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54cdbf84 BW |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* Copyright(c) 2022 Intel Corporation. All rights reserved. */ | |
3 | #include <linux/device.h> | |
4 | #include <linux/module.h> | |
5 | #include <linux/slab.h> | |
6 | ||
7 | #include "cxlmem.h" | |
8 | #include "cxlpci.h" | |
9 | ||
10 | /** | |
11 | * DOC: cxl port | |
12 | * | |
13 | * The port driver enumerates dport via PCI and scans for HDM | |
14 | * (Host-managed-Device-Memory) decoder resources via the | |
15 | * @component_reg_phys value passed in by the agent that registered the | |
16 | * port. All descendant ports of a CXL root port (described by platform | |
17 | * firmware) are managed in this drivers context. Each driver instance | |
18 | * is responsible for tearing down the driver context of immediate | |
19 | * descendant ports. The locking for this is validated by | |
20 | * CONFIG_PROVE_CXL_LOCKING. | |
21 | * | |
22 | * The primary service this driver provides is presenting APIs to other | |
23 | * drivers to utilize the decoders, and indicating to userspace (via bind | |
24 | * status) the connectivity of the CXL.mem protocol throughout the | |
25 | * PCIe topology. | |
26 | */ | |
27 | ||
8dd2bc0f BW |
28 | static void schedule_detach(void *cxlmd) |
29 | { | |
30 | schedule_cxl_memdev_detach(cxlmd); | |
31 | } | |
32 | ||
a32320b7 DW |
33 | static int discover_region(struct device *dev, void *root) |
34 | { | |
35 | struct cxl_endpoint_decoder *cxled; | |
36 | int rc; | |
37 | ||
38 | if (!is_endpoint_decoder(dev)) | |
39 | return 0; | |
40 | ||
41 | cxled = to_cxl_endpoint_decoder(dev); | |
42 | if ((cxled->cxld.flags & CXL_DECODER_F_ENABLE) == 0) | |
43 | return 0; | |
44 | ||
45 | if (cxled->state != CXL_DECODER_STATE_AUTO) | |
46 | return 0; | |
47 | ||
48 | /* | |
49 | * Region enumeration is opportunistic, if this add-event fails, | |
50 | * continue to the next endpoint decoder. | |
51 | */ | |
52 | rc = cxl_add_to_region(root, cxled); | |
53 | if (rc) | |
54 | dev_dbg(dev, "failed to add to region: %#llx-%#llx\n", | |
55 | cxled->cxld.hpa_range.start, cxled->cxld.hpa_range.end); | |
56 | ||
57 | return 0; | |
58 | } | |
59 | ||
32ce3f18 | 60 | static int cxl_switch_port_probe(struct cxl_port *port) |
54cdbf84 | 61 | { |
54cdbf84 | 62 | struct cxl_hdm *cxlhdm; |
8f0220af | 63 | int rc; |
fcfbc93c | 64 | |
8f0220af DW |
65 | rc = devm_cxl_port_enumerate_dports(port); |
66 | if (rc < 0) | |
eb0764b8 DW |
67 | return rc; |
68 | ||
8f0220af | 69 | cxlhdm = devm_cxl_setup_hdm(port, NULL); |
7bba261e DW |
70 | if (!IS_ERR(cxlhdm)) |
71 | return devm_cxl_enumerate_decoders(cxlhdm, NULL); | |
72 | ||
73 | if (PTR_ERR(cxlhdm) != -ENODEV) { | |
74 | dev_err(&port->dev, "Failed to map HDM decoder capability\n"); | |
fcfbc93c | 75 | return PTR_ERR(cxlhdm); |
7bba261e DW |
76 | } |
77 | ||
8f0220af | 78 | if (rc == 1) { |
7bba261e DW |
79 | dev_dbg(&port->dev, "Fallback to passthrough decoder\n"); |
80 | return devm_cxl_add_passthrough_decoder(port); | |
81 | } | |
fcfbc93c | 82 | |
7bba261e DW |
83 | dev_err(&port->dev, "HDM decoder capability not found\n"); |
84 | return -ENXIO; | |
32ce3f18 | 85 | } |
8dd2bc0f | 86 | |
32ce3f18 DW |
87 | static int cxl_endpoint_port_probe(struct cxl_port *port) |
88 | { | |
b70c2cf9 | 89 | struct cxl_endpoint_dvsec_info info = { .port = port }; |
7481653d | 90 | struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev); |
32ce3f18 DW |
91 | struct cxl_dev_state *cxlds = cxlmd->cxlds; |
92 | struct cxl_hdm *cxlhdm; | |
a32320b7 | 93 | struct cxl_port *root; |
32ce3f18 | 94 | int rc; |
c9700604 | 95 | |
a5fcd228 DW |
96 | rc = cxl_dvsec_rr_decode(cxlds->dev, cxlds->cxl_dvsec, &info); |
97 | if (rc < 0) | |
98 | return rc; | |
fcfbc93c | 99 | |
4474ce56 | 100 | cxlhdm = devm_cxl_setup_hdm(port, &info); |
f1d0525e RR |
101 | if (IS_ERR(cxlhdm)) { |
102 | if (PTR_ERR(cxlhdm) == -ENODEV) | |
103 | dev_err(&port->dev, "HDM decoder registers not found\n"); | |
32ce3f18 | 104 | return PTR_ERR(cxlhdm); |
f1d0525e | 105 | } |
5e5f4ad5 | 106 | |
32ce3f18 DW |
107 | /* Cache the data early to ensure is_visible() works */ |
108 | read_cdat_data(port); | |
5e5f4ad5 | 109 | |
32ce3f18 DW |
110 | get_device(&cxlmd->dev); |
111 | rc = devm_add_action_or_reset(&port->dev, schedule_detach, cxlmd); | |
112 | if (rc) | |
113 | return rc; | |
8dd2bc0f | 114 | |
a5fcd228 | 115 | rc = cxl_hdm_decode_init(cxlds, cxlhdm, &info); |
32ce3f18 DW |
116 | if (rc) |
117 | return rc; | |
118 | ||
b777e9be | 119 | rc = devm_cxl_enumerate_decoders(cxlhdm, &info); |
a32320b7 DW |
120 | if (rc) |
121 | return rc; | |
122 | ||
123 | /* | |
124 | * This can't fail in practice as CXL root exit unregisters all | |
125 | * descendant ports and that in turn synchronizes with cxl_port_probe() | |
126 | */ | |
d35b495d | 127 | root = find_cxl_root(port); |
a32320b7 DW |
128 | |
129 | /* | |
130 | * Now that all endpoint decoders are successfully enumerated, try to | |
131 | * assemble regions from committed decoders | |
132 | */ | |
133 | device_for_each_child(&port->dev, root, discover_region); | |
134 | put_device(&root->dev); | |
135 | ||
136 | return 0; | |
32ce3f18 DW |
137 | } |
138 | ||
139 | static int cxl_port_probe(struct device *dev) | |
140 | { | |
141 | struct cxl_port *port = to_cxl_port(dev); | |
142 | ||
143 | if (is_cxl_endpoint(port)) | |
144 | return cxl_endpoint_port_probe(port); | |
145 | return cxl_switch_port_probe(port); | |
54cdbf84 BW |
146 | } |
147 | ||
c9700604 IW |
148 | static ssize_t CDAT_read(struct file *filp, struct kobject *kobj, |
149 | struct bin_attribute *bin_attr, char *buf, | |
150 | loff_t offset, size_t count) | |
151 | { | |
152 | struct device *dev = kobj_to_dev(kobj); | |
153 | struct cxl_port *port = to_cxl_port(dev); | |
154 | ||
155 | if (!port->cdat_available) | |
156 | return -ENXIO; | |
157 | ||
158 | if (!port->cdat.table) | |
159 | return 0; | |
160 | ||
161 | return memory_read_from_buffer(buf, count, &offset, | |
162 | port->cdat.table, | |
163 | port->cdat.length); | |
164 | } | |
165 | ||
166 | static BIN_ATTR_ADMIN_RO(CDAT, 0); | |
167 | ||
168 | static umode_t cxl_port_bin_attr_is_visible(struct kobject *kobj, | |
169 | struct bin_attribute *attr, int i) | |
170 | { | |
171 | struct device *dev = kobj_to_dev(kobj); | |
172 | struct cxl_port *port = to_cxl_port(dev); | |
173 | ||
174 | if ((attr == &bin_attr_CDAT) && port->cdat_available) | |
175 | return attr->attr.mode; | |
176 | ||
177 | return 0; | |
178 | } | |
179 | ||
180 | static struct bin_attribute *cxl_cdat_bin_attributes[] = { | |
181 | &bin_attr_CDAT, | |
182 | NULL, | |
183 | }; | |
184 | ||
185 | static struct attribute_group cxl_cdat_attribute_group = { | |
186 | .bin_attrs = cxl_cdat_bin_attributes, | |
187 | .is_bin_visible = cxl_port_bin_attr_is_visible, | |
188 | }; | |
189 | ||
190 | static const struct attribute_group *cxl_port_attribute_groups[] = { | |
191 | &cxl_cdat_attribute_group, | |
192 | NULL, | |
193 | }; | |
194 | ||
54cdbf84 BW |
195 | static struct cxl_driver cxl_port_driver = { |
196 | .name = "cxl_port", | |
197 | .probe = cxl_port_probe, | |
198 | .id = CXL_DEVICE_PORT, | |
c9700604 IW |
199 | .drv = { |
200 | .dev_groups = cxl_port_attribute_groups, | |
201 | }, | |
54cdbf84 BW |
202 | }; |
203 | ||
204 | module_cxl_driver(cxl_port_driver); | |
205 | MODULE_LICENSE("GPL v2"); | |
206 | MODULE_IMPORT_NS(CXL); | |
207 | MODULE_ALIAS_CXL(CXL_DEVICE_PORT); |