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/io.h>
  12 #include <linux/kernel.h>
  13 #include <linux/kexec.h>
  14 #include <linux/mod_devicetable.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/types.h>
  18
  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 static int pvpanic_mmio_probe(struct platform_device *pdev)
  53 {
  54         struct device *dev = &pdev->dev;
  55         struct resource *res;
  56
  57         res = platform_get_mem_or_io(pdev, 0);
  58         if (!res)
  59                 return -EINVAL;
  60
  61         switch (resource_type(res)) {
  62         case IORESOURCE_IO:
  63                 base = devm_ioport_map(dev, res->start, resource_size(res));
  64                 if (!base)
  65                         return -ENOMEM;
  66                 break;
  67         case IORESOURCE_MEM:
  68                 base = devm_ioremap_resource(dev, res);
  69                 if (IS_ERR(base))
  70                         return PTR_ERR(base);
  71                 break;
  72         default:
  73                 return -EINVAL;
  74         }
  75
  76         atomic_notifier_chain_register(&panic_notifier_list,
  77                                        &pvpanic_panic_nb);
  78
  79         return 0;
  80 }
  81
  82 static int pvpanic_mmio_remove(struct platform_device *pdev)
  83 {
  84
  85         atomic_notifier_chain_unregister(&panic_notifier_list,
  86                                          &pvpanic_panic_nb);
  87
  88         return 0;
  89 }
  90
  91 static const struct of_device_id pvpanic_mmio_match[] = {
  92         { .compatible = "qemu,pvpanic-mmio", },
  93         {}
  94 };
  95
  96 static const struct acpi_device_id pvpanic_device_ids[] = {
  97         { "QEMU0001", 0 },
  98         { "", 0 }
  99 };
 100 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
 101
 102 static struct platform_driver pvpanic_mmio_driver = {
 103         .driver = {
 104                 .name = "pvpanic-mmio",
 105                 .of_match_table = pvpanic_mmio_match,
 106                 .acpi_match_table = pvpanic_device_ids,
 107         },
 108         .probe = pvpanic_mmio_probe,
 109         .remove = pvpanic_mmio_remove,
 110 };
 111 module_platform_driver(pvpanic_mmio_driver);