[PATCH 3/4] pvpanic: add access to pvpanic device information by using FDT

[Peng Hao <peng.hao2@zte.com.cn>]

By default, when ACPI tables and FDT coexist for ARM64,
kernel takes precedence over FDT to get device information.
This patch increases the way to get information through FDT.

Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
---
 drivers/misc/pvpanic.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/pvpanic.c b/drivers/misc/pvpanic.c
index bdcff8b..102a119 100644
--- a/drivers/misc/pvpanic.c
+++ b/drivers/misc/pvpanic.c
@@ -2,6 +2,7 @@
  *  pvpanic.c - pvpanic Device Support
  *
  *  Copyright (C) 2013 Fujitsu.
+ *  Copyright (C) 2018 ZTE.
  *
  *  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
@@ -25,6 +26,10 @@
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/acpi.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <asm/virt.h>
+#include <linux/platform_device.h>
 
 MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
 MODULE_DESCRIPTION("pvpanic device driver");
@@ -79,6 +84,37 @@
 	.priority = 1, /* let this called before broken drm_fb_helper */
 };
 
+static int pvpanic_mmio_probe(struct platform_device *pdev)
+{
+	struct resource *mem;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem)
+		return -EINVAL;
+
+	if (!devm_request_mem_region(&pdev->dev, mem->start,
+				     resource_size(mem), pdev->name))
+		return -EBUSY;
+
+	base = devm_ioremap(&pdev->dev, mem->start,
+			   resource_size(mem));
+	if (base == NULL)
+		return -EFAULT;
+	atomic_notifier_chain_register(&panic_notifier_list,
+				      &pvpanic_panic_nb);
+
+	return 0;
+}
+
+static int pvpanic_mmio_remove(struct platform_device *pdev)
+{
+
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					&pvpanic_panic_nb);
+
+	return 0;
+}
+
 
 static acpi_status
 pvpanic_walk_resources(struct acpi_resource *res, void *context)
@@ -135,4 +171,35 @@ static int pvpanic_remove(struct acpi_device *device)
 	return 0;
 }
 
-module_acpi_driver(pvpanic_driver);
+static const struct of_device_id pvpanic_mmio_match[] = {
+	{ .compatible = "qemu,pvpanic-mmio", },
+	{},
+};
+
+static struct platform_driver pvpanic_mmio_driver = {
+	.driver = {
+		.name = "pvpanic-mmio",
+		.of_match_table = pvpanic_mmio_match,
+	},
+	.probe = pvpanic_mmio_probe,
+	.remove = pvpanic_mmio_remove,
+};
+
+static int __init pvpanic_mmio_init(void)
+{
+	if (acpi_disabled)
+		return platform_driver_register(&pvpanic_mmio_driver);
+	else
+		return acpi_bus_register_driver(&pvpanic_driver);
+}
+
+static void __exit pvpanic_mmio_exit(void)
+{
+	if (acpi_disabled)
+		platform_driver_unregister(&pvpanic_mmio_driver);
+	else
+		acpi_bus_unregister_driver(&pvpanic_driver);
+}
+
+module_init(pvpanic_mmio_init);
+module_exit(pvpanic_mmio_exit);
-- 
1.8.3.1