1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Minimalist driver for a generic PCI-to-EISA bridge.
4 *
5 * (C) 2003 Marc Zyngier <maz@wild-wind.fr.eu.org>
6 *
7 * Ivan Kokshaysky <ink@jurassic.park.msu.ru> :
8 * Generalisation from i82375 to PCI_CLASS_BRIDGE_EISA.
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/device.h>
13 #include <linux/eisa.h>
14 #include <linux/pci.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17
18 /* There is only *one* pci_eisa device per machine, right ? */
19 static struct eisa_root_device pci_eisa_root;
20
21 static int __init pci_eisa_init(struct pci_dev *pdev)
22 {
23 int rc, i;
24 struct resource *res, *bus_res = NULL;
25
26 if ((rc = pci_enable_device (pdev))) {
27 dev_err(&pdev->dev, "Could not enable device\n");
28 return rc;
29 }
30
31 /*
32 * The Intel 82375 PCI-EISA bridge is a subtractive-decode PCI
33 * device, so the resources available on EISA are the same as those
34 * available on the 82375 bus. This works the same as a PCI-PCI
35 * bridge in subtractive-decode mode (see pci_read_bridge_bases()).
36 * We assume other PCI-EISA bridges are similar.
37 *
38 * eisa_root_register() can only deal with a single io port resource,
39 * so we use the first valid io port resource.
40 */
41 pci_bus_for_each_resource(pdev->bus, res, i)
42 if (res && (res->flags & IORESOURCE_IO)) {
43 bus_res = res;
44 break;
45 }
46
47 if (!bus_res) {
48 dev_err(&pdev->dev, "No resources available\n");
49 return -1;
50 }
51
52 pci_eisa_root.dev = &pdev->dev;
53 pci_eisa_root.res = bus_res;
54 pci_eisa_root.bus_base_addr = bus_res->start;
55 pci_eisa_root.slots = EISA_MAX_SLOTS;
56 pci_eisa_root.dma_mask = pdev->dma_mask;
57 dev_set_drvdata(pci_eisa_root.dev, &pci_eisa_root);
58
59 if (eisa_root_register (&pci_eisa_root)) {
60 dev_err(&pdev->dev, "Could not register EISA root\n");
61 return -1;
62 }
63
64 return 0;
65 }
66
67 /*
68 * We have to call pci_eisa_init_early() before pnpacpi_init()/isapnp_init().
69 * Otherwise pnp resource will get enabled early and could prevent eisa
70 * to be initialized.
71 * Also need to make sure pci_eisa_init_early() is called after
72 * x86/pci_subsys_init().
73 * So need to use subsys_initcall_sync with it.
74 */
75 static int __init pci_eisa_init_early(void)
76 {
77 struct pci_dev *dev = NULL;
78 int ret;
79
80 for_each_pci_dev(dev)
81 if ((dev->class >> 8) == PCI_CLASS_BRIDGE_EISA) {
82 ret = pci_eisa_init(dev);
83 if (ret)
84 return ret;
85 }
86
87 return 0;
88 }
89 subsys_initcall_sync(pci_eisa_init_early);