pvpanic: pvpanic device driver

pvpanic device is a qemu simulated device through which guest panic
event is sent to host.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>

3 files changed, 134 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 3338437b559b..85772616efbf 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -781,4 +781,12 @@ config APPLE_GMUX
           graphics as well as the backlight. Currently only backlight
           control is supported by the driver.
 
+config PVPANIC
+        tristate "pvpanic device support"
+        depends on ACPI
+        ---help---
+          This driver provides support for the pvpanic device.  pvpanic is
+          a paravirtualized device provided by QEMU; it lets a virtual machine
+          (guest) communicate panic events to the host.
+
 endif # X86_PLATFORM_DEVICES
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index ace2b38942fe..ef0ec746f78c 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -51,3 +51,5 @@ obj-$(CONFIG_INTEL_OAKTRAIL)	+= intel_oaktrail.o
 obj-$(CONFIG_SAMSUNG_Q10)       += samsung-q10.o
 obj-$(CONFIG_APPLE_GMUX)        += apple-gmux.o
 obj-$(CONFIG_CHROMEOS_LAPTOP)   += chromeos_laptop.o
+
+obj-$(CONFIG_PVPANIC)           += pvpanic.o
diff --git a/drivers/platform/x86/pvpanic.c b/drivers/platform/x86/pvpanic.c
new file mode 100644
index 000000000000..47ae0c47d4b5
--- /dev/null
+++ b/drivers/platform/x86/pvpanic.c
@@ -0,0 +1,124 @@
+/*
+ *  pvpanic.c - pvpanic Device Support
+ *
+ *  Copyright (C) 2013 Fujitsu.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+
+MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
+MODULE_DESCRIPTION("pvpanic device driver");
+MODULE_LICENSE("GPL");
+
+static int pvpanic_add(struct acpi_device *device);
+static int pvpanic_remove(struct acpi_device *device);
+
+static const struct acpi_device_id pvpanic_device_ids[] = {
+        { "QEMU0001", 0 },
+        { "", 0 },
+};
+MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
+
+#define PVPANIC_PANICKED        (1 << 0)
+
+static u16 port;
+
+static struct acpi_driver pvpanic_driver = {
+        .name =         "pvpanic",
+        .class =        "QEMU",
+        .ids =          pvpanic_device_ids,
+        .ops =          {
+                                .add =          pvpanic_add,
+                                .remove =       pvpanic_remove,
+                        },
+        .owner =        THIS_MODULE,
+};
+
+static void
+pvpanic_send_event(unsigned int event)
+{
+        outb(event, port);
+}
+
+static int
+pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
+                     void *unused)
+{
+        pvpanic_send_event(PVPANIC_PANICKED);
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block pvpanic_panic_nb = {
+        .notifier_call = pvpanic_panic_notify,
+};
+
+
+static acpi_status
+pvpanic_walk_resources(struct acpi_resource *res, void *context)
+{
+        switch (res->type) {
+        case ACPI_RESOURCE_TYPE_END_TAG:
+                return AE_OK;
+
+        case ACPI_RESOURCE_TYPE_IO:
+                port = res->data.io.minimum;
+                return AE_OK;
+
+        default:
+                return AE_ERROR;
+        }
+}
+
+static int pvpanic_add(struct acpi_device *device)
+{
+        acpi_status status;
+        u64 ret;
+
+        status = acpi_evaluate_integer(device->handle, "_STA", NULL,
+                                       &ret);
+
+        if (ACPI_FAILURE(status) || (ret & 0x0B) != 0x0B)
+                return -ENODEV;
+
+        acpi_walk_resources(device->handle, METHOD_NAME__CRS,
+                            pvpanic_walk_resources, NULL);
+
+        if (!port)
+                return -ENODEV;
+
+        atomic_notifier_chain_register(&panic_notifier_list,
+                                       &pvpanic_panic_nb);
+
+        return 0;
+}
+
+static int pvpanic_remove(struct acpi_device *device)
+{
+
+        atomic_notifier_chain_unregister(&panic_notifier_list,
+                                         &pvpanic_panic_nb);
+        return 0;
+}
+
+module_acpi_driver(pvpanic_driver);