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");