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	struct resource *mem;
147
148	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
149	if (!mem)
150		return -EINVAL;
151
152	base = devm_ioremap_resource(&pdev->dev, mem);
153	if (IS_ERR(base))
154		return PTR_ERR(base);
155
156	atomic_notifier_chain_register(&panic_notifier_list,
157				       &pvpanic_panic_nb);
158
159	return 0;
160}
161
162static int pvpanic_mmio_remove(struct platform_device *pdev)
163{
164
165	atomic_notifier_chain_unregister(&panic_notifier_list,
166					 &pvpanic_panic_nb);
167
168	return 0;
169}
170
171static const struct of_device_id pvpanic_mmio_match[] = {
172	{ .compatible = "qemu,pvpanic-mmio", },
173	{}
174};
175
176static struct platform_driver pvpanic_mmio_driver = {
177	.driver = {
178		.name = "pvpanic-mmio",
179		.of_match_table = pvpanic_mmio_match,
180	},
181	.probe = pvpanic_mmio_probe,
182	.remove = pvpanic_mmio_remove,
183};
184
185static int __init pvpanic_mmio_init(void)
186{
187	if (acpi_disabled)
188		return platform_driver_register(&pvpanic_mmio_driver);
189	else
190		return pvpanic_register_acpi_driver();
191}
192
193static void __exit pvpanic_mmio_exit(void)
194{
195	if (acpi_disabled)
196		platform_driver_unregister(&pvpanic_mmio_driver);
197	else
198		pvpanic_unregister_acpi_driver();
199}
200
201module_init(pvpanic_mmio_init);
202module_exit(pvpanic_mmio_exit);