rcec.c 4.4 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Root Complex Event Collector Support
  4. *
  5. * Authors:
  6. * Sean V Kelley <[email protected]>
  7. * Qiuxu Zhuo <[email protected]>
  8. *
  9. * Copyright (C) 2020 Intel Corp.
  10. */
  11. #include <linux/kernel.h>
  12. #include <linux/pci.h>
  13. #include <linux/pci_regs.h>
  14. #include "../pci.h"
  15. struct walk_rcec_data {
  16. struct pci_dev *rcec;
  17. int (*user_callback)(struct pci_dev *dev, void *data);
  18. void *user_data;
  19. };
  20. static bool rcec_assoc_rciep(struct pci_dev *rcec, struct pci_dev *rciep)
  21. {
  22. unsigned long bitmap = rcec->rcec_ea->bitmap;
  23. unsigned int devn;
  24. /* An RCiEP found on a different bus in range */
  25. if (rcec->bus->number != rciep->bus->number)
  26. return true;
  27. /* Same bus, so check bitmap */
  28. for_each_set_bit(devn, &bitmap, 32)
  29. if (devn == PCI_SLOT(rciep->devfn))
  30. return true;
  31. return false;
  32. }
  33. static int link_rcec_helper(struct pci_dev *dev, void *data)
  34. {
  35. struct walk_rcec_data *rcec_data = data;
  36. struct pci_dev *rcec = rcec_data->rcec;
  37. if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) &&
  38. rcec_assoc_rciep(rcec, dev)) {
  39. dev->rcec = rcec;
  40. pci_dbg(dev, "PME & error events signaled via %s\n",
  41. pci_name(rcec));
  42. }
  43. return 0;
  44. }
  45. static int walk_rcec_helper(struct pci_dev *dev, void *data)
  46. {
  47. struct walk_rcec_data *rcec_data = data;
  48. struct pci_dev *rcec = rcec_data->rcec;
  49. if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) &&
  50. rcec_assoc_rciep(rcec, dev))
  51. rcec_data->user_callback(dev, rcec_data->user_data);
  52. return 0;
  53. }
  54. static void walk_rcec(int (*cb)(struct pci_dev *dev, void *data),
  55. void *userdata)
  56. {
  57. struct walk_rcec_data *rcec_data = userdata;
  58. struct pci_dev *rcec = rcec_data->rcec;
  59. u8 nextbusn, lastbusn;
  60. struct pci_bus *bus;
  61. unsigned int bnr;
  62. if (!rcec->rcec_ea)
  63. return;
  64. /* Walk own bus for bitmap based association */
  65. pci_walk_bus(rcec->bus, cb, rcec_data);
  66. nextbusn = rcec->rcec_ea->nextbusn;
  67. lastbusn = rcec->rcec_ea->lastbusn;
  68. /* All RCiEP devices are on the same bus as the RCEC */
  69. if (nextbusn == 0xff && lastbusn == 0x00)
  70. return;
  71. for (bnr = nextbusn; bnr <= lastbusn; bnr++) {
  72. /* No association indicated (PCIe 5.0-1, 7.9.10.3) */
  73. if (bnr == rcec->bus->number)
  74. continue;
  75. bus = pci_find_bus(pci_domain_nr(rcec->bus), bnr);
  76. if (!bus)
  77. continue;
  78. /* Find RCiEP devices on the given bus ranges */
  79. pci_walk_bus(bus, cb, rcec_data);
  80. }
  81. }
  82. /**
  83. * pcie_link_rcec - Link RCiEP devices associated with RCEC.
  84. * @rcec: RCEC whose RCiEP devices should be linked.
  85. *
  86. * Link the given RCEC to each RCiEP device found.
  87. */
  88. void pcie_link_rcec(struct pci_dev *rcec)
  89. {
  90. struct walk_rcec_data rcec_data;
  91. if (!rcec->rcec_ea)
  92. return;
  93. rcec_data.rcec = rcec;
  94. rcec_data.user_callback = NULL;
  95. rcec_data.user_data = NULL;
  96. walk_rcec(link_rcec_helper, &rcec_data);
  97. }
  98. /**
  99. * pcie_walk_rcec - Walk RCiEP devices associating with RCEC and call callback.
  100. * @rcec: RCEC whose RCiEP devices should be walked
  101. * @cb: Callback to be called for each RCiEP device found
  102. * @userdata: Arbitrary pointer to be passed to callback
  103. *
  104. * Walk the given RCEC. Call the callback on each RCiEP found.
  105. *
  106. * If @cb returns anything other than 0, break out.
  107. */
  108. void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
  109. void *userdata)
  110. {
  111. struct walk_rcec_data rcec_data;
  112. if (!rcec->rcec_ea)
  113. return;
  114. rcec_data.rcec = rcec;
  115. rcec_data.user_callback = cb;
  116. rcec_data.user_data = userdata;
  117. walk_rcec(walk_rcec_helper, &rcec_data);
  118. }
  119. void pci_rcec_init(struct pci_dev *dev)
  120. {
  121. struct rcec_ea *rcec_ea;
  122. u32 rcec, hdr, busn;
  123. u8 ver;
  124. /* Only for Root Complex Event Collectors */
  125. if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_EC)
  126. return;
  127. rcec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_RCEC);
  128. if (!rcec)
  129. return;
  130. rcec_ea = kzalloc(sizeof(*rcec_ea), GFP_KERNEL);
  131. if (!rcec_ea)
  132. return;
  133. pci_read_config_dword(dev, rcec + PCI_RCEC_RCIEP_BITMAP,
  134. &rcec_ea->bitmap);
  135. /* Check whether RCEC BUSN register is present */
  136. pci_read_config_dword(dev, rcec, &hdr);
  137. ver = PCI_EXT_CAP_VER(hdr);
  138. if (ver >= PCI_RCEC_BUSN_REG_VER) {
  139. pci_read_config_dword(dev, rcec + PCI_RCEC_BUSN, &busn);
  140. rcec_ea->nextbusn = PCI_RCEC_BUSN_NEXT(busn);
  141. rcec_ea->lastbusn = PCI_RCEC_BUSN_LAST(busn);
  142. } else {
  143. /* Avoid later ver check by setting nextbusn */
  144. rcec_ea->nextbusn = 0xff;
  145. rcec_ea->lastbusn = 0x00;
  146. }
  147. dev->rcec_ea = rcec_ea;
  148. }
  149. void pci_rcec_exit(struct pci_dev *dev)
  150. {
  151. kfree(dev->rcec_ea);
  152. dev->rcec_ea = NULL;
  153. }