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 
zpci_iov_map_resources(struct pci_dev * pdev)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 
zpci_iov_remove_virtfn(struct pci_dev * pdev,int vfn)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 
zpci_iov_link_virtfn(struct pci_dev * pdev,struct pci_dev * virtfn,int vfid)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 
zpci_iov_setup_virtfn(struct zpci_bus * zbus,struct pci_dev * virtfn,int vfn)63 int zpci_iov_setup_virtfn(struct zpci_bus *zbus, struct pci_dev *virtfn, int vfn)
64 {
65 	int i, cand_devfn;
66 	struct zpci_dev *zdev;
67 	struct pci_dev *pdev;
68 	int vfid = vfn - 1; /* Linux' vfid's start at 0 vfn at 1*/
69 	int rc = 0;
70 
71 	if (!zbus->multifunction)
72 		return 0;
73 
74 	/* If the parent PF for the given VF is also configured in the
75 	 * instance, it must be on the same zbus.
76 	 * We can then identify the parent PF by checking what
77 	 * devfn the VF would have if it belonged to that PF using the PF's
78 	 * stride and offset. Only if this candidate devfn matches the
79 	 * actual devfn will we link both functions.
80 	 */
81 	for (i = 0; i < ZPCI_FUNCTIONS_PER_BUS; i++) {
82 		zdev = zbus->function[i];
83 		if (zdev && zdev->is_physfn) {
84 			pdev = pci_get_slot(zbus->bus, zdev->devfn);
85 			if (!pdev)
86 				continue;
87 			cand_devfn = pci_iov_virtfn_devfn(pdev, vfid);
88 			if (cand_devfn == virtfn->devfn) {
89 				rc = zpci_iov_link_virtfn(pdev, virtfn, vfid);
90 				/* balance pci_get_slot() */
91 				pci_dev_put(pdev);
92 				break;
93 			}
94 			/* balance pci_get_slot() */
95 			pci_dev_put(pdev);
96 		}
97 	}
98 	return rc;
99 }
100