linux/drivers/acpi/acpi_watchdog.c
Mika Westerberg 5a802a7a28 ACPI / watchdog: Prefer iTCO_wdt always when WDAT table uses RTC SRAM
After we added quirk for Lenovo Z50-70 it turns out there are at least
two more systems where WDAT table includes instructions accessing RTC
SRAM. Instead of quirking each system separately, look for such
instructions in the table and automatically prefer iTCO_wdt if found.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199033
Reported-by: Arnold Guy <aurnoldg@gmail.com>
Reported-by: Alois Nespor <nespor@fssp.cz>
Reported-by: Yury Pakin <zxwarior@gmail.com>
Reported-by: Ihor Chyhin <ihorchyhin@ukr.net>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-24 10:52:49 +02:00

186 lines
4.5 KiB
C

/*
* ACPI watchdog table parsing support.
*
* Copyright (C) 2016, Intel Corporation
* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
*
* 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"
#ifdef CONFIG_RTC_MC146818_LIB
#include <linux/mc146818rtc.h>
/*
* There are several systems where the WDAT table is accessing RTC SRAM to
* store persistent information. This does not work well with the Linux RTC
* driver so on those systems we skip WDAT driver and prefer iTCO_wdt
* instead.
*
* See also https://bugzilla.kernel.org/show_bug.cgi?id=199033.
*/
static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
{
const struct acpi_wdat_entry *entries;
int i;
entries = (struct acpi_wdat_entry *)(wdat + 1);
for (i = 0; i < wdat->entries; i++) {
const struct acpi_generic_address *gas;
gas = &entries[i].register_region;
if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
switch (gas->address) {
case RTC_PORT(0):
case RTC_PORT(1):
case RTC_PORT(2):
case RTC_PORT(3):
return true;
}
}
}
return false;
}
#else
static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
{
return false;
}
#endif
static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)
{
const struct acpi_table_wdat *wdat = NULL;
acpi_status status;
if (acpi_disabled)
return NULL;
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 NULL;
}
if (acpi_watchdog_uses_rtc(wdat)) {
pr_info("Skipping WDAT on this system because it uses RTC SRAM\n");
return NULL;
}
return wdat;
}
/**
* 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)
{
return !!acpi_watchdog_get_wdat();
}
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;
int i;
wdat = acpi_watchdog_get_wdat();
if (!wdat) {
/* 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) - 1;
} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
res.flags = IORESOURCE_IO;
res.end = res.start + gas->access_width - 1;
} 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 (rentry->res->flags == res.flags &&
resource_overlaps(rentry->res, &res)) {
if (res.start < rentry->res->start)
rentry->res->start = res.start;
if (res.end > rentry->res->end)
rentry->res->end = res.end;
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("Device creation failed: %ld\n", PTR_ERR(pdev));
kfree(resources);
fail_free_resource_list:
resource_list_free(&resource_list);
}