mm/early_ioremap.c

   1 /*
   2  * Provide common bits of early_ioremap() support for architectures needing
   3  * temporary mappings during boot before ioremap() is available.
   4  *
   5  * This is mostly a direct copy of the x86 early_ioremap implementation.
   6  *
   7  * (C) Copyright 1995 1996, 2014 Linus Torvalds
   8  *
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/io.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/mm.h>
  16 #include <linux/vmalloc.h>
  17 #include <asm/fixmap.h>
  18 #include <asm/early_ioremap.h>
  19
  20 #ifdef CONFIG_MMU
  21 static int early_ioremap_debug __initdata;
  22
  23 static int __init early_ioremap_debug_setup(char *str)
  24 {
  25         early_ioremap_debug = 1;
  26
  27         return 0;
  28 }
  29 early_param("early_ioremap_debug", early_ioremap_debug_setup);
  30
  31 static int after_paging_init __initdata;
  32
  33 void __init __weak early_ioremap_shutdown(void)
  34 {
  35 }
  36
  37 void __init early_ioremap_reset(void)
  38 {
  39         early_ioremap_shutdown();
  40         after_paging_init = 1;
  41 }
  42
  43 /*
  44  * Generally, ioremap() is available after paging_init() has been called.
  45  * Architectures wanting to allow early_ioremap after paging_init() can
  46  * define __late_set_fixmap and __late_clear_fixmap to do the right thing.
  47  */
  48 #ifndef __late_set_fixmap
  49 static inline void __init __late_set_fixmap(enum fixed_addresses idx,
  50                                             phys_addr_t phys, pgprot_t prot)
  51 {
  52         BUG();
  53 }
  54 #endif
  55
  56 #ifndef __late_clear_fixmap
  57 static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
  58 {
  59         BUG();
  60 }
  61 #endif
  62
  63 static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
  64 static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
  65 static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
  66
  67 void __init early_ioremap_setup(void)
  68 {
  69         int i;
  70
  71         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  72                 if (WARN_ON(prev_map[i]))
  73                         break;
  74
  75         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  76                 slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
  77 }
  78
  79 static int __init check_early_ioremap_leak(void)
  80 {
  81         int count = 0;
  82         int i;
  83
  84         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
  85                 if (prev_map[i])
  86                         count++;
  87
  88         if (WARN(count, KERN_WARNING
  89                  "Debug warning: early ioremap leak of %d areas detected.\n"
  90                  "please boot with early_ioremap_debug and report the dmesg.\n",
  91                  count))
  92                 return 1;
  93         return 0;
  94 }
  95 late_initcall(check_early_ioremap_leak);
  96
  97 static void __init __iomem *
  98 __early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
  99 {
 100         unsigned long offset;
 101         resource_size_t last_addr;
 102         unsigned int nrpages;
 103         enum fixed_addresses idx;
 104         int i, slot;
 105
 106         WARN_ON(system_state != SYSTEM_BOOTING);
 107
 108         slot = -1;
 109         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 110                 if (!prev_map[i]) {
 111                         slot = i;
 112                         break;
 113                 }
 114         }
 115
 116         if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
 117                  __func__, (u64)phys_addr, size))
 118                 return NULL;
 119
 120         /* Don't allow wraparound or zero size */
 121         last_addr = phys_addr + size - 1;
 122         if (WARN_ON(!size || last_addr < phys_addr))
 123                 return NULL;
 124
 125         prev_size[slot] = size;
 126         /*
 127          * Mappings have to be page-aligned
 128          */
 129         offset = phys_addr & ~PAGE_MASK;
 130         phys_addr &= PAGE_MASK;
 131         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 132
 133         /*
 134          * Mappings have to fit in the FIX_BTMAP area.
 135          */
 136         nrpages = size >> PAGE_SHIFT;
 137         if (WARN_ON(nrpages > NR_FIX_BTMAPS))
 138                 return NULL;
 139
 140         /*
 141          * Ok, go for it..
 142          */
 143         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 144         while (nrpages > 0) {
 145                 if (after_paging_init)
 146                         __late_set_fixmap(idx, phys_addr, prot);
 147                 else
 148                         __early_set_fixmap(idx, phys_addr, prot);
 149                 phys_addr += PAGE_SIZE;
 150                 --idx;
 151                 --nrpages;
 152         }
 153         WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
 154              __func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);
 155
 156         prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
 157         return prev_map[slot];
 158 }
 159
 160 void __init early_iounmap(void __iomem *addr, unsigned long size)
 161 {
 162         unsigned long virt_addr;
 163         unsigned long offset;
 164         unsigned int nrpages;
 165         enum fixed_addresses idx;
 166         int i, slot;
 167
 168         slot = -1;
 169         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 170                 if (prev_map[i] == addr) {
 171                         slot = i;
 172                         break;
 173                 }
 174         }
 175
 176         if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
 177                  addr, size))
 178                 return;
 179
 180         if (WARN(prev_size[slot] != size,
 181                  "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
 182                  addr, size, slot, prev_size[slot]))
 183                 return;
 184
 185         WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
 186              addr, size, slot);
 187
 188         virt_addr = (unsigned long)addr;
 189         if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
 190                 return;
 191
 192         offset = virt_addr & ~PAGE_MASK;
 193         nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
 194
 195         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 196         while (nrpages > 0) {
 197                 if (after_paging_init)
 198                         __late_clear_fixmap(idx);
 199                 else
 200                         __early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
 201                 --idx;
 202                 --nrpages;
 203         }
 204         prev_map[slot] = NULL;
 205 }
 206
 207 /* Remap an IO device */
 208 void __init __iomem *
 209 early_ioremap(resource_size_t phys_addr, unsigned long size)
 210 {
 211         return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
 212 }
 213
 214 /* Remap memory */
 215 void __init *
 216 early_memremap(resource_size_t phys_addr, unsigned long size)
 217 {
 218         return (__force void *)__early_ioremap(phys_addr, size,
 219                                                FIXMAP_PAGE_NORMAL);
 220 }
 221 #ifdef FIXMAP_PAGE_RO
 222 void __init *
 223 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
 224 {
 225         return (__force void *)__early_ioremap(phys_addr, size, FIXMAP_PAGE_RO);
 226 }
 227 #endif
 228
 229 #define MAX_MAP_CHUNK   (NR_FIX_BTMAPS << PAGE_SHIFT)
 230
 231 void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
 232 {
 233         unsigned long slop, clen;
 234         char *p;
 235
 236         while (size) {
 237                 slop = src & ~PAGE_MASK;
 238                 clen = size;
 239                 if (clen > MAX_MAP_CHUNK - slop)
 240                         clen = MAX_MAP_CHUNK - slop;
 241                 p = early_memremap(src & PAGE_MASK, clen + slop);
 242                 memcpy(dest, p + slop, clen);
 243                 early_memunmap(p, clen + slop);
 244                 dest += clen;
 245                 src += clen;
 246                 size -= clen;
 247         }
 248 }
 249
 250 #else /* CONFIG_MMU */
 251
 252 void __init __iomem *
 253 early_ioremap(resource_size_t phys_addr, unsigned long size)
 254 {
 255         return (__force void __iomem *)phys_addr;
 256 }
 257
 258 /* Remap memory */
 259 void __init *
 260 early_memremap(resource_size_t phys_addr, unsigned long size)
 261 {
 262         return (void *)phys_addr;
 263 }
 264 void __init *
 265 early_memremap_ro(resource_size_t phys_addr, unsigned long size)
 266 {
 267         return (void *)phys_addr;
 268 }
 269
 270 void __init early_iounmap(void __iomem *addr, unsigned long size)
 271 {
 272 }
 273
 274 #endif /* CONFIG_MMU */
 275
 276
 277 void __init early_memunmap(void *addr, unsigned long size)
 278 {
 279         early_iounmap((__force void __iomem *)addr, size);
 280 }