pci/pcie/rcec.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Root Complex Event Collector Support
0004  *
0005  * Authors:
0006  *  Sean V Kelley <sean.v.kelley@intel.com>
0007  *  Qiuxu Zhuo <qiuxu.zhuo@intel.com>
0008  *
0009  * Copyright (C) 2020 Intel Corp.
0010  */
0011
0012 #include <linux/kernel.h>
0013 #include <linux/pci.h>
0014 #include <linux/pci_regs.h>
0015
0016 #include "../pci.h"
0017
0018 struct walk_rcec_data {
0019     struct pci_dev *rcec;
0020     int (*user_callback)(struct pci_dev *dev, void *data);
0021     void *user_data;
0022 };
0023
0024 static bool rcec_assoc_rciep(struct pci_dev *rcec, struct pci_dev *rciep)
0025 {
0026     unsigned long bitmap = rcec->rcec_ea->bitmap;
0027     unsigned int devn;
0028
0029     /* An RCiEP found on a different bus in range */
0030     if (rcec->bus->number != rciep->bus->number)
0031         return true;
0032
0033     /* Same bus, so check bitmap */
0034     for_each_set_bit(devn, &bitmap, 32)
0035         if (devn == PCI_SLOT(rciep->devfn))
0036             return true;
0037
0038     return false;
0039 }
0040
0041 static int link_rcec_helper(struct pci_dev *dev, void *data)
0042 {
0043     struct walk_rcec_data *rcec_data = data;
0044     struct pci_dev *rcec = rcec_data->rcec;
0045
0046     if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) &&
0047         rcec_assoc_rciep(rcec, dev)) {
0048         dev->rcec = rcec;
0049         pci_dbg(dev, "PME & error events signaled via %s\n",
0050             pci_name(rcec));
0051     }
0052
0053     return 0;
0054 }
0055
0056 static int walk_rcec_helper(struct pci_dev *dev, void *data)
0057 {
0058     struct walk_rcec_data *rcec_data = data;
0059     struct pci_dev *rcec = rcec_data->rcec;
0060
0061     if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) &&
0062         rcec_assoc_rciep(rcec, dev))
0063         rcec_data->user_callback(dev, rcec_data->user_data);
0064
0065     return 0;
0066 }
0067
0068 static void walk_rcec(int (*cb)(struct pci_dev *dev, void *data),
0069               void *userdata)
0070 {
0071     struct walk_rcec_data *rcec_data = userdata;
0072     struct pci_dev *rcec = rcec_data->rcec;
0073     u8 nextbusn, lastbusn;
0074     struct pci_bus *bus;
0075     unsigned int bnr;
0076
0077     if (!rcec->rcec_ea)
0078         return;
0079
0080     /* Walk own bus for bitmap based association */
0081     pci_walk_bus(rcec->bus, cb, rcec_data);
0082
0083     nextbusn = rcec->rcec_ea->nextbusn;
0084     lastbusn = rcec->rcec_ea->lastbusn;
0085
0086     /* All RCiEP devices are on the same bus as the RCEC */
0087     if (nextbusn == 0xff && lastbusn == 0x00)
0088         return;
0089
0090     for (bnr = nextbusn; bnr <= lastbusn; bnr++) {
0091         /* No association indicated (PCIe 5.0-1, 7.9.10.3) */
0092         if (bnr == rcec->bus->number)
0093             continue;
0094
0095         bus = pci_find_bus(pci_domain_nr(rcec->bus), bnr);
0096         if (!bus)
0097             continue;
0098
0099         /* Find RCiEP devices on the given bus ranges */
0100         pci_walk_bus(bus, cb, rcec_data);
0101     }
0102 }
0103
0104 /**
0105  * pcie_link_rcec - Link RCiEP devices associated with RCEC.
0106  * @rcec: RCEC whose RCiEP devices should be linked.
0107  *
0108  * Link the given RCEC to each RCiEP device found.
0109  */
0110 void pcie_link_rcec(struct pci_dev *rcec)
0111 {
0112     struct walk_rcec_data rcec_data;
0113
0114     if (!rcec->rcec_ea)
0115         return;
0116
0117     rcec_data.rcec = rcec;
0118     rcec_data.user_callback = NULL;
0119     rcec_data.user_data = NULL;
0120
0121     walk_rcec(link_rcec_helper, &rcec_data);
0122 }
0123
0124 /**
0125  * pcie_walk_rcec - Walk RCiEP devices associating with RCEC and call callback.
0126  * @rcec:   RCEC whose RCiEP devices should be walked
0127  * @cb:     Callback to be called for each RCiEP device found
0128  * @userdata:   Arbitrary pointer to be passed to callback
0129  *
0130  * Walk the given RCEC. Call the callback on each RCiEP found.
0131  *
0132  * If @cb returns anything other than 0, break out.
0133  */
0134 void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
0135             void *userdata)
0136 {
0137     struct walk_rcec_data rcec_data;
0138
0139     if (!rcec->rcec_ea)
0140         return;
0141
0142     rcec_data.rcec = rcec;
0143     rcec_data.user_callback = cb;
0144     rcec_data.user_data = userdata;
0145
0146     walk_rcec(walk_rcec_helper, &rcec_data);
0147 }
0148
0149 void pci_rcec_init(struct pci_dev *dev)
0150 {
0151     struct rcec_ea *rcec_ea;
0152     u32 rcec, hdr, busn;
0153     u8 ver;
0154
0155     /* Only for Root Complex Event Collectors */
0156     if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_EC)
0157         return;
0158
0159     rcec = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_RCEC);
0160     if (!rcec)
0161         return;
0162
0163     rcec_ea = kzalloc(sizeof(*rcec_ea), GFP_KERNEL);
0164     if (!rcec_ea)
0165         return;
0166
0167     pci_read_config_dword(dev, rcec + PCI_RCEC_RCIEP_BITMAP,
0168                   &rcec_ea->bitmap);
0169
0170     /* Check whether RCEC BUSN register is present */
0171     pci_read_config_dword(dev, rcec, &hdr);
0172     ver = PCI_EXT_CAP_VER(hdr);
0173     if (ver >= PCI_RCEC_BUSN_REG_VER) {
0174         pci_read_config_dword(dev, rcec + PCI_RCEC_BUSN, &busn);
0175         rcec_ea->nextbusn = PCI_RCEC_BUSN_NEXT(busn);
0176         rcec_ea->lastbusn = PCI_RCEC_BUSN_LAST(busn);
0177     } else {
0178         /* Avoid later ver check by setting nextbusn */
0179         rcec_ea->nextbusn = 0xff;
0180         rcec_ea->lastbusn = 0x00;
0181     }
0182
0183     dev->rcec_ea = rcec_ea;
0184 }
0185
0186 void pci_rcec_exit(struct pci_dev *dev)
0187 {
0188     kfree(dev->rcec_ea);
0189     dev->rcec_ea = NULL;
0190 }