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// SPDX-License-Identifier: GPL-2.0
/*
* IBM System z PNET ID Support
*
* Copyright IBM Corp. 2018
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <asm/ccwgroup.h>
#include <asm/ccwdev.h>
#include <asm/pnet.h>
#include <asm/ebcdic.h>
#define PNETIDS_LEN 64 /* Total utility string length in bytes
* to cover up to 4 PNETIDs of 16 bytes
* for up to 4 device ports
*/
#define MAX_PNETID_LEN 16 /* Max.length of a single port PNETID */
#define MAX_PNETID_PORTS (PNETIDS_LEN / MAX_PNETID_LEN)
/* Max. # of ports with a PNETID */
/*
* Get the PNETIDs from a device.
* s390 hardware supports the definition of a so-called Physical Network
* Identifier (short PNETID) per network device port. These PNETIDs can be
* used to identify network devices that are attached to the same physical
* network (broadcast domain).
*
* The device can be
* - a ccwgroup device with all bundled subchannels having the same PNETID
* - a PCI attached network device
*
* Returns:
* 0: PNETIDs extracted from device.
* -ENOMEM: No memory to extract utility string.
* -EOPNOTSUPP: Device type without utility string support
*/
static int pnet_ids_by_device(struct device *dev, u8 *pnetids)
{
memset(pnetids, 0, PNETIDS_LEN);
if (dev_is_ccwgroup(dev)) {
struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
u8 *util_str;
util_str = ccw_device_get_util_str(gdev->cdev[0], 0);
if (!util_str)
return -ENOMEM;
memcpy(pnetids, util_str, PNETIDS_LEN);
EBCASC(pnetids, PNETIDS_LEN);
kfree(util_str);
return 0;
}
if (dev_is_pci(dev)) {
struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
memcpy(pnetids, zdev->util_str, sizeof(zdev->util_str));
EBCASC(pnetids, sizeof(zdev->util_str));
return 0;
}
return -EOPNOTSUPP;
}
/*
* Extract the pnetid for a device port.
*
* Return 0 if a pnetid is found and -ENOENT otherwise.
*/
int pnet_id_by_dev_port(struct device *dev, unsigned short port, u8 *pnetid)
{
u8 pnetids[MAX_PNETID_PORTS][MAX_PNETID_LEN];
static const u8 zero[MAX_PNETID_LEN] = { 0 };
int rc = 0;
if (!dev || port >= MAX_PNETID_PORTS)
return -ENOENT;
if (!pnet_ids_by_device(dev, (u8 *)pnetids) &&
memcmp(pnetids[port], zero, MAX_PNETID_LEN))
memcpy(pnetid, pnetids[port], MAX_PNETID_LEN);
else
rc = -ENOENT;
return rc;
}
EXPORT_SYMBOL_GPL(pnet_id_by_dev_port);
MODULE_DESCRIPTION("pnetid determination from utility strings");
MODULE_LICENSE("GPL");
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