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Linux/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 = offset_in_page(phys_addr);
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 = offset_in_page(virt_addr);
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 = offset_in_page(src);
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 }
281 

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