1 #include <linux/delay.h>
2 #include <linux/pci.h>
3 #include <linux/module.h>
4 #include <linux/sched.h>
5 #include <linux/slab.h>
6 #include <linux/ioport.h>
7 #include <linux/wait.h>
8
9 #include "pci.h"
10
11 /*
12 * This interrupt-safe spinlock protects all accesses to PCI
13 * configuration space.
14 */
15
16 DEFINE_RAW_SPINLOCK(pci_lock);
17
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) \
29 int 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; \
36 raw_spin_lock_irqsave(&pci_lock, flags); \
37 res = bus->ops->read(bus, devfn, pos, len, &data); \
38 *value = (type)data; \
39 raw_spin_unlock_irqrestore(&pci_lock, flags); \
40 return res; \
41 }
42
43 #define PCI_OP_WRITE(size,type,len) \
44 int 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; \
50 raw_spin_lock_irqsave(&pci_lock, flags); \
51 res = bus->ops->write(bus, devfn, pos, len, value); \
52 raw_spin_unlock_irqrestore(&pci_lock, flags); \
53 return res; \
54 }
55
56 PCI_OP_READ(byte, u8, 1)
57 PCI_OP_READ(word, u16, 2)
58 PCI_OP_READ(dword, u32, 4)
59 PCI_OP_WRITE(byte, u8, 1)
60 PCI_OP_WRITE(word, u16, 2)
61 PCI_OP_WRITE(dword, u32, 4)
62
63 EXPORT_SYMBOL(pci_bus_read_config_byte);
64 EXPORT_SYMBOL(pci_bus_read_config_word);
65 EXPORT_SYMBOL(pci_bus_read_config_dword);
66 EXPORT_SYMBOL(pci_bus_write_config_byte);
67 EXPORT_SYMBOL(pci_bus_write_config_word);
68 EXPORT_SYMBOL(pci_bus_write_config_dword);
69
70 /**
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 */
pci_bus_set_ops(struct pci_bus * bus,struct pci_ops * ops)77 struct 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
82 raw_spin_lock_irqsave(&pci_lock, flags);
83 old_ops = bus->ops;
84 bus->ops = ops;
85 raw_spin_unlock_irqrestore(&pci_lock, flags);
86 return old_ops;
87 }
88 EXPORT_SYMBOL(pci_bus_set_ops);
89
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 */
pci_read_vpd(struct pci_dev * dev,loff_t pos,size_t count,void * buf)98 ssize_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 }
104 EXPORT_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
110 * @count: number of bytes to write
111 * @buf: buffer containing write data
112 *
113 */
pci_write_vpd(struct pci_dev * dev,loff_t pos,size_t count,const void * buf)114 ssize_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 }
120 EXPORT_SYMBOL(pci_write_vpd);
121
122 /*
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 */
130 static DECLARE_WAIT_QUEUE_HEAD(pci_cfg_wait);
131
pci_wait_cfg(struct pci_dev * dev)132 static noinline void pci_wait_cfg(struct pci_dev *dev)
133 {
134 DECLARE_WAITQUEUE(wait, current);
135
136 __add_wait_queue(&pci_cfg_wait, &wait);
137 do {
138 set_current_state(TASK_UNINTERRUPTIBLE);
139 raw_spin_unlock_irq(&pci_lock);
140 schedule();
141 raw_spin_lock_irq(&pci_lock);
142 } while (dev->block_cfg_access);
143 __remove_wait_queue(&pci_cfg_wait, &wait);
144 }
145
146 /* Returns 0 on success, negative values indicate error. */
147 #define PCI_USER_READ_CONFIG(size,type) \
148 int pci_user_read_config_##size \
149 (struct pci_dev *dev, int pos, type *val) \
150 { \
151 int ret = 0; \
152 u32 data = -1; \
153 if (PCI_##size##_BAD) \
154 return -EINVAL; \
155 raw_spin_lock_irq(&pci_lock); \
156 if (unlikely(dev->block_cfg_access)) \
157 pci_wait_cfg(dev); \
158 ret = dev->bus->ops->read(dev->bus, dev->devfn, \
159 pos, sizeof(type), &data); \
160 raw_spin_unlock_irq(&pci_lock); \
161 *val = (type)data; \
162 if (ret > 0) \
163 ret = -EINVAL; \
164 return ret; \
165 }
166
167 /* Returns 0 on success, negative values indicate error. */
168 #define PCI_USER_WRITE_CONFIG(size,type) \
169 int pci_user_write_config_##size \
170 (struct pci_dev *dev, int pos, type val) \
171 { \
172 int ret = -EIO; \
173 if (PCI_##size##_BAD) \
174 return -EINVAL; \
175 raw_spin_lock_irq(&pci_lock); \
176 if (unlikely(dev->block_cfg_access)) \
177 pci_wait_cfg(dev); \
178 ret = dev->bus->ops->write(dev->bus, dev->devfn, \
179 pos, sizeof(type), val); \
180 raw_spin_unlock_irq(&pci_lock); \
181 if (ret > 0) \
182 ret = -EINVAL; \
183 return ret; \
184 }
185
186 PCI_USER_READ_CONFIG(byte, u8)
187 PCI_USER_READ_CONFIG(word, u16)
188 PCI_USER_READ_CONFIG(dword, u32)
189 PCI_USER_WRITE_CONFIG(byte, u8)
190 PCI_USER_WRITE_CONFIG(word, u16)
191 PCI_USER_WRITE_CONFIG(dword, u32)
192
193 /* VPD access through PCI 2.2+ VPD capability */
194
195 #define PCI_VPD_PCI22_SIZE (PCI_VPD_ADDR_MASK + 1)
196
197 struct pci_vpd_pci22 {
198 struct pci_vpd base;
199 struct mutex lock;
200 u16 flag;
201 bool busy;
202 u8 cap;
203 };
204
205 /*
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.
210 *
211 * Returns 0 on success, negative values indicate error.
212 */
pci_vpd_pci22_wait(struct pci_dev * dev)213 static 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);
217 unsigned long timeout = jiffies + HZ/20 + 2;
218 u16 status;
219 int ret;
220
221 if (!vpd->busy)
222 return 0;
223
224 for (;;) {
225 ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR,
226 &status);
227 if (ret < 0)
228 return ret;
229
230 if ((status & PCI_VPD_ADDR_F) == vpd->flag) {
231 vpd->busy = false;
232 return 0;
233 }
234
235 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.");
240 return -ETIMEDOUT;
241 }
242 if (fatal_signal_pending(current))
243 return -EINTR;
244 if (!cond_resched())
245 udelay(10);
246 }
247 }
248
pci_vpd_pci22_read(struct pci_dev * dev,loff_t pos,size_t count,void * arg)249 static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count,
250 void *arg)
251 {
252 struct pci_vpd_pci22 *vpd =
253 container_of(dev->vpd, struct pci_vpd_pci22, base);
254 int ret;
255 loff_t end = pos + count;
256 u8 *buf = arg;
257
258 if (pos < 0 || pos > vpd->base.len || end > vpd->base.len)
259 return -EINVAL;
260
261 if (mutex_lock_killable(&vpd->lock))
262 return -EINTR;
263
264 ret = pci_vpd_pci22_wait(dev);
265 if (ret < 0)
266 goto out;
267
268 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 }
296 out:
297 mutex_unlock(&vpd->lock);
298 return ret ? ret : count;
299 }
300
pci_vpd_pci22_write(struct pci_dev * dev,loff_t pos,size_t count,const void * arg)301 static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count,
302 const void *arg)
303 {
304 struct pci_vpd_pci22 *vpd =
305 container_of(dev->vpd, struct pci_vpd_pci22, base);
306 const u8 *buf = arg;
307 loff_t end = pos + count;
308 int ret = 0;
309
310 if (pos < 0 || (pos & 3) || (count & 3) || end > vpd->base.len)
311 return -EINVAL;
312
313 if (mutex_lock_killable(&vpd->lock))
314 return -EINTR;
315
316 ret = pci_vpd_pci22_wait(dev);
317 if (ret < 0)
318 goto out;
319
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);
339 if (ret < 0)
340 break;
341
342 pos += sizeof(u32);
343 }
344 out:
345 mutex_unlock(&vpd->lock);
346 return ret ? ret : count;
347 }
348
pci_vpd_pci22_release(struct pci_dev * dev)349 static void pci_vpd_pci22_release(struct pci_dev *dev)
350 {
351 kfree(container_of(dev->vpd, struct pci_vpd_pci22, base));
352 }
353
354 static const struct pci_vpd_ops pci_vpd_pci22_ops = {
355 .read = pci_vpd_pci22_read,
356 .write = pci_vpd_pci22_write,
357 .release = pci_vpd_pci22_release,
358 };
359
pci_vpd_pci22_init(struct pci_dev * dev)360 int 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
372 vpd->base.len = PCI_VPD_PCI22_SIZE;
373 vpd->base.ops = &pci_vpd_pci22_ops;
374 mutex_init(&vpd->lock);
375 vpd->cap = cap;
376 vpd->busy = false;
377 dev->vpd = &vpd->base;
378 return 0;
379 }
380
381 /**
382 * 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 */
pci_vpd_truncate(struct pci_dev * dev,size_t size)388 int 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;
398 if (dev->vpd->attr)
399 dev->vpd->attr->size = size;
400
401 return 0;
402 }
403 EXPORT_SYMBOL(pci_vpd_truncate);
404
405 /**
406 * pci_cfg_access_lock - Lock PCI config reads/writes
407 * @dev: pci device struct
408 *
409 * 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.
412 */
pci_cfg_access_lock(struct pci_dev * dev)413 void pci_cfg_access_lock(struct pci_dev *dev)
414 {
415 might_sleep();
416
417 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);
422 }
423 EXPORT_SYMBOL_GPL(pci_cfg_access_lock);
424
425 /**
426 * pci_cfg_access_trylock - try to lock PCI config reads/writes
427 * @dev: pci device struct
428 *
429 * 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.
432 */
pci_cfg_access_trylock(struct pci_dev * dev)433 bool 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 }
447 EXPORT_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 */
pci_cfg_access_unlock(struct pci_dev * dev)455 void pci_cfg_access_unlock(struct pci_dev *dev)
456 {
457 unsigned long flags;
458
459 raw_spin_lock_irqsave(&pci_lock, flags);
460
461 /* This indicates a problem in the caller, but we don't need
462 * to kill them, unlike a double-block above. */
463 WARN_ON(!dev->block_cfg_access);
464
465 dev->block_cfg_access = 0;
466 wake_up_all(&pci_cfg_wait);
467 raw_spin_unlock_irqrestore(&pci_lock, flags);
468 }
469 EXPORT_SYMBOL_GPL(pci_cfg_access_unlock);
470