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 static unsigned int capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
  23 static unsigned int events;
  24
  25 static ssize_t capability_show(struct device *dev,
  26                                struct device_attribute *attr, char *buf)
  27 {
  28         return sysfs_emit(buf, "%x\n", capability);
  29 }
  30 static DEVICE_ATTR_RO(capability);
  31
  32 static ssize_t events_show(struct device *dev,  struct device_attribute *attr, char *buf)
  33 {
  34         return sysfs_emit(buf, "%x\n", events);
  35 }
  36
  37 static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
  38                             const char *buf, size_t count)
  39 {
  40         unsigned int tmp;
  41         int err;
  42
  43         err = kstrtouint(buf, 16, &tmp);
  44         if (err)
  45                 return err;
  46
  47         if ((tmp & capability) != tmp)
  48                 return -EINVAL;
  49
  50         events = tmp;
  51
  52         return count;
  53
  54 }
  55 static DEVICE_ATTR_RW(events);
  56
  57 static struct attribute *pvpanic_dev_attrs[] = {
  58         &dev_attr_capability.attr,
  59         &dev_attr_events.attr,
  60         NULL
  61 };
  62 ATTRIBUTE_GROUPS(pvpanic_dev);
  63
  64 MODULE_AUTHOR("Hu Tao <[email protected]>");
  65 MODULE_DESCRIPTION("pvpanic device driver");
  66 MODULE_LICENSE("GPL");
  67
  68 static void
  69 pvpanic_send_event(unsigned int event)
  70 {
  71         if (event & capability & events)
  72                 iowrite8(event, base);
  73 }
  74
  75 static int
  76 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
  77                      void *unused)
  78 {
  79         unsigned int event = PVPANIC_PANICKED;
  80
  81         if (kexec_crash_loaded())
  82                 event = PVPANIC_CRASH_LOADED;
  83
  84         pvpanic_send_event(event);
  85
  86         return NOTIFY_DONE;
  87 }
  88
  89 static struct notifier_block pvpanic_panic_nb = {
  90         .notifier_call = pvpanic_panic_notify,
  91         .priority = 1, /* let this called before broken drm_fb_helper */
  92 };
  93
  94 static int pvpanic_mmio_probe(struct platform_device *pdev)
  95 {
  96         struct device *dev = &pdev->dev;
  97         struct resource *res;
  98
  99         res = platform_get_mem_or_io(pdev, 0);
 100         if (!res)
 101                 return -EINVAL;
 102
 103         switch (resource_type(res)) {
 104         case IORESOURCE_IO:
 105                 base = devm_ioport_map(dev, res->start, resource_size(res));
 106                 if (!base)
 107                         return -ENOMEM;
 108                 break;
 109         case IORESOURCE_MEM:
 110                 base = devm_ioremap_resource(dev, res);
 111                 if (IS_ERR(base))
 112                         return PTR_ERR(base);
 113                 break;
 114         default:
 115                 return -EINVAL;
 116         }
 117
 118         /* initlize capability by RDPT */
 119         capability &= ioread8(base);
 120         events = capability;
 121
 122         if (capability)
 123                 atomic_notifier_chain_register(&panic_notifier_list,
 124                                                &pvpanic_panic_nb);
 125
 126         return 0;
 127 }
 128
 129 static int pvpanic_mmio_remove(struct platform_device *pdev)
 130 {
 131
 132         if (capability)
 133                 atomic_notifier_chain_unregister(&panic_notifier_list,
 134                                                  &pvpanic_panic_nb);
 135
 136         return 0;
 137 }
 138
 139 static const struct of_device_id pvpanic_mmio_match[] = {
 140         { .compatible = "qemu,pvpanic-mmio", },
 141         {}
 142 };
 143 MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
 144
 145 static const struct acpi_device_id pvpanic_device_ids[] = {
 146         { "QEMU0001", 0 },
 147         { "", 0 }
 148 };
 149 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
 150
 151 static struct platform_driver pvpanic_mmio_driver = {
 152         .driver = {
 153                 .name = "pvpanic-mmio",
 154                 .of_match_table = pvpanic_mmio_match,
 155                 .acpi_match_table = pvpanic_device_ids,
 156                 .dev_groups = pvpanic_dev_groups,
 157         },
 158         .probe = pvpanic_mmio_probe,
 159         .remove = pvpanic_mmio_remove,
 160 };
 161 module_platform_driver(pvpanic_mmio_driver);