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/export.h>
10 #include <linux/module.h>
11 #include <linux/pci.h>
12 #include <linux/types.h>
13 #include <asm/ccwgroup.h>
14 #include <asm/ccwdev.h>
15 #include <asm/pnet.h>
16 #include <asm/ebcdic.h>
17
18 #define PNETIDS_LEN 64 /* Total utility string length in bytes
19 * to cover up to 4 PNETIDs of 16 bytes
20 * for up to 4 device ports
21 */
22 #define MAX_PNETID_LEN 16 /* Max.length of a single port PNETID */
23 #define MAX_PNETID_PORTS (PNETIDS_LEN / MAX_PNETID_LEN)
24 /* Max. # of ports with a PNETID */
25
26 /*
27 * Get the PNETIDs from a device.
28 * s390 hardware supports the definition of a so-called Physical Network
29 * Identifier (short PNETID) per network device port. These PNETIDs can be
30 * used to identify network devices that are attached to the same physical
31 * network (broadcast domain).
32 *
33 * The device can be
34 * - a ccwgroup device with all bundled subchannels having the same PNETID
35 * - a PCI attached network device
36 *
37 * Returns:
38 * 0: PNETIDs extracted from device.
39 * -ENOMEM: No memory to extract utility string.
40 * -EOPNOTSUPP: Device type without utility string support
41 */
pnet_ids_by_device(struct device * dev,u8 * pnetids)42 static int pnet_ids_by_device(struct device *dev, u8 *pnetids)
43 {
44 memset(pnetids, 0, PNETIDS_LEN);
45 if (dev_is_ccwgroup(dev)) {
46 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
47 u8 *util_str;
48
49 util_str = ccw_device_get_util_str(gdev->cdev[0], 0);
50 if (!util_str)
51 return -ENOMEM;
52 memcpy(pnetids, util_str, PNETIDS_LEN);
53 EBCASC(pnetids, PNETIDS_LEN);
54 kfree(util_str);
55 return 0;
56 }
57 if (dev_is_pci(dev)) {
58 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
59
60 memcpy(pnetids, zdev->util_str, sizeof(zdev->util_str));
61 EBCASC(pnetids, sizeof(zdev->util_str));
62 return 0;
63 }
64 return -EOPNOTSUPP;
65 }
66
67 /*
68 * Extract the pnetid for a device port.
69 *
70 * Return 0 if a pnetid is found and -ENOENT otherwise.
71 */
pnet_id_by_dev_port(struct device * dev,unsigned short port,u8 * pnetid)72 int pnet_id_by_dev_port(struct device *dev, unsigned short port, u8 *pnetid)
73 {
74 u8 pnetids[MAX_PNETID_PORTS][MAX_PNETID_LEN];
75 static const u8 zero[MAX_PNETID_LEN] = { 0 };
76 int rc = 0;
77
78 if (!dev || port >= MAX_PNETID_PORTS)
79 return -ENOENT;
80
81 if (!pnet_ids_by_device(dev, (u8 *)pnetids) &&
82 memcmp(pnetids[port], zero, MAX_PNETID_LEN))
83 memcpy(pnetid, pnetids[port], MAX_PNETID_LEN);
84 else
85 rc = -ENOENT;
86
87 return rc;
88 }
89 EXPORT_SYMBOL_GPL(pnet_id_by_dev_port);
90
91 MODULE_DESCRIPTION("pnetid determination from utility strings");
92 MODULE_LICENSE("GPL");
93