xref: /openbmc/linux/drivers/eisa/virtual_root.c (revision d1d24ed4)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Virtual EISA root driver.
4  * Acts as a placeholder if we don't have a proper EISA bridge.
5  *
6  * (C) 2003 Marc Zyngier <maz@wild-wind.fr.eu.org>
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/platform_device.h>
11 #include <linux/eisa.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/init.h>
15 
16 #if defined(CONFIG_ALPHA_JENSEN) || defined(CONFIG_EISA_VLB_PRIMING)
17 #define EISA_FORCE_PROBE_DEFAULT 1
18 #else
19 #define EISA_FORCE_PROBE_DEFAULT 0
20 #endif
21 
22 static int force_probe = EISA_FORCE_PROBE_DEFAULT;
23 static void virtual_eisa_release (struct device *);
24 
25 /* The default EISA device parent (virtual root device).
26  * Now use a platform device, since that's the obvious choice. */
27 
28 static struct platform_device eisa_root_dev = {
29 	.name = "eisa",
30 	.id   = 0,
31 	.dev  = {
32 		.release = virtual_eisa_release,
33 	},
34 };
35 
36 static struct eisa_root_device eisa_bus_root = {
37 	.dev		= &eisa_root_dev.dev,
38 	.bus_base_addr	= 0,
39 	.res		= &ioport_resource,
40 	.slots		= EISA_MAX_SLOTS,
41 	.dma_mask	= 0xffffffff,
42 };
43 
virtual_eisa_release(struct device * dev)44 static void virtual_eisa_release (struct device *dev)
45 {
46 	/* nothing really to do here */
47 }
48 
virtual_eisa_root_init(void)49 static int __init virtual_eisa_root_init (void)
50 {
51 	int r;
52 
53 	if ((r = platform_device_register (&eisa_root_dev)))
54 		return r;
55 
56 	eisa_bus_root.force_probe = force_probe;
57 
58 	dev_set_drvdata(&eisa_root_dev.dev, &eisa_bus_root);
59 
60 	if (eisa_root_register (&eisa_bus_root)) {
61 		/* A real bridge may have been registered before
62 		 * us. So quietly unregister. */
63 		platform_device_unregister (&eisa_root_dev);
64 		return -1;
65 	}
66 
67 	return 0;
68 }
69 
70 module_param (force_probe, int, 0444);
71 
72 device_initcall (virtual_eisa_root_init);
73