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/module.h>
  14 #include <linux/of.h>
  15 #include <linux/of_address.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/types.h>
  18
  19 static void __iomem *base;
  20
  21 #define PVPANIC_PANICKED        (1 << 0)
  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         pvpanic_send_event(PVPANIC_PANICKED);
  38         return NOTIFY_DONE;
  39 }
  40
  41 static struct notifier_block pvpanic_panic_nb = {
  42         .notifier_call = pvpanic_panic_notify,
  43         .priority = 1, /* let this called before broken drm_fb_helper */
  44 };
  45
  46 #ifdef CONFIG_ACPI
  47 static int pvpanic_add(struct acpi_device *device);
  48 static int pvpanic_remove(struct acpi_device *device);
  49
  50 static const struct acpi_device_id pvpanic_device_ids[] = {
  51         { "QEMU0001", 0 },
  52         { "", 0 }
  53 };
  54 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
  55
  56 static struct acpi_driver pvpanic_driver = {
  57         .name =         "pvpanic",
  58         .class =        "QEMU",
  59         .ids =          pvpanic_device_ids,
  60         .ops =          {
  61                                 .add =          pvpanic_add,
  62                                 .remove =       pvpanic_remove,
  63                         },
  64         .owner =        THIS_MODULE,
  65 };
  66
  67 static acpi_status
  68 pvpanic_walk_resources(struct acpi_resource *res, void *context)
  69 {
  70         struct resource r;
  71
  72         if (acpi_dev_resource_io(res, &r)) {
  73                 base = ioport_map(r.start, resource_size(&r));
  74                 return AE_OK;
  75         } else if (acpi_dev_resource_memory(res, &r)) {
  76                 base = ioremap(r.start, resource_size(&r));
  77                 return AE_OK;
  78         }
  79
  80         return AE_ERROR;
  81 }
  82
  83 static int pvpanic_add(struct acpi_device *device)
  84 {
  85         int ret;
  86
  87         ret = acpi_bus_get_status(device);
  88         if (ret < 0)
  89                 return ret;
  90
  91         if (!device->status.enabled || !device->status.functional)
  92                 return -ENODEV;
  93
  94         acpi_walk_resources(device->handle, METHOD_NAME__CRS,
  95                             pvpanic_walk_resources, NULL);
  96
  97         if (!base)
  98                 return -ENODEV;
  99
 100         atomic_notifier_chain_register(&panic_notifier_list,
 101                                        &pvpanic_panic_nb);
 102
 103         return 0;
 104 }
 105
 106 static int pvpanic_remove(struct acpi_device *device)
 107 {
 108
 109         atomic_notifier_chain_unregister(&panic_notifier_list,
 110                                          &pvpanic_panic_nb);
 111         iounmap(base);
 112
 113         return 0;
 114 }
 115
 116 static int pvpanic_register_acpi_driver(void)
 117 {
 118         return acpi_bus_register_driver(&pvpanic_driver);
 119 }
 120
 121 static void pvpanic_unregister_acpi_driver(void)
 122 {
 123         acpi_bus_unregister_driver(&pvpanic_driver);
 124 }
 125 #else
 126 static int pvpanic_register_acpi_driver(void)
 127 {
 128         return -ENODEV;
 129 }
 130
 131 static void pvpanic_unregister_acpi_driver(void) {}
 132 #endif
 133
 134 static int pvpanic_mmio_probe(struct platform_device *pdev)
 135 {
 136         struct resource *mem;
 137
 138         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 139         if (!mem)
 140                 return -EINVAL;
 141
 142         base = devm_ioremap_resource(&pdev->dev, mem);
 143         if (IS_ERR(base))
 144                 return PTR_ERR(base);
 145
 146         atomic_notifier_chain_register(&panic_notifier_list,
 147                                        &pvpanic_panic_nb);
 148
 149         return 0;
 150 }
 151
 152 static int pvpanic_mmio_remove(struct platform_device *pdev)
 153 {
 154
 155         atomic_notifier_chain_unregister(&panic_notifier_list,
 156                                          &pvpanic_panic_nb);
 157
 158         return 0;
 159 }
 160
 161 static const struct of_device_id pvpanic_mmio_match[] = {
 162         { .compatible = "qemu,pvpanic-mmio", },
 163         {}
 164 };
 165
 166 static struct platform_driver pvpanic_mmio_driver = {
 167         .driver = {
 168                 .name = "pvpanic-mmio",
 169                 .of_match_table = pvpanic_mmio_match,
 170         },
 171         .probe = pvpanic_mmio_probe,
 172         .remove = pvpanic_mmio_remove,
 173 };
 174
 175 static int __init pvpanic_mmio_init(void)
 176 {
 177         if (acpi_disabled)
 178                 return platform_driver_register(&pvpanic_mmio_driver);
 179         else
 180                 return pvpanic_register_acpi_driver();
 181 }
 182
 183 static void __exit pvpanic_mmio_exit(void)
 184 {
 185         if (acpi_disabled)
 186                 platform_driver_unregister(&pvpanic_mmio_driver);
 187         else
 188                 pvpanic_unregister_acpi_driver();
 189 }
 190
 191 module_init(pvpanic_mmio_init);
 192 module_exit(pvpanic_mmio_exit);