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/export.h> 10 #include <linux/module.h> 11 #include <linux/pci.h> 12 #include <linux/types.h> 13 #include <asm/ccwgroup.h> 14 #include <asm/ccwdev.h> 15 #include <asm/pnet.h> 16 #include <asm/ebcdic.h> 17 18 #define PNETIDS_LEN 64 /* Total utility string length in bytes 19 * to cover up to 4 PNETIDs of 16 bytes 20 * for up to 4 device ports 21 */ 22 #define MAX_PNETID_LEN 16 /* Max.length of a single port PNETID */ 23 #define MAX_PNETID_PORTS (PNETIDS_LEN / MAX_PNETID_LEN) 24 /* Max. # of ports with a PNETID */ 25 26 /* 27 * Get the PNETIDs from a device. 28 * s390 hardware supports the definition of a so-called Physical Network 29 * Identifier (short PNETID) per network device port. These PNETIDs can be 30 * used to identify network devices that are attached to the same physical 31 * network (broadcast domain). 32 * 33 * The device can be 34 * - a ccwgroup device with all bundled subchannels having the same PNETID 35 * - a PCI attached network device 36 * 37 * Returns: 38 * 0: PNETIDs extracted from device. 39 * -ENOMEM: No memory to extract utility string. 40 * -EOPNOTSUPP: Device type without utility string support 41 */ 42 static int pnet_ids_by_device(struct device *dev, u8 *pnetids) 43 { 44 memset(pnetids, 0, PNETIDS_LEN); 45 if (dev_is_ccwgroup(dev)) { 46 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 47 u8 *util_str; 48 49 util_str = ccw_device_get_util_str(gdev->cdev[0], 0); 50 if (!util_str) 51 return -ENOMEM; 52 memcpy(pnetids, util_str, PNETIDS_LEN); 53 EBCASC(pnetids, PNETIDS_LEN); 54 kfree(util_str); 55 return 0; 56 } 57 if (dev_is_pci(dev)) { 58 struct zpci_dev *zdev = to_zpci(to_pci_dev(dev)); 59 60 memcpy(pnetids, zdev->util_str, sizeof(zdev->util_str)); 61 EBCASC(pnetids, sizeof(zdev->util_str)); 62 return 0; 63 } 64 return -EOPNOTSUPP; 65 } 66 67 /* 68 * Extract the pnetid for a device port. 69 * 70 * Return 0 if a pnetid is found and -ENOENT otherwise. 71 */ 72 int pnet_id_by_dev_port(struct device *dev, unsigned short port, u8 *pnetid) 73 { 74 u8 pnetids[MAX_PNETID_PORTS][MAX_PNETID_LEN]; 75 static const u8 zero[MAX_PNETID_LEN] = { 0 }; 76 int rc = 0; 77 78 if (!dev || port >= MAX_PNETID_PORTS) 79 return -ENOENT; 80 81 if (!pnet_ids_by_device(dev, (u8 *)pnetids) && 82 memcmp(pnetids[port], zero, MAX_PNETID_LEN)) 83 memcpy(pnetid, pnetids[port], MAX_PNETID_LEN); 84 else 85 rc = -ENOENT; 86 87 return rc; 88 } 89 EXPORT_SYMBOL_GPL(pnet_id_by_dev_port); 90 91 MODULE_DESCRIPTION("pnetid determination from utility strings"); 92 MODULE_LICENSE("GPL"); 93