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Diffstat (limited to 'arch/avr32/mm/ioremap.c')
| -rw-r--r-- | arch/avr32/mm/ioremap.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/arch/avr32/mm/ioremap.c b/arch/avr32/mm/ioremap.c new file mode 100644 index 000000000000..536021877df6 --- /dev/null +++ b/arch/avr32/mm/ioremap.c @@ -0,0 +1,197 @@ +/* + * Copyright (C) 2004-2006 Atmel Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/vmalloc.h> +#include <linux/module.h> + +#include <asm/io.h> +#include <asm/pgtable.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm/addrspace.h> + +static inline int remap_area_pte(pte_t *pte, unsigned long address, + unsigned long end, unsigned long phys_addr, + pgprot_t prot) +{ + unsigned long pfn; + + pfn = phys_addr >> PAGE_SHIFT; + do { + WARN_ON(!pte_none(*pte)); + + set_pte(pte, pfn_pte(pfn, prot)); + address += PAGE_SIZE; + pfn++; + pte++; + } while (address && (address < end)); + + return 0; +} + +static inline int remap_area_pmd(pmd_t *pmd, unsigned long address, + unsigned long end, unsigned long phys_addr, + pgprot_t prot) +{ + unsigned long next; + + phys_addr -= address; + + do { + pte_t *pte = pte_alloc_kernel(pmd, address); + if (!pte) + return -ENOMEM; + + next = (address + PMD_SIZE) & PMD_MASK; + if (remap_area_pte(pte, address, next, + address + phys_addr, prot)) + return -ENOMEM; + + address = next; + pmd++; + } while (address && (address < end)); + return 0; +} + +static int remap_area_pud(pud_t *pud, unsigned long address, + unsigned long end, unsigned long phys_addr, + pgprot_t prot) +{ + unsigned long next; + + phys_addr -= address; + + do { + pmd_t *pmd = pmd_alloc(&init_mm, pud, address); + if (!pmd) + return -ENOMEM; + next = (address + PUD_SIZE) & PUD_MASK; + if (remap_area_pmd(pmd, address, next, + phys_addr + address, prot)) + return -ENOMEM; + + address = next; + pud++; + } while (address && address < end); + + return 0; +} + +static int remap_area_pages(unsigned long address, unsigned long phys_addr, + size_t size, pgprot_t prot) +{ + unsigned long end = address + size; + unsigned long next; + pgd_t *pgd; + int err = 0; + + phys_addr -= address; + + pgd = pgd_offset_k(address); + flush_cache_all(); + BUG_ON(address >= end); + + spin_lock(&init_mm.page_table_lock); + do { + pud_t *pud = pud_alloc(&init_mm, pgd, address); + + err = -ENOMEM; + if (!pud) + break; + + next = (address + PGDIR_SIZE) & PGDIR_MASK; + if (next < address || next > end) + next = end; + err = remap_area_pud(pud, address, next, + phys_addr + address, prot); + if (err) + break; + + address = next; + pgd++; + } while (address && (address < end)); + + spin_unlock(&init_mm.page_table_lock); + flush_tlb_all(); + return err; +} + +/* + * Re-map an arbitrary physical address space into the kernel virtual + * address space. Needed when the kernel wants to access physical + * memory directly. + */ +void __iomem *__ioremap(unsigned long phys_addr, size_t size, + unsigned long flags) +{ + void *addr; + struct vm_struct *area; + unsigned long offset, last_addr; + pgprot_t prot; + + /* + * Check if we can simply use the P4 segment. This area is + * uncacheable, so if caching/buffering is requested, we can't + * use it. + */ + if ((phys_addr >= P4SEG) && (flags == 0)) + return (void __iomem *)phys_addr; + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) + return NULL; + + /* + * XXX: When mapping regular RAM, we'd better make damn sure + * it's never used for anything else. But this is really the + * caller's responsibility... + */ + if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr) + return (void __iomem *)P2SEGADDR(phys_addr); + + /* Mappings have to be page-aligned */ + offset = phys_addr & ~PAGE_MASK; + phys_addr &= PAGE_MASK; + size = PAGE_ALIGN(last_addr + 1) - phys_addr; + + prot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY + | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags); + + /* + * Ok, go for it.. + */ + area = get_vm_area(size, VM_IOREMAP); + if (!area) + return NULL; + area->phys_addr = phys_addr; + addr = area->addr; + if (remap_area_pages((unsigned long)addr, phys_addr, size, prot)) { + vunmap(addr); + return NULL; + } + + return (void __iomem *)(offset + (char *)addr); +} +EXPORT_SYMBOL(__ioremap); + +void __iounmap(void __iomem *addr) +{ + struct vm_struct *p; + + if ((unsigned long)addr >= P4SEG) + return; + + p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr)); + if (unlikely(!p)) { + printk (KERN_ERR "iounmap: bad address %p\n", addr); + return; + } + + kfree (p); +} +EXPORT_SYMBOL(__iounmap); |