xref: /openbmc/linux/drivers/eisa/virtual_root.c (revision be709d48)
1 /*
2  * Virtual EISA root driver.
3  * Acts as a placeholder if we don't have a proper EISA bridge.
4  *
5  * (C) 2003 Marc Zyngier <maz@wild-wind.fr.eu.org>
6  *
7  * This code is released under the GPL version 2.
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/platform_device.h>
12 #include <linux/eisa.h>
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/init.h>
16 
17 #if defined(CONFIG_ALPHA_JENSEN) || defined(CONFIG_EISA_VLB_PRIMING)
18 #define EISA_FORCE_PROBE_DEFAULT 1
19 #else
20 #define EISA_FORCE_PROBE_DEFAULT 0
21 #endif
22 
23 static int force_probe = EISA_FORCE_PROBE_DEFAULT;
24 static void virtual_eisa_release (struct device *);
25 
26 /* The default EISA device parent (virtual root device).
27  * Now use a platform device, since that's the obvious choice. */
28 
29 static struct platform_device eisa_root_dev = {
30 	.name = "eisa",
31 	.id   = 0,
32 	.dev  = {
33 		.release = virtual_eisa_release,
34 	},
35 };
36 
37 static struct eisa_root_device eisa_bus_root = {
38 	.dev		= &eisa_root_dev.dev,
39 	.bus_base_addr	= 0,
40 	.res		= &ioport_resource,
41 	.slots		= EISA_MAX_SLOTS,
42 	.dma_mask	= 0xffffffff,
43 };
44 
45 static void virtual_eisa_release (struct device *dev)
46 {
47 	/* nothing really to do here */
48 }
49 
50 static int __init virtual_eisa_root_init (void)
51 {
52 	int r;
53 
54 	if ((r = platform_device_register (&eisa_root_dev)))
55 		return r;
56 
57 	eisa_bus_root.force_probe = force_probe;
58 
59 	dev_set_drvdata(&eisa_root_dev.dev, &eisa_bus_root);
60 
61 	if (eisa_root_register (&eisa_bus_root)) {
62 		/* A real bridge may have been registered before
63 		 * us. So quietly unregister. */
64 		platform_device_unregister (&eisa_root_dev);
65 		return -1;
66 	}
67 
68 	return 0;
69 }
70 
71 module_param (force_probe, int, 0444);
72 
73 device_initcall (virtual_eisa_root_init);
74