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
schedule_detach(void * cxlmd)28 static void schedule_detach(void *cxlmd)
29 {
30 schedule_cxl_memdev_detach(cxlmd);
31 }
32
cxl_port_probe(struct device * dev)33 static int cxl_port_probe(struct device *dev)
34 {
35 struct cxl_port *port = to_cxl_port(dev);
36 struct cxl_hdm *cxlhdm;
37 int rc;
38
39
40 if (!is_cxl_endpoint(port)) {
41 rc = devm_cxl_port_enumerate_dports(port);
42 if (rc < 0)
43 return rc;
44 if (rc == 1)
45 return devm_cxl_add_passthrough_decoder(port);
46 }
47
48 cxlhdm = devm_cxl_setup_hdm(port);
49 if (IS_ERR(cxlhdm))
50 return PTR_ERR(cxlhdm);
51
52 if (is_cxl_endpoint(port)) {
53 struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport);
54 struct cxl_dev_state *cxlds = cxlmd->cxlds;
55
56 get_device(&cxlmd->dev);
57 rc = devm_add_action_or_reset(dev, schedule_detach, cxlmd);
58 if (rc)
59 return rc;
60
61 rc = cxl_hdm_decode_init(cxlds, cxlhdm);
62 if (rc)
63 return rc;
64
65 rc = cxl_await_media_ready(cxlds);
66 if (rc) {
67 dev_err(dev, "Media not active (%d)\n", rc);
68 return rc;
69 }
70 }
71
72 rc = devm_cxl_enumerate_decoders(cxlhdm);
73 if (rc) {
74 dev_err(dev, "Couldn't enumerate decoders (%d)\n", rc);
75 return rc;
76 }
77
78 return 0;
79 }
80
81 static struct cxl_driver cxl_port_driver = {
82 .name = "cxl_port",
83 .probe = cxl_port_probe,
84 .id = CXL_DEVICE_PORT,
85 };
86
87 module_cxl_driver(cxl_port_driver);
88 MODULE_LICENSE("GPL v2");
89 MODULE_IMPORT_NS(CXL);
90 MODULE_ALIAS_CXL(CXL_DEVICE_PORT);
91