drivers/misc/pvpanic.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  Pvpanic Device Support
   4  *
   5  *  Copyright (C) 2013 Fujitsu.
   6  *  Copyright (C) 2018 ZTE.
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/acpi.h>
  12 #include <linux/kernel.h>
  13 #include <linux/kexec.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_address.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/types.h>
  19 #include <uapi/misc/pvpanic.h>
  20
  21 static void __iomem *base;
  22
  23 MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
  24 MODULE_DESCRIPTION("pvpanic device driver");
  25 MODULE_LICENSE("GPL");
  26
  27 static void
  28 pvpanic_send_event(unsigned int event)
  29 {
  30         iowrite8(event, base);
  31 }
  32
  33 static int
  34 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
  35                      void *unused)
  36 {
  37         unsigned int event = PVPANIC_PANICKED;
  38
  39         if (kexec_crash_loaded())
  40                 event = PVPANIC_CRASH_LOADED;
  41
  42         pvpanic_send_event(event);
  43
  44         return NOTIFY_DONE;
  45 }
  46
  47 static struct notifier_block pvpanic_panic_nb = {
  48         .notifier_call = pvpanic_panic_notify,
  49         .priority = 1, /* let this called before broken drm_fb_helper */
  50 };
  51
  52 #ifdef CONFIG_ACPI
  53 static int pvpanic_add(struct acpi_device *device);
  54 static int pvpanic_remove(struct acpi_device *device);
  55
  56 static const struct acpi_device_id pvpanic_device_ids[] = {
  57         { "QEMU0001", 0 },
  58         { "", 0 }
  59 };
  60 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
  61
  62 static struct acpi_driver pvpanic_driver = {
  63         .name =         "pvpanic",
  64         .class =        "QEMU",
  65         .ids =          pvpanic_device_ids,
  66         .ops =          {
  67                                 .add =          pvpanic_add,
  68                                 .remove =       pvpanic_remove,
  69                         },
  70         .owner =        THIS_MODULE,
  71 };
  72
  73 static acpi_status
  74 pvpanic_walk_resources(struct acpi_resource *res, void *context)
  75 {
  76         struct resource r;
  77
  78         if (acpi_dev_resource_io(res, &r)) {
  79 #ifdef CONFIG_HAS_IOPORT_MAP
  80                 base = ioport_map(r.start, resource_size(&r));
  81                 return AE_OK;
  82 #else
  83                 return AE_ERROR;
  84 #endif
  85         } else if (acpi_dev_resource_memory(res, &r)) {
  86                 base = ioremap(r.start, resource_size(&r));
  87                 return AE_OK;
  88         }
  89
  90         return AE_ERROR;
  91 }
  92
  93 static int pvpanic_add(struct acpi_device *device)
  94 {
  95         int ret;
  96
  97         ret = acpi_bus_get_status(device);
  98         if (ret < 0)
  99                 return ret;
 100
 101         if (!device->status.enabled || !device->status.functional)
 102                 return -ENODEV;
 103
 104         acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 105                             pvpanic_walk_resources, NULL);
 106
 107         if (!base)
 108                 return -ENODEV;
 109
 110         atomic_notifier_chain_register(&panic_notifier_list,
 111                                        &pvpanic_panic_nb);
 112
 113         return 0;
 114 }
 115
 116 static int pvpanic_remove(struct acpi_device *device)
 117 {
 118
 119         atomic_notifier_chain_unregister(&panic_notifier_list,
 120                                          &pvpanic_panic_nb);
 121         iounmap(base);
 122
 123         return 0;
 124 }
 125
 126 static int pvpanic_register_acpi_driver(void)
 127 {
 128         return acpi_bus_register_driver(&pvpanic_driver);
 129 }
 130
 131 static void pvpanic_unregister_acpi_driver(void)
 132 {
 133         acpi_bus_unregister_driver(&pvpanic_driver);
 134 }
 135 #else
 136 static int pvpanic_register_acpi_driver(void)
 137 {
 138         return -ENODEV;
 139 }
 140
 141 static void pvpanic_unregister_acpi_driver(void) {}
 142 #endif
 143
 144 static int pvpanic_mmio_probe(struct platform_device *pdev)
 145 {
 146         base = devm_platform_ioremap_resource(pdev, 0);
 147         if (IS_ERR(base))
 148                 return PTR_ERR(base);
 149
 150         atomic_notifier_chain_register(&panic_notifier_list,
 151                                        &pvpanic_panic_nb);
 152
 153         return 0;
 154 }
 155
 156 static int pvpanic_mmio_remove(struct platform_device *pdev)
 157 {
 158
 159         atomic_notifier_chain_unregister(&panic_notifier_list,
 160                                          &pvpanic_panic_nb);
 161
 162         return 0;
 163 }
 164
 165 static const struct of_device_id pvpanic_mmio_match[] = {
 166         { .compatible = "qemu,pvpanic-mmio", },
 167         {}
 168 };
 169
 170 static struct platform_driver pvpanic_mmio_driver = {
 171         .driver = {
 172                 .name = "pvpanic-mmio",
 173                 .of_match_table = pvpanic_mmio_match,
 174         },
 175         .probe = pvpanic_mmio_probe,
 176         .remove = pvpanic_mmio_remove,
 177 };
 178
 179 static int __init pvpanic_mmio_init(void)
 180 {
 181         if (acpi_disabled)
 182                 return platform_driver_register(&pvpanic_mmio_driver);
 183         else
 184                 return pvpanic_register_acpi_driver();
 185 }
 186
 187 static void __exit pvpanic_mmio_exit(void)
 188 {
 189         if (acpi_disabled)
 190                 platform_driver_unregister(&pvpanic_mmio_driver);
 191         else
 192                 pvpanic_unregister_acpi_driver();
 193 }
 194
 195 module_init(pvpanic_mmio_init);
 196 module_exit(pvpanic_mmio_exit);