drivers/misc/pvpanic/pvpanic-mmio.c

   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 <[email protected]>");
  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);