1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2020 4 * 5 * Author(s): 6 * Niklas Schnelle <schnelle@linux.ibm.com> 7 * 8 */ 9 10 #define KMSG_COMPONENT "zpci" 11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 12 13 #include <linux/kernel.h> 14 #include <linux/pci.h> 15 16 #include "pci_iov.h" 17 18 static struct resource iov_res = { 19 .name = "PCI IOV res", 20 .start = 0, 21 .end = -1, 22 .flags = IORESOURCE_MEM, 23 }; 24 25 void zpci_iov_map_resources(struct pci_dev *pdev) 26 { 27 resource_size_t len; 28 int i; 29 30 for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) { 31 int bar = i + PCI_IOV_RESOURCES; 32 33 len = pci_resource_len(pdev, bar); 34 if (!len) 35 continue; 36 pdev->resource[bar].parent = &iov_res; 37 } 38 } 39 40 void zpci_iov_remove_virtfn(struct pci_dev *pdev, int vfn) 41 { 42 pci_lock_rescan_remove(); 43 /* Linux' vfid's start at 0 vfn at 1 */ 44 pci_iov_remove_virtfn(pdev->physfn, vfn - 1); 45 pci_unlock_rescan_remove(); 46 } 47 48 static int zpci_iov_link_virtfn(struct pci_dev *pdev, struct pci_dev *virtfn, int vfid) 49 { 50 int rc; 51 52 rc = pci_iov_sysfs_link(pdev, virtfn, vfid); 53 if (rc) 54 return rc; 55 56 virtfn->is_virtfn = 1; 57 virtfn->multifunction = 0; 58 virtfn->physfn = pci_dev_get(pdev); 59 60 return 0; 61 } 62 63 /** 64 * zpci_iov_find_parent_pf - Find the parent PF, if any, of the given function 65 * @zbus: The bus that the PCI function is on, or would be added on 66 * @zdev: The PCI function 67 * 68 * Finds the parent PF, if it exists and is configured, of the given PCI function 69 * and increments its refcount. Th PF is searched for on the provided bus so the 70 * caller has to ensure that this is the correct bus to search. This function may 71 * be used before adding the PCI function to a zbus. 72 * 73 * Return: Pointer to the struct pci_dev of the parent PF or NULL if it not 74 * found. If the function is not a VF or has no RequesterID information, 75 * NULL is returned as well. 76 */ 77 struct pci_dev *zpci_iov_find_parent_pf(struct zpci_bus *zbus, struct zpci_dev *zdev) 78 { 79 int i, vfid, devfn, cand_devfn; 80 struct pci_dev *pdev; 81 82 if (!zbus->multifunction) 83 return NULL; 84 /* Non-VFs and VFs without RID available don't have a parent */ 85 if (!zdev->vfn || !zdev->rid_available) 86 return NULL; 87 /* Linux vfid starts at 0 vfn at 1 */ 88 vfid = zdev->vfn - 1; 89 devfn = zdev->rid & ZPCI_RID_MASK_DEVFN; 90 /* 91 * If the parent PF for the given VF is also configured in the 92 * instance, it must be on the same zbus. 93 * We can then identify the parent PF by checking what 94 * devfn the VF would have if it belonged to that PF using the PF's 95 * stride and offset. Only if this candidate devfn matches the 96 * actual devfn will we link both functions. 97 */ 98 for (i = 0; i < ZPCI_FUNCTIONS_PER_BUS; i++) { 99 zdev = zbus->function[i]; 100 if (zdev && zdev->is_physfn) { 101 pdev = pci_get_slot(zbus->bus, zdev->devfn); 102 if (!pdev) 103 continue; 104 cand_devfn = pci_iov_virtfn_devfn(pdev, vfid); 105 if (cand_devfn == devfn) 106 return pdev; 107 /* balance pci_get_slot() */ 108 pci_dev_put(pdev); 109 } 110 } 111 return NULL; 112 } 113 114 int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn) 115 { 116 struct zpci_dev *zdev = to_zpci(virtfn); 117 struct pci_dev *pdev_pf; 118 int rc = 0; 119 120 pdev_pf = zpci_iov_find_parent_pf(zbus, zdev); 121 if (pdev_pf) { 122 /* Linux' vfids start at 0 while zdev->vfn starts at 1 */ 123 rc = zpci_iov_link_virtfn(pdev_pf, virtfn, zdev->vfn - 1); 124 pci_dev_put(pdev_pf); 125 } 126 return rc; 127 } 128