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f7499785c8
Since we have resource_union() helper, let's utilize it here. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Tested-by: Hanjun Guo <guohanjun@huawei.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
191 lines
4.5 KiB
C
191 lines
4.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#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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#ifdef CONFIG_RTC_MC146818_LIB
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#include <linux/mc146818rtc.h>
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/*
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* There are several systems where the WDAT table is accessing RTC SRAM to
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* store persistent information. This does not work well with the Linux RTC
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* driver so on those systems we skip WDAT driver and prefer iTCO_wdt
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* instead.
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*
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* See also https://bugzilla.kernel.org/show_bug.cgi?id=199033.
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*/
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static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
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{
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const struct acpi_wdat_entry *entries;
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int i;
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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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gas = &entries[i].register_region;
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if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
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switch (gas->address) {
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case RTC_PORT(0):
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case RTC_PORT(1):
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case RTC_PORT(2):
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case RTC_PORT(3):
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return true;
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}
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}
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}
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return false;
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}
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#else
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static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
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{
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return false;
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}
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#endif
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static bool acpi_no_watchdog;
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static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)
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{
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const struct acpi_table_wdat *wdat = NULL;
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acpi_status status;
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if (acpi_disabled || acpi_no_watchdog)
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return NULL;
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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 NULL;
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}
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if (acpi_watchdog_uses_rtc(wdat)) {
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acpi_put_table((struct acpi_table_header *)wdat);
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pr_info("Skipping WDAT on this system because it uses RTC SRAM\n");
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return NULL;
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}
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return wdat;
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}
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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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return !!acpi_watchdog_get_wdat();
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}
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EXPORT_SYMBOL_GPL(acpi_has_watchdog);
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/* ACPI watchdog can be disabled on boot command line */
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static int __init disable_acpi_watchdog(char *str)
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{
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acpi_no_watchdog = true;
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return 1;
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}
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__setup("acpi_no_watchdog", disable_acpi_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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int i;
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wdat = acpi_watchdog_get_wdat();
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if (!wdat) {
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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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goto fail_put_wdat;
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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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goto fail_put_wdat;
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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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res.end = res.start + ACPI_ACCESS_BYTE_WIDTH(gas->access_width) - 1;
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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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} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
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res.flags = IORESOURCE_IO;
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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_union(rentry->res, &res, rentry->res)) {
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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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fail_put_wdat:
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acpi_put_table((struct acpi_table_header *)wdat);
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}
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