misc/pvpanic/pvpanic-mmio.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  *  Pvpanic MMIO Device Support
0004  *
0005  *  Copyright (C) 2013 Fujitsu.
0006  *  Copyright (C) 2018 ZTE.
0007  *  Copyright (C) 2021 Oracle.
0008  */
0009
0010 #include <linux/io.h>
0011 #include <linux/kernel.h>
0012 #include <linux/kexec.h>
0013 #include <linux/mod_devicetable.h>
0014 #include <linux/module.h>
0015 #include <linux/platform_device.h>
0016 #include <linux/types.h>
0017 #include <linux/slab.h>
0018
0019 #include <uapi/misc/pvpanic.h>
0020
0021 #include "pvpanic.h"
0022
0023 MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
0024 MODULE_DESCRIPTION("pvpanic-mmio device driver");
0025 MODULE_LICENSE("GPL");
0026
0027 static ssize_t capability_show(struct device *dev, struct device_attribute *attr, char *buf)
0028 {
0029     struct pvpanic_instance *pi = dev_get_drvdata(dev);
0030
0031     return sysfs_emit(buf, "%x\n", pi->capability);
0032 }
0033 static DEVICE_ATTR_RO(capability);
0034
0035 static ssize_t events_show(struct device *dev, struct device_attribute *attr, char *buf)
0036 {
0037     struct pvpanic_instance *pi = dev_get_drvdata(dev);
0038
0039     return sysfs_emit(buf, "%x\n", pi->events);
0040 }
0041
0042 static ssize_t events_store(struct device *dev, struct device_attribute *attr,
0043                 const char *buf, size_t count)
0044 {
0045     struct pvpanic_instance *pi = dev_get_drvdata(dev);
0046     unsigned int tmp;
0047     int err;
0048
0049     err = kstrtouint(buf, 16, &tmp);
0050     if (err)
0051         return err;
0052
0053     if ((tmp & pi->capability) != tmp)
0054         return -EINVAL;
0055
0056     pi->events = tmp;
0057
0058     return count;
0059 }
0060 static DEVICE_ATTR_RW(events);
0061
0062 static struct attribute *pvpanic_mmio_dev_attrs[] = {
0063     &dev_attr_capability.attr,
0064     &dev_attr_events.attr,
0065     NULL
0066 };
0067 ATTRIBUTE_GROUPS(pvpanic_mmio_dev);
0068
0069 static int pvpanic_mmio_probe(struct platform_device *pdev)
0070 {
0071     struct device *dev = &pdev->dev;
0072     struct pvpanic_instance *pi;
0073     struct resource *res;
0074     void __iomem *base;
0075
0076     res = platform_get_mem_or_io(pdev, 0);
0077     if (!res)
0078         return -EINVAL;
0079
0080     switch (resource_type(res)) {
0081     case IORESOURCE_IO:
0082         base = devm_ioport_map(dev, res->start, resource_size(res));
0083         if (!base)
0084             return -ENOMEM;
0085         break;
0086     case IORESOURCE_MEM:
0087         base = devm_ioremap_resource(dev, res);
0088         if (IS_ERR(base))
0089             return PTR_ERR(base);
0090         break;
0091     default:
0092         return -EINVAL;
0093     }
0094
0095     pi = devm_kmalloc(dev, sizeof(*pi), GFP_KERNEL);
0096     if (!pi)
0097         return -ENOMEM;
0098
0099     pi->base = base;
0100     pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
0101
0102     /* initialize capability by RDPT */
0103     pi->capability &= ioread8(base);
0104     pi->events = pi->capability;
0105
0106     return devm_pvpanic_probe(dev, pi);
0107 }
0108
0109 static const struct of_device_id pvpanic_mmio_match[] = {
0110     { .compatible = "qemu,pvpanic-mmio", },
0111     {}
0112 };
0113 MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
0114
0115 static const struct acpi_device_id pvpanic_device_ids[] = {
0116     { "QEMU0001", 0 },
0117     { "", 0 }
0118 };
0119 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
0120
0121 static struct platform_driver pvpanic_mmio_driver = {
0122     .driver = {
0123         .name = "pvpanic-mmio",
0124         .of_match_table = pvpanic_mmio_match,
0125         .acpi_match_table = pvpanic_device_ids,
0126         .dev_groups = pvpanic_mmio_dev_groups,
0127     },
0128     .probe = pvpanic_mmio_probe,
0129 };
0130 module_platform_driver(pvpanic_mmio_driver);