xref: /openbmc/linux/drivers/eisa/pci_eisa.c (revision 93f5715e)
1 /*
2  * Minimalist driver for a generic PCI-to-EISA bridge.
3  *
4  * (C) 2003 Marc Zyngier <maz@wild-wind.fr.eu.org>
5  *
6  * This code is released under the GPL version 2.
7  *
8  * Ivan Kokshaysky <ink@jurassic.park.msu.ru> :
9  * Generalisation from i82375 to PCI_CLASS_BRIDGE_EISA.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/device.h>
14 #include <linux/eisa.h>
15 #include <linux/pci.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 
19 /* There is only *one* pci_eisa device per machine, right ? */
20 static struct eisa_root_device pci_eisa_root;
21 
22 static int __init pci_eisa_init(struct pci_dev *pdev)
23 {
24 	int rc, i;
25 	struct resource *res, *bus_res = NULL;
26 
27 	if ((rc = pci_enable_device (pdev))) {
28 		dev_err(&pdev->dev, "Could not enable device\n");
29 		return rc;
30 	}
31 
32 	/*
33 	 * The Intel 82375 PCI-EISA bridge is a subtractive-decode PCI
34 	 * device, so the resources available on EISA are the same as those
35 	 * available on the 82375 bus.  This works the same as a PCI-PCI
36 	 * bridge in subtractive-decode mode (see pci_read_bridge_bases()).
37 	 * We assume other PCI-EISA bridges are similar.
38 	 *
39 	 * eisa_root_register() can only deal with a single io port resource,
40 	*  so we use the first valid io port resource.
41 	 */
42 	pci_bus_for_each_resource(pdev->bus, res, i)
43 		if (res && (res->flags & IORESOURCE_IO)) {
44 			bus_res = res;
45 			break;
46 		}
47 
48 	if (!bus_res) {
49 		dev_err(&pdev->dev, "No resources available\n");
50 		return -1;
51 	}
52 
53 	pci_eisa_root.dev		= &pdev->dev;
54 	pci_eisa_root.res		= bus_res;
55 	pci_eisa_root.bus_base_addr	= bus_res->start;
56 	pci_eisa_root.slots		= EISA_MAX_SLOTS;
57 	pci_eisa_root.dma_mask		= pdev->dma_mask;
58 	dev_set_drvdata(pci_eisa_root.dev, &pci_eisa_root);
59 
60 	if (eisa_root_register (&pci_eisa_root)) {
61 		dev_err(&pdev->dev, "Could not register EISA root\n");
62 		return -1;
63 	}
64 
65 	return 0;
66 }
67 
68 /*
69  * We have to call pci_eisa_init_early() before pnpacpi_init()/isapnp_init().
70  *   Otherwise pnp resource will get enabled early and could prevent eisa
71  *   to be initialized.
72  * Also need to make sure pci_eisa_init_early() is called after
73  * x86/pci_subsys_init().
74  * So need to use subsys_initcall_sync with it.
75  */
76 static int __init pci_eisa_init_early(void)
77 {
78 	struct pci_dev *dev = NULL;
79 	int ret;
80 
81 	for_each_pci_dev(dev)
82 		if ((dev->class >> 8) == PCI_CLASS_BRIDGE_EISA) {
83 			ret = pci_eisa_init(dev);
84 			if (ret)
85 				return ret;
86 		}
87 
88 	return 0;
89 }
90 subsys_initcall_sync(pci_eisa_init_early);
91