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-rw-r--r--drivers/acpi/atomicio.c360
1 files changed, 360 insertions, 0 deletions
diff --git a/drivers/acpi/atomicio.c b/drivers/acpi/atomicio.c
new file mode 100644
index 000000000000..814b19249616
--- /dev/null
+++ b/drivers/acpi/atomicio.c
@@ -0,0 +1,360 @@
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>
34#include <acpi/atomicio.h>
35
36#define ACPI_PFX "ACPI: "
37
38static LIST_HEAD(acpi_iomaps);
39/*
40 * Used for mutual exclusion between writers of acpi_iomaps list, for
41 * synchronization between readers and writer, RCU is used.
42 */
43static DEFINE_SPINLOCK(acpi_iomaps_lock);
44
45struct acpi_iomap {
46 struct list_head list;
47 void __iomem *vaddr;
48 unsigned long size;
49 phys_addr_t paddr;
50 struct kref ref;
51};
52
53/* acpi_iomaps_lock or RCU read lock must be held before calling */
54static struct acpi_iomap *__acpi_find_iomap(phys_addr_t paddr,
55 unsigned long size)
56{
57 struct acpi_iomap *map;
58
59 list_for_each_entry_rcu(map, &acpi_iomaps, list) {
60 if (map->paddr + map->size >= paddr + size &&
61 map->paddr <= paddr)
62 return map;
63 }
64 return NULL;
65}
66
67/*
68 * Atomic "ioremap" used by NMI handler, if the specified IO memory
69 * area is not pre-mapped, NULL will be returned.
70 *
71 * acpi_iomaps_lock or RCU read lock must be held before calling
72 */
73static void __iomem *__acpi_ioremap_fast(phys_addr_t paddr,
74 unsigned long size)
75{
76 struct acpi_iomap *map;
77
78 map = __acpi_find_iomap(paddr, size);
79 if (map)
80 return map->vaddr + (paddr - map->paddr);
81 else
82 return NULL;
83}
84
85/* acpi_iomaps_lock must be held before calling */
86static void __iomem *__acpi_try_ioremap(phys_addr_t paddr,
87 unsigned long size)
88{
89 struct acpi_iomap *map;
90
91 map = __acpi_find_iomap(paddr, size);
92 if (map) {
93 kref_get(&map->ref);
94 return map->vaddr + (paddr - map->paddr);
95 } else
96 return NULL;
97}
98
99/*
100 * Used to pre-map the specified IO memory area. First try to find
101 * whether the area is already pre-mapped, if it is, increase the
102 * reference count (in __acpi_try_ioremap) and return; otherwise, do
103 * the real ioremap, and add the mapping into acpi_iomaps list.
104 */
105static void __iomem *acpi_pre_map(phys_addr_t paddr,
106 unsigned long size)
107{
108 void __iomem *vaddr;
109 struct acpi_iomap *map;
110 unsigned long pg_sz, flags;
111 phys_addr_t pg_off;
112
113 spin_lock_irqsave(&acpi_iomaps_lock, flags);
114 vaddr = __acpi_try_ioremap(paddr, size);
115 spin_unlock_irqrestore(&acpi_iomaps_lock, flags);
116 if (vaddr)
117 return vaddr;
118
119 pg_off = paddr & PAGE_MASK;
120 pg_sz = ((paddr + size + PAGE_SIZE - 1) & PAGE_MASK) - pg_off;
121 vaddr = ioremap(pg_off, pg_sz);
122 if (!vaddr)
123 return NULL;
124 map = kmalloc(sizeof(*map), GFP_KERNEL);
125 if (!map)
126 goto err_unmap;
127 INIT_LIST_HEAD(&map->list);
128 map->paddr = pg_off;
129 map->size = pg_sz;
130 map->vaddr = vaddr;
131 kref_init(&map->ref);
132
133 spin_lock_irqsave(&acpi_iomaps_lock, flags);
134 vaddr = __acpi_try_ioremap(paddr, size);
135 if (vaddr) {
136 spin_unlock_irqrestore(&acpi_iomaps_lock, flags);
137 iounmap(map->vaddr);
138 kfree(map);
139 return vaddr;
140 }
141 list_add_tail_rcu(&map->list, &acpi_iomaps);
142 spin_unlock_irqrestore(&acpi_iomaps_lock, flags);
143
144 return vaddr + (paddr - pg_off);
145err_unmap:
146 iounmap(vaddr);
147 return NULL;
148}
149
150/* acpi_iomaps_lock must be held before calling */
151static void __acpi_kref_del_iomap(struct kref *ref)
152{
153 struct acpi_iomap *map;
154
155 map = container_of(ref, struct acpi_iomap, ref);
156 list_del_rcu(&map->list);
157}
158
159/*
160 * Used to post-unmap the specified IO memory area. The iounmap is
161 * done only if the reference count goes zero.
162 */
163static void acpi_post_unmap(phys_addr_t paddr, unsigned long size)
164{
165 struct acpi_iomap *map;
166 unsigned long flags;
167 int del;
168
169 spin_lock_irqsave(&acpi_iomaps_lock, flags);
170 map = __acpi_find_iomap(paddr, size);
171 BUG_ON(!map);
172 del = kref_put(&map->ref, __acpi_kref_del_iomap);
173 spin_unlock_irqrestore(&acpi_iomaps_lock, flags);
174
175 if (!del)
176 return;
177
178 synchronize_rcu();
179 iounmap(map->vaddr);
180 kfree(map);
181}
182
183/* In NMI handler, should set silent = 1 */
184static int acpi_check_gar(struct acpi_generic_address *reg,
185 u64 *paddr, int silent)
186{
187 u32 width, space_id;
188
189 width = reg->bit_width;
190 space_id = reg->space_id;
191 /* Handle possible alignment issues */
192 memcpy(paddr, &reg->address, sizeof(*paddr));
193 if (!*paddr) {
194 if (!silent)
195 pr_warning(FW_BUG ACPI_PFX
196 "Invalid physical address in GAR [0x%llx/%u/%u]\n",
197 *paddr, width, space_id);
198 return -EINVAL;
199 }
200
201 if ((width != 8) && (width != 16) && (width != 32) && (width != 64)) {
202 if (!silent)
203 pr_warning(FW_BUG ACPI_PFX
204 "Invalid bit width in GAR [0x%llx/%u/%u]\n",
205 *paddr, width, space_id);
206 return -EINVAL;
207 }
208
209 if (space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY &&
210 space_id != ACPI_ADR_SPACE_SYSTEM_IO) {
211 if (!silent)
212 pr_warning(FW_BUG ACPI_PFX
213 "Invalid address space type in GAR [0x%llx/%u/%u]\n",
214 *paddr, width, space_id);
215 return -EINVAL;
216 }
217
218 return 0;
219}
220
221/* Pre-map, working on GAR */
222int acpi_pre_map_gar(struct acpi_generic_address *reg)
223{
224 u64 paddr;
225 void __iomem *vaddr;
226 int rc;
227
228 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
229 return 0;
230
231 rc = acpi_check_gar(reg, &paddr, 0);
232 if (rc)
233 return rc;
234
235 vaddr = acpi_pre_map(paddr, reg->bit_width / 8);
236 if (!vaddr)
237 return -EIO;
238
239 return 0;
240}
241EXPORT_SYMBOL_GPL(acpi_pre_map_gar);
242
243/* Post-unmap, working on GAR */
244int acpi_post_unmap_gar(struct acpi_generic_address *reg)
245{
246 u64 paddr;
247 int rc;
248
249 if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY)
250 return 0;
251
252 rc = acpi_check_gar(reg, &paddr, 0);
253 if (rc)
254 return rc;
255
256 acpi_post_unmap(paddr, reg->bit_width / 8);
257
258 return 0;
259}
260EXPORT_SYMBOL_GPL(acpi_post_unmap_gar);
261
262/*
263 * Can be used in atomic (including NMI) or process context. RCU read
264 * lock can only be released after the IO memory area accessing.
265 */
266static int acpi_atomic_read_mem(u64 paddr, u64 *val, u32 width)
267{
268 void __iomem *addr;
269
270 rcu_read_lock();
271 addr = __acpi_ioremap_fast(paddr, width);
272 switch (width) {
273 case 8:
274 *val = readb(addr);
275 break;
276 case 16:
277 *val = readw(addr);
278 break;
279 case 32:
280 *val = readl(addr);
281 break;
282 case 64:
283 *val = readq(addr);
284 break;
285 default:
286 return -EINVAL;
287 }
288 rcu_read_unlock();
289
290 return 0;
291}
292
293static int acpi_atomic_write_mem(u64 paddr, u64 val, u32 width)
294{
295 void __iomem *addr;
296
297 rcu_read_lock();
298 addr = __acpi_ioremap_fast(paddr, width);
299 switch (width) {
300 case 8:
301 writeb(val, addr);
302 break;
303 case 16:
304 writew(val, addr);
305 break;
306 case 32:
307 writel(val, addr);
308 break;
309 case 64:
310 writeq(val, addr);
311 break;
312 default:
313 return -EINVAL;
314 }
315 rcu_read_unlock();
316
317 return 0;
318}
319
320/* GAR accessing in atomic (including NMI) or process context */
321int acpi_atomic_read(u64 *val, struct acpi_generic_address *reg)
322{
323 u64 paddr;
324 int rc;
325
326 rc = acpi_check_gar(reg, &paddr, 1);
327 if (rc)
328 return rc;
329
330 *val = 0;
331 switch (reg->space_id) {
332 case ACPI_ADR_SPACE_SYSTEM_MEMORY:
333 return acpi_atomic_read_mem(paddr, val, reg->bit_width);
334 case ACPI_ADR_SPACE_SYSTEM_IO:
335 return acpi_os_read_port(paddr, (u32 *)val, reg->bit_width);
336 default:
337 return -EINVAL;
338 }
339}
340EXPORT_SYMBOL_GPL(acpi_atomic_read);
341
342int acpi_atomic_write(u64 val, struct acpi_generic_address *reg)
343{
344 u64 paddr;
345 int rc;
346
347 rc = acpi_check_gar(reg, &paddr, 1);
348 if (rc)
349 return rc;
350
351 switch (reg->space_id) {
352 case ACPI_ADR_SPACE_SYSTEM_MEMORY:
353 return acpi_atomic_write_mem(paddr, val, reg->bit_width);
354 case ACPI_ADR_SPACE_SYSTEM_IO:
355 return acpi_os_write_port(paddr, val, reg->bit_width);
356 default:
357 return -EINVAL;
358 }
359}
360EXPORT_SYMBOL_GPL(acpi_atomic_write);
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