alistair23-linux/drivers/acpi/acpi_watchdog.c
Ryan Kennedy 31e86cb99a ACPI / watchdog: Fix init failure with overlapping register regions
Partially overlapping regions cause platform device creation
to fail. The latter of two overlapping resources will fail to be
reserved. Fix this by merging overlapping resource ranges while
enumerating WDAT table entries.

Signed-off-by: Ryan Kennedy <ryan5544@gmail.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26 02:09:41 +02:00

129 lines
3.2 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"
/**
* 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 (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);
}