1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Root Complex Event Collector Support 4 * 5 * Authors: 6 * Sean V Kelley <sean.v.kelley@intel.com> 7 * Qiuxu Zhuo <qiuxu.zhuo@intel.com> 8 * 9 * Copyright (C) 2020 Intel Corp. 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/pci.h> 14 #include <linux/pci_regs.h> 15 16 #include "../pci.h" 17 18 struct walk_rcec_data { 19 struct pci_dev *rcec; 20 int (*user_callback)(struct pci_dev *dev, void *data); 21 void *user_data; 22 }; 23 24 static bool rcec_assoc_rciep(struct pci_dev *rcec, struct pci_dev *rciep) 25 { 26 unsigned long bitmap = rcec->rcec_ea->bitmap; 27 unsigned int devn; 28 29 /* An RCiEP found on a different bus in range */ 30 if (rcec->bus->number != rciep->bus->number) 31 return true; 32 33 /* Same bus, so check bitmap */ 34 for_each_set_bit(devn, &bitmap, 32) 35 if (devn == PCI_SLOT(rciep->devfn)) 36 return true; 37 38 return false; 39 } 40 41 static int link_rcec_helper(struct pci_dev *dev, void *data) 42 { 43 struct walk_rcec_data *rcec_data = data; 44 struct pci_dev *rcec = rcec_data->rcec; 45 46 if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) && 47 rcec_assoc_rciep(rcec, dev)) { 48 dev->rcec = rcec; 49 pci_dbg(dev, "PME & error events signaled via %s\n", 50 pci_name(rcec)); 51 } 52 53 return 0; 54 } 55 56 static int walk_rcec_helper(struct pci_dev *dev, void *data) 57 { 58 struct walk_rcec_data *rcec_data = data; 59 struct pci_dev *rcec = rcec_data->rcec; 60 61 if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) && 62 rcec_assoc_rciep(rcec, dev)) 63 rcec_data->user_callback(dev, rcec_data->user_data); 64 65 return 0; 66 } 67 68 static void walk_rcec(int (*cb)(struct pci_dev *dev, void *data), 69 void *userdata) 70 { 71 struct walk_rcec_data *rcec_data = userdata; 72 struct pci_dev *rcec = rcec_data->rcec; 73 u8 nextbusn, lastbusn; 74 struct pci_bus *bus; 75 unsigned int bnr; 76 77 if (!rcec->rcec_ea) 78 return; 79 80 /* Walk own bus for bitmap based association */ 81 pci_walk_bus(rcec->bus, cb, rcec_data); 82 83 nextbusn = rcec->rcec_ea->nextbusn; 84 lastbusn = rcec->rcec_ea->lastbusn; 85 86 /* All RCiEP devices are on the same bus as the RCEC */ 87 if (nextbusn == 0xff && lastbusn == 0x00) 88 return; 89 90 for (bnr = nextbusn; bnr <= lastbusn; bnr++) { 91 /* No association indicated (PCIe 5.0-1, 7.9.10.3) */ 92 if (bnr == rcec->bus->number) 93 continue; 94 95 bus = pci_find_bus(pci_domain_nr(rcec->bus), bnr); 96 if (!bus) 97 continue; 98 99 /* Find RCiEP devices on the given bus ranges */ 100 pci_walk_bus(bus, cb, rcec_data); 101 } 102 } 103 104 /** 105 * pcie_link_rcec - Link RCiEP devices associated with RCEC. 106 * @rcec: RCEC whose RCiEP devices should be linked. 107 * 108 * Link the given RCEC to each RCiEP device found. 109 */ 110 void pcie_link_rcec(struct pci_dev *rcec) 111 { 112 struct walk_rcec_data rcec_data; 113 114 if (!rcec->rcec_ea) 115 return; 116 117 rcec_data.rcec = rcec; 118 rcec_data.user_callback = NULL; 119 rcec_data.user_data = NULL; 120 121 walk_rcec(link_rcec_helper, &rcec_data); 122 } 123 124 /** 125 * pcie_walk_rcec - Walk RCiEP devices associating with RCEC and call callback. 126 * @rcec: RCEC whose RCiEP devices should be walked 127 * @cb: Callback to be called for each RCiEP device found 128 * @userdata: Arbitrary pointer to be passed to callback 129 * 130 * Walk the given RCEC. Call the callback on each RCiEP found. 131 * 132 * If @cb returns anything other than 0, break out. 133 */ 134 void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *), 135 void *userdata) 136 { 137 struct walk_rcec_data rcec_data; 138 139 if (!rcec->rcec_ea) 140 return; 141 142 rcec_data.rcec = rcec; 143 rcec_data.user_callback = cb; 144 rcec_data.user_data = userdata; 145 146 walk_rcec(walk_rcec_helper, &rcec_data); 147 } 148 149 void pci_rcec_init(struct pci_dev *dev) 150 { 151 struct rcec_ea *rcec_ea; 152 u32 rcec, hdr, busn; 153 u8 ver; 154 155 /* Only for Root Complex Event Collectors */ 156 if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_EC) 157 return; 158 159 rcec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_RCEC); 160 if (!rcec) 161 return; 162 163 rcec_ea = kzalloc(sizeof(*rcec_ea), GFP_KERNEL); 164 if (!rcec_ea) 165 return; 166 167 pci_read_config_dword(dev, rcec + PCI_RCEC_RCIEP_BITMAP, 168 &rcec_ea->bitmap); 169 170 /* Check whether RCEC BUSN register is present */ 171 pci_read_config_dword(dev, rcec, &hdr); 172 ver = PCI_EXT_CAP_VER(hdr); 173 if (ver >= PCI_RCEC_BUSN_REG_VER) { 174 pci_read_config_dword(dev, rcec + PCI_RCEC_BUSN, &busn); 175 rcec_ea->nextbusn = PCI_RCEC_BUSN_NEXT(busn); 176 rcec_ea->lastbusn = PCI_RCEC_BUSN_LAST(busn); 177 } else { 178 /* Avoid later ver check by setting nextbusn */ 179 rcec_ea->nextbusn = 0xff; 180 rcec_ea->lastbusn = 0x00; 181 } 182 183 dev->rcec_ea = rcec_ea; 184 } 185 186 void pci_rcec_exit(struct pci_dev *dev) 187 { 188 kfree(dev->rcec_ea); 189 dev->rcec_ea = NULL; 190 } 191