ALSA: mips: Convert to the common vmalloc memalloc
[sfrench/cifs-2.6.git] / arch / s390 / net / pnet.c
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");