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