1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Pvpanic MMIO Device Support
4  *
5  *  Copyright (C) 2013 Fujitsu.
6  *  Copyright (C) 2018 ZTE.
7  *  Copyright (C) 2021 Oracle.
8  */
9 
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/kexec.h>
13 #include <linux/mod_devicetable.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/types.h>
17 #include <linux/slab.h>
18 
19 #include <uapi/misc/pvpanic.h>
20 
21 #include "pvpanic.h"
22 
23 MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
24 MODULE_DESCRIPTION("pvpanic-mmio device driver");
25 MODULE_LICENSE("GPL");
26 
27 static ssize_t capability_show(struct device *dev,
28 			       struct device_attribute *attr, char *buf)
29 {
30 	struct pvpanic_instance *pi = dev_get_drvdata(dev);
31 
32 	return sysfs_emit(buf, "%x\n", pi->capability);
33 }
34 static DEVICE_ATTR_RO(capability);
35 
36 static ssize_t events_show(struct device *dev,  struct device_attribute *attr, char *buf)
37 {
38 	struct pvpanic_instance *pi = dev_get_drvdata(dev);
39 
40 	return sysfs_emit(buf, "%x\n", pi->events);
41 }
42 
43 static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
44 			    const char *buf, size_t count)
45 {
46 	struct pvpanic_instance *pi = dev_get_drvdata(dev);
47 	unsigned int tmp;
48 	int err;
49 
50 	err = kstrtouint(buf, 16, &tmp);
51 	if (err)
52 		return err;
53 
54 	if ((tmp & pi->capability) != tmp)
55 		return -EINVAL;
56 
57 	pi->events = tmp;
58 
59 	return count;
60 }
61 static DEVICE_ATTR_RW(events);
62 
63 static struct attribute *pvpanic_mmio_dev_attrs[] = {
64 	&dev_attr_capability.attr,
65 	&dev_attr_events.attr,
66 	NULL
67 };
68 ATTRIBUTE_GROUPS(pvpanic_mmio_dev);
69 
70 static int pvpanic_mmio_probe(struct platform_device *pdev)
71 {
72 	struct device *dev = &pdev->dev;
73 	struct pvpanic_instance *pi;
74 	struct resource *res;
75 	void __iomem *base;
76 
77 	res = platform_get_mem_or_io(pdev, 0);
78 	if (!res)
79 		return -EINVAL;
80 
81 	switch (resource_type(res)) {
82 	case IORESOURCE_IO:
83 		base = devm_ioport_map(dev, res->start, resource_size(res));
84 		if (!base)
85 			return -ENOMEM;
86 		break;
87 	case IORESOURCE_MEM:
88 		base = devm_ioremap_resource(dev, res);
89 		if (IS_ERR(base))
90 			return PTR_ERR(base);
91 		break;
92 	default:
93 		return -EINVAL;
94 	}
95 
96 	pi = kmalloc(sizeof(*pi), GFP_ATOMIC);
97 	if (!pi)
98 		return -ENOMEM;
99 
100 	pi->base = base;
101 	pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
102 
103 	/* initlize capability by RDPT */
104 	pi->capability &= ioread8(base);
105 	pi->events = pi->capability;
106 
107 	dev_set_drvdata(dev, pi);
108 
109 	return pvpanic_probe(pi);
110 }
111 
112 static int pvpanic_mmio_remove(struct platform_device *pdev)
113 {
114 	struct pvpanic_instance *pi = dev_get_drvdata(&pdev->dev);
115 
116 	pvpanic_remove(pi);
117 	kfree(pi);
118 
119 	return 0;
120 }
121 
122 static const struct of_device_id pvpanic_mmio_match[] = {
123 	{ .compatible = "qemu,pvpanic-mmio", },
124 	{}
125 };
126 MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
127 
128 static const struct acpi_device_id pvpanic_device_ids[] = {
129 	{ "QEMU0001", 0 },
130 	{ "", 0 }
131 };
132 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
133 
134 static struct platform_driver pvpanic_mmio_driver = {
135 	.driver = {
136 		.name = "pvpanic-mmio",
137 		.of_match_table = pvpanic_mmio_match,
138 		.acpi_match_table = pvpanic_device_ids,
139 		.dev_groups = pvpanic_mmio_dev_groups,
140 	},
141 	.probe = pvpanic_mmio_probe,
142 	.remove = pvpanic_mmio_remove,
143 };
144 module_platform_driver(pvpanic_mmio_driver);
145