| /* |
| * 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> |
| |
| /* |
| * 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, pgprot_t prot) |
| { |
| 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), 0); |
| 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, |
| pgprot_t prot) |
| { |
| 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, prot); |
| 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, |
| unsigned long size, unsigned long flags) |
| { |
| unsigned long addr = start; |
| unsigned long next, end = start + size; |
| unsigned long phys_addr = __pfn_to_phys(pfn); |
| pgprot_t prot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | |
| L_PTE_DIRTY | L_PTE_WRITE | flags); |
| 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, prot); |
| 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, |
| unsigned long size, unsigned long flags) |
| { |
| unsigned long prot, 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); |
| |
| prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_DOMAIN(DOMAIN_IO) | |
| (flags & (L_PTE_CACHEABLE | L_PTE_BUFFERABLE)); |
| |
| /* |
| * ARMv6 and above need XN set to prevent speculative prefetches |
| * hitting IO. |
| */ |
| if (cpu_architecture() >= CPU_ARCH_ARMv6) |
| prot |= PMD_SECT_XN; |
| |
| pgd = pgd_offset_k(addr); |
| do { |
| pmd_t *pmd = pmd_offset(pgd, addr); |
| |
| pmd[0] = __pmd(__pfn_to_phys(pfn) | prot); |
| pfn += SZ_1M >> PAGE_SHIFT; |
| pmd[1] = __pmd(__pfn_to_phys(pfn) | prot); |
| 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, |
| unsigned long size, unsigned long flags) |
| { |
| unsigned long prot, 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); |
| |
| prot = PMD_TYPE_SECT | PMD_SECT_SUPER | PMD_SECT_AP_WRITE | |
| PMD_DOMAIN(DOMAIN_IO) | |
| (flags & (L_PTE_CACHEABLE | L_PTE_BUFFERABLE)); |
| |
| /* |
| * ARMv6 and above need XN set to prevent speculative prefetches |
| * hitting IO. |
| */ |
| if (cpu_architecture() >= CPU_ARCH_ARMv6) |
| prot |= PMD_SECT_XN; |
| |
| pgd = pgd_offset_k(virt); |
| do { |
| unsigned long super_pmd_val, i; |
| |
| super_pmd_val = __pfn_to_phys(pfn) | prot; |
| 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 * |
| __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, |
| unsigned long flags) |
| { |
| 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; |
| |
| area = get_vm_area(size, VM_IOREMAP); |
| if (!area) |
| return NULL; |
| addr = (unsigned long)area->addr; |
| |
| #ifndef CONFIG_SMP |
| if ((((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) || |
| cpu_is_xsc3()) && |
| !((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) { |
| area->flags |= VM_ARM_SECTION_MAPPING; |
| err = remap_area_supersections(addr, pfn, size, flags); |
| } else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { |
| area->flags |= VM_ARM_SECTION_MAPPING; |
| err = remap_area_sections(addr, pfn, size, flags); |
| } else |
| #endif |
| err = remap_area_pages(addr, pfn, size, flags); |
| |
| if (err) { |
| vunmap((void *)addr); |
| return NULL; |
| } |
| |
| flush_cache_vmap(addr, addr + size); |
| return (void __iomem *) (offset + addr); |
| } |
| EXPORT_SYMBOL(__ioremap_pfn); |
| |
| void __iomem * |
| __ioremap(unsigned long phys_addr, size_t size, unsigned long flags) |
| { |
| 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; |
| |
| /* |
| * Page align the mapping size |
| */ |
| size = PAGE_ALIGN(last_addr + 1) - phys_addr; |
| |
| return __ioremap_pfn(pfn, offset, size, flags); |
| } |
| EXPORT_SYMBOL(__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 subysystem 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); |