/* * 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 * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include "mm.h" int ioremap_page(unsigned long virt, unsigned long phys, const struct mem_type *mtype) { return ioremap_page_range(virt, virt + PAGE_SIZE, phys, __pgprot(mtype->prot_pte)); } EXPORT_SYMBOL(ioremap_page); int ioremap_pages(unsigned long virt, unsigned long phys, unsigned long size, const struct mem_type *mtype) { return ioremap_page_range(virt, virt + size, phys, __pgprot(mtype->prot_pte)); } EXPORT_SYMBOL(ioremap_pages); 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); } #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) /* * 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_caller() 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 - 1)); pgd_t *pgd; pud_t *pud; pmd_t *pmdp; flush_cache_vunmap(addr, end); pgd = pgd_offset_k(addr); pud = pud_offset(pgd, addr); pmdp = pmd_offset(pud, addr); do { pmd_t 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(&init_mm, pmd_page_vaddr(pmd)); } addr += PMD_SIZE; pmdp += 2; } 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; pud_t *pud; pmd_t *pmd; /* * Remove and free any PTE-based mapping, and * sync the current kernel mapping. */ unmap_area_sections(virt, size); pgd = pgd_offset_k(addr); pud = pud_offset(pgd, addr); pmd = pmd_offset(pud, addr); do { 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 += PMD_SIZE; pmd += 2; } 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; pud_t *pud; pmd_t *pmd; /* * Remove and free any PTE-based mapping, and * sync the current kernel mapping. */ unmap_area_sections(virt, size); pgd = pgd_offset_k(virt); pud = pud_offset(pgd, addr); pmd = pmd_offset(pud, addr); 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[0] = __pmd(super_pmd_val); pmd[1] = __pmd(super_pmd_val); flush_pmd_entry(pmd); addr += PMD_SIZE; pmd += 2; } pfn += SUPERSECTION_SIZE >> PAGE_SHIFT; } while (addr < end); return 0; } #endif void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, unsigned long offset, size_t size, unsigned int mtype, void *caller) { const struct mem_type *type; int err; unsigned long addr; struct vm_struct * area; #ifndef CONFIG_ARM_LPAE /* * High mappings must be supersection aligned */ if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK)) return NULL; #endif type = get_mem_type(mtype); if (!type) return NULL; /* * Page align the mapping size, taking account of any offset. */ size = PAGE_ALIGN(offset + size); /* * Try to reuse one of the static mapping whenever possible. */ read_lock(&vmlist_lock); for (area = vmlist; area; area = area->next) { if (!size || (sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) break; if (!(area->flags & VM_ARM_STATIC_MAPPING)) continue; if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype)) continue; if (__phys_to_pfn(area->phys_addr) > pfn || __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1) continue; /* we can drop the lock here as we know *area is static */ read_unlock(&vmlist_lock); addr = (unsigned long)area->addr; addr += __pfn_to_phys(pfn) - area->phys_addr; return (void __iomem *) (offset + addr); } read_unlock(&vmlist_lock); /* * Don't allow RAM to be mapped - this causes problems with ARMv6+ */ if (WARN_ON(pfn_valid(pfn))) return NULL; area = get_vm_area_caller(size, VM_IOREMAP, caller); if (!area) return NULL; addr = (unsigned long)area->addr; #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) 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 = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn), __pgprot(type->prot_pte)); if (err) { vunmap((void *)addr); return NULL; } flush_cache_vmap(addr, addr + size); return (void __iomem *) (offset + addr); } void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size, unsigned int mtype, void *caller) { phys_addr_t last_addr; phys_addr_t 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_caller(pfn, offset, size, mtype, caller); } /* * 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. */ void __iomem * __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, unsigned int mtype) { return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, __builtin_return_address(0)); } EXPORT_SYMBOL(__arm_ioremap_pfn); void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t, unsigned int, void *) = __arm_ioremap_caller; void __iomem * __arm_ioremap(phys_addr_t phys_addr, size_t size, unsigned int mtype) { return arch_ioremap_caller(phys_addr, size, mtype, __builtin_return_address(0)); } EXPORT_SYMBOL(__arm_ioremap); /* * Remap an arbitrary physical address space into the kernel virtual * address space as memory. Needed when the kernel wants to execute * code in external memory. This is needed for reprogramming source * clocks that would affect normal memory for example. Please see * CONFIG_GENERIC_ALLOCATOR for allocating external memory. */ void __iomem * __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached) { unsigned int mtype; if (cached) mtype = MT_MEMORY; else mtype = MT_MEMORY_NONCACHED; return __arm_ioremap_caller(phys_addr, size, mtype, __builtin_return_address(0)); } void __iounmap(volatile void __iomem *io_addr) { void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); struct vm_struct *vm; read_lock(&vmlist_lock); for (vm = vmlist; vm; vm = vm->next) { if (vm->addr > addr) break; if (!(vm->flags & VM_IOREMAP)) continue; /* If this is a static mapping we must leave it alone */ if ((vm->flags & VM_ARM_STATIC_MAPPING) && (vm->addr <= addr) && (vm->addr + vm->size > addr)) { read_unlock(&vmlist_lock); return; } #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) /* * 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. */ if ((vm->addr == addr) && (vm->flags & VM_ARM_SECTION_MAPPING)) { unmap_area_sections((unsigned long)vm->addr, vm->size); break; } #endif } read_unlock(&vmlist_lock); vunmap(addr); } void (*arch_iounmap)(volatile void __iomem *) = __iounmap; void __arm_iounmap(volatile void __iomem *io_addr) { arch_iounmap(io_addr); } EXPORT_SYMBOL(__arm_iounmap);