| /* |
| * arch/x86_64/mm/ioremap.c |
| * |
| * Re-map IO memory to kernel address space so that we can access it. |
| * This is needed for high PCI addresses that aren't mapped in the |
| * 640k-1MB IO memory area on PC's |
| * |
| * (C) Copyright 1995 1996 Linus Torvalds |
| */ |
| |
| #include <linux/vmalloc.h> |
| #include <linux/init.h> |
| #include <linux/slab.h> |
| #include <asm/io.h> |
| #include <asm/pgalloc.h> |
| #include <asm/fixmap.h> |
| #include <asm/cacheflush.h> |
| #include <asm/tlbflush.h> |
| #include <asm/proto.h> |
| |
| #define ISA_START_ADDRESS 0xa0000 |
| #define ISA_END_ADDRESS 0x100000 |
| |
| static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, |
| unsigned long phys_addr, unsigned long flags) |
| { |
| unsigned long end; |
| unsigned long pfn; |
| |
| address &= ~PMD_MASK; |
| end = address + size; |
| if (end > PMD_SIZE) |
| end = PMD_SIZE; |
| if (address >= end) |
| BUG(); |
| pfn = phys_addr >> PAGE_SHIFT; |
| do { |
| if (!pte_none(*pte)) { |
| printk("remap_area_pte: page already exists\n"); |
| BUG(); |
| } |
| set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT | _PAGE_RW | |
| _PAGE_GLOBAL | _PAGE_DIRTY | _PAGE_ACCESSED | flags))); |
| address += PAGE_SIZE; |
| pfn++; |
| pte++; |
| } while (address && (address < end)); |
| } |
| |
| static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, |
| unsigned long phys_addr, unsigned long flags) |
| { |
| unsigned long end; |
| |
| address &= ~PUD_MASK; |
| end = address + size; |
| if (end > PUD_SIZE) |
| end = PUD_SIZE; |
| phys_addr -= address; |
| if (address >= end) |
| BUG(); |
| do { |
| pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address); |
| if (!pte) |
| return -ENOMEM; |
| remap_area_pte(pte, address, end - address, address + phys_addr, flags); |
| address = (address + PMD_SIZE) & PMD_MASK; |
| pmd++; |
| } while (address && (address < end)); |
| return 0; |
| } |
| |
| static inline int remap_area_pud(pud_t * pud, unsigned long address, unsigned long size, |
| unsigned long phys_addr, unsigned long flags) |
| { |
| unsigned long end; |
| |
| address &= ~PGDIR_MASK; |
| end = address + size; |
| if (end > PGDIR_SIZE) |
| end = PGDIR_SIZE; |
| phys_addr -= address; |
| if (address >= end) |
| BUG(); |
| do { |
| pmd_t * pmd = pmd_alloc(&init_mm, pud, address); |
| if (!pmd) |
| return -ENOMEM; |
| remap_area_pmd(pmd, address, end - address, address + phys_addr, flags); |
| address = (address + PUD_SIZE) & PUD_MASK; |
| pud++; |
| } while (address && (address < end)); |
| return 0; |
| } |
| |
| static int remap_area_pages(unsigned long address, unsigned long phys_addr, |
| unsigned long size, unsigned long flags) |
| { |
| int error; |
| pgd_t *pgd; |
| unsigned long end = address + size; |
| |
| phys_addr -= address; |
| pgd = pgd_offset_k(address); |
| flush_cache_all(); |
| if (address >= end) |
| BUG(); |
| spin_lock(&init_mm.page_table_lock); |
| do { |
| pud_t *pud; |
| pud = pud_alloc(&init_mm, pgd, address); |
| error = -ENOMEM; |
| if (!pud) |
| break; |
| if (remap_area_pud(pud, address, end - address, |
| phys_addr + address, flags)) |
| break; |
| error = 0; |
| address = (address + PGDIR_SIZE) & PGDIR_MASK; |
| pgd++; |
| } while (address && (address < end)); |
| spin_unlock(&init_mm.page_table_lock); |
| flush_tlb_all(); |
| return error; |
| } |
| |
| /* |
| * Fix up the linear direct mapping of the kernel to avoid cache attribute |
| * conflicts. |
| */ |
| static int |
| ioremap_change_attr(unsigned long phys_addr, unsigned long size, |
| unsigned long flags) |
| { |
| int err = 0; |
| if (phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) { |
| unsigned long npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| unsigned long vaddr = (unsigned long) __va(phys_addr); |
| |
| /* |
| * Must use a address here and not struct page because the phys addr |
| * can be a in hole between nodes and not have an memmap entry. |
| */ |
| err = change_page_attr_addr(vaddr,npages,__pgprot(__PAGE_KERNEL|flags)); |
| if (!err) |
| global_flush_tlb(); |
| } |
| return err; |
| } |
| |
| /* |
| * Generic mapping function |
| */ |
| |
| /* |
| * 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 * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) |
| { |
| void * addr; |
| struct vm_struct * area; |
| unsigned long offset, last_addr; |
| |
| /* Don't allow wraparound or zero size */ |
| last_addr = phys_addr + size - 1; |
| if (!size || last_addr < phys_addr) |
| return NULL; |
| |
| /* |
| * Don't remap the low PCI/ISA area, it's always mapped.. |
| */ |
| if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS) |
| return (__force void __iomem *)phys_to_virt(phys_addr); |
| |
| #ifdef CONFIG_FLATMEM |
| /* |
| * Don't allow anybody to remap normal RAM that we're using.. |
| */ |
| if (last_addr < virt_to_phys(high_memory)) { |
| char *t_addr, *t_end; |
| struct page *page; |
| |
| t_addr = __va(phys_addr); |
| t_end = t_addr + (size - 1); |
| |
| for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) |
| if(!PageReserved(page)) |
| return NULL; |
| } |
| #endif |
| |
| /* |
| * Mappings have to be page-aligned |
| */ |
| offset = phys_addr & ~PAGE_MASK; |
| phys_addr &= PAGE_MASK; |
| size = PAGE_ALIGN(last_addr+1) - phys_addr; |
| |
| /* |
| * Ok, go for it.. |
| */ |
| area = get_vm_area(size, VM_IOREMAP | (flags << 20)); |
| if (!area) |
| return NULL; |
| area->phys_addr = phys_addr; |
| addr = area->addr; |
| if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { |
| remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr)); |
| return NULL; |
| } |
| if (flags && ioremap_change_attr(phys_addr, size, flags) < 0) { |
| area->flags &= 0xffffff; |
| vunmap(addr); |
| return NULL; |
| } |
| return (__force void __iomem *) (offset + (char *)addr); |
| } |
| |
| /** |
| * ioremap_nocache - map bus memory into CPU space |
| * @offset: bus address of the memory |
| * @size: size of the resource to map |
| * |
| * ioremap_nocache performs a platform specific sequence of operations to |
| * make bus memory CPU accessible via the readb/readw/readl/writeb/ |
| * writew/writel functions and the other mmio helpers. The returned |
| * address is not guaranteed to be usable directly as a virtual |
| * address. |
| * |
| * This version of ioremap ensures that the memory is marked uncachable |
| * on the CPU as well as honouring existing caching rules from things like |
| * the PCI bus. Note that there are other caches and buffers on many |
| * busses. In particular driver authors should read up on PCI writes |
| * |
| * It's useful if some control registers are in such an area and |
| * write combining or read caching is not desirable: |
| * |
| * Must be freed with iounmap. |
| */ |
| |
| void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size) |
| { |
| return __ioremap(phys_addr, size, _PAGE_PCD); |
| } |
| |
| void iounmap(volatile void __iomem *addr) |
| { |
| struct vm_struct *p; |
| |
| if (addr <= high_memory) |
| return; |
| if (addr >= phys_to_virt(ISA_START_ADDRESS) && |
| addr < phys_to_virt(ISA_END_ADDRESS)) |
| return; |
| |
| write_lock(&vmlist_lock); |
| p = __remove_vm_area((void *)((unsigned long)addr & PAGE_MASK)); |
| if (!p) |
| printk("iounmap: bad address %p\n", addr); |
| else if (p->flags >> 20) |
| ioremap_change_attr(p->phys_addr, p->size, 0); |
| write_unlock(&vmlist_lock); |
| kfree(p); |
| } |