1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * Copyright (C) 2020-2022 Loongson Technology !! 2 * arch/i386/mm/ioremap.c
>> 3 *
>> 4 * Re-map IO memory to kernel address space so that we can access it.
>> 5 * This is needed for high PCI addresses that aren't mapped in the
>> 6 * 640k-1MB IO memory area on PC's
>> 7 *
>> 8 * (C) Copyright 1995 1996 Linus Torvalds
4 */ 9 */
5 10
>> 11 #include <linux/vmalloc.h>
6 #include <asm/io.h> 12 #include <asm/io.h>
7 #include <asm-generic/early_ioremap.h> !! 13 #include <asm/pgalloc.h>
8 14
9 void __init __iomem *early_ioremap(u64 phys_ad !! 15 static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
>> 16 unsigned long phys_addr, unsigned long flags)
10 { 17 {
11 return ((void __iomem *)TO_CACHE(phys_ !! 18 unsigned long end;
>> 19
>> 20 address &= ~PMD_MASK;
>> 21 end = address + size;
>> 22 if (end > PMD_SIZE)
>> 23 end = PMD_SIZE;
>> 24 if (address >= end)
>> 25 BUG();
>> 26 do {
>> 27 if (!pte_none(*pte)) {
>> 28 printk("remap_area_pte: page already exists\n");
>> 29 BUG();
>> 30 }
>> 31 set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | _PAGE_RW |
>> 32 _PAGE_DIRTY | _PAGE_ACCESSED | flags)));
>> 33 address += PAGE_SIZE;
>> 34 phys_addr += PAGE_SIZE;
>> 35 pte++;
>> 36 } while (address && (address < end));
>> 37 }
>> 38
>> 39 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
>> 40 unsigned long phys_addr, unsigned long flags)
>> 41 {
>> 42 unsigned long end;
>> 43
>> 44 address &= ~PGDIR_MASK;
>> 45 end = address + size;
>> 46 if (end > PGDIR_SIZE)
>> 47 end = PGDIR_SIZE;
>> 48 phys_addr -= address;
>> 49 if (address >= end)
>> 50 BUG();
>> 51 do {
>> 52 pte_t * pte = pte_alloc(&init_mm, pmd, address);
>> 53 if (!pte)
>> 54 return -ENOMEM;
>> 55 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
>> 56 address = (address + PMD_SIZE) & PMD_MASK;
>> 57 pmd++;
>> 58 } while (address && (address < end));
>> 59 return 0;
12 } 60 }
13 61
14 void __init early_iounmap(void __iomem *addr, !! 62 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
>> 63 unsigned long size, unsigned long flags)
15 { 64 {
>> 65 int error;
>> 66 pgd_t * dir;
>> 67 unsigned long end = address + size;
>> 68
>> 69 phys_addr -= address;
>> 70 dir = pgd_offset(&init_mm, address);
>> 71 flush_cache_all();
>> 72 if (address >= end)
>> 73 BUG();
>> 74 spin_lock(&init_mm.page_table_lock);
>> 75 do {
>> 76 pmd_t *pmd;
>> 77 pmd = pmd_alloc(&init_mm, dir, address);
>> 78 error = -ENOMEM;
>> 79 if (!pmd)
>> 80 break;
>> 81 if (remap_area_pmd(pmd, address, end - address,
>> 82 phys_addr + address, flags))
>> 83 break;
>> 84 error = 0;
>> 85 address = (address + PGDIR_SIZE) & PGDIR_MASK;
>> 86 dir++;
>> 87 } while (address && (address < end));
>> 88 spin_unlock(&init_mm.page_table_lock);
>> 89 flush_tlb_all();
>> 90 return error;
>> 91 }
16 92
>> 93 /*
>> 94 * Generic mapping function (not visible outside):
>> 95 */
>> 96
>> 97 /*
>> 98 * Remap an arbitrary physical address space into the kernel virtual
>> 99 * address space. Needed when the kernel wants to access high addresses
>> 100 * directly.
>> 101 *
>> 102 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
>> 103 * have to convert them into an offset in a page-aligned mapping, but the
>> 104 * caller shouldn't need to know that small detail.
>> 105 */
>> 106 void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
>> 107 {
>> 108 void * addr;
>> 109 struct vm_struct * area;
>> 110 unsigned long offset, last_addr;
>> 111
>> 112 /* Don't allow wraparound or zero size */
>> 113 last_addr = phys_addr + size - 1;
>> 114 if (!size || last_addr < phys_addr)
>> 115 return NULL;
>> 116
>> 117 /*
>> 118 * Don't remap the low PCI/ISA area, it's always mapped..
>> 119 */
>> 120 if (phys_addr >= 0xA0000 && last_addr < 0x100000)
>> 121 return phys_to_virt(phys_addr);
>> 122
>> 123 /*
>> 124 * Don't allow anybody to remap normal RAM that we're using..
>> 125 */
>> 126 if (phys_addr < virt_to_phys(high_memory)) {
>> 127 char *t_addr, *t_end;
>> 128 struct page *page;
>> 129
>> 130 t_addr = __va(phys_addr);
>> 131 t_end = t_addr + (size - 1);
>> 132
>> 133 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
>> 134 if(!PageReserved(page))
>> 135 return NULL;
>> 136 }
>> 137
>> 138 /*
>> 139 * Mappings have to be page-aligned
>> 140 */
>> 141 offset = phys_addr & ~PAGE_MASK;
>> 142 phys_addr &= PAGE_MASK;
>> 143 size = PAGE_ALIGN(last_addr+1) - phys_addr;
>> 144
>> 145 /*
>> 146 * Ok, go for it..
>> 147 */
>> 148 area = get_vm_area(size, VM_IOREMAP);
>> 149 if (!area)
>> 150 return NULL;
>> 151 addr = area->addr;
>> 152 if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) {
>> 153 vfree(addr);
>> 154 return NULL;
>> 155 }
>> 156 return (void *) (offset + (char *)addr);
>> 157 }
>> 158
>> 159 void iounmap(void *addr)
>> 160 {
>> 161 if (addr > high_memory)
>> 162 return vfree((void *) (PAGE_MASK & (unsigned long) addr));
17 } 163 }
18 164
19 void *early_memremap_ro(resource_size_t phys_a !! 165 void __init *bt_ioremap(unsigned long phys_addr, unsigned long size)
20 { 166 {
21 return early_memremap(phys_addr, size) !! 167 unsigned long offset, last_addr;
>> 168 unsigned int nrpages;
>> 169 enum fixed_addresses idx;
>> 170
>> 171 /* Don't allow wraparound or zero size */
>> 172 last_addr = phys_addr + size - 1;
>> 173 if (!size || last_addr < phys_addr)
>> 174 return NULL;
>> 175
>> 176 /*
>> 177 * Don't remap the low PCI/ISA area, it's always mapped..
>> 178 */
>> 179 if (phys_addr >= 0xA0000 && last_addr < 0x100000)
>> 180 return phys_to_virt(phys_addr);
>> 181
>> 182 /*
>> 183 * Mappings have to be page-aligned
>> 184 */
>> 185 offset = phys_addr & ~PAGE_MASK;
>> 186 phys_addr &= PAGE_MASK;
>> 187 size = PAGE_ALIGN(last_addr) - phys_addr;
>> 188
>> 189 /*
>> 190 * Mappings have to fit in the FIX_BTMAP area.
>> 191 */
>> 192 nrpages = size >> PAGE_SHIFT;
>> 193 if (nrpages > NR_FIX_BTMAPS)
>> 194 return NULL;
>> 195
>> 196 /*
>> 197 * Ok, go for it..
>> 198 */
>> 199 idx = FIX_BTMAP_BEGIN;
>> 200 while (nrpages > 0) {
>> 201 set_fixmap(idx, phys_addr);
>> 202 phys_addr += PAGE_SIZE;
>> 203 --idx;
>> 204 --nrpages;
>> 205 }
>> 206 return (void*) (offset + fix_to_virt(FIX_BTMAP_BEGIN));
22 } 207 }
23 208
24 void *early_memremap_prot(resource_size_t phys !! 209 void __init bt_iounmap(void *addr, unsigned long size)
25 unsigned long prot_val) <<
26 { 210 {
27 return early_memremap(phys_addr, size) !! 211 unsigned long virt_addr;
>> 212 unsigned long offset;
>> 213 unsigned int nrpages;
>> 214 enum fixed_addresses idx;
>> 215
>> 216 virt_addr = (unsigned long)addr;
>> 217 if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN))
>> 218 return;
>> 219 offset = virt_addr & ~PAGE_MASK;
>> 220 nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
>> 221
>> 222 idx = FIX_BTMAP_BEGIN;
>> 223 while (nrpages > 0) {
>> 224 __set_fixmap(idx, 0, __pgprot(0));
>> 225 --idx;
>> 226 --nrpages;
>> 227 }
28 } 228 }
29 229
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