1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * IBM System z PNET ID Support
4 *
5 * Copyright IBM Corp. 2018
6 */
7
8 #include <linux/device.h>
9 #include <linux/module.h>
10 #include <linux/pci.h>
11 #include <linux/types.h>
12 #include <asm/ccwgroup.h>
13 #include <asm/ccwdev.h>
14 #include <asm/pnet.h>
15 #include <asm/ebcdic.h>
16
17 #define PNETIDS_LEN 64 /* Total utility string length in bytes
18 * to cover up to 4 PNETIDs of 16 bytes
19 * for up to 4 device ports
20 */
21 #define MAX_PNETID_LEN 16 /* Max.length of a single port PNETID */
22 #define MAX_PNETID_PORTS (PNETIDS_LEN / MAX_PNETID_LEN)
23 /* Max. # of ports with a PNETID */
24
25 /*
26 * Get the PNETIDs from a device.
27 * s390 hardware supports the definition of a so-called Physical Network
28 * Identifier (short PNETID) per network device port. These PNETIDs can be
29 * used to identify network devices that are attached to the same physical
30 * network (broadcast domain).
31 *
32 * The device can be
33 * - a ccwgroup device with all bundled subchannels having the same PNETID
34 * - a PCI attached network device
35 *
36 * Returns:
37 * 0: PNETIDs extracted from device.
38 * -ENOMEM: No memory to extract utility string.
39 * -EOPNOTSUPP: Device type without utility string support
40 */
41 static int pnet_ids_by_device(struct device *dev, u8 *pnetids)
42 {
43 memset(pnetids, 0, PNETIDS_LEN);
44 if (dev_is_ccwgroup(dev)) {
45 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
46 u8 *util_str;
47
48 util_str = ccw_device_get_util_str(gdev->cdev[0], 0);
49 if (!util_str)
50 return -ENOMEM;
51 memcpy(pnetids, util_str, PNETIDS_LEN);
52 EBCASC(pnetids, PNETIDS_LEN);
53 kfree(util_str);
54 return 0;
55 }
56 if (dev_is_pci(dev)) {
57 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
58
59 memcpy(pnetids, zdev->util_str, sizeof(zdev->util_str));
60 EBCASC(pnetids, sizeof(zdev->util_str));
61 return 0;
62 }
63 return -EOPNOTSUPP;
64 }
65
66 /*
67 * Extract the pnetid for a device port.
68 *
69 * Return 0 if a pnetid is found and -ENOENT otherwise.
70 */
71 int pnet_id_by_dev_port(struct device *dev, unsigned short port, u8 *pnetid)
72 {
73 u8 pnetids[MAX_PNETID_PORTS][MAX_PNETID_LEN];
74 static const u8 zero[MAX_PNETID_LEN] = { 0 };
75 int rc = 0;
76
77 if (!dev || port >= MAX_PNETID_PORTS)
78 return -ENOENT;
79
80 if (!pnet_ids_by_device(dev, (u8 *)pnetids) &&
81 memcmp(pnetids[port], zero, MAX_PNETID_LEN))
82 memcpy(pnetid, pnetids[port], MAX_PNETID_LEN);
83 else
84 rc = -ENOENT;
85
86 return rc;
87 }
88 EXPORT_SYMBOL_GPL(pnet_id_by_dev_port);
89
90 MODULE_DESCRIPTION("pnetid determination from utility strings");
91 MODULE_LICENSE("GPL");
92
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