xref: /openbmc/linux/drivers/eisa/virtual_root.c (revision d052d1be)
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/config.h>
11 #include <linux/kernel.h>
12 #include <linux/platform_device.h>
13 #include <linux/eisa.h>
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/init.h>
17 
18 #if defined(CONFIG_ALPHA_JENSEN) || defined(CONFIG_EISA_VLB_PRIMING)
19 #define EISA_FORCE_PROBE_DEFAULT 1
20 #else
21 #define EISA_FORCE_PROBE_DEFAULT 0
22 #endif
23 
24 static int force_probe = EISA_FORCE_PROBE_DEFAULT;
25 static void virtual_eisa_release (struct device *);
26 
27 /* The default EISA device parent (virtual root device).
28  * Now use a platform device, since that's the obvious choice. */
29 
30 static struct platform_device eisa_root_dev = {
31 	.name = "eisa",
32 	.id   = 0,
33 	.dev  = {
34 		.release = virtual_eisa_release,
35 	},
36 };
37 
38 static struct eisa_root_device eisa_bus_root = {
39 	.dev           = &eisa_root_dev.dev,
40 	.bus_base_addr = 0,
41 	.res	       = &ioport_resource,
42 	.slots	       = EISA_MAX_SLOTS,
43 	.dma_mask      = 0xffffffff,
44 };
45 
46 static void virtual_eisa_release (struct device *dev)
47 {
48 	/* nothing really to do here */
49 }
50 
51 static int virtual_eisa_root_init (void)
52 {
53 	int r;
54 
55         if ((r = platform_device_register (&eisa_root_dev))) {
56                 return r;
57         }
58 
59 	eisa_bus_root.force_probe = force_probe;
60 
61 	eisa_root_dev.dev.driver_data = &eisa_bus_root;
62 
63 	if (eisa_root_register (&eisa_bus_root)) {
64 		/* A real bridge may have been registered before
65 		 * us. So quietly unregister. */
66 		platform_device_unregister (&eisa_root_dev);
67 		return -1;
68 	}
69 
70 	return 0;
71 }
72 
73 module_param (force_probe, int, 0444);
74 
75 device_initcall (virtual_eisa_root_init);
76