2 * Copyright © 2008 Ingo Molnar
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
19 #include <asm/iomap.h>
21 #include <linux/bitops.h>
22 #include <linux/module.h>
23 #include <linux/highmem.h>
25 static int is_io_mapping_possible(resource_size_t base, unsigned long size)
27 #if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT)
28 /* There is no way to map greater than 1 << 32 address without PAE */
29 if (base + size > 0x100000000ULL)
35 int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot)
37 unsigned long flag = _PAGE_CACHE_WC;
40 if (!is_io_mapping_possible(base, size))
43 ret = io_reserve_memtype(base, base + size, &flag);
47 *prot = __pgprot(__PAGE_KERNEL | flag);
50 EXPORT_SYMBOL_GPL(iomap_create_wc);
52 void iomap_free(resource_size_t base, unsigned long size)
54 io_free_memtype(base, base + size);
56 EXPORT_SYMBOL_GPL(iomap_free);
58 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
65 type = kmap_atomic_idx_push();
66 idx = type + KM_TYPE_NR * smp_processor_id();
67 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
68 set_pte_at(&init_mm, vaddr, kmap_pte - idx, pfn_pte(pfn, prot));
69 /*arch_flush_lazy_mmu_mode();*/
75 * Map 'mfn' using protections 'prot'
78 iomap_atomic_prot_pfn(unsigned long mfn, pgprot_t prot)
81 * For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS.
82 * PAGE_KERNEL_WC maps to PWT, which translates to uncached if the
83 * MTRR is UC or WC. UC_MINUS gets the real intention, of the
84 * user, which is "WC if the MTRR is WC, UC if you can't do that."
86 if (!pat_enabled && pgprot_val(prot) == pgprot_val(PAGE_KERNEL_WC))
87 prot = PAGE_KERNEL_UC_MINUS;
89 pgprot_val(prot) |= _PAGE_IOMAP;
90 return (void __force __iomem *) kmap_atomic_prot_pfn(mfn, prot);
92 EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
95 iounmap_atomic(void __iomem *kvaddr)
97 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
99 if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
100 vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
103 type = kmap_atomic_idx();
104 idx = type + KM_TYPE_NR * smp_processor_id();
106 #ifdef CONFIG_DEBUG_HIGHMEM
107 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
110 * Force other mappings to Oops if they'll try to access this
111 * pte without first remap it. Keeping stale mappings around
112 * is a bad idea also, in case the page changes cacheability
113 * attributes or becomes a protected page in a hypervisor.
115 kpte_clear_flush(kmap_pte-idx, vaddr);
116 kmap_atomic_idx_pop();
121 EXPORT_SYMBOL_GPL(iounmap_atomic);