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"); 92