1// SPDX-License-Identifier: GPL-2.0
2/*
3 * system.c - a driver for reserving pnp system resources
4 *
5 * Some code is based on pnpbios_core.c
6 * Copyright 2002 Adam Belay <ambx1@neo.rr.com>
7 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
8 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
9 */
10
11#include <linux/pnp.h>
12#include <linux/device.h>
13#include <linux/init.h>
14#include <linux/slab.h>
15#include <linux/kernel.h>
16#include <linux/ioport.h>
17
18static const struct pnp_device_id pnp_dev_table[] = {
19	/* General ID for reserving resources */
20	{"PNP0c02", 0},
21	/* memory controller */
22	{"PNP0c01", 0},
23	{"", 0}
24};
25
26static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
27{
28	char *regionid;
29	const char *pnpid = dev_name(&dev->dev);
30	resource_size_t start = r->start, end = r->end;
31	struct resource *res;
32
33	regionid = kmalloc(16, GFP_KERNEL);
34	if (!regionid)
35		return;
36
37	snprintf(regionid, 16, "pnp %s", pnpid);
38	if (port)
39		res = request_region(start, end - start + 1, regionid);
40	else
41		res = request_mem_region(start, end - start + 1, regionid);
42	if (res)
43		res->flags &= ~IORESOURCE_BUSY;
44	else
45		kfree(regionid);
46
47	/*
48	 * Failures at this point are usually harmless. pci quirks for
49	 * example do reserve stuff they know about too, so we may well
50	 * have double reservations.
51	 */
52	dev_info(&dev->dev, "%pR %s reserved\n", r,
53		 res ? "has been" : "could not be");
54}
55
56static void reserve_resources_of_dev(struct pnp_dev *dev)
57{
58	struct resource *res;
59	int i;
60
61	for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_IO, i)); i++) {
62		if (res->flags & IORESOURCE_DISABLED)
63			continue;
64		if (res->start == 0)
65			continue;	/* disabled */
66		if (res->start < 0x100)
67			/*
68			 * Below 0x100 is only standard PC hardware
69			 * (pics, kbd, timer, dma, ...)
70			 * We should not get resource conflicts there,
71			 * and the kernel reserves these anyway
72			 * (see arch/i386/kernel/setup.c).
73			 * So, do nothing
74			 */
75			continue;
76		if (res->end < res->start)
77			continue;	/* invalid */
78
79		reserve_range(dev, res, 1);
80	}
81
82	for (i = 0; (res = pnp_get_resource(dev, IORESOURCE_MEM, i)); i++) {
83		if (res->flags & IORESOURCE_DISABLED)
84			continue;
85
86		reserve_range(dev, res, 0);
87	}
88}
89
90static int system_pnp_probe(struct pnp_dev *dev,
91			    const struct pnp_device_id *dev_id)
92{
93	reserve_resources_of_dev(dev);
94	return 0;
95}
96
97static struct pnp_driver system_pnp_driver = {
98	.name     = "system",
99	.id_table = pnp_dev_table,
100	.flags    = PNP_DRIVER_RES_DO_NOT_CHANGE,
101	.probe    = system_pnp_probe,
102};
103
104static int __init pnp_system_init(void)
105{
106	return pnp_register_driver(&system_pnp_driver);
107}
108
109/*
110 * Reserve motherboard resources after PCI claim BARs,
111 * but before PCI assign resources for uninitialized PCI devices
112 */
113fs_initcall(pnp_system_init);
114