1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Simple, generic PCI host controller driver targeting firmware-initialised
4  * systems and virtual machines (e.g. the PCI emulation provided by kvmtool).
5  *
6  * Copyright (C) 2014 ARM Limited
7  *
8  * Author: Will Deacon <will.deacon@arm.com>
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/of_address.h>
14 #include <linux/of_pci.h>
15 #include <linux/pci-ecam.h>
16 #include <linux/platform_device.h>
17 
18 static struct pci_ecam_ops gen_pci_cfg_cam_bus_ops = {
19 	.bus_shift	= 16,
20 	.pci_ops	= {
21 		.map_bus	= pci_ecam_map_bus,
22 		.read		= pci_generic_config_read,
23 		.write		= pci_generic_config_write,
24 	}
25 };
26 
27 static bool pci_dw_valid_device(struct pci_bus *bus, unsigned int devfn)
28 {
29 	struct pci_config_window *cfg = bus->sysdata;
30 
31 	/*
32 	 * The Synopsys DesignWare PCIe controller in ECAM mode will not filter
33 	 * type 0 config TLPs sent to devices 1 and up on its downstream port,
34 	 * resulting in devices appearing multiple times on bus 0 unless we
35 	 * filter out those accesses here.
36 	 */
37 	if (bus->number == cfg->busr.start && PCI_SLOT(devfn) > 0)
38 		return false;
39 
40 	return true;
41 }
42 
43 static void __iomem *pci_dw_ecam_map_bus(struct pci_bus *bus,
44 					 unsigned int devfn, int where)
45 {
46 	if (!pci_dw_valid_device(bus, devfn))
47 		return NULL;
48 
49 	return pci_ecam_map_bus(bus, devfn, where);
50 }
51 
52 static struct pci_ecam_ops pci_dw_ecam_bus_ops = {
53 	.bus_shift	= 20,
54 	.pci_ops	= {
55 		.map_bus	= pci_dw_ecam_map_bus,
56 		.read		= pci_generic_config_read,
57 		.write		= pci_generic_config_write,
58 	}
59 };
60 
61 static const struct of_device_id gen_pci_of_match[] = {
62 	{ .compatible = "pci-host-cam-generic",
63 	  .data = &gen_pci_cfg_cam_bus_ops },
64 
65 	{ .compatible = "pci-host-ecam-generic",
66 	  .data = &pci_generic_ecam_ops },
67 
68 	{ .compatible = "marvell,armada8k-pcie-ecam",
69 	  .data = &pci_dw_ecam_bus_ops },
70 
71 	{ .compatible = "socionext,synquacer-pcie-ecam",
72 	  .data = &pci_dw_ecam_bus_ops },
73 
74 	{ .compatible = "snps,dw-pcie-ecam",
75 	  .data = &pci_dw_ecam_bus_ops },
76 
77 	{ },
78 };
79 
80 static int gen_pci_probe(struct platform_device *pdev)
81 {
82 	const struct of_device_id *of_id;
83 	struct pci_ecam_ops *ops;
84 
85 	of_id = of_match_node(gen_pci_of_match, pdev->dev.of_node);
86 	ops = (struct pci_ecam_ops *)of_id->data;
87 
88 	return pci_host_common_probe(pdev, ops);
89 }
90 
91 static struct platform_driver gen_pci_driver = {
92 	.driver = {
93 		.name = "pci-host-generic",
94 		.of_match_table = gen_pci_of_match,
95 		.suppress_bind_attrs = true,
96 	},
97 	.probe = gen_pci_probe,
98 	.remove = pci_host_common_remove,
99 };
100 builtin_platform_driver(gen_pci_driver);
101