msi.c 9.9 KB

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  1. // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
  2. #include <linux/irq.h>
  3. #include <linux/module.h>
  4. #include <linux/ntb.h>
  5. #include <linux/msi.h>
  6. #include <linux/pci.h>
  7. struct ntb_msi {
  8. u64 base_addr;
  9. u64 end_addr;
  10. void (*desc_changed)(void *ctx);
  11. u32 __iomem *peer_mws[];
  12. };
  13. /**
  14. * ntb_msi_init() - Initialize the MSI context
  15. * @ntb: NTB device context
  16. *
  17. * This function must be called before any other ntb_msi function.
  18. * It initializes the context for MSI operations and maps
  19. * the peer memory windows.
  20. *
  21. * This function reserves the last N outbound memory windows (where N
  22. * is the number of peers).
  23. *
  24. * Return: Zero on success, otherwise a negative error number.
  25. */
  26. int ntb_msi_init(struct ntb_dev *ntb,
  27. void (*desc_changed)(void *ctx))
  28. {
  29. phys_addr_t mw_phys_addr;
  30. resource_size_t mw_size;
  31. size_t struct_size;
  32. int peer_widx;
  33. int peers;
  34. int ret;
  35. int i;
  36. peers = ntb_peer_port_count(ntb);
  37. if (peers <= 0)
  38. return -EINVAL;
  39. struct_size = sizeof(*ntb->msi) + sizeof(*ntb->msi->peer_mws) * peers;
  40. ntb->msi = devm_kzalloc(&ntb->dev, struct_size, GFP_KERNEL);
  41. if (!ntb->msi)
  42. return -ENOMEM;
  43. ntb->msi->desc_changed = desc_changed;
  44. for (i = 0; i < peers; i++) {
  45. peer_widx = ntb_peer_mw_count(ntb) - 1 - i;
  46. ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr,
  47. &mw_size);
  48. if (ret)
  49. goto unroll;
  50. ntb->msi->peer_mws[i] = devm_ioremap(&ntb->dev, mw_phys_addr,
  51. mw_size);
  52. if (!ntb->msi->peer_mws[i]) {
  53. ret = -EFAULT;
  54. goto unroll;
  55. }
  56. }
  57. return 0;
  58. unroll:
  59. for (i = 0; i < peers; i++)
  60. if (ntb->msi->peer_mws[i])
  61. devm_iounmap(&ntb->dev, ntb->msi->peer_mws[i]);
  62. devm_kfree(&ntb->dev, ntb->msi);
  63. ntb->msi = NULL;
  64. return ret;
  65. }
  66. EXPORT_SYMBOL(ntb_msi_init);
  67. /**
  68. * ntb_msi_setup_mws() - Initialize the MSI inbound memory windows
  69. * @ntb: NTB device context
  70. *
  71. * This function sets up the required inbound memory windows. It should be
  72. * called from a work function after a link up event.
  73. *
  74. * Over the entire network, this function will reserves the last N
  75. * inbound memory windows for each peer (where N is the number of peers).
  76. *
  77. * ntb_msi_init() must be called before this function.
  78. *
  79. * Return: Zero on success, otherwise a negative error number.
  80. */
  81. int ntb_msi_setup_mws(struct ntb_dev *ntb)
  82. {
  83. struct msi_desc *desc;
  84. u64 addr;
  85. int peer, peer_widx;
  86. resource_size_t addr_align, size_align, size_max;
  87. resource_size_t mw_size = SZ_32K;
  88. resource_size_t mw_min_size = mw_size;
  89. int i;
  90. int ret;
  91. if (!ntb->msi)
  92. return -EINVAL;
  93. desc = first_msi_entry(&ntb->pdev->dev);
  94. addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
  95. for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
  96. peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
  97. if (peer_widx < 0)
  98. return peer_widx;
  99. ret = ntb_mw_get_align(ntb, peer, peer_widx, &addr_align,
  100. NULL, NULL);
  101. if (ret)
  102. return ret;
  103. addr &= ~(addr_align - 1);
  104. }
  105. for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
  106. peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
  107. if (peer_widx < 0) {
  108. ret = peer_widx;
  109. goto error_out;
  110. }
  111. ret = ntb_mw_get_align(ntb, peer, peer_widx, NULL,
  112. &size_align, &size_max);
  113. if (ret)
  114. goto error_out;
  115. mw_size = round_up(mw_size, size_align);
  116. mw_size = max(mw_size, size_max);
  117. if (mw_size < mw_min_size)
  118. mw_min_size = mw_size;
  119. ret = ntb_mw_set_trans(ntb, peer, peer_widx,
  120. addr, mw_size);
  121. if (ret)
  122. goto error_out;
  123. }
  124. ntb->msi->base_addr = addr;
  125. ntb->msi->end_addr = addr + mw_min_size;
  126. return 0;
  127. error_out:
  128. for (i = 0; i < peer; i++) {
  129. peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
  130. if (peer_widx < 0)
  131. continue;
  132. ntb_mw_clear_trans(ntb, i, peer_widx);
  133. }
  134. return ret;
  135. }
  136. EXPORT_SYMBOL(ntb_msi_setup_mws);
  137. /**
  138. * ntb_msi_clear_mws() - Clear all inbound memory windows
  139. * @ntb: NTB device context
  140. *
  141. * This function tears down the resources used by ntb_msi_setup_mws().
  142. */
  143. void ntb_msi_clear_mws(struct ntb_dev *ntb)
  144. {
  145. int peer;
  146. int peer_widx;
  147. for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
  148. peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
  149. if (peer_widx < 0)
  150. continue;
  151. ntb_mw_clear_trans(ntb, peer, peer_widx);
  152. }
  153. }
  154. EXPORT_SYMBOL(ntb_msi_clear_mws);
  155. struct ntb_msi_devres {
  156. struct ntb_dev *ntb;
  157. struct msi_desc *entry;
  158. struct ntb_msi_desc *msi_desc;
  159. };
  160. static int ntb_msi_set_desc(struct ntb_dev *ntb, struct msi_desc *entry,
  161. struct ntb_msi_desc *msi_desc)
  162. {
  163. u64 addr;
  164. addr = entry->msg.address_lo +
  165. ((uint64_t)entry->msg.address_hi << 32);
  166. if (addr < ntb->msi->base_addr || addr >= ntb->msi->end_addr) {
  167. dev_warn_once(&ntb->dev,
  168. "IRQ %d: MSI Address not within the memory window (%llx, [%llx %llx])\n",
  169. entry->irq, addr, ntb->msi->base_addr,
  170. ntb->msi->end_addr);
  171. return -EFAULT;
  172. }
  173. msi_desc->addr_offset = addr - ntb->msi->base_addr;
  174. msi_desc->data = entry->msg.data;
  175. return 0;
  176. }
  177. static void ntb_msi_write_msg(struct msi_desc *entry, void *data)
  178. {
  179. struct ntb_msi_devres *dr = data;
  180. WARN_ON(ntb_msi_set_desc(dr->ntb, entry, dr->msi_desc));
  181. if (dr->ntb->msi->desc_changed)
  182. dr->ntb->msi->desc_changed(dr->ntb->ctx);
  183. }
  184. static void ntbm_msi_callback_release(struct device *dev, void *res)
  185. {
  186. struct ntb_msi_devres *dr = res;
  187. dr->entry->write_msi_msg = NULL;
  188. dr->entry->write_msi_msg_data = NULL;
  189. }
  190. static int ntbm_msi_setup_callback(struct ntb_dev *ntb, struct msi_desc *entry,
  191. struct ntb_msi_desc *msi_desc)
  192. {
  193. struct ntb_msi_devres *dr;
  194. dr = devres_alloc(ntbm_msi_callback_release,
  195. sizeof(struct ntb_msi_devres), GFP_KERNEL);
  196. if (!dr)
  197. return -ENOMEM;
  198. dr->ntb = ntb;
  199. dr->entry = entry;
  200. dr->msi_desc = msi_desc;
  201. devres_add(&ntb->dev, dr);
  202. dr->entry->write_msi_msg = ntb_msi_write_msg;
  203. dr->entry->write_msi_msg_data = dr;
  204. return 0;
  205. }
  206. /**
  207. * ntbm_msi_request_threaded_irq() - allocate an MSI interrupt
  208. * @ntb: NTB device context
  209. * @handler: Function to be called when the IRQ occurs
  210. * @thread_fn: Function to be called in a threaded interrupt context. NULL
  211. * for clients which handle everything in @handler
  212. * @devname: An ascii name for the claiming device, dev_name(dev) if NULL
  213. * @dev_id: A cookie passed back to the handler function
  214. *
  215. * This function assigns an interrupt handler to an unused
  216. * MSI interrupt and returns the descriptor used to trigger
  217. * it. The descriptor can then be sent to a peer to trigger
  218. * the interrupt.
  219. *
  220. * The interrupt resource is managed with devres so it will
  221. * be automatically freed when the NTB device is torn down.
  222. *
  223. * If an IRQ allocated with this function needs to be freed
  224. * separately, ntbm_free_irq() must be used.
  225. *
  226. * Return: IRQ number assigned on success, otherwise a negative error number.
  227. */
  228. int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
  229. irq_handler_t thread_fn,
  230. const char *name, void *dev_id,
  231. struct ntb_msi_desc *msi_desc)
  232. {
  233. struct msi_desc *entry;
  234. struct irq_desc *desc;
  235. int ret;
  236. if (!ntb->msi)
  237. return -EINVAL;
  238. for_each_pci_msi_entry(entry, ntb->pdev) {
  239. desc = irq_to_desc(entry->irq);
  240. if (desc->action)
  241. continue;
  242. ret = devm_request_threaded_irq(&ntb->dev, entry->irq, handler,
  243. thread_fn, 0, name, dev_id);
  244. if (ret)
  245. continue;
  246. if (ntb_msi_set_desc(ntb, entry, msi_desc)) {
  247. devm_free_irq(&ntb->dev, entry->irq, dev_id);
  248. continue;
  249. }
  250. ret = ntbm_msi_setup_callback(ntb, entry, msi_desc);
  251. if (ret) {
  252. devm_free_irq(&ntb->dev, entry->irq, dev_id);
  253. return ret;
  254. }
  255. return entry->irq;
  256. }
  257. return -ENODEV;
  258. }
  259. EXPORT_SYMBOL(ntbm_msi_request_threaded_irq);
  260. static int ntbm_msi_callback_match(struct device *dev, void *res, void *data)
  261. {
  262. struct ntb_dev *ntb = dev_ntb(dev);
  263. struct ntb_msi_devres *dr = res;
  264. return dr->ntb == ntb && dr->entry == data;
  265. }
  266. /**
  267. * ntbm_msi_free_irq() - free an interrupt
  268. * @ntb: NTB device context
  269. * @irq: Interrupt line to free
  270. * @dev_id: Device identity to free
  271. *
  272. * This function should be used to manually free IRQs allocated with
  273. * ntbm_request_[threaded_]irq().
  274. */
  275. void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id)
  276. {
  277. struct msi_desc *entry = irq_get_msi_desc(irq);
  278. entry->write_msi_msg = NULL;
  279. entry->write_msi_msg_data = NULL;
  280. WARN_ON(devres_destroy(&ntb->dev, ntbm_msi_callback_release,
  281. ntbm_msi_callback_match, entry));
  282. devm_free_irq(&ntb->dev, irq, dev_id);
  283. }
  284. EXPORT_SYMBOL(ntbm_msi_free_irq);
  285. /**
  286. * ntb_msi_peer_trigger() - Trigger an interrupt handler on a peer
  287. * @ntb: NTB device context
  288. * @peer: Peer index
  289. * @desc: MSI descriptor data which triggers the interrupt
  290. *
  291. * This function triggers an interrupt on a peer. It requires
  292. * the descriptor structure to have been passed from that peer
  293. * by some other means.
  294. *
  295. * Return: Zero on success, otherwise a negative error number.
  296. */
  297. int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
  298. struct ntb_msi_desc *desc)
  299. {
  300. int idx;
  301. if (!ntb->msi)
  302. return -EINVAL;
  303. idx = desc->addr_offset / sizeof(*ntb->msi->peer_mws[peer]);
  304. iowrite32(desc->data, &ntb->msi->peer_mws[peer][idx]);
  305. return 0;
  306. }
  307. EXPORT_SYMBOL(ntb_msi_peer_trigger);
  308. /**
  309. * ntb_msi_peer_addr() - Get the DMA address to trigger a peer's MSI interrupt
  310. * @ntb: NTB device context
  311. * @peer: Peer index
  312. * @desc: MSI descriptor data which triggers the interrupt
  313. * @msi_addr: Physical address to trigger the interrupt
  314. *
  315. * This function allows using DMA engines to trigger an interrupt
  316. * (for example, trigger an interrupt to process the data after
  317. * sending it). To trigger the interrupt, write @desc.data to the address
  318. * returned in @msi_addr
  319. *
  320. * Return: Zero on success, otherwise a negative error number.
  321. */
  322. int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
  323. struct ntb_msi_desc *desc,
  324. phys_addr_t *msi_addr)
  325. {
  326. int peer_widx = ntb_peer_mw_count(ntb) - 1 - peer;
  327. phys_addr_t mw_phys_addr;
  328. int ret;
  329. ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr, NULL);
  330. if (ret)
  331. return ret;
  332. if (msi_addr)
  333. *msi_addr = mw_phys_addr + desc->addr_offset;
  334. return 0;
  335. }
  336. EXPORT_SYMBOL(ntb_msi_peer_addr);