/* * arch/i386/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 <asm/io.h> #include <asm/pgalloc.h> 15 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; address &= ~PMD_MASK; end = address + size; 22 if (end > PMD_SIZE) end = PMD_SIZE; 24 if (address >= end) 25 BUG(); 26 do { 27 if (!pte_none(*pte)) { printk("remap_area_pte: page already exists\n"); 29 BUG(); } set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | flags))); address += PAGE_SIZE; phys_addr += PAGE_SIZE; pte++; 36 } while (address && (address < end)); } 39 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 &= ~PGDIR_MASK; end = address + size; 46 if (end > PGDIR_SIZE) end = PGDIR_SIZE; phys_addr -= address; 49 if (address >= end) 50 BUG(); 51 do { pte_t * pte = pte_alloc_kernel(pmd, address); 53 if (!pte) 54 return -ENOMEM; remap_area_pte(pte, address, end - address, address + phys_addr, flags); address = (address + PMD_SIZE) & PMD_MASK; pmd++; 58 } while (address && (address < end)); 59 return 0; } 62 static int remap_area_pages(unsigned long address, unsigned long phys_addr, unsigned long size, unsigned long flags) { pgd_t * dir; unsigned long end = address + size; phys_addr -= address; dir = pgd_offset(&init_mm, address); 70 flush_cache_all(); 71 if (address >= end) 72 BUG(); 73 do { pmd_t *pmd; pmd = pmd_alloc_kernel(dir, address); 76 if (!pmd) 77 return -ENOMEM; if (remap_area_pmd(pmd, address, end - address, 79 phys_addr + address, flags)) 80 return -ENOMEM; address = (address + PGDIR_SIZE) & PGDIR_MASK; dir++; 83 } while (address && (address < end)); 84 flush_tlb_all(); 85 return 0; } /* * 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. */ 101 void * __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; 109 if (!size || last_addr < phys_addr) 110 return NULL; /* * Don't remap the low PCI/ISA area, it's always mapped.. */ 115 if (phys_addr >= 0xA0000 && last_addr < 0x100000) 116 return phys_to_virt(phys_addr); /* * Don't allow anybody to remap normal RAM that we're using.. */ 121 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); 128 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) 129 if(!PageReserved(page)) 130 return NULL; } /* * Mappings have to be page-aligned */ offset = phys_addr & ~PAGE_MASK; phys_addr &= PAGE_MASK; size = PAGE_ALIGN(last_addr) - phys_addr; /* * Ok, go for it.. */ area = get_vm_area(size, VM_IOREMAP); 144 if (!area) 145 return NULL; addr = area->addr; 147 if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) { vfree(addr); 149 return NULL; } 151 return (void *) (offset + (char *)addr); } 154 void iounmap(void *addr) { 156 if (addr > high_memory) 157 return vfree((void *) (PAGE_MASK & (unsigned long) addr)); }