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, 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 | |
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, rciep: 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(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 | */ |
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(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 | */ |
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(cb: walk_rcec_helper, userdata: &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(size: 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 | |
186 | void pci_rcec_exit(struct pci_dev *dev) |
187 | { |
188 | kfree(objp: dev->rcec_ea); |
189 | dev->rcec_ea = NULL; |
190 | } |
191 | |