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

source code of linux/arch/s390/pci/pci_iov.c