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15651291 HY |
1 | /* |
2 | * atomicio.c - ACPI IO memory pre-mapping/post-unmapping, then | |
3 | * accessing in atomic context. | |
4 | * | |
5 | * This is used for NMI handler to access IO memory area, because | |
6 | * ioremap/iounmap can not be used in NMI handler. The IO memory area | |
7 | * is pre-mapped in process context and accessed in NMI handler. | |
8 | * | |
9 | * Copyright (C) 2009-2010, Intel Corp. | |
10 | * Author: Huang Ying <ying.huang@intel.com> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License version | |
14 | * 2 as published by the Free Software Foundation. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | * GNU General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License | |
22 | * along with this program; if not, write to the Free Software | |
23 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/acpi.h> | |
30 | #include <linux/io.h> | |
31 | #include <linux/kref.h> | |
32 | #include <linux/rculist.h> | |
33 | #include <linux/interrupt.h> | |
e0fb8c41 | 34 | #include <linux/slab.h> |
15651291 HY |
35 | #include <acpi/atomicio.h> |
36 | ||
37 | #define ACPI_PFX "ACPI: " | |
38 | ||
39 | static LIST_HEAD(acpi_iomaps); | |
40 | /* | |
41 | * Used for mutual exclusion between writers of acpi_iomaps list, for | |
42 | * synchronization between readers and writer, RCU is used. | |
43 | */ | |
44 | static DEFINE_SPINLOCK(acpi_iomaps_lock); | |
45 | ||
46 | struct acpi_iomap { | |
47 | struct list_head list; | |
48 | void __iomem *vaddr; | |
49 | unsigned long size; | |
50 | phys_addr_t paddr; | |
51 | struct kref ref; | |
52 | }; | |
53 | ||
54 | /* acpi_iomaps_lock or RCU read lock must be held before calling */ | |
55 | static struct acpi_iomap *__acpi_find_iomap(phys_addr_t paddr, | |
56 | unsigned long size) | |
57 | { | |
58 | struct acpi_iomap *map; | |
59 | ||
60 | list_for_each_entry_rcu(map, &acpi_iomaps, list) { | |
61 | if (map->paddr + map->size >= paddr + size && | |
62 | map->paddr <= paddr) | |
63 | return map; | |
64 | } | |
65 | return NULL; | |
66 | } | |
67 | ||
68 | /* | |
69 | * Atomic "ioremap" used by NMI handler, if the specified IO memory | |
70 | * area is not pre-mapped, NULL will be returned. | |
71 | * | |
72 | * acpi_iomaps_lock or RCU read lock must be held before calling | |
73 | */ | |
74 | static void __iomem *__acpi_ioremap_fast(phys_addr_t paddr, | |
75 | unsigned long size) | |
76 | { | |
77 | struct acpi_iomap *map; | |
78 | ||
79 | map = __acpi_find_iomap(paddr, size); | |
80 | if (map) | |
81 | return map->vaddr + (paddr - map->paddr); | |
82 | else | |
83 | return NULL; | |
84 | } | |
85 | ||
86 | /* acpi_iomaps_lock must be held before calling */ | |
87 | static void __iomem *__acpi_try_ioremap(phys_addr_t paddr, | |
88 | unsigned long size) | |
89 | { | |
90 | struct acpi_iomap *map; | |
91 | ||
92 | map = __acpi_find_iomap(paddr, size); | |
93 | if (map) { | |
94 | kref_get(&map->ref); | |
95 | return map->vaddr + (paddr - map->paddr); | |
96 | } else | |
97 | return NULL; | |
98 | } | |
99 | ||
100 | /* | |
101 | * Used to pre-map the specified IO memory area. First try to find | |
102 | * whether the area is already pre-mapped, if it is, increase the | |
103 | * reference count (in __acpi_try_ioremap) and return; otherwise, do | |
104 | * the real ioremap, and add the mapping into acpi_iomaps list. | |
105 | */ | |
106 | static void __iomem *acpi_pre_map(phys_addr_t paddr, | |
107 | unsigned long size) | |
108 | { | |
109 | void __iomem *vaddr; | |
110 | struct acpi_iomap *map; | |
111 | unsigned long pg_sz, flags; | |
112 | phys_addr_t pg_off; | |
113 | ||
114 | spin_lock_irqsave(&acpi_iomaps_lock, flags); | |
115 | vaddr = __acpi_try_ioremap(paddr, size); | |
116 | spin_unlock_irqrestore(&acpi_iomaps_lock, flags); | |
117 | if (vaddr) | |
118 | return vaddr; | |
119 | ||
120 | pg_off = paddr & PAGE_MASK; | |
121 | pg_sz = ((paddr + size + PAGE_SIZE - 1) & PAGE_MASK) - pg_off; | |
122 | vaddr = ioremap(pg_off, pg_sz); | |
123 | if (!vaddr) | |
124 | return NULL; | |
125 | map = kmalloc(sizeof(*map), GFP_KERNEL); | |
126 | if (!map) | |
127 | goto err_unmap; | |
128 | INIT_LIST_HEAD(&map->list); | |
129 | map->paddr = pg_off; | |
130 | map->size = pg_sz; | |
131 | map->vaddr = vaddr; | |
132 | kref_init(&map->ref); | |
133 | ||
134 | spin_lock_irqsave(&acpi_iomaps_lock, flags); | |
135 | vaddr = __acpi_try_ioremap(paddr, size); | |
136 | if (vaddr) { | |
137 | spin_unlock_irqrestore(&acpi_iomaps_lock, flags); | |
138 | iounmap(map->vaddr); | |
139 | kfree(map); | |
140 | return vaddr; | |
141 | } | |
142 | list_add_tail_rcu(&map->list, &acpi_iomaps); | |
143 | spin_unlock_irqrestore(&acpi_iomaps_lock, flags); | |
144 | ||
145 | return vaddr + (paddr - pg_off); | |
146 | err_unmap: | |
147 | iounmap(vaddr); | |
148 | return NULL; | |
149 | } | |
150 | ||
151 | /* acpi_iomaps_lock must be held before calling */ | |
152 | static void __acpi_kref_del_iomap(struct kref *ref) | |
153 | { | |
154 | struct acpi_iomap *map; | |
155 | ||
156 | map = container_of(ref, struct acpi_iomap, ref); | |
157 | list_del_rcu(&map->list); | |
158 | } | |
159 | ||
160 | /* | |
161 | * Used to post-unmap the specified IO memory area. The iounmap is | |
162 | * done only if the reference count goes zero. | |
163 | */ | |
164 | static void acpi_post_unmap(phys_addr_t paddr, unsigned long size) | |
165 | { | |
166 | struct acpi_iomap *map; | |
167 | unsigned long flags; | |
168 | int del; | |
169 | ||
170 | spin_lock_irqsave(&acpi_iomaps_lock, flags); | |
171 | map = __acpi_find_iomap(paddr, size); | |
172 | BUG_ON(!map); | |
173 | del = kref_put(&map->ref, __acpi_kref_del_iomap); | |
174 | spin_unlock_irqrestore(&acpi_iomaps_lock, flags); | |
175 | ||
176 | if (!del) | |
177 | return; | |
178 | ||
179 | synchronize_rcu(); | |
180 | iounmap(map->vaddr); | |
181 | kfree(map); | |
182 | } | |
183 | ||
184 | /* In NMI handler, should set silent = 1 */ | |
185 | static int acpi_check_gar(struct acpi_generic_address *reg, | |
186 | u64 *paddr, int silent) | |
187 | { | |
188 | u32 width, space_id; | |
189 | ||
190 | width = reg->bit_width; | |
191 | space_id = reg->space_id; | |
192 | /* Handle possible alignment issues */ | |
193 | memcpy(paddr, ®->address, sizeof(*paddr)); | |
194 | if (!*paddr) { | |
195 | if (!silent) | |
196 | pr_warning(FW_BUG ACPI_PFX | |
197 | "Invalid physical address in GAR [0x%llx/%u/%u]\n", | |
198 | *paddr, width, space_id); | |
199 | return -EINVAL; | |
200 | } | |
201 | ||
202 | if ((width != 8) && (width != 16) && (width != 32) && (width != 64)) { | |
203 | if (!silent) | |
204 | pr_warning(FW_BUG ACPI_PFX | |
205 | "Invalid bit width in GAR [0x%llx/%u/%u]\n", | |
206 | *paddr, width, space_id); | |
207 | return -EINVAL; | |
208 | } | |
209 | ||
210 | if (space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY && | |
211 | space_id != ACPI_ADR_SPACE_SYSTEM_IO) { | |
212 | if (!silent) | |
213 | pr_warning(FW_BUG ACPI_PFX | |
214 | "Invalid address space type in GAR [0x%llx/%u/%u]\n", | |
215 | *paddr, width, space_id); | |
216 | return -EINVAL; | |
217 | } | |
218 | ||
219 | return 0; | |
220 | } | |
221 | ||
222 | /* Pre-map, working on GAR */ | |
223 | int acpi_pre_map_gar(struct acpi_generic_address *reg) | |
224 | { | |
225 | u64 paddr; | |
226 | void __iomem *vaddr; | |
227 | int rc; | |
228 | ||
229 | if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) | |
230 | return 0; | |
231 | ||
232 | rc = acpi_check_gar(reg, &paddr, 0); | |
233 | if (rc) | |
234 | return rc; | |
235 | ||
236 | vaddr = acpi_pre_map(paddr, reg->bit_width / 8); | |
237 | if (!vaddr) | |
238 | return -EIO; | |
239 | ||
240 | return 0; | |
241 | } | |
242 | EXPORT_SYMBOL_GPL(acpi_pre_map_gar); | |
243 | ||
244 | /* Post-unmap, working on GAR */ | |
245 | int acpi_post_unmap_gar(struct acpi_generic_address *reg) | |
246 | { | |
247 | u64 paddr; | |
248 | int rc; | |
249 | ||
250 | if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) | |
251 | return 0; | |
252 | ||
253 | rc = acpi_check_gar(reg, &paddr, 0); | |
254 | if (rc) | |
255 | return rc; | |
256 | ||
257 | acpi_post_unmap(paddr, reg->bit_width / 8); | |
258 | ||
259 | return 0; | |
260 | } | |
261 | EXPORT_SYMBOL_GPL(acpi_post_unmap_gar); | |
262 | ||
263 | /* | |
264 | * Can be used in atomic (including NMI) or process context. RCU read | |
265 | * lock can only be released after the IO memory area accessing. | |
266 | */ | |
267 | static int acpi_atomic_read_mem(u64 paddr, u64 *val, u32 width) | |
268 | { | |
269 | void __iomem *addr; | |
270 | ||
271 | rcu_read_lock(); | |
272 | addr = __acpi_ioremap_fast(paddr, width); | |
273 | switch (width) { | |
274 | case 8: | |
275 | *val = readb(addr); | |
276 | break; | |
277 | case 16: | |
278 | *val = readw(addr); | |
279 | break; | |
280 | case 32: | |
281 | *val = readl(addr); | |
282 | break; | |
283 | case 64: | |
284 | *val = readq(addr); | |
285 | break; | |
286 | default: | |
287 | return -EINVAL; | |
288 | } | |
289 | rcu_read_unlock(); | |
290 | ||
291 | return 0; | |
292 | } | |
293 | ||
294 | static int acpi_atomic_write_mem(u64 paddr, u64 val, u32 width) | |
295 | { | |
296 | void __iomem *addr; | |
297 | ||
298 | rcu_read_lock(); | |
299 | addr = __acpi_ioremap_fast(paddr, width); | |
300 | switch (width) { | |
301 | case 8: | |
302 | writeb(val, addr); | |
303 | break; | |
304 | case 16: | |
305 | writew(val, addr); | |
306 | break; | |
307 | case 32: | |
308 | writel(val, addr); | |
309 | break; | |
310 | case 64: | |
311 | writeq(val, addr); | |
312 | break; | |
313 | default: | |
314 | return -EINVAL; | |
315 | } | |
316 | rcu_read_unlock(); | |
317 | ||
318 | return 0; | |
319 | } | |
320 | ||
321 | /* GAR accessing in atomic (including NMI) or process context */ | |
322 | int acpi_atomic_read(u64 *val, struct acpi_generic_address *reg) | |
323 | { | |
324 | u64 paddr; | |
325 | int rc; | |
326 | ||
327 | rc = acpi_check_gar(reg, &paddr, 1); | |
328 | if (rc) | |
329 | return rc; | |
330 | ||
331 | *val = 0; | |
332 | switch (reg->space_id) { | |
333 | case ACPI_ADR_SPACE_SYSTEM_MEMORY: | |
334 | return acpi_atomic_read_mem(paddr, val, reg->bit_width); | |
335 | case ACPI_ADR_SPACE_SYSTEM_IO: | |
336 | return acpi_os_read_port(paddr, (u32 *)val, reg->bit_width); | |
337 | default: | |
338 | return -EINVAL; | |
339 | } | |
340 | } | |
341 | EXPORT_SYMBOL_GPL(acpi_atomic_read); | |
342 | ||
343 | int acpi_atomic_write(u64 val, struct acpi_generic_address *reg) | |
344 | { | |
345 | u64 paddr; | |
346 | int rc; | |
347 | ||
348 | rc = acpi_check_gar(reg, &paddr, 1); | |
349 | if (rc) | |
350 | return rc; | |
351 | ||
352 | switch (reg->space_id) { | |
353 | case ACPI_ADR_SPACE_SYSTEM_MEMORY: | |
354 | return acpi_atomic_write_mem(paddr, val, reg->bit_width); | |
355 | case ACPI_ADR_SPACE_SYSTEM_IO: | |
356 | return acpi_os_write_port(paddr, val, reg->bit_width); | |
357 | default: | |
358 | return -EINVAL; | |
359 | } | |
360 | } | |
361 | EXPORT_SYMBOL_GPL(acpi_atomic_write); |