xref: /kernel/linux/linux-5.10/drivers/misc/pvpanic.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 *  Pvpanic Device Support
4 *
5 *  Copyright (C) 2013 Fujitsu.
6 *  Copyright (C) 2018 ZTE.
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/acpi.h>
12#include <linux/kernel.h>
13#include <linux/kexec.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/of_address.h>
17#include <linux/platform_device.h>
18#include <linux/types.h>
19#include <uapi/misc/pvpanic.h>
20
21static void __iomem *base;
22
23MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
24MODULE_DESCRIPTION("pvpanic device driver");
25MODULE_LICENSE("GPL");
26
27static void
28pvpanic_send_event(unsigned int event)
29{
30	iowrite8(event, base);
31}
32
33static int
34pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
35		     void *unused)
36{
37	unsigned int event = PVPANIC_PANICKED;
38
39	if (kexec_crash_loaded())
40		event = PVPANIC_CRASH_LOADED;
41
42	pvpanic_send_event(event);
43
44	return NOTIFY_DONE;
45}
46
47static struct notifier_block pvpanic_panic_nb = {
48	.notifier_call = pvpanic_panic_notify,
49	.priority = 1, /* let this called before broken drm_fb_helper */
50};
51
52#ifdef CONFIG_ACPI
53static int pvpanic_add(struct acpi_device *device);
54static int pvpanic_remove(struct acpi_device *device);
55
56static const struct acpi_device_id pvpanic_device_ids[] = {
57	{ "QEMU0001", 0 },
58	{ "", 0 }
59};
60MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
61
62static struct acpi_driver pvpanic_driver = {
63	.name =		"pvpanic",
64	.class =	"QEMU",
65	.ids =		pvpanic_device_ids,
66	.ops =		{
67				.add =		pvpanic_add,
68				.remove =	pvpanic_remove,
69			},
70	.owner =	THIS_MODULE,
71};
72
73static acpi_status
74pvpanic_walk_resources(struct acpi_resource *res, void *context)
75{
76	struct resource r;
77
78	if (acpi_dev_resource_io(res, &r)) {
79#ifdef CONFIG_HAS_IOPORT_MAP
80		base = ioport_map(r.start, resource_size(&r));
81		return AE_OK;
82#else
83		return AE_ERROR;
84#endif
85	} else if (acpi_dev_resource_memory(res, &r)) {
86		base = ioremap(r.start, resource_size(&r));
87		return AE_OK;
88	}
89
90	return AE_ERROR;
91}
92
93static int pvpanic_add(struct acpi_device *device)
94{
95	int ret;
96
97	ret = acpi_bus_get_status(device);
98	if (ret < 0)
99		return ret;
100
101	if (!device->status.enabled || !device->status.functional)
102		return -ENODEV;
103
104	acpi_walk_resources(device->handle, METHOD_NAME__CRS,
105			    pvpanic_walk_resources, NULL);
106
107	if (!base)
108		return -ENODEV;
109
110	atomic_notifier_chain_register(&panic_notifier_list,
111				       &pvpanic_panic_nb);
112
113	return 0;
114}
115
116static int pvpanic_remove(struct acpi_device *device)
117{
118
119	atomic_notifier_chain_unregister(&panic_notifier_list,
120					 &pvpanic_panic_nb);
121	iounmap(base);
122
123	return 0;
124}
125
126static int pvpanic_register_acpi_driver(void)
127{
128	return acpi_bus_register_driver(&pvpanic_driver);
129}
130
131static void pvpanic_unregister_acpi_driver(void)
132{
133	acpi_bus_unregister_driver(&pvpanic_driver);
134}
135#else
136static int pvpanic_register_acpi_driver(void)
137{
138	return -ENODEV;
139}
140
141static void pvpanic_unregister_acpi_driver(void) {}
142#endif
143
144static int pvpanic_mmio_probe(struct platform_device *pdev)
145{
146	base = devm_platform_ioremap_resource(pdev, 0);
147	if (IS_ERR(base))
148		return PTR_ERR(base);
149
150	atomic_notifier_chain_register(&panic_notifier_list,
151				       &pvpanic_panic_nb);
152
153	return 0;
154}
155
156static int pvpanic_mmio_remove(struct platform_device *pdev)
157{
158
159	atomic_notifier_chain_unregister(&panic_notifier_list,
160					 &pvpanic_panic_nb);
161
162	return 0;
163}
164
165static const struct of_device_id pvpanic_mmio_match[] = {
166	{ .compatible = "qemu,pvpanic-mmio", },
167	{}
168};
169MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
170
171static struct platform_driver pvpanic_mmio_driver = {
172	.driver = {
173		.name = "pvpanic-mmio",
174		.of_match_table = pvpanic_mmio_match,
175	},
176	.probe = pvpanic_mmio_probe,
177	.remove = pvpanic_mmio_remove,
178};
179
180static int __init pvpanic_mmio_init(void)
181{
182	if (acpi_disabled)
183		return platform_driver_register(&pvpanic_mmio_driver);
184	else
185		return pvpanic_register_acpi_driver();
186}
187
188static void __exit pvpanic_mmio_exit(void)
189{
190	if (acpi_disabled)
191		platform_driver_unregister(&pvpanic_mmio_driver);
192	else
193		pvpanic_unregister_acpi_driver();
194}
195
196module_init(pvpanic_mmio_init);
197module_exit(pvpanic_mmio_exit);
198