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/module.h>
 14#include <linux/of.h>
 15#include <linux/of_address.h>
 16#include <linux/platform_device.h>
 17#include <linux/types.h>
 18
 19static void __iomem *base;
 20
 21#define PVPANIC_PANICKED        (1 << 0)
 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	pvpanic_send_event(PVPANIC_PANICKED);
 38	return NOTIFY_DONE;
 39}
 40
 41static struct notifier_block pvpanic_panic_nb = {
 42	.notifier_call = pvpanic_panic_notify,
 43	.priority = 1, /* let this called before broken drm_fb_helper */
 44};
 45
 46#ifdef CONFIG_ACPI
 47static int pvpanic_add(struct acpi_device *device);
 48static int pvpanic_remove(struct acpi_device *device);
 49
 50static const struct acpi_device_id pvpanic_device_ids[] = {
 51	{ "QEMU0001", 0 },
 52	{ "", 0 }
 53};
 54MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
 55
 56static struct acpi_driver pvpanic_driver = {
 57	.name =		"pvpanic",
 58	.class =	"QEMU",
 59	.ids =		pvpanic_device_ids,
 60	.ops =		{
 61				.add =		pvpanic_add,
 62				.remove =	pvpanic_remove,
 63			},
 64	.owner =	THIS_MODULE,
 65};
 66
 67static acpi_status
 68pvpanic_walk_resources(struct acpi_resource *res, void *context)
 69{
 70	struct resource r;
 71
 72	if (acpi_dev_resource_io(res, &r)) {
 73#ifdef CONFIG_HAS_IOPORT_MAP
 74		base = ioport_map(r.start, resource_size(&r));
 75		return AE_OK;
 76#else
 77		return AE_ERROR;
 78#endif
 79	} else if (acpi_dev_resource_memory(res, &r)) {
 80		base = ioremap(r.start, resource_size(&r));
 81		return AE_OK;
 82	}
 83
 84	return AE_ERROR;
 85}
 86
 87static int pvpanic_add(struct acpi_device *device)
 88{
 89	int ret;
 90
 91	ret = acpi_bus_get_status(device);
 92	if (ret < 0)
 93		return ret;
 94
 95	if (!device->status.enabled || !device->status.functional)
 96		return -ENODEV;
 97
 98	acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 99			    pvpanic_walk_resources, NULL);
100
101	if (!base)
102		return -ENODEV;
103
104	atomic_notifier_chain_register(&panic_notifier_list,
105				       &pvpanic_panic_nb);
106
107	return 0;
108}
109
110static int pvpanic_remove(struct acpi_device *device)
111{
112
113	atomic_notifier_chain_unregister(&panic_notifier_list,
114					 &pvpanic_panic_nb);
115	iounmap(base);
116
117	return 0;
118}
119
120static int pvpanic_register_acpi_driver(void)
121{
122	return acpi_bus_register_driver(&pvpanic_driver);
123}
124
125static void pvpanic_unregister_acpi_driver(void)
126{
127	acpi_bus_unregister_driver(&pvpanic_driver);
128}
129#else
130static int pvpanic_register_acpi_driver(void)
131{
132	return -ENODEV;
133}
134
135static void pvpanic_unregister_acpi_driver(void) {}
136#endif
137
138static int pvpanic_mmio_probe(struct platform_device *pdev)
139{
140	struct resource *mem;
141
142	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
143	if (!mem)
144		return -EINVAL;
145
146	base = devm_ioremap_resource(&pdev->dev, mem);
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};
169
170static struct platform_driver pvpanic_mmio_driver = {
171	.driver = {
172		.name = "pvpanic-mmio",
173		.of_match_table = pvpanic_mmio_match,
174	},
175	.probe = pvpanic_mmio_probe,
176	.remove = pvpanic_mmio_remove,
177};
178
179static int __init pvpanic_mmio_init(void)
180{
181	if (acpi_disabled)
182		return platform_driver_register(&pvpanic_mmio_driver);
183	else
184		return pvpanic_register_acpi_driver();
185}
186
187static void __exit pvpanic_mmio_exit(void)
188{
189	if (acpi_disabled)
190		platform_driver_unregister(&pvpanic_mmio_driver);
191	else
192		pvpanic_unregister_acpi_driver();
193}
194
195module_init(pvpanic_mmio_init);
196module_exit(pvpanic_mmio_exit);