linux/drivers/watchdog/wdat_wdt.c
Thomas Weißschuh 00bdbc9a86 watchdog: wdat_wdt: Avoid unimplemented get_timeleft
As per the specification the action QUERY_COUNTDOWN_PERIOD is optional.
If the action is not implemented by the physical device the driver would
always report "0" from get_timeleft().
Avoid confusing userspace by only providing get_timeleft() when
implemented by the hardware.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221221-wdat_wdt-timeleft-v1-1-8e8a314c36cc@weissschuh.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-02-12 15:32:53 +01:00

550 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* ACPI Hardware Watchdog (WDAT) driver.
*
* Copyright (C) 2016, Intel Corporation
* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
*/
#include <linux/acpi.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/watchdog.h>
#define MAX_WDAT_ACTIONS ACPI_WDAT_ACTION_RESERVED
/**
* struct wdat_instruction - Single ACPI WDAT instruction
* @entry: Copy of the ACPI table instruction
* @reg: Register the instruction is accessing
* @node: Next instruction in action sequence
*/
struct wdat_instruction {
struct acpi_wdat_entry entry;
void __iomem *reg;
struct list_head node;
};
/**
* struct wdat_wdt - ACPI WDAT watchdog device
* @pdev: Parent platform device
* @wdd: Watchdog core device
* @period: How long is one watchdog period in ms
* @stopped_in_sleep: Is this watchdog stopped by the firmware in S1-S5
* @stopped: Was the watchdog stopped by the driver in suspend
* @instructions: An array of instruction lists indexed by an action number from
* the WDAT table. There can be %NULL entries for not implemented
* actions.
*/
struct wdat_wdt {
struct platform_device *pdev;
struct watchdog_device wdd;
unsigned int period;
bool stopped_in_sleep;
bool stopped;
struct list_head *instructions[MAX_WDAT_ACTIONS];
};
#define to_wdat_wdt(wdd) container_of(wdd, struct wdat_wdt, wdd)
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#define WDAT_DEFAULT_TIMEOUT 30
static int timeout = WDAT_DEFAULT_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
__MODULE_STRING(WDAT_DEFAULT_TIMEOUT) ")");
static int wdat_wdt_read(struct wdat_wdt *wdat,
const struct wdat_instruction *instr, u32 *value)
{
const struct acpi_generic_address *gas = &instr->entry.register_region;
switch (gas->access_width) {
case 1:
*value = ioread8(instr->reg);
break;
case 2:
*value = ioread16(instr->reg);
break;
case 3:
*value = ioread32(instr->reg);
break;
default:
return -EINVAL;
}
dev_dbg(&wdat->pdev->dev, "Read %#x from 0x%08llx\n", *value,
gas->address);
return 0;
}
static int wdat_wdt_write(struct wdat_wdt *wdat,
const struct wdat_instruction *instr, u32 value)
{
const struct acpi_generic_address *gas = &instr->entry.register_region;
switch (gas->access_width) {
case 1:
iowrite8((u8)value, instr->reg);
break;
case 2:
iowrite16((u16)value, instr->reg);
break;
case 3:
iowrite32(value, instr->reg);
break;
default:
return -EINVAL;
}
dev_dbg(&wdat->pdev->dev, "Wrote %#x to 0x%08llx\n", value,
gas->address);
return 0;
}
static int wdat_wdt_run_action(struct wdat_wdt *wdat, unsigned int action,
u32 param, u32 *retval)
{
struct wdat_instruction *instr;
if (action >= ARRAY_SIZE(wdat->instructions))
return -EINVAL;
if (!wdat->instructions[action])
return -EOPNOTSUPP;
dev_dbg(&wdat->pdev->dev, "Running action %#x\n", action);
/* Run each instruction sequentially */
list_for_each_entry(instr, wdat->instructions[action], node) {
const struct acpi_wdat_entry *entry = &instr->entry;
const struct acpi_generic_address *gas;
u32 flags, value, mask, x, y;
bool preserve;
int ret;
gas = &entry->register_region;
preserve = entry->instruction & ACPI_WDAT_PRESERVE_REGISTER;
flags = entry->instruction & ~ACPI_WDAT_PRESERVE_REGISTER;
value = entry->value;
mask = entry->mask;
switch (flags) {
case ACPI_WDAT_READ_VALUE:
ret = wdat_wdt_read(wdat, instr, &x);
if (ret)
return ret;
x >>= gas->bit_offset;
x &= mask;
if (retval)
*retval = x == value;
break;
case ACPI_WDAT_READ_COUNTDOWN:
ret = wdat_wdt_read(wdat, instr, &x);
if (ret)
return ret;
x >>= gas->bit_offset;
x &= mask;
if (retval)
*retval = x;
break;
case ACPI_WDAT_WRITE_VALUE:
x = value & mask;
x <<= gas->bit_offset;
if (preserve) {
ret = wdat_wdt_read(wdat, instr, &y);
if (ret)
return ret;
y = y & ~(mask << gas->bit_offset);
x |= y;
}
ret = wdat_wdt_write(wdat, instr, x);
if (ret)
return ret;
break;
case ACPI_WDAT_WRITE_COUNTDOWN:
x = param;
x &= mask;
x <<= gas->bit_offset;
if (preserve) {
ret = wdat_wdt_read(wdat, instr, &y);
if (ret)
return ret;
y = y & ~(mask << gas->bit_offset);
x |= y;
}
ret = wdat_wdt_write(wdat, instr, x);
if (ret)
return ret;
break;
default:
dev_err(&wdat->pdev->dev, "Unknown instruction: %u\n",
flags);
return -EINVAL;
}
}
return 0;
}
static int wdat_wdt_enable_reboot(struct wdat_wdt *wdat)
{
int ret;
/*
* WDAT specification says that the watchdog is required to reboot
* the system when it fires. However, it also states that it is
* recommended to make it configurable through hardware register. We
* enable reboot now if it is configurable, just in case.
*/
ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_REBOOT, 0, NULL);
if (ret && ret != -EOPNOTSUPP) {
dev_err(&wdat->pdev->dev,
"Failed to enable reboot when watchdog triggers\n");
return ret;
}
return 0;
}
static void wdat_wdt_boot_status(struct wdat_wdt *wdat)
{
u32 boot_status = 0;
int ret;
ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_STATUS, 0, &boot_status);
if (ret && ret != -EOPNOTSUPP) {
dev_err(&wdat->pdev->dev, "Failed to read boot status\n");
return;
}
if (boot_status)
wdat->wdd.bootstatus = WDIOF_CARDRESET;
/* Clear the boot status in case BIOS did not do it */
ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_STATUS, 0, NULL);
if (ret && ret != -EOPNOTSUPP)
dev_err(&wdat->pdev->dev, "Failed to clear boot status\n");
}
static void wdat_wdt_set_running(struct wdat_wdt *wdat)
{
u32 running = 0;
int ret;
ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_RUNNING_STATE, 0,
&running);
if (ret && ret != -EOPNOTSUPP)
dev_err(&wdat->pdev->dev, "Failed to read running state\n");
if (running)
set_bit(WDOG_HW_RUNNING, &wdat->wdd.status);
}
static int wdat_wdt_start(struct watchdog_device *wdd)
{
return wdat_wdt_run_action(to_wdat_wdt(wdd),
ACPI_WDAT_SET_RUNNING_STATE, 0, NULL);
}
static int wdat_wdt_stop(struct watchdog_device *wdd)
{
return wdat_wdt_run_action(to_wdat_wdt(wdd),
ACPI_WDAT_SET_STOPPED_STATE, 0, NULL);
}
static int wdat_wdt_ping(struct watchdog_device *wdd)
{
return wdat_wdt_run_action(to_wdat_wdt(wdd), ACPI_WDAT_RESET, 0, NULL);
}
static int wdat_wdt_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct wdat_wdt *wdat = to_wdat_wdt(wdd);
unsigned int periods;
int ret;
periods = timeout * 1000 / wdat->period;
ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_COUNTDOWN, periods, NULL);
if (!ret)
wdd->timeout = timeout;
return ret;
}
static unsigned int wdat_wdt_get_timeleft(struct watchdog_device *wdd)
{
struct wdat_wdt *wdat = to_wdat_wdt(wdd);
u32 periods = 0;
wdat_wdt_run_action(wdat, ACPI_WDAT_GET_CURRENT_COUNTDOWN, 0, &periods);
return periods * wdat->period / 1000;
}
static const struct watchdog_info wdat_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "wdat_wdt",
};
static struct watchdog_ops wdat_wdt_ops = {
.owner = THIS_MODULE,
.start = wdat_wdt_start,
.stop = wdat_wdt_stop,
.ping = wdat_wdt_ping,
.set_timeout = wdat_wdt_set_timeout,
};
static int wdat_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct acpi_wdat_entry *entries;
const struct acpi_table_wdat *tbl;
struct wdat_wdt *wdat;
struct resource *res;
void __iomem **regs;
acpi_status status;
int i, ret;
status = acpi_get_table(ACPI_SIG_WDAT, 0,
(struct acpi_table_header **)&tbl);
if (ACPI_FAILURE(status))
return -ENODEV;
wdat = devm_kzalloc(dev, sizeof(*wdat), GFP_KERNEL);
if (!wdat)
return -ENOMEM;
regs = devm_kcalloc(dev, pdev->num_resources, sizeof(*regs),
GFP_KERNEL);
if (!regs)
return -ENOMEM;
/* WDAT specification wants to have >= 1ms period */
if (tbl->timer_period < 1)
return -EINVAL;
if (tbl->min_count > tbl->max_count)
return -EINVAL;
wdat->period = tbl->timer_period;
wdat->wdd.min_timeout = DIV_ROUND_UP(wdat->period * tbl->min_count, 1000);
wdat->wdd.max_timeout = wdat->period * tbl->max_count / 1000;
wdat->stopped_in_sleep = tbl->flags & ACPI_WDAT_STOPPED;
wdat->wdd.info = &wdat_wdt_info;
wdat->wdd.ops = &wdat_wdt_ops;
wdat->pdev = pdev;
/* Request and map all resources */
for (i = 0; i < pdev->num_resources; i++) {
void __iomem *reg;
res = &pdev->resource[i];
if (resource_type(res) == IORESOURCE_MEM) {
reg = devm_ioremap_resource(dev, res);
if (IS_ERR(reg))
return PTR_ERR(reg);
} else if (resource_type(res) == IORESOURCE_IO) {
reg = devm_ioport_map(dev, res->start, 1);
if (!reg)
return -ENOMEM;
} else {
dev_err(dev, "Unsupported resource\n");
return -EINVAL;
}
regs[i] = reg;
}
entries = (struct acpi_wdat_entry *)(tbl + 1);
for (i = 0; i < tbl->entries; i++) {
const struct acpi_generic_address *gas;
struct wdat_instruction *instr;
struct list_head *instructions;
unsigned int action;
struct resource r;
int j;
action = entries[i].action;
if (action >= MAX_WDAT_ACTIONS) {
dev_dbg(dev, "Skipping unknown action: %u\n", action);
continue;
}
instr = devm_kzalloc(dev, sizeof(*instr), GFP_KERNEL);
if (!instr)
return -ENOMEM;
INIT_LIST_HEAD(&instr->node);
instr->entry = entries[i];
gas = &entries[i].register_region;
memset(&r, 0, sizeof(r));
r.start = gas->address;
r.end = r.start + ACPI_ACCESS_BYTE_WIDTH(gas->access_width) - 1;
if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
r.flags = IORESOURCE_MEM;
} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
r.flags = IORESOURCE_IO;
} else {
dev_dbg(dev, "Unsupported address space: %d\n",
gas->space_id);
continue;
}
/* Find the matching resource */
for (j = 0; j < pdev->num_resources; j++) {
res = &pdev->resource[j];
if (resource_contains(res, &r)) {
instr->reg = regs[j] + r.start - res->start;
break;
}
}
if (!instr->reg) {
dev_err(dev, "I/O resource not found\n");
return -EINVAL;
}
instructions = wdat->instructions[action];
if (!instructions) {
instructions = devm_kzalloc(dev,
sizeof(*instructions),
GFP_KERNEL);
if (!instructions)
return -ENOMEM;
INIT_LIST_HEAD(instructions);
wdat->instructions[action] = instructions;
}
list_add_tail(&instr->node, instructions);
}
if (wdat->instructions[ACPI_WDAT_GET_CURRENT_COUNTDOWN])
wdat_wdt_ops.get_timeleft = wdat_wdt_get_timeleft;
wdat_wdt_boot_status(wdat);
wdat_wdt_set_running(wdat);
ret = wdat_wdt_enable_reboot(wdat);
if (ret)
return ret;
platform_set_drvdata(pdev, wdat);
/*
* Set initial timeout so that userspace has time to configure the
* watchdog properly after it has opened the device. In some cases
* the BIOS default is too short and causes immediate reboot.
*/
if (watchdog_timeout_invalid(&wdat->wdd, timeout)) {
dev_warn(dev, "Invalid timeout %d given, using %d\n",
timeout, WDAT_DEFAULT_TIMEOUT);
timeout = WDAT_DEFAULT_TIMEOUT;
}
ret = wdat_wdt_set_timeout(&wdat->wdd, timeout);
if (ret)
return ret;
watchdog_set_nowayout(&wdat->wdd, nowayout);
watchdog_stop_on_reboot(&wdat->wdd);
watchdog_stop_on_unregister(&wdat->wdd);
return devm_watchdog_register_device(dev, &wdat->wdd);
}
static int wdat_wdt_suspend_noirq(struct device *dev)
{
struct wdat_wdt *wdat = dev_get_drvdata(dev);
int ret;
if (!watchdog_active(&wdat->wdd))
return 0;
/*
* We need to stop the watchdog if firmware is not doing it or if we
* are going suspend to idle (where firmware is not involved). If
* firmware is stopping the watchdog we kick it here one more time
* to give it some time.
*/
wdat->stopped = false;
if (acpi_target_system_state() == ACPI_STATE_S0 ||
!wdat->stopped_in_sleep) {
ret = wdat_wdt_stop(&wdat->wdd);
if (!ret)
wdat->stopped = true;
} else {
ret = wdat_wdt_ping(&wdat->wdd);
}
return ret;
}
static int wdat_wdt_resume_noirq(struct device *dev)
{
struct wdat_wdt *wdat = dev_get_drvdata(dev);
int ret;
if (!watchdog_active(&wdat->wdd))
return 0;
if (!wdat->stopped) {
/*
* Looks like the boot firmware reinitializes the watchdog
* before it hands off to the OS on resume from sleep so we
* stop and reprogram the watchdog here.
*/
ret = wdat_wdt_stop(&wdat->wdd);
if (ret)
return ret;
ret = wdat_wdt_set_timeout(&wdat->wdd, wdat->wdd.timeout);
if (ret)
return ret;
ret = wdat_wdt_enable_reboot(wdat);
if (ret)
return ret;
ret = wdat_wdt_ping(&wdat->wdd);
if (ret)
return ret;
}
return wdat_wdt_start(&wdat->wdd);
}
static const struct dev_pm_ops wdat_wdt_pm_ops = {
NOIRQ_SYSTEM_SLEEP_PM_OPS(wdat_wdt_suspend_noirq, wdat_wdt_resume_noirq)
};
static struct platform_driver wdat_wdt_driver = {
.probe = wdat_wdt_probe,
.driver = {
.name = "wdat_wdt",
.pm = pm_sleep_ptr(&wdat_wdt_pm_ops),
},
};
module_platform_driver(wdat_wdt_driver);
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_DESCRIPTION("ACPI Hardware Watchdog (WDAT) driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:wdat_wdt");