Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / drivers / pci / access.c
blobfdaa42aac7c6ecffb46955b27901f1bfa0658dd3
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>
9 #include "pci.h"
12 * This interrupt-safe spinlock protects all accesses to PCI
13 * configuration space.
16 static DEFINE_RAW_SPINLOCK(pci_lock);
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.
24 #define PCI_byte_BAD 0
25 #define PCI_word_BAD (pos & 1)
26 #define PCI_dword_BAD (pos & 3)
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; \
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; \
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)
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);
70 /**
71 * pci_bus_set_ops - Set raw operations of pci bus
72 * @bus: pci bus struct
73 * @ops: new raw operations
75 * Return previous raw operations
77 struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops)
79 struct pci_ops *old_ops;
80 unsigned long flags;
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;
88 EXPORT_SYMBOL(pci_bus_set_ops);
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
98 ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf)
100 if (!dev->vpd || !dev->vpd->ops)
101 return -ENODEV;
102 return dev->vpd->ops->read(dev, pos, count, buf);
104 EXPORT_SYMBOL(pci_read_vpd);
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
114 ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf)
116 if (!dev->vpd || !dev->vpd->ops)
117 return -ENODEV;
118 return dev->vpd->ops->write(dev, pos, count, buf);
120 EXPORT_SYMBOL(pci_write_vpd);
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.
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.
130 static DECLARE_WAIT_QUEUE_HEAD(pci_ucfg_wait);
132 static noinline void pci_wait_ucfg(struct pci_dev *dev)
134 DECLARE_WAITQUEUE(wait, current);
136 __add_wait_queue(&pci_ucfg_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_ucfg_access);
143 __remove_wait_queue(&pci_ucfg_wait, &wait);
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) \
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_ucfg_access)) pci_wait_ucfg(dev); \
157 ret = dev->bus->ops->read(dev->bus, dev->devfn, \
158 pos, sizeof(type), &data); \
159 raw_spin_unlock_irq(&pci_lock); \
160 *val = (type)data; \
161 if (ret > 0) \
162 ret = -EINVAL; \
163 return ret; \
166 /* Returns 0 on success, negative values indicate error. */
167 #define PCI_USER_WRITE_CONFIG(size,type) \
168 int pci_user_write_config_##size \
169 (struct pci_dev *dev, int pos, type val) \
171 int ret = -EIO; \
172 if (PCI_##size##_BAD) \
173 return -EINVAL; \
174 raw_spin_lock_irq(&pci_lock); \
175 if (unlikely(dev->block_ucfg_access)) pci_wait_ucfg(dev); \
176 ret = dev->bus->ops->write(dev->bus, dev->devfn, \
177 pos, sizeof(type), val); \
178 raw_spin_unlock_irq(&pci_lock); \
179 if (ret > 0) \
180 ret = -EINVAL; \
181 return ret; \
184 PCI_USER_READ_CONFIG(byte, u8)
185 PCI_USER_READ_CONFIG(word, u16)
186 PCI_USER_READ_CONFIG(dword, u32)
187 PCI_USER_WRITE_CONFIG(byte, u8)
188 PCI_USER_WRITE_CONFIG(word, u16)
189 PCI_USER_WRITE_CONFIG(dword, u32)
191 /* VPD access through PCI 2.2+ VPD capability */
193 #define PCI_VPD_PCI22_SIZE (PCI_VPD_ADDR_MASK + 1)
195 struct pci_vpd_pci22 {
196 struct pci_vpd base;
197 struct mutex lock;
198 u16 flag;
199 bool busy;
200 u8 cap;
204 * Wait for last operation to complete.
205 * This code has to spin since there is no other notification from the PCI
206 * hardware. Since the VPD is often implemented by serial attachment to an
207 * EEPROM, it may take many milliseconds to complete.
209 * Returns 0 on success, negative values indicate error.
211 static int pci_vpd_pci22_wait(struct pci_dev *dev)
213 struct pci_vpd_pci22 *vpd =
214 container_of(dev->vpd, struct pci_vpd_pci22, base);
215 unsigned long timeout = jiffies + HZ/20 + 2;
216 u16 status;
217 int ret;
219 if (!vpd->busy)
220 return 0;
222 for (;;) {
223 ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR,
224 &status);
225 if (ret < 0)
226 return ret;
228 if ((status & PCI_VPD_ADDR_F) == vpd->flag) {
229 vpd->busy = false;
230 return 0;
233 if (time_after(jiffies, timeout)) {
234 dev_printk(KERN_DEBUG, &dev->dev,
235 "vpd r/w failed. This is likely a firmware "
236 "bug on this device. Contact the card "
237 "vendor for a firmware update.");
238 return -ETIMEDOUT;
240 if (fatal_signal_pending(current))
241 return -EINTR;
242 if (!cond_resched())
243 udelay(10);
247 static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count,
248 void *arg)
250 struct pci_vpd_pci22 *vpd =
251 container_of(dev->vpd, struct pci_vpd_pci22, base);
252 int ret;
253 loff_t end = pos + count;
254 u8 *buf = arg;
256 if (pos < 0 || pos > vpd->base.len || end > vpd->base.len)
257 return -EINVAL;
259 if (mutex_lock_killable(&vpd->lock))
260 return -EINTR;
262 ret = pci_vpd_pci22_wait(dev);
263 if (ret < 0)
264 goto out;
266 while (pos < end) {
267 u32 val;
268 unsigned int i, skip;
270 ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
271 pos & ~3);
272 if (ret < 0)
273 break;
274 vpd->busy = true;
275 vpd->flag = PCI_VPD_ADDR_F;
276 ret = pci_vpd_pci22_wait(dev);
277 if (ret < 0)
278 break;
280 ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val);
281 if (ret < 0)
282 break;
284 skip = pos & 3;
285 for (i = 0; i < sizeof(u32); i++) {
286 if (i >= skip) {
287 *buf++ = val;
288 if (++pos == end)
289 break;
291 val >>= 8;
294 out:
295 mutex_unlock(&vpd->lock);
296 return ret ? ret : count;
299 static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count,
300 const void *arg)
302 struct pci_vpd_pci22 *vpd =
303 container_of(dev->vpd, struct pci_vpd_pci22, base);
304 const u8 *buf = arg;
305 loff_t end = pos + count;
306 int ret = 0;
308 if (pos < 0 || (pos & 3) || (count & 3) || end > vpd->base.len)
309 return -EINVAL;
311 if (mutex_lock_killable(&vpd->lock))
312 return -EINTR;
314 ret = pci_vpd_pci22_wait(dev);
315 if (ret < 0)
316 goto out;
318 while (pos < end) {
319 u32 val;
321 val = *buf++;
322 val |= *buf++ << 8;
323 val |= *buf++ << 16;
324 val |= *buf++ << 24;
326 ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val);
327 if (ret < 0)
328 break;
329 ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
330 pos | PCI_VPD_ADDR_F);
331 if (ret < 0)
332 break;
334 vpd->busy = true;
335 vpd->flag = 0;
336 ret = pci_vpd_pci22_wait(dev);
337 if (ret < 0)
338 break;
340 pos += sizeof(u32);
342 out:
343 mutex_unlock(&vpd->lock);
344 return ret ? ret : count;
347 static void pci_vpd_pci22_release(struct pci_dev *dev)
349 kfree(container_of(dev->vpd, struct pci_vpd_pci22, base));
352 static const struct pci_vpd_ops pci_vpd_pci22_ops = {
353 .read = pci_vpd_pci22_read,
354 .write = pci_vpd_pci22_write,
355 .release = pci_vpd_pci22_release,
358 int pci_vpd_pci22_init(struct pci_dev *dev)
360 struct pci_vpd_pci22 *vpd;
361 u8 cap;
363 cap = pci_find_capability(dev, PCI_CAP_ID_VPD);
364 if (!cap)
365 return -ENODEV;
366 vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC);
367 if (!vpd)
368 return -ENOMEM;
370 vpd->base.len = PCI_VPD_PCI22_SIZE;
371 vpd->base.ops = &pci_vpd_pci22_ops;
372 mutex_init(&vpd->lock);
373 vpd->cap = cap;
374 vpd->busy = false;
375 dev->vpd = &vpd->base;
376 return 0;
380 * pci_vpd_truncate - Set available Vital Product Data size
381 * @dev: pci device struct
382 * @size: available memory in bytes
384 * Adjust size of available VPD area.
386 int pci_vpd_truncate(struct pci_dev *dev, size_t size)
388 if (!dev->vpd)
389 return -EINVAL;
391 /* limited by the access method */
392 if (size > dev->vpd->len)
393 return -EINVAL;
395 dev->vpd->len = size;
396 if (dev->vpd->attr)
397 dev->vpd->attr->size = size;
399 return 0;
401 EXPORT_SYMBOL(pci_vpd_truncate);
404 * pci_block_user_cfg_access - Block userspace PCI config reads/writes
405 * @dev: pci device struct
407 * When user access is blocked, any reads or writes to config space will
408 * sleep until access is unblocked again. We don't allow nesting of
409 * block/unblock calls.
411 void pci_block_user_cfg_access(struct pci_dev *dev)
413 unsigned long flags;
414 int was_blocked;
416 raw_spin_lock_irqsave(&pci_lock, flags);
417 was_blocked = dev->block_ucfg_access;
418 dev->block_ucfg_access = 1;
419 raw_spin_unlock_irqrestore(&pci_lock, flags);
421 /* If we BUG() inside the pci_lock, we're guaranteed to hose
422 * the machine */
423 BUG_ON(was_blocked);
425 EXPORT_SYMBOL_GPL(pci_block_user_cfg_access);
428 * pci_unblock_user_cfg_access - Unblock userspace PCI config reads/writes
429 * @dev: pci device struct
431 * This function allows userspace PCI config accesses to resume.
433 void pci_unblock_user_cfg_access(struct pci_dev *dev)
435 unsigned long flags;
437 raw_spin_lock_irqsave(&pci_lock, flags);
439 /* This indicates a problem in the caller, but we don't need
440 * to kill them, unlike a double-block above. */
441 WARN_ON(!dev->block_ucfg_access);
443 dev->block_ucfg_access = 0;
444 wake_up_all(&pci_ucfg_wait);
445 raw_spin_unlock_irqrestore(&pci_lock, flags);
447 EXPORT_SYMBOL_GPL(pci_unblock_user_cfg_access);