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"); 81