drivers/pci/pcie/rcec.c

   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 }