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 <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 = devm_kmalloc(dev, sizeof(*pi), GFP_KERNEL);
  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         return devm_pvpanic_probe(dev, pi);
 108 }
 109
 110 static const struct of_device_id pvpanic_mmio_match[] = {
 111         { .compatible = "qemu,pvpanic-mmio", },
 112         {}
 113 };
 114 MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
 115
 116 static const struct acpi_device_id pvpanic_device_ids[] = {
 117         { "QEMU0001", 0 },
 118         { "", 0 }
 119 };
 120 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
 121
 122 static struct platform_driver pvpanic_mmio_driver = {
 123         .driver = {
 124                 .name = "pvpanic-mmio",
 125                 .of_match_table = pvpanic_mmio_match,
 126                 .acpi_match_table = pvpanic_device_ids,
 127                 .dev_groups = pvpanic_mmio_dev_groups,
 128         },
 129         .probe = pvpanic_mmio_probe,
 130 };
 131 module_platform_driver(pvpanic_mmio_driver);