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, struct device_attribute *attr, char *buf)
28 {
29 	struct pvpanic_instance *pi = dev_get_drvdata(dev);
30 
31 	return sysfs_emit(buf, "%x\n", pi->capability);
32 }
33 static DEVICE_ATTR_RO(capability);
34 
35 static ssize_t events_show(struct device *dev, struct device_attribute *attr, char *buf)
36 {
37 	struct pvpanic_instance *pi = dev_get_drvdata(dev);
38 
39 	return sysfs_emit(buf, "%x\n", pi->events);
40 }
41 
42 static ssize_t events_store(struct device *dev, struct device_attribute *attr,
43 			    const char *buf, size_t count)
44 {
45 	struct pvpanic_instance *pi = dev_get_drvdata(dev);
46 	unsigned int tmp;
47 	int err;
48 
49 	err = kstrtouint(buf, 16, &tmp);
50 	if (err)
51 		return err;
52 
53 	if ((tmp & pi->capability) != tmp)
54 		return -EINVAL;
55 
56 	pi->events = tmp;
57 
58 	return count;
59 }
60 static DEVICE_ATTR_RW(events);
61 
62 static struct attribute *pvpanic_mmio_dev_attrs[] = {
63 	&dev_attr_capability.attr,
64 	&dev_attr_events.attr,
65 	NULL
66 };
67 ATTRIBUTE_GROUPS(pvpanic_mmio_dev);
68 
69 static int pvpanic_mmio_probe(struct platform_device *pdev)
70 {
71 	struct device *dev = &pdev->dev;
72 	struct pvpanic_instance *pi;
73 	struct resource *res;
74 	void __iomem *base;
75 
76 	res = platform_get_mem_or_io(pdev, 0);
77 	if (!res)
78 		return -EINVAL;
79 
80 	switch (resource_type(res)) {
81 	case IORESOURCE_IO:
82 		base = devm_ioport_map(dev, res->start, resource_size(res));
83 		if (!base)
84 			return -ENOMEM;
85 		break;
86 	case IORESOURCE_MEM:
87 		base = devm_ioremap_resource(dev, res);
88 		if (IS_ERR(base))
89 			return PTR_ERR(base);
90 		break;
91 	default:
92 		return -EINVAL;
93 	}
94 
95 	pi = devm_kmalloc(dev, sizeof(*pi), GFP_KERNEL);
96 	if (!pi)
97 		return -ENOMEM;
98 
99 	pi->base = base;
100 	pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
101 
102 	/* initialize capability by RDPT */
103 	pi->capability &= ioread8(base);
104 	pi->events = pi->capability;
105 
106 	return devm_pvpanic_probe(dev, pi);
107 }
108 
109 static const struct of_device_id pvpanic_mmio_match[] = {
110 	{ .compatible = "qemu,pvpanic-mmio", },
111 	{}
112 };
113 MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
114 
115 static const struct acpi_device_id pvpanic_device_ids[] = {
116 	{ "QEMU0001", 0 },
117 	{ "", 0 }
118 };
119 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
120 
121 static struct platform_driver pvpanic_mmio_driver = {
122 	.driver = {
123 		.name = "pvpanic-mmio",
124 		.of_match_table = pvpanic_mmio_match,
125 		.acpi_match_table = pvpanic_device_ids,
126 		.dev_groups = pvpanic_mmio_dev_groups,
127 	},
128 	.probe = pvpanic_mmio_probe,
129 };
130 module_platform_driver(pvpanic_mmio_driver);
131