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
 23MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
 24MODULE_DESCRIPTION("pvpanic-mmio device driver");
 25MODULE_LICENSE("GPL");
 26
 27static 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}
 33static DEVICE_ATTR_RO(capability);
 34
 35static 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
 42static 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}
 60static DEVICE_ATTR_RW(events);
 61
 62static struct attribute *pvpanic_mmio_dev_attrs[] = {
 63	&dev_attr_capability.attr,
 64	&dev_attr_events.attr,
 65	NULL
 66};
 67ATTRIBUTE_GROUPS(pvpanic_mmio_dev);
 68
 69static 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
109static const struct of_device_id pvpanic_mmio_match[] = {
110	{ .compatible = "qemu,pvpanic-mmio", },
111	{}
112};
113MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
114
115static const struct acpi_device_id pvpanic_device_ids[] = {
116	{ "QEMU0001", 0 },
117	{ "", 0 }
118};
119MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
120
121static 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};
130module_platform_driver(pvpanic_mmio_driver);