1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_watchdog.c b/drivers/acpi/acpi_watchdog.c
new file mode 100644
index 000000000000..13caebd679f5
--- /dev/null
+++ b/drivers/acpi/acpi_watchdog.c
@@ -0,0 +1,123 @@
+/*
+ * ACPI watchdog table parsing support.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Mika Westerberg <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) "ACPI: watchdog: " fmt
+
+#include <linux/acpi.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+
+#include "internal.h"
+
+/**
+ * Returns true if this system should prefer ACPI based watchdog instead of
+ * the native one (which are typically the same hardware).
+ */
+bool acpi_has_watchdog(void)
+{
+	struct acpi_table_header hdr;
+
+	if (acpi_disabled)
+		return false;
+
+	return ACPI_SUCCESS(acpi_get_table_header(ACPI_SIG_WDAT, 0, &hdr));
+}
+EXPORT_SYMBOL_GPL(acpi_has_watchdog);
+
+void __init acpi_watchdog_init(void)
+{
+	const struct acpi_wdat_entry *entries;
+	const struct acpi_table_wdat *wdat;
+	struct list_head resource_list;
+	struct resource_entry *rentry;
+	struct platform_device *pdev;
+	struct resource *resources;
+	size_t nresources = 0;
+	acpi_status status;
+	int i;
+
+	status = acpi_get_table(ACPI_SIG_WDAT, 0,
+				(struct acpi_table_header **)&wdat);
+	if (ACPI_FAILURE(status)) {
+		/* It is fine if there is no WDAT */
+		return;
+	}
+
+	/* Watchdog disabled by BIOS */
+	if (!(wdat->flags & ACPI_WDAT_ENABLED))
+		return;
+
+	/* Skip legacy PCI WDT devices */
+	if (wdat->pci_segment != 0xff || wdat->pci_bus != 0xff ||
+	    wdat->pci_device != 0xff || wdat->pci_function != 0xff)
+		return;
+
+	INIT_LIST_HEAD(&resource_list);
+
+	entries = (struct acpi_wdat_entry *)(wdat + 1);
+	for (i = 0; i < wdat->entries; i++) {
+		const struct acpi_generic_address *gas;
+		struct resource_entry *rentry;
+		struct resource res;
+		bool found;
+
+		gas = &entries[i].register_region;
+
+		res.start = gas->address;
+		if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+			res.flags = IORESOURCE_MEM;
+			res.end = res.start + ALIGN(gas->access_width, 4);
+		} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+			res.flags = IORESOURCE_IO;
+			res.end = res.start + gas->access_width;
+		} else {
+			pr_warn("Unsupported address space: %u\n",
+				gas->space_id);
+			goto fail_free_resource_list;
+		}
+
+		found = false;
+		resource_list_for_each_entry(rentry, &resource_list) {
+			if (resource_contains(rentry->res, &res)) {
+				found = true;
+				break;
+			}
+		}
+
+		if (!found) {
+			rentry = resource_list_create_entry(NULL, 0);
+			if (!rentry)
+				goto fail_free_resource_list;
+
+			*rentry->res = res;
+			resource_list_add_tail(rentry, &resource_list);
+			nresources++;
+		}
+	}
+
+	resources = kcalloc(nresources, sizeof(*resources), GFP_KERNEL);
+	if (!resources)
+		goto fail_free_resource_list;
+
+	i = 0;
+	resource_list_for_each_entry(rentry, &resource_list)
+		resources[i++] = *rentry->res;
+
+	pdev = platform_device_register_simple("wdat_wdt", PLATFORM_DEVID_NONE,
+					       resources, nresources);
+	if (IS_ERR(pdev))
+		pr_err("Failed to create platform device\n");
+
+	kfree(resources);
+
+fail_free_resource_list:
+	resource_list_free(&resource_list);
+}