1/*
  2 * ACPI watchdog table parsing support.
  3 *
  4 * Copyright (C) 2016, Intel Corporation
  5 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 */
 11
 12#define pr_fmt(fmt) "ACPI: watchdog: " fmt
 13
 14#include <linux/acpi.h>
 15#include <linux/ioport.h>
 16#include <linux/platform_device.h>
 17
 18#include "internal.h"
 19
 20/**
 21 * Returns true if this system should prefer ACPI based watchdog instead of
 22 * the native one (which are typically the same hardware).
 23 */
 24bool acpi_has_watchdog(void)
 25{
 26	struct acpi_table_header hdr;
 27
 28	if (acpi_disabled)
 29		return false;
 30
 31	return ACPI_SUCCESS(acpi_get_table_header(ACPI_SIG_WDAT, 0, &hdr));
 32}
 33EXPORT_SYMBOL_GPL(acpi_has_watchdog);
 34
 35void __init acpi_watchdog_init(void)
 36{
 37	const struct acpi_wdat_entry *entries;
 38	const struct acpi_table_wdat *wdat;
 39	struct list_head resource_list;
 40	struct resource_entry *rentry;
 41	struct platform_device *pdev;
 42	struct resource *resources;
 43	size_t nresources = 0;
 44	acpi_status status;
 45	int i;
 46
 47	status = acpi_get_table(ACPI_SIG_WDAT, 0,
 48				(struct acpi_table_header **)&wdat);
 49	if (ACPI_FAILURE(status)) {
 50		/* It is fine if there is no WDAT */
 51		return;
 52	}
 53
 54	/* Watchdog disabled by BIOS */
 55	if (!(wdat->flags & ACPI_WDAT_ENABLED))
 56		return;
 57
 58	/* Skip legacy PCI WDT devices */
 59	if (wdat->pci_segment != 0xff || wdat->pci_bus != 0xff ||
 60	    wdat->pci_device != 0xff || wdat->pci_function != 0xff)
 61		return;
 62
 63	INIT_LIST_HEAD(&resource_list);
 64
 65	entries = (struct acpi_wdat_entry *)(wdat + 1);
 66	for (i = 0; i < wdat->entries; i++) {
 67		const struct acpi_generic_address *gas;
 68		struct resource_entry *rentry;
 69		struct resource res;
 70		bool found;
 71
 72		gas = &entries[i].register_region;
 73
 74		res.start = gas->address;
 75		if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 76			res.flags = IORESOURCE_MEM;
 77			res.end = res.start + ALIGN(gas->access_width, 4);
 78		} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 79			res.flags = IORESOURCE_IO;
 80			res.end = res.start + gas->access_width;
 81		} else {
 82			pr_warn("Unsupported address space: %u\n",
 83				gas->space_id);
 84			goto fail_free_resource_list;
 85		}
 86
 87		found = false;
 88		resource_list_for_each_entry(rentry, &resource_list) {
 89			if (resource_contains(rentry->res, &res)) {
 90				found = true;
 91				break;
 92			}
 93		}
 94
 95		if (!found) {
 96			rentry = resource_list_create_entry(NULL, 0);
 97			if (!rentry)
 98				goto fail_free_resource_list;
 99
100			*rentry->res = res;
101			resource_list_add_tail(rentry, &resource_list);
102			nresources++;
103		}
104	}
105
106	resources = kcalloc(nresources, sizeof(*resources), GFP_KERNEL);
107	if (!resources)
108		goto fail_free_resource_list;
109
110	i = 0;
111	resource_list_for_each_entry(rentry, &resource_list)
112		resources[i++] = *rentry->res;
113
114	pdev = platform_device_register_simple("wdat_wdt", PLATFORM_DEVID_NONE,
115					       resources, nresources);
116	if (IS_ERR(pdev))
117		pr_err("Device creation failed: %ld\n", PTR_ERR(pdev));
118
119	kfree(resources);
120
121fail_free_resource_list:
122	resource_list_free(&resource_list);
123}