blob: 2a581642c237b74a4b71a70d04c86c8365f8aff8 [file] [log] [blame]
Ben Hutchings94e61082008-03-05 16:52:39 +00001#include <linux/delay.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002#include <linux/pci.h>
3#include <linux/module.h>
Al Virof6a57032006-10-18 01:47:25 -04004#include <linux/sched.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09005#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006#include <linux/ioport.h>
Matthew Wilcox7ea7e982006-10-19 09:41:28 -06007#include <linux/wait.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008
Adrian Bunk48b19142005-11-06 01:45:08 +01009#include "pci.h"
10
Linus Torvalds1da177e2005-04-16 15:20:36 -070011/*
12 * This interrupt-safe spinlock protects all accesses to PCI
13 * configuration space.
14 */
15
Jan Kiszkaa2e27782011-11-04 09:46:00 +010016DEFINE_RAW_SPINLOCK(pci_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
18/*
19 * Wrappers for all PCI configuration access functions. They just check
20 * alignment, do locking and call the low-level functions pointed to
21 * by pci_dev->ops.
22 */
23
24#define PCI_byte_BAD 0
25#define PCI_word_BAD (pos & 1)
26#define PCI_dword_BAD (pos & 3)
27
28#define PCI_OP_READ(size,type,len) \
29int pci_bus_read_config_##size \
30 (struct pci_bus *bus, unsigned int devfn, int pos, type *value) \
31{ \
32 int res; \
33 unsigned long flags; \
34 u32 data = 0; \
35 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
Thomas Gleixner511dd982010-02-17 14:35:19 +000036 raw_spin_lock_irqsave(&pci_lock, flags); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 res = bus->ops->read(bus, devfn, pos, len, &data); \
38 *value = (type)data; \
Thomas Gleixner511dd982010-02-17 14:35:19 +000039 raw_spin_unlock_irqrestore(&pci_lock, flags); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 return res; \
41}
42
43#define PCI_OP_WRITE(size,type,len) \
44int pci_bus_write_config_##size \
45 (struct pci_bus *bus, unsigned int devfn, int pos, type value) \
46{ \
47 int res; \
48 unsigned long flags; \
49 if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
Thomas Gleixner511dd982010-02-17 14:35:19 +000050 raw_spin_lock_irqsave(&pci_lock, flags); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 res = bus->ops->write(bus, devfn, pos, len, value); \
Thomas Gleixner511dd982010-02-17 14:35:19 +000052 raw_spin_unlock_irqrestore(&pci_lock, flags); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 return res; \
54}
55
56PCI_OP_READ(byte, u8, 1)
57PCI_OP_READ(word, u16, 2)
58PCI_OP_READ(dword, u32, 4)
59PCI_OP_WRITE(byte, u8, 1)
60PCI_OP_WRITE(word, u16, 2)
61PCI_OP_WRITE(dword, u32, 4)
62
63EXPORT_SYMBOL(pci_bus_read_config_byte);
64EXPORT_SYMBOL(pci_bus_read_config_word);
65EXPORT_SYMBOL(pci_bus_read_config_dword);
66EXPORT_SYMBOL(pci_bus_write_config_byte);
67EXPORT_SYMBOL(pci_bus_write_config_word);
68EXPORT_SYMBOL(pci_bus_write_config_dword);
Brian Kinge04b0ea2005-09-27 01:21:55 -070069
Huang Yinga72b46c2009-04-24 10:45:17 +080070/**
71 * pci_bus_set_ops - Set raw operations of pci bus
72 * @bus: pci bus struct
73 * @ops: new raw operations
74 *
75 * Return previous raw operations
76 */
77struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops)
78{
79 struct pci_ops *old_ops;
80 unsigned long flags;
81
Thomas Gleixner511dd982010-02-17 14:35:19 +000082 raw_spin_lock_irqsave(&pci_lock, flags);
Huang Yinga72b46c2009-04-24 10:45:17 +080083 old_ops = bus->ops;
84 bus->ops = ops;
Thomas Gleixner511dd982010-02-17 14:35:19 +000085 raw_spin_unlock_irqrestore(&pci_lock, flags);
Huang Yinga72b46c2009-04-24 10:45:17 +080086 return old_ops;
87}
88EXPORT_SYMBOL(pci_bus_set_ops);
Stephen Hemminger287d19c2008-12-18 09:17:16 -080089
90/**
91 * pci_read_vpd - Read one entry from Vital Product Data
92 * @dev: pci device struct
93 * @pos: offset in vpd space
94 * @count: number of bytes to read
95 * @buf: pointer to where to store result
96 *
97 */
98ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf)
99{
100 if (!dev->vpd || !dev->vpd->ops)
101 return -ENODEV;
102 return dev->vpd->ops->read(dev, pos, count, buf);
103}
104EXPORT_SYMBOL(pci_read_vpd);
105
106/**
107 * pci_write_vpd - Write entry to Vital Product Data
108 * @dev: pci device struct
109 * @pos: offset in vpd space
Randy Dunlapcffb2fa2009-04-10 15:17:50 -0700110 * @count: number of bytes to write
111 * @buf: buffer containing write data
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800112 *
113 */
114ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf)
115{
116 if (!dev->vpd || !dev->vpd->ops)
117 return -ENODEV;
118 return dev->vpd->ops->write(dev, pos, count, buf);
119}
120EXPORT_SYMBOL(pci_write_vpd);
121
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600122/*
123 * The following routines are to prevent the user from accessing PCI config
124 * space when it's unsafe to do so. Some devices require this during BIST and
125 * we're required to prevent it during D-state transitions.
126 *
127 * We have a bit per device to indicate it's blocked and a global wait queue
128 * for callers to sleep on until devices are unblocked.
129 */
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100130static DECLARE_WAIT_QUEUE_HEAD(pci_cfg_wait);
Brian Kinge04b0ea2005-09-27 01:21:55 -0700131
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100132static noinline void pci_wait_cfg(struct pci_dev *dev)
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600133{
134 DECLARE_WAITQUEUE(wait, current);
135
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100136 __add_wait_queue(&pci_cfg_wait, &wait);
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600137 do {
138 set_current_state(TASK_UNINTERRUPTIBLE);
Thomas Gleixner511dd982010-02-17 14:35:19 +0000139 raw_spin_unlock_irq(&pci_lock);
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600140 schedule();
Thomas Gleixner511dd982010-02-17 14:35:19 +0000141 raw_spin_lock_irq(&pci_lock);
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100142 } while (dev->block_cfg_access);
143 __remove_wait_queue(&pci_cfg_wait, &wait);
Brian Kinge04b0ea2005-09-27 01:21:55 -0700144}
145
Greg Thelen34e32072011-04-17 08:20:32 -0700146/* Returns 0 on success, negative values indicate error. */
Brian Kinge04b0ea2005-09-27 01:21:55 -0700147#define PCI_USER_READ_CONFIG(size,type) \
148int pci_user_read_config_##size \
149 (struct pci_dev *dev, int pos, type *val) \
150{ \
Brian Kinge04b0ea2005-09-27 01:21:55 -0700151 int ret = 0; \
152 u32 data = -1; \
Greg Thelen34e32072011-04-17 08:20:32 -0700153 if (PCI_##size##_BAD) \
154 return -EINVAL; \
Thomas Gleixner511dd982010-02-17 14:35:19 +0000155 raw_spin_lock_irq(&pci_lock); \
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100156 if (unlikely(dev->block_cfg_access)) \
157 pci_wait_cfg(dev); \
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600158 ret = dev->bus->ops->read(dev->bus, dev->devfn, \
Brian Kinge04b0ea2005-09-27 01:21:55 -0700159 pos, sizeof(type), &data); \
Thomas Gleixner511dd982010-02-17 14:35:19 +0000160 raw_spin_unlock_irq(&pci_lock); \
Brian Kinge04b0ea2005-09-27 01:21:55 -0700161 *val = (type)data; \
Greg Thelen34e32072011-04-17 08:20:32 -0700162 if (ret > 0) \
163 ret = -EINVAL; \
Brian Kinge04b0ea2005-09-27 01:21:55 -0700164 return ret; \
165}
166
Greg Thelen34e32072011-04-17 08:20:32 -0700167/* Returns 0 on success, negative values indicate error. */
Brian Kinge04b0ea2005-09-27 01:21:55 -0700168#define PCI_USER_WRITE_CONFIG(size,type) \
169int pci_user_write_config_##size \
170 (struct pci_dev *dev, int pos, type val) \
171{ \
Brian Kinge04b0ea2005-09-27 01:21:55 -0700172 int ret = -EIO; \
Greg Thelen34e32072011-04-17 08:20:32 -0700173 if (PCI_##size##_BAD) \
174 return -EINVAL; \
Thomas Gleixner511dd982010-02-17 14:35:19 +0000175 raw_spin_lock_irq(&pci_lock); \
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100176 if (unlikely(dev->block_cfg_access)) \
177 pci_wait_cfg(dev); \
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600178 ret = dev->bus->ops->write(dev->bus, dev->devfn, \
Brian Kinge04b0ea2005-09-27 01:21:55 -0700179 pos, sizeof(type), val); \
Thomas Gleixner511dd982010-02-17 14:35:19 +0000180 raw_spin_unlock_irq(&pci_lock); \
Greg Thelen34e32072011-04-17 08:20:32 -0700181 if (ret > 0) \
182 ret = -EINVAL; \
Brian Kinge04b0ea2005-09-27 01:21:55 -0700183 return ret; \
184}
185
186PCI_USER_READ_CONFIG(byte, u8)
187PCI_USER_READ_CONFIG(word, u16)
188PCI_USER_READ_CONFIG(dword, u32)
189PCI_USER_WRITE_CONFIG(byte, u8)
190PCI_USER_WRITE_CONFIG(word, u16)
191PCI_USER_WRITE_CONFIG(dword, u32)
192
Ben Hutchings94e61082008-03-05 16:52:39 +0000193/* VPD access through PCI 2.2+ VPD capability */
194
195#define PCI_VPD_PCI22_SIZE (PCI_VPD_ADDR_MASK + 1)
196
197struct pci_vpd_pci22 {
198 struct pci_vpd base;
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800199 struct mutex lock;
200 u16 flag;
Ben Hutchings94e61082008-03-05 16:52:39 +0000201 bool busy;
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800202 u8 cap;
Ben Hutchings94e61082008-03-05 16:52:39 +0000203};
204
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800205/*
206 * Wait for last operation to complete.
207 * This code has to spin since there is no other notification from the PCI
208 * hardware. Since the VPD is often implemented by serial attachment to an
209 * EEPROM, it may take many milliseconds to complete.
Greg Thelen34e32072011-04-17 08:20:32 -0700210 *
211 * Returns 0 on success, negative values indicate error.
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800212 */
Ben Hutchings94e61082008-03-05 16:52:39 +0000213static int pci_vpd_pci22_wait(struct pci_dev *dev)
214{
215 struct pci_vpd_pci22 *vpd =
216 container_of(dev->vpd, struct pci_vpd_pci22, base);
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800217 unsigned long timeout = jiffies + HZ/20 + 2;
218 u16 status;
Ben Hutchings94e61082008-03-05 16:52:39 +0000219 int ret;
220
221 if (!vpd->busy)
222 return 0;
223
Ben Hutchings94e61082008-03-05 16:52:39 +0000224 for (;;) {
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800225 ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR,
Ben Hutchings94e61082008-03-05 16:52:39 +0000226 &status);
Greg Thelen34e32072011-04-17 08:20:32 -0700227 if (ret < 0)
Ben Hutchings94e61082008-03-05 16:52:39 +0000228 return ret;
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800229
230 if ((status & PCI_VPD_ADDR_F) == vpd->flag) {
Ben Hutchings94e61082008-03-05 16:52:39 +0000231 vpd->busy = false;
232 return 0;
233 }
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800234
Prarit Bhargava50307182010-05-17 14:25:14 -0400235 if (time_after(jiffies, timeout)) {
236 dev_printk(KERN_DEBUG, &dev->dev,
237 "vpd r/w failed. This is likely a firmware "
238 "bug on this device. Contact the card "
239 "vendor for a firmware update.");
Ben Hutchings94e61082008-03-05 16:52:39 +0000240 return -ETIMEDOUT;
Prarit Bhargava50307182010-05-17 14:25:14 -0400241 }
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800242 if (fatal_signal_pending(current))
243 return -EINTR;
244 if (!cond_resched())
245 udelay(10);
Ben Hutchings94e61082008-03-05 16:52:39 +0000246 }
247}
248
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800249static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count,
250 void *arg)
Ben Hutchings94e61082008-03-05 16:52:39 +0000251{
252 struct pci_vpd_pci22 *vpd =
253 container_of(dev->vpd, struct pci_vpd_pci22, base);
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800254 int ret;
255 loff_t end = pos + count;
256 u8 *buf = arg;
Ben Hutchings94e61082008-03-05 16:52:39 +0000257
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800258 if (pos < 0 || pos > vpd->base.len || end > vpd->base.len)
Ben Hutchings94e61082008-03-05 16:52:39 +0000259 return -EINVAL;
Ben Hutchings94e61082008-03-05 16:52:39 +0000260
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800261 if (mutex_lock_killable(&vpd->lock))
262 return -EINTR;
263
Ben Hutchings94e61082008-03-05 16:52:39 +0000264 ret = pci_vpd_pci22_wait(dev);
265 if (ret < 0)
266 goto out;
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800267
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800268 while (pos < end) {
269 u32 val;
270 unsigned int i, skip;
271
272 ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
273 pos & ~3);
274 if (ret < 0)
275 break;
276 vpd->busy = true;
277 vpd->flag = PCI_VPD_ADDR_F;
278 ret = pci_vpd_pci22_wait(dev);
279 if (ret < 0)
280 break;
281
282 ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val);
283 if (ret < 0)
284 break;
285
286 skip = pos & 3;
287 for (i = 0; i < sizeof(u32); i++) {
288 if (i >= skip) {
289 *buf++ = val;
290 if (++pos == end)
291 break;
292 }
293 val >>= 8;
294 }
295 }
Ben Hutchings94e61082008-03-05 16:52:39 +0000296out:
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800297 mutex_unlock(&vpd->lock);
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800298 return ret ? ret : count;
Ben Hutchings94e61082008-03-05 16:52:39 +0000299}
300
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800301static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count,
302 const void *arg)
Ben Hutchings94e61082008-03-05 16:52:39 +0000303{
304 struct pci_vpd_pci22 *vpd =
305 container_of(dev->vpd, struct pci_vpd_pci22, base);
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800306 const u8 *buf = arg;
307 loff_t end = pos + count;
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800308 int ret = 0;
Ben Hutchings94e61082008-03-05 16:52:39 +0000309
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800310 if (pos < 0 || (pos & 3) || (count & 3) || end > vpd->base.len)
Ben Hutchings94e61082008-03-05 16:52:39 +0000311 return -EINVAL;
312
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800313 if (mutex_lock_killable(&vpd->lock))
314 return -EINTR;
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800315
Ben Hutchings94e61082008-03-05 16:52:39 +0000316 ret = pci_vpd_pci22_wait(dev);
317 if (ret < 0)
318 goto out;
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800319
320 while (pos < end) {
321 u32 val;
322
323 val = *buf++;
324 val |= *buf++ << 8;
325 val |= *buf++ << 16;
326 val |= *buf++ << 24;
327
328 ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val);
329 if (ret < 0)
330 break;
331 ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
332 pos | PCI_VPD_ADDR_F);
333 if (ret < 0)
334 break;
335
336 vpd->busy = true;
337 vpd->flag = 0;
338 ret = pci_vpd_pci22_wait(dev);
Greg Thelend97ecd82011-04-17 08:22:21 -0700339 if (ret < 0)
340 break;
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800341
342 pos += sizeof(u32);
343 }
Ben Hutchings94e61082008-03-05 16:52:39 +0000344out:
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800345 mutex_unlock(&vpd->lock);
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800346 return ret ? ret : count;
Ben Hutchings94e61082008-03-05 16:52:39 +0000347}
348
Ben Hutchings94e61082008-03-05 16:52:39 +0000349static void pci_vpd_pci22_release(struct pci_dev *dev)
350{
351 kfree(container_of(dev->vpd, struct pci_vpd_pci22, base));
352}
353
Stephen Hemminger287d19c2008-12-18 09:17:16 -0800354static const struct pci_vpd_ops pci_vpd_pci22_ops = {
Ben Hutchings94e61082008-03-05 16:52:39 +0000355 .read = pci_vpd_pci22_read,
356 .write = pci_vpd_pci22_write,
Ben Hutchings94e61082008-03-05 16:52:39 +0000357 .release = pci_vpd_pci22_release,
358};
359
360int pci_vpd_pci22_init(struct pci_dev *dev)
361{
362 struct pci_vpd_pci22 *vpd;
363 u8 cap;
364
365 cap = pci_find_capability(dev, PCI_CAP_ID_VPD);
366 if (!cap)
367 return -ENODEV;
368 vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC);
369 if (!vpd)
370 return -ENOMEM;
371
Benjamin Li99cb233d2008-07-02 10:59:04 -0700372 vpd->base.len = PCI_VPD_PCI22_SIZE;
Ben Hutchings94e61082008-03-05 16:52:39 +0000373 vpd->base.ops = &pci_vpd_pci22_ops;
Stephen Hemminger1120f8b2008-12-18 09:17:16 -0800374 mutex_init(&vpd->lock);
Ben Hutchings94e61082008-03-05 16:52:39 +0000375 vpd->cap = cap;
376 vpd->busy = false;
377 dev->vpd = &vpd->base;
378 return 0;
379}
380
Brian Kinge04b0ea2005-09-27 01:21:55 -0700381/**
Stephen Hemmingerdb567942008-12-18 09:17:16 -0800382 * pci_vpd_truncate - Set available Vital Product Data size
383 * @dev: pci device struct
384 * @size: available memory in bytes
385 *
386 * Adjust size of available VPD area.
387 */
388int pci_vpd_truncate(struct pci_dev *dev, size_t size)
389{
390 if (!dev->vpd)
391 return -EINVAL;
392
393 /* limited by the access method */
394 if (size > dev->vpd->len)
395 return -EINVAL;
396
397 dev->vpd->len = size;
Anton Vorontsovd407e322009-04-01 02:23:41 +0400398 if (dev->vpd->attr)
399 dev->vpd->attr->size = size;
Stephen Hemmingerdb567942008-12-18 09:17:16 -0800400
401 return 0;
402}
403EXPORT_SYMBOL(pci_vpd_truncate);
404
405/**
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100406 * pci_cfg_access_lock - Lock PCI config reads/writes
Brian Kinge04b0ea2005-09-27 01:21:55 -0700407 * @dev: pci device struct
408 *
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100409 * When access is locked, any userspace reads or writes to config
410 * space and concurrent lock requests will sleep until access is
411 * allowed via pci_cfg_access_unlocked again.
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600412 */
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100413void pci_cfg_access_lock(struct pci_dev *dev)
Brian Kinge04b0ea2005-09-27 01:21:55 -0700414{
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100415 might_sleep();
Brian Kinge04b0ea2005-09-27 01:21:55 -0700416
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100417 raw_spin_lock_irq(&pci_lock);
418 if (dev->block_cfg_access)
419 pci_wait_cfg(dev);
420 dev->block_cfg_access = 1;
421 raw_spin_unlock_irq(&pci_lock);
Brian Kinge04b0ea2005-09-27 01:21:55 -0700422}
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100423EXPORT_SYMBOL_GPL(pci_cfg_access_lock);
Brian Kinge04b0ea2005-09-27 01:21:55 -0700424
425/**
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100426 * pci_cfg_access_trylock - try to lock PCI config reads/writes
Brian Kinge04b0ea2005-09-27 01:21:55 -0700427 * @dev: pci device struct
428 *
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100429 * Same as pci_cfg_access_lock, but will return 0 if access is
430 * already locked, 1 otherwise. This function can be used from
431 * atomic contexts.
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600432 */
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100433bool pci_cfg_access_trylock(struct pci_dev *dev)
434{
435 unsigned long flags;
436 bool locked = true;
437
438 raw_spin_lock_irqsave(&pci_lock, flags);
439 if (dev->block_cfg_access)
440 locked = false;
441 else
442 dev->block_cfg_access = 1;
443 raw_spin_unlock_irqrestore(&pci_lock, flags);
444
445 return locked;
446}
447EXPORT_SYMBOL_GPL(pci_cfg_access_trylock);
448
449/**
450 * pci_cfg_access_unlock - Unlock PCI config reads/writes
451 * @dev: pci device struct
452 *
453 * This function allows PCI config accesses to resume.
454 */
455void pci_cfg_access_unlock(struct pci_dev *dev)
Brian Kinge04b0ea2005-09-27 01:21:55 -0700456{
457 unsigned long flags;
458
Thomas Gleixner511dd982010-02-17 14:35:19 +0000459 raw_spin_lock_irqsave(&pci_lock, flags);
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600460
461 /* This indicates a problem in the caller, but we don't need
462 * to kill them, unlike a double-block above. */
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100463 WARN_ON(!dev->block_cfg_access);
Matthew Wilcox7ea7e982006-10-19 09:41:28 -0600464
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100465 dev->block_cfg_access = 0;
466 wake_up_all(&pci_cfg_wait);
Thomas Gleixner511dd982010-02-17 14:35:19 +0000467 raw_spin_unlock_irqrestore(&pci_lock, flags);
Brian Kinge04b0ea2005-09-27 01:21:55 -0700468}
Jan Kiszkafb51ccb2011-11-04 09:45:59 +0100469EXPORT_SYMBOL_GPL(pci_cfg_access_unlock);