diff options
Diffstat (limited to 'arch/mips/mm/ioremap.c')
| -rw-r--r-- | arch/mips/mm/ioremap.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/mips/mm/ioremap.c b/arch/mips/mm/ioremap.c new file mode 100644 index 000000000000..adf352273f63 --- /dev/null +++ b/arch/mips/mm/ioremap.c @@ -0,0 +1,202 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * (C) Copyright 1995 1996 Linus Torvalds + * (C) Copyright 2001, 2002 Ralf Baechle + */ +#include <linux/module.h> +#include <asm/addrspace.h> +#include <asm/byteorder.h> + +#include <linux/vmalloc.h> +#include <asm/cacheflush.h> +#include <asm/io.h> +#include <asm/tlbflush.h> + +static inline void remap_area_pte(pte_t * pte, unsigned long address, + phys_t size, phys_t phys_addr, unsigned long flags) +{ + phys_t end; + unsigned long pfn; + pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE + | __WRITEABLE | flags); + + 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)); + address += PAGE_SIZE; + pfn++; + pte++; + } while (address && (address < end)); +} + +static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, + phys_t size, phys_t phys_addr, unsigned long flags) +{ + phys_t end; + + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_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 int remap_area_pages(unsigned long address, phys_t phys_addr, + phys_t size, unsigned long flags) +{ + int error; + pgd_t * dir; + unsigned long end = address + size; + + phys_addr -= address; + dir = pgd_offset(&init_mm, address); + flush_cache_all(); + if (address >= end) + BUG(); + spin_lock(&init_mm.page_table_lock); + do { + pmd_t *pmd; + pmd = pmd_alloc(&init_mm, dir, address); + error = -ENOMEM; + if (!pmd) + break; + if (remap_area_pmd(pmd, address, end - address, + phys_addr + address, flags)) + break; + error = 0; + address = (address + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } while (address && (address < end)); + spin_unlock(&init_mm.page_table_lock); + flush_tlb_all(); + return error; +} + +/* + * Allow physical addresses to be fixed up to help 36 bit peripherals. + */ +phys_t __attribute__ ((weak)) +fixup_bigphys_addr(phys_t phys_addr, phys_t size) +{ + return phys_addr; +} + +/* + * Generic mapping function (not visible outside): + */ + +/* + * 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. + */ + +#define IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL)) + +void * __ioremap(phys_t phys_addr, phys_t size, unsigned long flags) +{ + struct vm_struct * area; + unsigned long offset; + phys_t last_addr; + void * addr; + + phys_addr = fixup_bigphys_addr(phys_addr, size); + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) + return NULL; + + /* + * Map uncached objects in the low 512mb of address space using KSEG1, + * otherwise map using page tables. + */ + if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) && + flags == _CACHE_UNCACHED) + return (void *) KSEG1ADDR(phys_addr); + + /* + * Don't allow anybody to remap normal RAM that we're using.. + */ + if (phys_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; + } + + /* + * 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); + if (!area) + return NULL; + addr = area->addr; + if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { + vunmap(addr); + return NULL; + } + + return (void *) (offset + (char *)addr); +} + +#define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == KSEG1) + +void __iounmap(volatile void __iomem *addr) +{ + struct vm_struct *p; + + if (IS_KSEG1(addr)) + return; + + p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); + if (!p) { + printk(KERN_ERR "iounmap: bad address %p\n", addr); + return; + } + + kfree(p); +} + +EXPORT_SYMBOL(__ioremap); +EXPORT_SYMBOL(__iounmap); |