msi.c 20 KB

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  1. /*
  2. * File: msi.c
  3. * Purpose: PCI Message Signaled Interrupt (MSI)
  4. *
  5. * Copyright (C) 2003-2004 Intel
  6. * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
  7. */
  8. #include <linux/err.h>
  9. #include <linux/mm.h>
  10. #include <linux/irq.h>
  11. #include <linux/interrupt.h>
  12. #include <linux/init.h>
  13. #include <linux/ioport.h>
  14. #include <linux/pci.h>
  15. #include <linux/proc_fs.h>
  16. #include <linux/msi.h>
  17. #include <linux/smp.h>
  18. #include <asm/errno.h>
  19. #include <asm/io.h>
  20. #include "pci.h"
  21. #include "msi.h"
  22. static int pci_msi_enable = 1;
  23. /* Arch hooks */
  24. #ifndef arch_msi_check_device
  25. int arch_msi_check_device(struct pci_dev *dev, int nvec, int type)
  26. {
  27. return 0;
  28. }
  29. #endif
  30. #ifndef arch_setup_msi_irqs
  31. int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
  32. {
  33. struct msi_desc *entry;
  34. int ret;
  35. /*
  36. * If an architecture wants to support multiple MSI, it needs to
  37. * override arch_setup_msi_irqs()
  38. */
  39. if (type == PCI_CAP_ID_MSI && nvec > 1)
  40. return 1;
  41. list_for_each_entry(entry, &dev->msi_list, list) {
  42. ret = arch_setup_msi_irq(dev, entry);
  43. if (ret < 0)
  44. return ret;
  45. if (ret > 0)
  46. return -ENOSPC;
  47. }
  48. return 0;
  49. }
  50. #endif
  51. #ifndef arch_teardown_msi_irqs
  52. void arch_teardown_msi_irqs(struct pci_dev *dev)
  53. {
  54. struct msi_desc *entry;
  55. list_for_each_entry(entry, &dev->msi_list, list) {
  56. int i, nvec;
  57. if (entry->irq == 0)
  58. continue;
  59. nvec = 1 << entry->msi_attrib.multiple;
  60. for (i = 0; i < nvec; i++)
  61. arch_teardown_msi_irq(entry->irq + i);
  62. }
  63. }
  64. #endif
  65. static void __msi_set_enable(struct pci_dev *dev, int pos, int enable)
  66. {
  67. u16 control;
  68. if (pos) {
  69. pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
  70. control &= ~PCI_MSI_FLAGS_ENABLE;
  71. if (enable)
  72. control |= PCI_MSI_FLAGS_ENABLE;
  73. pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
  74. }
  75. }
  76. static void msi_set_enable(struct pci_dev *dev, int enable)
  77. {
  78. __msi_set_enable(dev, pci_find_capability(dev, PCI_CAP_ID_MSI), enable);
  79. }
  80. static void msix_set_enable(struct pci_dev *dev, int enable)
  81. {
  82. int pos;
  83. u16 control;
  84. pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
  85. if (pos) {
  86. pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
  87. control &= ~PCI_MSIX_FLAGS_ENABLE;
  88. if (enable)
  89. control |= PCI_MSIX_FLAGS_ENABLE;
  90. pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
  91. }
  92. }
  93. static inline __attribute_const__ u32 msi_mask(unsigned x)
  94. {
  95. /* Don't shift by >= width of type */
  96. if (x >= 5)
  97. return 0xffffffff;
  98. return (1 << (1 << x)) - 1;
  99. }
  100. static inline __attribute_const__ u32 msi_capable_mask(u16 control)
  101. {
  102. return msi_mask((control >> 1) & 7);
  103. }
  104. static inline __attribute_const__ u32 msi_enabled_mask(u16 control)
  105. {
  106. return msi_mask((control >> 4) & 7);
  107. }
  108. /*
  109. * PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to
  110. * mask all MSI interrupts by clearing the MSI enable bit does not work
  111. * reliably as devices without an INTx disable bit will then generate a
  112. * level IRQ which will never be cleared.
  113. */
  114. static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
  115. {
  116. u32 mask_bits = desc->masked;
  117. if (!desc->msi_attrib.maskbit)
  118. return;
  119. mask_bits &= ~mask;
  120. mask_bits |= flag;
  121. pci_write_config_dword(desc->dev, desc->mask_pos, mask_bits);
  122. desc->masked = mask_bits;
  123. }
  124. /*
  125. * This internal function does not flush PCI writes to the device.
  126. * All users must ensure that they read from the device before either
  127. * assuming that the device state is up to date, or returning out of this
  128. * file. This saves a few milliseconds when initialising devices with lots
  129. * of MSI-X interrupts.
  130. */
  131. static void msix_mask_irq(struct msi_desc *desc, u32 flag)
  132. {
  133. u32 mask_bits = desc->masked;
  134. unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
  135. PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET;
  136. mask_bits &= ~1;
  137. mask_bits |= flag;
  138. writel(mask_bits, desc->mask_base + offset);
  139. desc->masked = mask_bits;
  140. }
  141. static void msi_set_mask_bit(unsigned irq, u32 flag)
  142. {
  143. struct msi_desc *desc = get_irq_msi(irq);
  144. if (desc->msi_attrib.is_msix) {
  145. msix_mask_irq(desc, flag);
  146. readl(desc->mask_base); /* Flush write to device */
  147. } else {
  148. unsigned offset = irq - desc->dev->irq;
  149. msi_mask_irq(desc, 1 << offset, flag << offset);
  150. }
  151. }
  152. void mask_msi_irq(unsigned int irq)
  153. {
  154. msi_set_mask_bit(irq, 1);
  155. }
  156. void unmask_msi_irq(unsigned int irq)
  157. {
  158. msi_set_mask_bit(irq, 0);
  159. }
  160. void read_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
  161. {
  162. struct msi_desc *entry = get_irq_desc_msi(desc);
  163. if (entry->msi_attrib.is_msix) {
  164. void __iomem *base = entry->mask_base +
  165. entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
  166. msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
  167. msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
  168. msg->data = readl(base + PCI_MSIX_ENTRY_DATA_OFFSET);
  169. } else {
  170. struct pci_dev *dev = entry->dev;
  171. int pos = entry->msi_attrib.pos;
  172. u16 data;
  173. pci_read_config_dword(dev, msi_lower_address_reg(pos),
  174. &msg->address_lo);
  175. if (entry->msi_attrib.is_64) {
  176. pci_read_config_dword(dev, msi_upper_address_reg(pos),
  177. &msg->address_hi);
  178. pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
  179. } else {
  180. msg->address_hi = 0;
  181. pci_read_config_word(dev, msi_data_reg(pos, 0), &data);
  182. }
  183. msg->data = data;
  184. }
  185. }
  186. void read_msi_msg(unsigned int irq, struct msi_msg *msg)
  187. {
  188. struct irq_desc *desc = irq_to_desc(irq);
  189. read_msi_msg_desc(desc, msg);
  190. }
  191. void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
  192. {
  193. struct msi_desc *entry = get_irq_desc_msi(desc);
  194. if (entry->msi_attrib.is_msix) {
  195. void __iomem *base;
  196. base = entry->mask_base +
  197. entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
  198. writel(msg->address_lo,
  199. base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
  200. writel(msg->address_hi,
  201. base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
  202. writel(msg->data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
  203. } else {
  204. struct pci_dev *dev = entry->dev;
  205. int pos = entry->msi_attrib.pos;
  206. u16 msgctl;
  207. pci_read_config_word(dev, msi_control_reg(pos), &msgctl);
  208. msgctl &= ~PCI_MSI_FLAGS_QSIZE;
  209. msgctl |= entry->msi_attrib.multiple << 4;
  210. pci_write_config_word(dev, msi_control_reg(pos), msgctl);
  211. pci_write_config_dword(dev, msi_lower_address_reg(pos),
  212. msg->address_lo);
  213. if (entry->msi_attrib.is_64) {
  214. pci_write_config_dword(dev, msi_upper_address_reg(pos),
  215. msg->address_hi);
  216. pci_write_config_word(dev, msi_data_reg(pos, 1),
  217. msg->data);
  218. } else {
  219. pci_write_config_word(dev, msi_data_reg(pos, 0),
  220. msg->data);
  221. }
  222. }
  223. entry->msg = *msg;
  224. }
  225. void write_msi_msg(unsigned int irq, struct msi_msg *msg)
  226. {
  227. struct irq_desc *desc = irq_to_desc(irq);
  228. write_msi_msg_desc(desc, msg);
  229. }
  230. static int msi_free_irqs(struct pci_dev* dev);
  231. static struct msi_desc *alloc_msi_entry(struct pci_dev *dev)
  232. {
  233. struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL);
  234. if (!desc)
  235. return NULL;
  236. INIT_LIST_HEAD(&desc->list);
  237. desc->dev = dev;
  238. return desc;
  239. }
  240. static void pci_intx_for_msi(struct pci_dev *dev, int enable)
  241. {
  242. if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
  243. pci_intx(dev, enable);
  244. }
  245. static void __pci_restore_msi_state(struct pci_dev *dev)
  246. {
  247. int pos;
  248. u16 control;
  249. struct msi_desc *entry;
  250. if (!dev->msi_enabled)
  251. return;
  252. entry = get_irq_msi(dev->irq);
  253. pos = entry->msi_attrib.pos;
  254. pci_intx_for_msi(dev, 0);
  255. msi_set_enable(dev, 0);
  256. write_msi_msg(dev->irq, &entry->msg);
  257. pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
  258. msi_mask_irq(entry, msi_capable_mask(control), entry->masked);
  259. control &= ~PCI_MSI_FLAGS_QSIZE;
  260. control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
  261. pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
  262. }
  263. static void __pci_restore_msix_state(struct pci_dev *dev)
  264. {
  265. int pos;
  266. struct msi_desc *entry;
  267. u16 control;
  268. if (!dev->msix_enabled)
  269. return;
  270. /* route the table */
  271. pci_intx_for_msi(dev, 0);
  272. msix_set_enable(dev, 0);
  273. list_for_each_entry(entry, &dev->msi_list, list) {
  274. write_msi_msg(entry->irq, &entry->msg);
  275. msix_mask_irq(entry, entry->masked);
  276. }
  277. BUG_ON(list_empty(&dev->msi_list));
  278. entry = list_entry(dev->msi_list.next, struct msi_desc, list);
  279. pos = entry->msi_attrib.pos;
  280. pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
  281. control &= ~PCI_MSIX_FLAGS_MASKALL;
  282. control |= PCI_MSIX_FLAGS_ENABLE;
  283. pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
  284. }
  285. void pci_restore_msi_state(struct pci_dev *dev)
  286. {
  287. __pci_restore_msi_state(dev);
  288. __pci_restore_msix_state(dev);
  289. }
  290. EXPORT_SYMBOL_GPL(pci_restore_msi_state);
  291. /**
  292. * msi_capability_init - configure device's MSI capability structure
  293. * @dev: pointer to the pci_dev data structure of MSI device function
  294. * @nvec: number of interrupts to allocate
  295. *
  296. * Setup the MSI capability structure of the device with the requested
  297. * number of interrupts. A return value of zero indicates the successful
  298. * setup of an entry with the new MSI irq. A negative return value indicates
  299. * an error, and a positive return value indicates the number of interrupts
  300. * which could have been allocated.
  301. */
  302. static int msi_capability_init(struct pci_dev *dev, int nvec)
  303. {
  304. struct msi_desc *entry;
  305. int pos, ret;
  306. u16 control;
  307. unsigned mask;
  308. msi_set_enable(dev, 0); /* Ensure msi is disabled as I set it up */
  309. pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
  310. pci_read_config_word(dev, msi_control_reg(pos), &control);
  311. /* MSI Entry Initialization */
  312. entry = alloc_msi_entry(dev);
  313. if (!entry)
  314. return -ENOMEM;
  315. entry->msi_attrib.is_msix = 0;
  316. entry->msi_attrib.is_64 = is_64bit_address(control);
  317. entry->msi_attrib.entry_nr = 0;
  318. entry->msi_attrib.maskbit = is_mask_bit_support(control);
  319. entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
  320. entry->msi_attrib.pos = pos;
  321. entry->mask_pos = msi_mask_reg(pos, entry->msi_attrib.is_64);
  322. /* All MSIs are unmasked by default, Mask them all */
  323. if (entry->msi_attrib.maskbit)
  324. pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
  325. mask = msi_capable_mask(control);
  326. msi_mask_irq(entry, mask, mask);
  327. list_add_tail(&entry->list, &dev->msi_list);
  328. /* Configure MSI capability structure */
  329. ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
  330. if (ret) {
  331. msi_free_irqs(dev);
  332. return ret;
  333. }
  334. /* Set MSI enabled bits */
  335. pci_intx_for_msi(dev, 0);
  336. msi_set_enable(dev, 1);
  337. dev->msi_enabled = 1;
  338. dev->irq = entry->irq;
  339. return 0;
  340. }
  341. /**
  342. * msix_capability_init - configure device's MSI-X capability
  343. * @dev: pointer to the pci_dev data structure of MSI-X device function
  344. * @entries: pointer to an array of struct msix_entry entries
  345. * @nvec: number of @entries
  346. *
  347. * Setup the MSI-X capability structure of device function with a
  348. * single MSI-X irq. A return of zero indicates the successful setup of
  349. * requested MSI-X entries with allocated irqs or non-zero for otherwise.
  350. **/
  351. static int msix_capability_init(struct pci_dev *dev,
  352. struct msix_entry *entries, int nvec)
  353. {
  354. struct msi_desc *entry;
  355. int pos, i, j, nr_entries, ret;
  356. unsigned long phys_addr;
  357. u32 table_offset;
  358. u16 control;
  359. u8 bir;
  360. void __iomem *base;
  361. msix_set_enable(dev, 0);/* Ensure msix is disabled as I set it up */
  362. pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
  363. /* Request & Map MSI-X table region */
  364. pci_read_config_word(dev, msi_control_reg(pos), &control);
  365. nr_entries = multi_msix_capable(control);
  366. pci_read_config_dword(dev, msix_table_offset_reg(pos), &table_offset);
  367. bir = (u8)(table_offset & PCI_MSIX_FLAGS_BIRMASK);
  368. table_offset &= ~PCI_MSIX_FLAGS_BIRMASK;
  369. phys_addr = pci_resource_start (dev, bir) + table_offset;
  370. base = ioremap_nocache(phys_addr, nr_entries * PCI_MSIX_ENTRY_SIZE);
  371. if (base == NULL)
  372. return -ENOMEM;
  373. /* MSI-X Table Initialization */
  374. for (i = 0; i < nvec; i++) {
  375. entry = alloc_msi_entry(dev);
  376. if (!entry)
  377. break;
  378. j = entries[i].entry;
  379. entry->msi_attrib.is_msix = 1;
  380. entry->msi_attrib.is_64 = 1;
  381. entry->msi_attrib.entry_nr = j;
  382. entry->msi_attrib.default_irq = dev->irq;
  383. entry->msi_attrib.pos = pos;
  384. entry->mask_base = base;
  385. msix_mask_irq(entry, 1);
  386. list_add_tail(&entry->list, &dev->msi_list);
  387. }
  388. ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
  389. if (ret < 0) {
  390. /* If we had some success report the number of irqs
  391. * we succeeded in setting up. */
  392. int avail = 0;
  393. list_for_each_entry(entry, &dev->msi_list, list) {
  394. if (entry->irq != 0) {
  395. avail++;
  396. }
  397. }
  398. if (avail != 0)
  399. ret = avail;
  400. }
  401. if (ret) {
  402. msi_free_irqs(dev);
  403. return ret;
  404. }
  405. i = 0;
  406. list_for_each_entry(entry, &dev->msi_list, list) {
  407. entries[i].vector = entry->irq;
  408. set_irq_msi(entry->irq, entry);
  409. i++;
  410. }
  411. /* Set MSI-X enabled bits */
  412. pci_intx_for_msi(dev, 0);
  413. msix_set_enable(dev, 1);
  414. dev->msix_enabled = 1;
  415. list_for_each_entry(entry, &dev->msi_list, list) {
  416. int vector = entry->msi_attrib.entry_nr;
  417. entry->masked = readl(base + vector * PCI_MSIX_ENTRY_SIZE +
  418. PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
  419. }
  420. return 0;
  421. }
  422. /**
  423. * pci_msi_check_device - check whether MSI may be enabled on a device
  424. * @dev: pointer to the pci_dev data structure of MSI device function
  425. * @nvec: how many MSIs have been requested ?
  426. * @type: are we checking for MSI or MSI-X ?
  427. *
  428. * Look at global flags, the device itself, and its parent busses
  429. * to determine if MSI/-X are supported for the device. If MSI/-X is
  430. * supported return 0, else return an error code.
  431. **/
  432. static int pci_msi_check_device(struct pci_dev* dev, int nvec, int type)
  433. {
  434. struct pci_bus *bus;
  435. int ret;
  436. /* MSI must be globally enabled and supported by the device */
  437. if (!pci_msi_enable || !dev || dev->no_msi)
  438. return -EINVAL;
  439. /*
  440. * You can't ask to have 0 or less MSIs configured.
  441. * a) it's stupid ..
  442. * b) the list manipulation code assumes nvec >= 1.
  443. */
  444. if (nvec < 1)
  445. return -ERANGE;
  446. /* Any bridge which does NOT route MSI transactions from it's
  447. * secondary bus to it's primary bus must set NO_MSI flag on
  448. * the secondary pci_bus.
  449. * We expect only arch-specific PCI host bus controller driver
  450. * or quirks for specific PCI bridges to be setting NO_MSI.
  451. */
  452. for (bus = dev->bus; bus; bus = bus->parent)
  453. if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
  454. return -EINVAL;
  455. ret = arch_msi_check_device(dev, nvec, type);
  456. if (ret)
  457. return ret;
  458. if (!pci_find_capability(dev, type))
  459. return -EINVAL;
  460. return 0;
  461. }
  462. /**
  463. * pci_enable_msi_block - configure device's MSI capability structure
  464. * @dev: device to configure
  465. * @nvec: number of interrupts to configure
  466. *
  467. * Allocate IRQs for a device with the MSI capability.
  468. * This function returns a negative errno if an error occurs. If it
  469. * is unable to allocate the number of interrupts requested, it returns
  470. * the number of interrupts it might be able to allocate. If it successfully
  471. * allocates at least the number of interrupts requested, it returns 0 and
  472. * updates the @dev's irq member to the lowest new interrupt number; the
  473. * other interrupt numbers allocated to this device are consecutive.
  474. */
  475. int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
  476. {
  477. int status, pos, maxvec;
  478. u16 msgctl;
  479. pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
  480. if (!pos)
  481. return -EINVAL;
  482. pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
  483. maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
  484. if (nvec > maxvec)
  485. return maxvec;
  486. status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSI);
  487. if (status)
  488. return status;
  489. WARN_ON(!!dev->msi_enabled);
  490. /* Check whether driver already requested MSI-X irqs */
  491. if (dev->msix_enabled) {
  492. dev_info(&dev->dev, "can't enable MSI "
  493. "(MSI-X already enabled)\n");
  494. return -EINVAL;
  495. }
  496. status = msi_capability_init(dev, nvec);
  497. return status;
  498. }
  499. EXPORT_SYMBOL(pci_enable_msi_block);
  500. void pci_msi_shutdown(struct pci_dev *dev)
  501. {
  502. struct msi_desc *desc;
  503. u32 mask;
  504. u16 ctrl;
  505. if (!pci_msi_enable || !dev || !dev->msi_enabled)
  506. return;
  507. msi_set_enable(dev, 0);
  508. pci_intx_for_msi(dev, 1);
  509. dev->msi_enabled = 0;
  510. BUG_ON(list_empty(&dev->msi_list));
  511. desc = list_first_entry(&dev->msi_list, struct msi_desc, list);
  512. pci_read_config_word(dev, desc->msi_attrib.pos + PCI_MSI_FLAGS, &ctrl);
  513. mask = msi_capable_mask(ctrl);
  514. msi_mask_irq(desc, mask, ~mask);
  515. /* Restore dev->irq to its default pin-assertion irq */
  516. dev->irq = desc->msi_attrib.default_irq;
  517. }
  518. void pci_disable_msi(struct pci_dev* dev)
  519. {
  520. struct msi_desc *entry;
  521. if (!pci_msi_enable || !dev || !dev->msi_enabled)
  522. return;
  523. pci_msi_shutdown(dev);
  524. entry = list_entry(dev->msi_list.next, struct msi_desc, list);
  525. if (entry->msi_attrib.is_msix)
  526. return;
  527. msi_free_irqs(dev);
  528. }
  529. EXPORT_SYMBOL(pci_disable_msi);
  530. static int msi_free_irqs(struct pci_dev* dev)
  531. {
  532. struct msi_desc *entry, *tmp;
  533. list_for_each_entry(entry, &dev->msi_list, list) {
  534. int i, nvec;
  535. if (!entry->irq)
  536. continue;
  537. nvec = 1 << entry->msi_attrib.multiple;
  538. for (i = 0; i < nvec; i++)
  539. BUG_ON(irq_has_action(entry->irq + i));
  540. }
  541. arch_teardown_msi_irqs(dev);
  542. list_for_each_entry_safe(entry, tmp, &dev->msi_list, list) {
  543. if (entry->msi_attrib.is_msix) {
  544. writel(1, entry->mask_base + entry->msi_attrib.entry_nr
  545. * PCI_MSIX_ENTRY_SIZE
  546. + PCI_MSIX_ENTRY_VECTOR_CTRL_OFFSET);
  547. if (list_is_last(&entry->list, &dev->msi_list))
  548. iounmap(entry->mask_base);
  549. }
  550. list_del(&entry->list);
  551. kfree(entry);
  552. }
  553. return 0;
  554. }
  555. /**
  556. * pci_msix_table_size - return the number of device's MSI-X table entries
  557. * @dev: pointer to the pci_dev data structure of MSI-X device function
  558. */
  559. int pci_msix_table_size(struct pci_dev *dev)
  560. {
  561. int pos;
  562. u16 control;
  563. pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
  564. if (!pos)
  565. return 0;
  566. pci_read_config_word(dev, msi_control_reg(pos), &control);
  567. return multi_msix_capable(control);
  568. }
  569. /**
  570. * pci_enable_msix - configure device's MSI-X capability structure
  571. * @dev: pointer to the pci_dev data structure of MSI-X device function
  572. * @entries: pointer to an array of MSI-X entries
  573. * @nvec: number of MSI-X irqs requested for allocation by device driver
  574. *
  575. * Setup the MSI-X capability structure of device function with the number
  576. * of requested irqs upon its software driver call to request for
  577. * MSI-X mode enabled on its hardware device function. A return of zero
  578. * indicates the successful configuration of MSI-X capability structure
  579. * with new allocated MSI-X irqs. A return of < 0 indicates a failure.
  580. * Or a return of > 0 indicates that driver request is exceeding the number
  581. * of irqs or MSI-X vectors available. Driver should use the returned value to
  582. * re-send its request.
  583. **/
  584. int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
  585. {
  586. int status, nr_entries;
  587. int i, j;
  588. if (!entries)
  589. return -EINVAL;
  590. status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSIX);
  591. if (status)
  592. return status;
  593. nr_entries = pci_msix_table_size(dev);
  594. if (nvec > nr_entries)
  595. return nr_entries;
  596. /* Check for any invalid entries */
  597. for (i = 0; i < nvec; i++) {
  598. if (entries[i].entry >= nr_entries)
  599. return -EINVAL; /* invalid entry */
  600. for (j = i + 1; j < nvec; j++) {
  601. if (entries[i].entry == entries[j].entry)
  602. return -EINVAL; /* duplicate entry */
  603. }
  604. }
  605. WARN_ON(!!dev->msix_enabled);
  606. /* Check whether driver already requested for MSI irq */
  607. if (dev->msi_enabled) {
  608. dev_info(&dev->dev, "can't enable MSI-X "
  609. "(MSI IRQ already assigned)\n");
  610. return -EINVAL;
  611. }
  612. status = msix_capability_init(dev, entries, nvec);
  613. return status;
  614. }
  615. EXPORT_SYMBOL(pci_enable_msix);
  616. static void msix_free_all_irqs(struct pci_dev *dev)
  617. {
  618. msi_free_irqs(dev);
  619. }
  620. void pci_msix_shutdown(struct pci_dev* dev)
  621. {
  622. if (!pci_msi_enable || !dev || !dev->msix_enabled)
  623. return;
  624. msix_set_enable(dev, 0);
  625. pci_intx_for_msi(dev, 1);
  626. dev->msix_enabled = 0;
  627. }
  628. void pci_disable_msix(struct pci_dev* dev)
  629. {
  630. if (!pci_msi_enable || !dev || !dev->msix_enabled)
  631. return;
  632. pci_msix_shutdown(dev);
  633. msix_free_all_irqs(dev);
  634. }
  635. EXPORT_SYMBOL(pci_disable_msix);
  636. /**
  637. * msi_remove_pci_irq_vectors - reclaim MSI(X) irqs to unused state
  638. * @dev: pointer to the pci_dev data structure of MSI(X) device function
  639. *
  640. * Being called during hotplug remove, from which the device function
  641. * is hot-removed. All previous assigned MSI/MSI-X irqs, if
  642. * allocated for this device function, are reclaimed to unused state,
  643. * which may be used later on.
  644. **/
  645. void msi_remove_pci_irq_vectors(struct pci_dev* dev)
  646. {
  647. if (!pci_msi_enable || !dev)
  648. return;
  649. if (dev->msi_enabled)
  650. msi_free_irqs(dev);
  651. if (dev->msix_enabled)
  652. msix_free_all_irqs(dev);
  653. }
  654. void pci_no_msi(void)
  655. {
  656. pci_msi_enable = 0;
  657. }
  658. /**
  659. * pci_msi_enabled - is MSI enabled?
  660. *
  661. * Returns true if MSI has not been disabled by the command-line option
  662. * pci=nomsi.
  663. **/
  664. int pci_msi_enabled(void)
  665. {
  666. return pci_msi_enable;
  667. }
  668. EXPORT_SYMBOL(pci_msi_enabled);
  669. void pci_msi_init_pci_dev(struct pci_dev *dev)
  670. {
  671. INIT_LIST_HEAD(&dev->msi_list);
  672. }