198 lines
4.3 KiB
C
198 lines
4.3 KiB
C
![]() |
/*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/vmalloc.h>
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#include <linux/module.h>
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#include <asm/io.h>
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#include <asm/pgtable.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include <asm/addrspace.h>
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static inline int remap_area_pte(pte_t *pte, unsigned long address,
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unsigned long end, unsigned long phys_addr,
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pgprot_t prot)
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{
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unsigned long pfn;
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pfn = phys_addr >> PAGE_SHIFT;
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do {
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WARN_ON(!pte_none(*pte));
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set_pte(pte, pfn_pte(pfn, prot));
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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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return 0;
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}
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static inline int remap_area_pmd(pmd_t *pmd, unsigned long address,
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unsigned long end, unsigned long phys_addr,
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pgprot_t prot)
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{
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unsigned long next;
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phys_addr -= address;
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do {
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pte_t *pte = pte_alloc_kernel(pmd, address);
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if (!pte)
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return -ENOMEM;
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next = (address + PMD_SIZE) & PMD_MASK;
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if (remap_area_pte(pte, address, next,
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address + phys_addr, prot))
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return -ENOMEM;
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address = next;
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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 int remap_area_pud(pud_t *pud, unsigned long address,
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unsigned long end, unsigned long phys_addr,
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pgprot_t prot)
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{
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unsigned long next;
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phys_addr -= address;
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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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next = (address + PUD_SIZE) & PUD_MASK;
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if (remap_area_pmd(pmd, address, next,
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phys_addr + address, prot))
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return -ENOMEM;
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address = next;
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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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size_t size, pgprot_t prot)
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{
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unsigned long end = address + size;
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unsigned long next;
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pgd_t *pgd;
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int err = 0;
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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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BUG_ON(address >= end);
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spin_lock(&init_mm.page_table_lock);
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do {
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pud_t *pud = pud_alloc(&init_mm, pgd, address);
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err = -ENOMEM;
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if (!pud)
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break;
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next = (address + PGDIR_SIZE) & PGDIR_MASK;
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if (next < address || next > end)
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next = end;
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err = remap_area_pud(pud, address, next,
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phys_addr + address, prot);
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if (err)
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break;
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address = next;
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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 err;
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}
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/*
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* Re-map an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access physical
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* memory directly.
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*/
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void __iomem *__ioremap(unsigned long phys_addr, size_t size,
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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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pgprot_t prot;
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/*
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* Check if we can simply use the P4 segment. This area is
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* uncacheable, so if caching/buffering is requested, we can't
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* use it.
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*/
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if ((phys_addr >= P4SEG) && (flags == 0))
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return (void __iomem *)phys_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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* XXX: When mapping regular RAM, we'd better make damn sure
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* it's never used for anything else. But this is really the
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* caller's responsibility...
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*/
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if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
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return (void __iomem *)P2SEGADDR(phys_addr);
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/* Mappings have to be page-aligned */
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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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prot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY
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| _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
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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);
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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, prot)) {
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vunmap(addr);
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return NULL;
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}
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return (void __iomem *)(offset + (char *)addr);
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}
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EXPORT_SYMBOL(__ioremap);
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void __iounmap(void __iomem *addr)
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{
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struct vm_struct *p;
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if ((unsigned long)addr >= P4SEG)
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return;
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p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
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if (unlikely(!p)) {
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printk (KERN_ERR "iounmap: bad address %p\n", addr);
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return;
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}
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kfree (p);
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}
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EXPORT_SYMBOL(__iounmap);
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