[linux.git] / drivers / acpi / acpi_watchdog.c

/*
 * ACPI watchdog table parsing support.
 *
 * Copyright (C) 2016, Intel Corporation
 * Author: Mika Westerberg <[email protected]>
 *
 * 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);
}
Commit	Line	Data
058dfc76 MW	1	/*
	2	* ACPI watchdog table parsing support.
	3	*
	4	* Copyright (C) 2016, Intel Corporation
	5	* Author: Mika Westerberg <[email protected]>
	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
5a802a7a MW	20	#ifdef CONFIG_RTC_MC146818_LIB
	21	#include <linux/mc146818rtc.h>
	22
	23	/*
	24	* There are several systems where the WDAT table is accessing RTC SRAM to
	25	* store persistent information. This does not work well with the Linux RTC
	26	* driver so on those systems we skip WDAT driver and prefer iTCO_wdt
	27	* instead.
	28	*
	29	* See also https://bugzilla.kernel.org/show_bug.cgi?id=199033.
	30	*/
	31	static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
	32	{
	33	const struct acpi_wdat_entry *entries;
	34	int i;
	35
	36	entries = (struct acpi_wdat_entry *)(wdat + 1);
	37	for (i = 0; i < wdat->entries; i++) {
	38	const struct acpi_generic_address *gas;
	39
	40	gas = &entries[i].register_region;
	41	if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
	42	switch (gas->address) {
	43	case RTC_PORT(0):
	44	case RTC_PORT(1):
	45	case RTC_PORT(2):
	46	case RTC_PORT(3):
	47	return true;
	48	}
	49	}
	50	}
	51
	52	return false;
	53	}
	54	#else
	55	static bool acpi_watchdog_uses_rtc(const struct acpi_table_wdat *wdat)
	56	{
	57	return false;
	58	}
	59	#endif
a0a37862 MW	60
	61	static const struct acpi_table_wdat *acpi_watchdog_get_wdat(void)
	62	{
	63	const struct acpi_table_wdat *wdat = NULL;
	64	acpi_status status;
	65
	66	if (acpi_disabled)
	67	return NULL;
	68
a0a37862 MW	69	status = acpi_get_table(ACPI_SIG_WDAT, 0,
	70	(struct acpi_table_header **)&wdat);
	71	if (ACPI_FAILURE(status)) {
	72	/* It is fine if there is no WDAT */
	73	return NULL;
	74	}
	75
5a802a7a MW	76	if (acpi_watchdog_uses_rtc(wdat)) {
	77	pr_info("Skipping WDAT on this system because it uses RTC SRAM\n");
	78	return NULL;
	79	}
	80
a0a37862 MW	81	return wdat;
	82	}
	83
058dfc76 MW	84	/**
	85	* Returns true if this system should prefer ACPI based watchdog instead of
	86	* the native one (which are typically the same hardware).
	87	*/
	88	bool acpi_has_watchdog(void)
	89	{
a0a37862	90	return !!acpi_watchdog_get_wdat();
058dfc76 MW	91	}
	92	EXPORT_SYMBOL_GPL(acpi_has_watchdog);
	93
	94	void __init acpi_watchdog_init(void)
	95	{
	96	const struct acpi_wdat_entry *entries;
	97	const struct acpi_table_wdat *wdat;
	98	struct list_head resource_list;
	99	struct resource_entry *rentry;
	100	struct platform_device *pdev;
	101	struct resource *resources;
	102	size_t nresources = 0;
058dfc76 MW	103	int i;
058dfc76 MW	104
a0a37862 MW	105	wdat = acpi_watchdog_get_wdat();
a0a37862 MW	106	if (!wdat) {
058dfc76 MW	107	/* It is fine if there is no WDAT */
	108	return;
	109	}
	110
	111	/* Watchdog disabled by BIOS */
	112	if (!(wdat->flags & ACPI_WDAT_ENABLED))
	113	return;
	114
	115	/* Skip legacy PCI WDT devices */
	116	if (wdat->pci_segment != 0xff \|\| wdat->pci_bus != 0xff \|\|
	117	wdat->pci_device != 0xff \|\| wdat->pci_function != 0xff)
	118	return;
	119
	120	INIT_LIST_HEAD(&resource_list);
	121
	122	entries = (struct acpi_wdat_entry *)(wdat + 1);
	123	for (i = 0; i < wdat->entries; i++) {
	124	const struct acpi_generic_address *gas;
	125	struct resource_entry *rentry;
6ce14f64	126	struct resource res = {};
058dfc76 MW	127	bool found;
	128
	129	gas = &entries[i].register_region;
	130
	131	res.start = gas->address;
	132	if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
	133	res.flags = IORESOURCE_MEM;
b1abf6fc	134	res.end = res.start + ALIGN(gas->access_width, 4) - 1;
058dfc76 MW	135	} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
058dfc76 MW	136	res.flags = IORESOURCE_IO;
b1abf6fc	137	res.end = res.start + gas->access_width - 1;
058dfc76 MW	138	} else {
	139	pr_warn("Unsupported address space: %u\n",
	140	gas->space_id);
	141	goto fail_free_resource_list;
	142	}
	143
	144	found = false;
	145	resource_list_for_each_entry(rentry, &resource_list) {
31e86cb9 RK	146	if (rentry->res->flags == res.flags &&
	147	resource_overlaps(rentry->res, &res)) {
	148	if (res.start < rentry->res->start)
	149	rentry->res->start = res.start;
	150	if (res.end > rentry->res->end)
	151	rentry->res->end = res.end;
058dfc76 MW	152	found = true;
	153	break;
	154	}
	155	}
	156
	157	if (!found) {
	158	rentry = resource_list_create_entry(NULL, 0);
	159	if (!rentry)
	160	goto fail_free_resource_list;
	161
	162	*rentry->res = res;
	163	resource_list_add_tail(rentry, &resource_list);
	164	nresources++;
	165	}
	166	}
	167
	168	resources = kcalloc(nresources, sizeof(*resources), GFP_KERNEL);
	169	if (!resources)
	170	goto fail_free_resource_list;
	171
	172	i = 0;
	173	resource_list_for_each_entry(rentry, &resource_list)
	174	resources[i++] = *rentry->res;
	175
	176	pdev = platform_device_register_simple("wdat_wdt", PLATFORM_DEVID_NONE,
	177	resources, nresources);
	178	if (IS_ERR(pdev))
c6e2c1e1	179	pr_err("Device creation failed: %ld\n", PTR_ERR(pdev));
058dfc76 MW	180
	181	kfree(resources);
	182
	183	fail_free_resource_list:
	184	resource_list_free(&resource_list);
	185	}