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
18struct walk_rcec_data {
19 struct pci_dev *rcec;
20 int (*user_callback)(struct pci_dev *dev, void *data);
21 void *user_data;
22};
23
24static 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
41static 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, rciep: 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
56static 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, rciep: dev))
63 rcec_data->user_callback(dev, rcec_data->user_data);
64
65 return 0;
66}
67
68static 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(top: rcec->bus, cb, userdata: 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(domain: pci_domain_nr(bus: rcec->bus), busnr: bnr);
96 if (!bus)
97 continue;
98
99 /* Find RCiEP devices on the given bus ranges */
100 pci_walk_bus(top: bus, cb, userdata: 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 */
110void 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(cb: link_rcec_helper, userdata: &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 */
134void 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(cb: walk_rcec_helper, userdata: &rcec_data);
147}
148
149void 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, where: rcec + PCI_RCEC_RCIEP_BITMAP,
168 val: &rcec_ea->bitmap);
169
170 /* Check whether RCEC BUSN register is present */
171 pci_read_config_dword(dev, where: rcec, val: &hdr);
172 ver = PCI_EXT_CAP_VER(hdr);
173 if (ver >= PCI_RCEC_BUSN_REG_VER) {
174 pci_read_config_dword(dev, where: rcec + PCI_RCEC_BUSN, val: &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
186void pci_rcec_exit(struct pci_dev *dev)
187{
188 kfree(objp: dev->rcec_ea);
189 dev->rcec_ea = NULL;
190}
191