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