LXR linux/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 */
  41static 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 */
  71int 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}
  88EXPORT_SYMBOL_GPL(pnet_id_by_dev_port);
  89
  90MODULE_DESCRIPTION("pnetid determination from utility strings");
  91MODULE_LICENSE("GPL");
  92