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