alistair23-linux/drivers/rtc/rtc-cros-ec.c
Stephen Boyd d6752e185c rtc: cros-ec: Fail suspend/resume if wake IRQ can't be configured
If we encounter a failure during suspend where this RTC was programmed
to wakeup the system from suspend, but that wakeup couldn't be
configured because the system didn't support wakeup interrupts, we'll
run into the following warning:

	Unbalanced IRQ 166 wake disable
	WARNING: CPU: 7 PID: 3071 at kernel/irq/manage.c:669 irq_set_irq_wake+0x108/0x278

This happens because the suspend process isn't aborted when the RTC
fails to configure the wakeup IRQ. Instead, we continue suspending the
system and then another suspend callback fails the suspend process and
"unwinds" the previously suspended drivers by calling their resume
callbacks. When we get back to resuming this RTC driver, we'll call
disable_irq_wake() on an IRQ that hasn't been configured for wake.

Let's just fail suspend/resume here if we can't configure the system to
wake and the user has chosen to wakeup with this device. This fixes this
warning and makes the code more robust in case there are systems out
there that can't wakeup from suspend on this line but the user has
chosen to do so.

Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Cc: Evan Green <evgreen@chromium.org>
Cc: Benson Leung <bleung@chromium.org>
Cc: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Acked-By: Benson Leung <bleung@chromium.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2019-03-20 11:36:46 +01:00

403 lines
9.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
// RTC driver for ChromeOS Embedded Controller.
//
// Copyright (C) 2017 Google, Inc.
// Author: Stephen Barber <smbarber@chromium.org>
#include <linux/kernel.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#define DRV_NAME "cros-ec-rtc"
/**
* struct cros_ec_rtc - Driver data for EC RTC
*
* @cros_ec: Pointer to EC device
* @rtc: Pointer to RTC device
* @notifier: Notifier info for responding to EC events
* @saved_alarm: Alarm to restore when interrupts are reenabled
*/
struct cros_ec_rtc {
struct cros_ec_device *cros_ec;
struct rtc_device *rtc;
struct notifier_block notifier;
u32 saved_alarm;
};
static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command,
u32 *response)
{
int ret;
struct {
struct cros_ec_command msg;
struct ec_response_rtc data;
} __packed msg;
memset(&msg, 0, sizeof(msg));
msg.msg.command = command;
msg.msg.insize = sizeof(msg.data);
ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
if (ret < 0) {
dev_err(cros_ec->dev,
"error getting %s from EC: %d\n",
command == EC_CMD_RTC_GET_VALUE ? "time" : "alarm",
ret);
return ret;
}
*response = msg.data.time;
return 0;
}
static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command,
u32 param)
{
int ret = 0;
struct {
struct cros_ec_command msg;
struct ec_response_rtc data;
} __packed msg;
memset(&msg, 0, sizeof(msg));
msg.msg.command = command;
msg.msg.outsize = sizeof(msg.data);
msg.data.time = param;
ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
if (ret < 0) {
dev_err(cros_ec->dev, "error setting %s on EC: %d\n",
command == EC_CMD_RTC_SET_VALUE ? "time" : "alarm",
ret);
return ret;
}
return 0;
}
/* Read the current time from the EC. */
static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
int ret;
u32 time;
ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time);
if (ret) {
dev_err(dev, "error getting time: %d\n", ret);
return ret;
}
rtc_time64_to_tm(time, tm);
return 0;
}
/* Set the current EC time. */
static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
int ret;
time64_t time;
time = rtc_tm_to_time64(tm);
if (time < 0 || time > U32_MAX)
return -EINVAL;
ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time);
if (ret < 0) {
dev_err(dev, "error setting time: %d\n", ret);
return ret;
}
return 0;
}
/* Read alarm time from RTC. */
static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
int ret;
u32 current_time, alarm_offset;
/*
* The EC host command for getting the alarm is relative (i.e. 5
* seconds from now) whereas rtc_wkalrm is absolute. Get the current
* RTC time first so we can calculate the relative time.
*/
ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
if (ret < 0) {
dev_err(dev, "error getting time: %d\n", ret);
return ret;
}
ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset);
if (ret < 0) {
dev_err(dev, "error getting alarm: %d\n", ret);
return ret;
}
rtc_time64_to_tm(current_time + alarm_offset, &alrm->time);
return 0;
}
/* Set the EC's RTC alarm. */
static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
int ret;
time64_t alarm_time;
u32 current_time, alarm_offset;
/*
* The EC host command for setting the alarm is relative
* (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute.
* Get the current RTC time first so we can calculate the
* relative time.
*/
ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
if (ret < 0) {
dev_err(dev, "error getting time: %d\n", ret);
return ret;
}
alarm_time = rtc_tm_to_time64(&alrm->time);
if (alarm_time < 0 || alarm_time > U32_MAX)
return -EINVAL;
if (!alrm->enabled) {
/*
* If the alarm is being disabled, send an alarm
* clear command.
*/
alarm_offset = EC_RTC_ALARM_CLEAR;
cros_ec_rtc->saved_alarm = (u32)alarm_time;
} else {
/* Don't set an alarm in the past. */
if ((u32)alarm_time <= current_time)
return -ETIME;
alarm_offset = (u32)alarm_time - current_time;
}
ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset);
if (ret < 0) {
dev_err(dev, "error setting alarm: %d\n", ret);
return ret;
}
return 0;
}
static int cros_ec_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
int ret;
u32 current_time, alarm_offset, alarm_value;
ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
if (ret < 0) {
dev_err(dev, "error getting time: %d\n", ret);
return ret;
}
if (enabled) {
/* Restore saved alarm if it's still in the future. */
if (cros_ec_rtc->saved_alarm < current_time)
alarm_offset = EC_RTC_ALARM_CLEAR;
else
alarm_offset = cros_ec_rtc->saved_alarm - current_time;
ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
alarm_offset);
if (ret < 0) {
dev_err(dev, "error restoring alarm: %d\n", ret);
return ret;
}
} else {
/* Disable alarm, saving the old alarm value. */
ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM,
&alarm_offset);
if (ret < 0) {
dev_err(dev, "error saving alarm: %d\n", ret);
return ret;
}
alarm_value = current_time + alarm_offset;
/*
* If the current EC alarm is already past, we don't want
* to set an alarm when we go through the alarm irq enable
* path.
*/
if (alarm_value < current_time)
cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR;
else
cros_ec_rtc->saved_alarm = alarm_value;
alarm_offset = EC_RTC_ALARM_CLEAR;
ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
alarm_offset);
if (ret < 0) {
dev_err(dev, "error disabling alarm: %d\n", ret);
return ret;
}
}
return 0;
}
static int cros_ec_rtc_event(struct notifier_block *nb,
unsigned long queued_during_suspend,
void *_notify)
{
struct cros_ec_rtc *cros_ec_rtc;
struct rtc_device *rtc;
struct cros_ec_device *cros_ec;
u32 host_event;
cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier);
rtc = cros_ec_rtc->rtc;
cros_ec = cros_ec_rtc->cros_ec;
host_event = cros_ec_get_host_event(cros_ec);
if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) {
rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
return NOTIFY_OK;
} else {
return NOTIFY_DONE;
}
}
static const struct rtc_class_ops cros_ec_rtc_ops = {
.read_time = cros_ec_rtc_read_time,
.set_time = cros_ec_rtc_set_time,
.read_alarm = cros_ec_rtc_read_alarm,
.set_alarm = cros_ec_rtc_set_alarm,
.alarm_irq_enable = cros_ec_rtc_alarm_irq_enable,
};
#ifdef CONFIG_PM_SLEEP
static int cros_ec_rtc_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
if (device_may_wakeup(dev))
return enable_irq_wake(cros_ec_rtc->cros_ec->irq);
return 0;
}
static int cros_ec_rtc_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);
if (device_may_wakeup(dev))
return disable_irq_wake(cros_ec_rtc->cros_ec->irq);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend,
cros_ec_rtc_resume);
static int cros_ec_rtc_probe(struct platform_device *pdev)
{
struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
struct cros_ec_device *cros_ec = ec_dev->ec_dev;
struct cros_ec_rtc *cros_ec_rtc;
struct rtc_time tm;
int ret;
cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc),
GFP_KERNEL);
if (!cros_ec_rtc)
return -ENOMEM;
platform_set_drvdata(pdev, cros_ec_rtc);
cros_ec_rtc->cros_ec = cros_ec;
/* Get initial time */
ret = cros_ec_rtc_read_time(&pdev->dev, &tm);
if (ret) {
dev_err(&pdev->dev, "failed to read RTC time\n");
return ret;
}
ret = device_init_wakeup(&pdev->dev, 1);
if (ret) {
dev_err(&pdev->dev, "failed to initialize wakeup\n");
return ret;
}
cros_ec_rtc->rtc = devm_rtc_device_register(&pdev->dev, DRV_NAME,
&cros_ec_rtc_ops,
THIS_MODULE);
if (IS_ERR(cros_ec_rtc->rtc)) {
ret = PTR_ERR(cros_ec_rtc->rtc);
dev_err(&pdev->dev, "failed to register rtc device\n");
return ret;
}
/* Get RTC events from the EC. */
cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event;
ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
&cros_ec_rtc->notifier);
if (ret) {
dev_err(&pdev->dev, "failed to register notifier\n");
return ret;
}
return 0;
}
static int cros_ec_rtc_remove(struct platform_device *pdev)
{
struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev);
struct device *dev = &pdev->dev;
int ret;
ret = blocking_notifier_chain_unregister(
&cros_ec_rtc->cros_ec->event_notifier,
&cros_ec_rtc->notifier);
if (ret) {
dev_err(dev, "failed to unregister notifier\n");
return ret;
}
return 0;
}
static struct platform_driver cros_ec_rtc_driver = {
.probe = cros_ec_rtc_probe,
.remove = cros_ec_rtc_remove,
.driver = {
.name = DRV_NAME,
.pm = &cros_ec_rtc_pm_ops,
},
};
module_platform_driver(cros_ec_rtc_driver);
MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRV_NAME);