ static void unmap_area_sections(unsigned long virt, unsigned long size) { unsigned long addr = virt, end = virt + (size & ~SZ_1M); pgd_t *pgd; flush_cache_vunmap(addr, end); pgd = pgd_offset_k(addr); do { pmd_t pmd, *pmdp = pmd_offset(pgd, addr); pmd = *pmdp; if (!pmd_none(pmd)) { /* * Clear the PMD from the page table, and * increment the kvm sequence so others * notice this change. * * Note: this is still racy on SMP machines. */ pmd_clear(pmdp); init_mm.context.kvm_seq++; /* * Free the page table, if there was one. */ if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) pte_free_kernel(pmd_page_vaddr(pmd)); } addr += PGDIR_SIZE; pgd++; } while (addr < end); /* * Ensure that the active_mm is up to date - we want to * catch any use-after-iounmap cases. */ if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq) __check_kvm_seq(current->active_mm); flush_tlb_kernel_range(virt, end); } static int remap_area_sections(unsigned long virt, unsigned long pfn, size_t size, const struct mem_type *type) { unsigned long addr = virt, end = virt + size; pgd_t *pgd; /* * Remove and free any PTE-based mapping, and * sync the current kernel mapping. */ unmap_area_sections(virt, size); pgd = pgd_offset_k(addr); do { pmd_t *pmd = pmd_offset(pgd, addr); pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); pfn += SZ_1M >> PAGE_SHIFT; pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect); pfn += SZ_1M >> PAGE_SHIFT; flush_pmd_entry(pmd); addr += PGDIR_SIZE; pgd++; } while (addr < end); return 0; } static int remap_area_supersections(unsigned long virt, unsigned long pfn, size_t size, const struct mem_type *type) { unsigned long addr = virt, end = virt + size; pgd_t *pgd; /* * Remove and free any PTE-based mapping, and * sync the current kernel mapping. */ unmap_area_sections(virt, size); pgd = pgd_offset_k(virt); do { unsigned long super_pmd_val, i; super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect | PMD_SECT_SUPER; super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20; for (i = 0; i < 8; i++) { pmd_t *pmd = pmd_offset(pgd, addr); pmd[0] = __pmd(super_pmd_val); pmd[1] = __pmd(super_pmd_val); flush_pmd_entry(pmd); addr += PGDIR_SIZE; pgd++; } pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; } while (addr < end); return 0; } #endif /* * Remap an arbitrary physical address space into the kernel virtual * address space. Needed when the kernel wants to access high addresses * directly. * * NOTE! We need to allow non-page-aligned mappings too: we will obviously * have to convert them into an offset in a page-aligned mapping, but the * caller shouldn't need to know that small detail. * * 'flags' are the extra L_PTE_ flags that you want to specify for this * mapping. See include/asm-arm/proc-armv/pgtable.h for more information. */ void __iomem * __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, unsigned int mtype) { const struct mem_type *type; int err; unsigned long addr; struct vm_struct * area; /* * High mappings must be supersection aligned */ if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) return NULL; type = get_mem_type(mtype); if (!type) return NULL; /* * Page align the mapping size, taking account of any offset. */ size = PAGE_ALIGN(offset + size); area = get_vm_area(size, VM_IOREMAP); if (!area) return NULL; addr = (unsigned long)area->addr; #ifndef CONFIG_SMP if (DOMAIN_IO == 0 && (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || cpu_is_xsc3()) && pfn >= 0x100000 && !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) { area->flags |= VM_ARM_SECTION_MAPPING; err = remap_area_supersections(addr, pfn, size, type); } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { area->flags |= VM_ARM_SECTION_MAPPING; err = remap_area_sections(addr, pfn, size, type); } else #endif err = remap_area_pages(addr, pfn, size, type); if (err) { vunmap((void *)addr); return NULL; } flush_cache_vmap(addr, addr + size); return (void __iomem *) (offset + addr); } EXPORT_SYMBOL(__arm_ioremap_pfn); void __iomem * __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype) { unsigned long last_addr; unsigned long offset = phys_addr & ~PAGE_MASK; unsigned long pfn = __phys_to_pfn(phys_addr); /* * Don't allow wraparound or zero size */ last_addr = phys_addr + size - 1; if (!size || last_addr < phys_addr) return NULL; return __arm_ioremap_pfn(pfn, offset, size, mtype); } EXPORT_SYMBOL(__arm_ioremap); void __iounmap(volatile void __iomem *addr) { #ifndef CONFIG_SMP struct vm_struct **p, *tmp; #endif unsigned int section_mapping = 0; addr = (volatile void __iomem *)(PAGE_MASK & (unsigned long)addr); #ifndef CONFIG_SMP /* * If this is a section based mapping we need to handle it * specially as the VM subsystem does not know how to handle * such a beast. We need the lock here b/c we need to clear * all the mappings before the area can be reclaimed * by someone else. */ write_lock(&vmlist_lock); for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { if((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) { if (tmp->flags & VM_ARM_SECTION_MAPPING) { *p = tmp->next; unmap_area_sections((unsigned long)tmp->addr, tmp->size); kfree(tmp); section_mapping = 1; } break; } } write_unlock(&vmlist_lock); #endif if (!section_mapping) vunmap((void __force *)addr); } EXPORT_SYMBOL(__iounmap);